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Mechanism and control of the combined genetoxicity produced from chlorinated compounds in source drinking water
No full text氯是饮用水中最常用的消毒剂之一。在氯化过程中，它能与天然有机物、人工合成物和无机盐离子等反应，生成具有遗传毒性效应、致突变和致癌活性的消毒副产物（disinfection by products，DBPs）。尽管水中大多数 DBPs的浓度很低（〜1至 100 μg/L），但由于持续暴露和/或联合效应的存在，它们对人体的健康构成了危害。目前大多数研究者仅关注了单个消毒副产物的毒性或者单个前驱体消毒后生成 DBPs的毒性。这些研究都忽略了 DBPs之间联合作用而造成的毒性放大和缩小效应，导致低估或高估了复合体系的生态环境风险。因此，研究多个前驱体混合氯化后复合毒性的发生机理及相应的控制技术是非常必要的。 为研究氯化复合致毒机制，我们采用 SOS/umu方法考察了两种前驱物（酪氨酸和二苯甲酮（BP-4））混合氯化后遗传毒性与单独氯化后毒性加合的差异关系，试验结果证实了这种差异并发现 pH是导致差异的关键因子。在 pH 5.0–6.1范围内，混合氯化后毒性大于单独氯化后毒性的加和；而在 pH 6.3–8.0的范围内，与之相反。研究进一步发现含氮消毒副产物的产量和联合作用（协同作用和拮抗作用）共同决定了毒性差异的大小。非线性回归分析发现有机氮（ total organic nitrogen，TON）比值（TON混合氯化产物/TON单独氯化产物之和）可以估算这种毒性差异。 在复合毒性控制上，研究首先考察了常规工艺中 KMnO4预氧化对酪氨酸和BP-4混合与单独氯化后毒性的去除作用。结果表明尽管 KMnO4不能氧化 BP-4，但能通过氧化 BP-4的氯化产物，降低其毒性。而在 KMnO4和酪氨酸初始摩尔比为 1:1时，对其氯化产物毒性的降低作用最为显著。研究证明，KMnO4和生成的MnO2（KMnO4的还原产物）对酪氨酸的氧化作用，以及 MnO2对其氯化产物的氧化作用，都能降低产物毒性。值得关注的是，预氧化生成的 Mn与酪氨酸竞2+争氯，使得与酪氨酸反应的氯量减少，从而升高产物的毒性。此外，由于酪氨酸和 BP-4的预氧化-氯化产物之间存在联合作用，所以随着 KMnO4投加量的升高，混合预氧化-氯化产物的毒性由高于转变为低于单独预氧化 -氯化产物的毒性加和。 适量 KMnO4预氧化虽能降低 DBPs的毒性，但同时带来了余锰的问题。已有研究证明 Mn2+对余锰及消毒副产物前驱物的去除。研究利用具有锰氧化能力的假单胞菌 QJX-1作为模式菌种来考察它对酪氨酸、BP-4和Mn2+的去除效果。结果发现，QJX-1能够利用酪氨酸作为唯一的C/N源进行生长，并将 Mn2+具有遗传毒性效应。因此，我们探讨了后续工艺（如生物滤池）氧化为生物氧化锰（biological manganese oxide，BMO）。而生成的 BMO通过吸附氧化作用能够去除水体中的微量污染物 BP-4。同时，BP-4的存在刺激了 QJX-1的生长，并促进了锰氧化的发生。研究利用 RNA-seq技术和蛋白组学技术在分子水平上探究产生这种现象的原因。发现 BP-4主要刺激了酪氨酸代谢过程中的丙酮酸和糖异生代谢通路，加快了 QJX-1的生长。而蛋白组学和超氧自由基检测结果表明，锰离子的氧化主要和由于饥饿效应产生的超氧自由基相关。BP-4的加入导致了超氧自由基的提前产生，从而促进了锰氧化的发生。hlorine is one of the most commonly used disinfectants in drinking water. It can react with natural organic materials, anthropogenic chemicals and salts, and produces a wide variety of disinfection by-products (DBPs) with genotoxic, mutagenic and carcinogenic activities during chlorination. Although the concentrations of most DBPs in water are at low levels (~1 to 100 μg/L), they pose a human health hazard as a result of persistent exposure and/or their combined effects. Many previous studies have focused on the toxicity of a single DBP or a single chlorinated compound. However,these studies ignore the combied effects of different DBPs, thus leading to an unreasonable estimation of their ecological risks. Therefore, it is essential to study the mechanism and control of combined toxicity of DBPs produced from multiple precursors. Here we examined the genotoxicity using the SOS/umu test when two precursors (tyrosine (Tyr) and benzophenone-4 (BP-4)) were chlorinated together and separately.We sought to examine whether the genotoxicity of the mixture (GCM) could be estimated from the sum of the genotoxicities of the individual precursors (GCI), which were chlorinated separately. The results revealed that GCM was not identical to GCI. pH was an important factor in determining the difference in genotoxicity between GCM and GCI (GΔ). GCM was higher than GCI (GΔ > 0) at pH 5.0–6.1, and lower than GCI (GΔ < 0) at pH 6.3–8.0. We found that GΔ was determined by the nitrogen-containing DBPs and combined effects between DBPs produced from Tyr and BP-4. We propose that the total organic nitrogen (TON) ratio, TON(chlorinated mixture)/TON(the sum of chlorinated individuals), is useful to estimate GΔ. Based on the above, we investigated the effect of potassium permanganate (KMnO4)preoxidation on the decrease/removal in/of DBPs’genotoxicity from signle and mixture precursors. Results revealed that although KMnO4 could not oxidize BP-4, after chlorination KMnO4 could oxidize the chlorination byproducts of BP-4 and thus decrease the genotoxicity production. For Tyr, the optimal initial molar ratio of KMnO4 to Tyr was confirmed to be 1:1. It has been proved that both the oxidation of Tyr by KMnO4 and manganese dioxide (MnO2, the reduction product of KMnO4) and the oxidation of chlorination byproducts by MnO2 can decrease the genotoxicity production of chlorinated Tyr. Remarkably, during chlorination, the competition of Mn oxidation with Tyr oxidation can result in less chlorine reacting with Tyr, to induce an increase in genotoxicity. This is the main cause for the increase in genotoxicity of chlorinated Tyr after KMnO4 preoxidation. Additionally, the genotoxicity of the chlorinated mixture was shifted from being higher than the sum of individual genotoxicities of the chlorinated precursors to being lower than their sum with increasing KMnO4 dosage, due to the combined effects between the preoxidation-chlorination products from the two compounds. Although a proper dose of KMnO4 preoxidation could decrease the genetoxicity of DBPs, it resulted in the production of Mn2+ explore whether the subsequent conventional treatment (e.g., biolfilter) can remove the DBPs’ precursors and Mn2+ together. We adapted a Mn2+ -oxidizing Pseudomonas sp. QJX-1 as the model strain to investigate its effect on the removal of Tyr, BP-4, and . Results showed that QJX-1 could utilize Tyr as the sole carbon and nitrogen source, and catalyze the transformation of Mn2+ to biological manganese oxide (BMO). The formed BMO further adsorbed and oxidized BP-4. Concurrently, BP-4 promoted the growth and Mn2+ oxidation of QJX-1. RNA-seq data suggests that BP-4 stimulates with genetoxic activity. Thus, it is urgent to Mn2+ the up-regulation of the pyruvate and gluconeogenesis metabolic pathway of Tyr for QJX-1 growth. Further, protein identification and extracellular superoxide detection indicate that Mn2+ oxidation is largely driven by the formation of superoxide in response to starvation; the acceleration of superoxide production, due to BP-4 accelerating Tyr consumption, is responsible for the promotion effect of BP-4 on the Mn2+ oxidation of QJX-1
Development of Visible-Light Photocatalysts Based on Layered Materials/Ag/AgX (X=Br, I) and the Mechanism of Organic Pollutants Degradation
No full text光催化太阳能转化是解决当前人类社会面临的环境污染和能源危机问题的
重要手段。然而，光吸收范围窄、量子效率低或催化稳定性差等因素限制了众多
光催化体系的实际应用。卤化银材料具有良好的感光性，在光催化研究中表现出
了卓越的反应活性。但是这类材料容易发生光腐蚀，并向反应体系中释放 Ag+，
造成二次污染。近几年，二维层状结构材料由于多方面的良好性能获得了研究者
的关注。本论文研制了系列层状光催化材料，并用来修饰卤化银光催化剂。制备
的复合材料在可见光甚至近红外光照射下都具有良好的催化降解有机污染物活
性，卤化银复合光催化剂显示了很好的催化稳定性，反应过程中未检测到卤化银
的分解和 Ag+的释放。提出了一种基于光生载流子转移和补偿的光催化反应机理，
为光催化技术的实际应用提供了思路。具体的研究内容如下：
1.层状 g-C3N4剥离制备 CN/Ag/AgBr：采用超声剥离法由体相 g-C3N4获得了在
水中高分散的 CN纳米片，并成功地在 CN纳米片上生长 AgBr颗粒制备了
CN/Ag/AgBr光催化剂。CN修饰的 Ag/AgBr具有较小的颗粒直径，更大的比表
面积和光电流密度等特点；研究结果表明制备条件（加料顺序，合成温度，溶剂
等）对催化剂活性有较大影响。CN/Ag/AgBr催化剂在可见光照射下对有机染料
甲基橙（MO）、2-氯酚显示了很好的光催化降解能力。
2.能带可调控的 BiO(OH)xI1-x固溶体制备:基于[Bi2O22+]层间阴离子的可替代性，
采用共沉淀法制备了系列 BiO(OH)xI1-x固溶体材料。发现随着 OH‒逐渐取代 I‒，
制备的催化剂具有从 400到 800 nm范围内可调节的光吸收范围，其带隙结构亦
随着材料组成的变化而变化，并在材料中引入了具有良好吸光性和活性的氧空位。
实验表明制备的固溶体材料具有很好的光催化降解 2-氯酚的能力，并保持了优良
的光反应稳定性。
3.化学键联的 BiO(OH)xI1-x-AgI异质结催化剂:通过共沉淀法将 BiO(OH)xI1-x固
溶体与 AgI颗粒复合制备半导体 p-n结光催化剂。由于 I的同离子效应，在
BiO(OH)xI1-x和 AgI的界面上形成了 Bi-I-Ag化学键。紧密的界面接触和化学键
的存在促进了光生载流子的传递，并且在异质结的 Z型价带结构中，AgI光激发
产生的导带电子迅速转移到 BiO(OH)xI1-x固溶体上，从而抑制了晶格 Ag+的还原，
提高了 AgI稳定性。光生空穴则转移到 AgI导带上，抑制了载流子的复合。在
光催化降解氯酚类有机污染物反应中，异质结材料没有发现 AgI的光腐蚀，反应
活性提高 9倍。
4.氧空位增强的 BiO(OH)0.06Br0.94/Ag/AgBr表面等离子基元光催化：在
BiO(OH)xBr1-x/AgBr材料中经光还原生成了 Ag等离子基元，制备的“三明治”
结构 BiO(OH)xBr1-x/Ag/AgBr等离子基元光催化剂具有 2000 nm以上的光吸收，
在可见光和近红外光照射下均具有光催化活性。在光催化降解有机污染物的反应
中没有检测到 Ag表面等离子激发产生的电子转移到 AgBr半导体导带，同时 BiO(OH)xBr1-x中的
氧空位又向 Ag纳米颗粒补偿电子，由此形成循环，抑制了催化反应中从 Ag+释放，对 2-CP和 MO可以在数分钟内完全降解。研究表明 Ag0到Ag的氧化反应，在提高光吸收范围和量子效率的同时，增强了催化剂的稳定性，
为 Ag+表面等离子基元光催化材料的实际应用提供了思路。Photocatalysis is a promising technology to address the issues of the energy crisis
and environmental pollution that have gained considerable interdisciplinary attention.
A number of photocatalytic systems have been developed. But most of these
photocatalytic materials are troubled by: (1) insufficient solar energy harvest, (2) low
efficient photon utilizing and (3) poor catalytic stability. Silver halides (AgX, X=Cl,
Br, I), well-known photosensitive materials, have been intensively studied in the
fields of photocatalytic hydrogen evolution and photodegradation of organic
pollutants due to their prominent photoactivity. However, they are unavoidably
decomposed under visible-light irradiation. Recently, materials possessing a laminated
structure have aroused much attention due to their excellent physico-chemical
properties. In this dissertation, a series of layered materials were developed and used
to modify AgX photocatalysts. The prepared heterojunction photocatalysts shown
enhanced activity for organic pollutants degradation under visible even near-infrared
light irradiation. AgX photo-decomposition was completely inhibited, and no release
of Ag + was observed in the photoreaction. The photocatalysis mechanisms were
carefully study. The main contents of this thesis are as follows:
1. CN/Ag/AgBr photocatalyst prepared from layered g-C3N4 exfoliation: High
dispersing CN nanosheets in water solution were obtained by a simple ultrasonic
exfoliation mothed from bulk g-C3N4. CN/Ag/AgBr was successfully synthesized by
growed AgBr on the CN sheets. The CN/Ag/AgBr photocatalyst possessed smaller
particle size， larger BET surface，greater photo-current intensity than Ag/AgBr，and
shown enhanced pollutants photodegradation activity. Research results proved that
preparation conditions much affected the property of CN/Ag/AgBr.
2. Developing BiO(OH)xI1-x solid solution with tunable band-gap structure: In
consideration of the alternative inorganic ions between [Bi2O2]2+ layers, A proportion
of I in BiOI were exchanged with OH to generate BiO(OH)xI1-x solid solution.
Experimental results demonstrate that the light harvest and energy band were
adjustable with the change of BiO(OH)xI1-x composition. Oxygen vacancies (OVs)
were found in the solid solution contributed the excellent photocatalytic performance.
3. Chemical-Bond Conjugated BiO(OH)xI1-x-AgI Heterojunction: A layered
BiO(OH)xI1-x solid solution was grown in situ on the surface of AgI particles by a
one-pot co-crystallization method to prapare a p-n heterojunction photocatalyst. It was
verified the Ag-I-Bi cross-linking bonds formed in the interface of BiO(OH)xI1-x
and－AgI due to the common species of I ions. The strong interfacial interaction between
BiO(OH)xI1-x and AgI by the Ag-I-Bi bond junction accelerated interfacial charge
transfer and separation. BiO(OH)xI1-x-AgI exhibited high efficiency and stability for
photodegradation of phenolic compounds with visible light irradiation. No significant
AgI decomposition or release of Ag+ was observed in the photoreaction, and the
photoactivity of AgI was enhanced almost 9-fold.
4. Oxygen Vacancy Enhanced Photostability and Activity of Plasmon-Ag
Composites: BiO(OH)0.06Br0.94 solid solution with abundant oxygen vacancies was
supported on Ag/AgBr using precipitation and deposition–precipitation methods. The
photocatalyst showed high and stable photocatalytic activity for the degradation of
chlorophenols and azodyes in water under visible to NIR light irradiation without any
release of Ag . The plasmon-induced electrons from Ag NPs transfered to the CB of
AgBr, while the electrons trapped on the oxygen vacancies of BiO(OH)0.06Br0.94
transfered to Ag NPs recombining with the plasmon-induced holes, inhibiting the
release of Ag+
Optimal design and economical running of UV disinfection reactors based on computational fluid dynamic simulations
No full text饮用水水源中耐氯性致病微生物（如隐孢子虫和贾第鞭毛虫）的发现以及氯 代消毒副产物的广泛检出使得传统饮用水加氯消毒工艺面临着巨大挑战。由于可 以高效杀灭“两虫”并且几乎不产生消毒副产物，近年来，紫外线技术在国内外 饮用水消毒过程中得到了广泛的应用。然而，紫外消毒技术在实际应用过程中的 效率受到紫外消毒器具体构型、处理的水质和水量以及消毒器的运行维护情况等 诸多因素的影响。 为保证紫外消毒器在实际工程应用中的运行效果，需要对上述种种因素对紫 外消毒器性能的影响进行评估，并据此采取相关应对措施。计算流体动力学（CFD） 技术可以在无需加工紫外消毒器的情况下通过模拟获得某一构型消毒器的性能， 并对其在不同处理水质和水量以及灯管输出功率条件下的表现进行评估。目前， 有关紫外消毒器 CFD模拟的基础理论和实际应用研究还比较缺乏，紫外消毒器 的设计加工很粗放，导致紫外线技术在应用过程中时常出现效果差或能耗高的问 题。在此背景下，本文进行了基于 CFD模拟的紫外消毒器优化设计及应用研究， 取得的主要成果如下： 确定了紫外消毒器的 CFD模拟过程：（1）根据消毒器构型建立相应的几何 模型并划分计算网格；（2）选择合适的湍流模型，设定流动相关边界条件；（3） 选择合适的辐射模型，设定辐射相关边界条件；（4）打开离散相模型，设定模拟 微粒投加方式，加载用户自定义程序积分计算相应紫外剂量。基于紫外强度分布 原位测试平台评估了不同紫外强度分布模型的准确性。结果表明，校正后的离散 坐标（DO）辐射模型（校正因子为 0.8）可以准确地模拟紫外消毒器内的光场分 布。微生物灭活率验证结果表明，本研究开发的紫外消毒器 CFD模拟方法（即 可实现 k-模型、校正后 DO辐射模型以及拉格朗日离散相模型的组合）具有很 高的准确性，可以准确地评估紫外消毒器的性能。 采用上述开发的紫外消毒器 CFD模拟方法对三灯管紫外消毒器构型进行了 优化设计，重点考察了灯管布置和进出水管直径对消毒器性能的影响。通过理论 推导和 CFD模拟分析，确定了可以用最小紫外剂量（Dmin）替代等效还原剂量 （RED）作为紫外消毒器构型优化过程中的消毒器性能指标，从而使得优化设计 目标更为明确并显著降低了紫外消毒器优化设计工作量。总体而言，灯管正三角 形布置（NOR）的消毒器具有比灯管倒三角形布置（REV）的消毒器更大的 Dmin 值，即更好的消毒器性能。构型为 NOR-0.4-75的消毒器具有最大的 Dmin 值，这 主要是因为该构型下水流混流程度高。具有最优化构型的紫外消毒器的最大消毒 流量相对其他非优化构型消毒器的提高了 47100%，对应的节能效率为 3250%。 研究了采用高反射内壁以提高紫外消毒器性能的可行性。研究结果表明，具 有反射性内壁紫外消毒器内的光强分布可以通过校正后 DO辐射模型来准确模 拟。高反射内壁（R = 0.80）消毒器内紫外强度要显著高于普通内壁（R = 0.26） 消毒器内的，该差异在高 UVT时更为突出。相对于普通内壁消毒器而言，高反 射内壁消毒器 RED的提升主要源于消毒器内体平均紫外强度（FRva）的提升。 内壁漫反射可以提高消毒器内紫外强度分布均匀性，但后者对消毒器性能的贡献 是条件性的：对水流流态接近于推流的 L型消毒器而言，其可以在一定程度上提 高消毒器 RED；对水流混流程度足够高的 U型消毒器而言，其对消毒器 RED的 贡献几乎可以忽略。 提出了分时段调节灯管输出功率（LOP）的紫外消毒器节能运行方案以应对 二次供水流量周期性变化导致的能量浪费问题。根据二次供水流量的变化规律， 将一天 24 h分为 6个连续的特征时段，并为每个特征时段确定了一个用于灯管 策略验证的关键流量（Qc）。灯管策略评估结果表明，对于同一 LOP而言，最优 消毒器性能总是由灯管切换类策略而非功率调节类策略产生。将经相应时段 Qc 验证的具有适宜 LOP值的最优灯管策略进行顺序组合，得到紫外消毒器的节能 运行方案。该方案可以在不影响消毒效果的同时降低 32%的运行能耗，相当于一 天节电 4.8 kWh。The discovery of anti-chlorine pathogenic microorganisms (e.g., Cryptosporidium and Giardia) in water sources and the detection of chlorinated disinfection by products (DBPs) bring about a big challenge for the traditional chlorine disinfection process. Because of its high efficiency in inactivating Cryptosporidium and Giardia and almost no DBPs is generated, recently, UV technology has been widely employed for water disinfection all over the world. Nonetheless, the efficiency of the UV disinfection technology during the practical application depends on the specific configuration of the UV disinfection reactor, the target water quality and flow rate, and the reactor operation and maintenance. To ensure a high efficiency of the UV disinfection reactor in the practical application, appropriate actions should be conducted based on an accurate evaluation of the reactor performances under the above various conditions. Computational fluid dynamics (CFD) simulation can evaluate the UV reactor performance without a manufactured UV reactor. By far, researches on the fundamental theory and engineering application of UV reactor simulations are still rare in China and the UV reactor design and manufacturing are coarse. As a consequence, the domestically produced UV reactors are usually troubled with low efficiency and high cost. Against this background, this study researches on the optimal design and economical running of UV reactors based on CFD simulation. The principal conclusions are shown following: The key steps for CFD simulation of UV disinfection reactors are to: 1) build the geometric model based on the UV reactor configuration and generate meshes across the whole computational domain; 2) employ an appropriate turbulent model for the hydrodynamics modeling and set the velocity boundary conditions; 3) employ an appropriate radiation model and set the radiation boundary conditions; 4) active the discrete phase model, set the delivery of the simulating micro particles, compile an user- defined function to integrate the UV doses along the particle trajectories. The accuracies of various radiation models were evaluated with the in-situ fluence rate distribution measurement platform. The result showed that the fluence rate distribution in a UV reactor could be predicted accurately with a calibrated discrete ordinates (DO) radiation model (calibration factor = 0.8). The predicted microbial inactivation ratio by the CFD simulation procedure developed in this study (i.e., with Realizable k-turbulent model, calibrated DO radiation model and Lagragian approach of the discrete phase model) agreed very well with that by experimental test. Hence, this CFD simulation procedure is reliable and has an accurate evaluation of UV reactor performances. The above developed CFD simulation procedure was employed for the configuration optimization of a 3-lamp UV disinfection reactor, with a focus on the lamp arrangement and inlet/outlet internal diameter. Both the theoretical deduction and the CFD simulation proved that the reactor minimum UV dose (Dmin) could be employed to replace reduction equivalent dose (RED) as the reactor performance indicator, during the configuration optimization process of UV reactors, which clarified the target and reduced the efforts for UV reactor optimization. In general, the reactors with normal positioned lamps (NOR reactors) had larger Dmin values and thus better reactor performances than those with reverse positioned lamps (REV reactors). The NOR-0.4-75 reactor had the largest Dmin, mainly because of a better mixing as the influent flow dispersed by the lamps right below the reactor inlet. The UV reactor with the optimized configuration had an increased maximum disinfection flow rate by 47100%, corresponding to an energy saving efficiency of 3250%. The feasibility of employing a highly reflective inner wall to improve the UV disinfection reactor performance was evaluated. The results showed that the fluence rate distributions in a UV reactor with a reflective inner wall can be predicted accurately by the calibrated DO radiation model. UV reactors with a highly reflective inner wall (R = 0.80) had significantly higher fluence rates than those with a common inner wall (R = 0.26), which was more pronounced at high water UVTs. Correspondingly, the former had improved reactor performance (larger RED) as compared to the latter, which was resulted from the increased volume-averaged fluence rate (FRva). The inner-wall diffuse reflection could increase the fluence rate distribution uniformity inside the reactor chamber, but the latter had limited and conditioned contribution to the reactor performance: In UV reactors with the L-shape configuration with a plug-like flow, the increased fluence rate distribution uniformity could increase the RED to some extent; In UV reactors with the U-shape configuration with a sufficiently mixing flow, the effect on the RED could be reasonably omitted. An economical running strategy based on periodical adjustments of the lamp output power (LOP) was developed for UV disinfection reactors in secondary water supply systems, to avoid the energy waste at low flow rate periods. The daily 24 h were divided into 6 periods according to the daily flow rate variation pattern, and a critical flow rate (Qc) was determined for each period for the individual lamp mode verification. The lamp mode assessment results showed that for a constant LOP, the best reactor performance was always found with the lamp switching mode rather than the power adjusting mode. Sequential combination of the verified lamp modes with proper LOPs for the 6 periods resulted in the economical running strategy of the UV disinfection reactor. This strategy could reduce the reactor running cost by 32% without any adverse effect on the disinfection, which corresponded to a daily electrical energy cut of 4.8 kWh
Study on Thermal Environment Effect of Urbanization in China
No full text全球正经历快速、高强度的城镇化，导致城市热岛加剧，并对城市、区域乃 至全球许多的生态环境要素直接或间接地产生多方面的影响，与人类福祉密切相 关。本文分析了中国 1449个城市 2010年的地表热岛强度（SUHII）的年内变化 时空规律、2003 - 2013年间这些城市及对应乡村的地表温度（LST）及这些城市 SUHII的年际变化规律；探索了影响 SUHII年内时空演变的相关决定要素并对其 进行预测；并从区域尺度上准确估算了 1977 - 2014年中国城镇化对区域气温变 化趋势的影响。主要的研究结果如下。 （1）中国白天较大的年均 SUHII出现在湿热的南方地区与湿冷的东北地区， 最小出现在干旱半干旱的西北部地区。最强的在长三角及台湾沿海的许多城市。 温带地区除西北部地区外，各季 SUHII的大小顺序为夏季 >春季 >秋季 >冬 季；热带地区雨季显著大于旱季，但雨旱两季内部的季节间并无显著差异。白天 全年最大的 SUHII在各环境区中均最多出现在夏季；最小则在冬季。夜间 SUHII 的时空变异性通常小于白天的，其季节变化规律复杂。北方地区的年均 SUHII 高于南方；最大和最小值分别出现在西北部地区及南方的亚热带地区。存有一定 的夜间冷岛现象。昼夜及全天的 SUHII的最大值与最小值在中国各环境区各时 间段均显著正相关，夜间关系最强，全天最弱。昼夜 SUHII幅度间并无显著或 仅有微弱的相关性。在 50%的情况下，昼夜平均 SUHII间并无显著相关性。 （2）2003 – 2013年间，中国绝大多数或大多数参考乡村的昼夜的 LST均未 显著变化。LST的显著变化具有明显的空间集聚和分异规律。夏季除在白天的新 疆的一些参考乡村的 LST显著降低外，其他的多为不显著或正向显著的变化， 其幅度多为 0.0 – 0.1 °C (yr-1)，但仍有一些为 0.2 – 0.5 °C (yr-1)。与之鲜明对比 的是，冬季基本上或未显著变化，或为负向的显著变化，特别是东北和中北地区 的一些参考乡村，其幅度多为-0.4 – -0.1 °C (yr-1)。秋季昼夜显著变化的速率以负 值为主，其幅度多为-0.4 - -0.1 °C (yr-1 )。春季规律略复杂，其中白天东北地区中 南部的一些变化幅度可为-1.0 - -0.5 °C (yr-1)。 城区LST的变化规律与对应参考乡村的密切相关。白天，城乡间全年、冬季和秋季均值间的变化规律差异很小；夏季差异最大，显著正向变化的城市数量 和变化速率均明显加大；在春季，城区的变化速率有所加大，特别是在长江中下 游的一些城市。夜间，4季上城乡间均有一定的差异，城镇化可加速 LST增温。 中国绝大多数或大多数城市的 SUHII均未显著变化，但夜间的 SUHII显著 变化的比例明显高于城乡夜间 LST的。SUHII的变化具有明显的空间集聚和分 异性。全国昼夜的SUHII显著变化的速率的年均值分别为 0.03± 0.11和0.05± 0.03 °C (yr-1)。白天 SUHII的年际变化具有明显的季节规律，夏季变化速率明显 最大，范围也最大，春季次之，仍主要为正向速率，秋季再次之，冬季最弱，甚 至在中北地区的一些城市为负向速率。夜间 SUHII的变化的季节性波动不大， 变化速率基本不变，均多为 0.0 – 0.1 °C (yr-1 )。 （3）城乡夜间灯光强度和建筑密度差值与 SUHII的正向偏相关关系均在夜 间比白天存在的更广泛，后两者在夜间的关系也会更强；城乡增强型植被指数差 值普遍与昼夜 SUHII显著负向偏相关；城乡白色天空反照率差值与夜间 SUHII 普遍负向偏相关，但与白天的关系复杂；湿润指数或降水量分别与昼夜 SUHII 在一定情况下显著正向或负向偏相关；平均气温与夜间 SUHII在 40%的情况下 显著正向偏相关；城乡气溶胶的差值与昼夜 SUHII分别在 48.00%和 56.00%的情 况下显著正相关，相关系数在干旱半干旱的西北部地区明显要大，两者间显著的 偏相关关系很少存在且关系很弱；城区面积大小和总人口普遍与昼夜 SUHII显 著正相关，但很少显著偏相关；城乡人口密度差值与夜间 SUHII在 32%的情况 下显著正向偏相关，特别是在南方地区。在 72%的情况下，白天的解释率大于夜 间的。最大和最小的解释率分别出现在夏季白天的湿冷的东北地区及湿热的南方 地区，分别为 63.84%和 10.44%。 （4）基于遗传算法的支持向量机和与 SUHII显著偏相关的变量可较好预测 全国及各环境区内的全年及 4季的平均昼夜 SUHII。夜间的预测精度高于白天。 全国尺度上的 RMSE的范围为[0.49，1.54] °C，区域尺度上为[0.38，2.18] °C。 （5）均一化前后的平均最低气温（Tmin）、平均最高气温（Tmax）和平均 气温（Tm）的全年及 4季均值序列均差异显著。Tmin对观测系统的改变最为敏 感。大部分调整幅度在-1 – 1 °C，但一些调整的绝对值大于 1 °C，最大为 7.84 °C。 （6）1977 - 2014年间中国乡村背景场具有 6个不同气温变化趋势的分区：I： 东北和胶东半岛地区；II：北部及中部内蒙古地区；III：北疆外的西北地区；IV： 北疆地区；V：青藏滇高原地区；VI：长江-淮河流域及南部地区。中国乡村背景 场的年均 Tmin、Tmax和 Tm的变化速率分别为 0.424、0.339和 0.352 °C（10yr-1）， Tmin、Tmax和 Tm的最大增速均出现在春季；Tmax和 Tm的最小增速出现在夏 季，Tmin的出现在冬季，但仅比夏季的低 0.011 °C（10yr-1）。近几十年来，Tmin、 Tmax和 Tm均普遍存在明显的跃变上升现象；近几年来，少数明显跃变下降。 （7）城镇化效应对气温变化速率的贡献量与 3种反映城镇化强度的指标间 显著的相关关系并不一直存在且正负均有。以不透水面为主的聚落生态系统面积 的增量是最好的相关指标。定标后的夜间灯光数据可克服未经定标数据的饱和问 题，更好地反映出城区内部的城镇化强度的变化。1977 - 2014年间中国城镇化效 应对区域尺度上年均 Tmin、Tmax和 Tm变化速率的贡献率分别为-0.08%、0.21% 和-0.09%。Rapid and high intensity urbanization is currently ccurring in the world, resulting in increasingly more serious urban heat island phenomenon. Urban heat islands have direct and indirect impacts on various ecoenvironment factors of cities, regions, and the world, which are closely related to the human well-being. This study analysed the inner-annual spatiotemporal variation laws of surface urban heat island intensity (SUHII) of 1449 cities in 2010 in China, and the interannual variability laws of land surface temperature (LST) of these cities and the corrosponding villiages, and SUHII of these cities from 2003 to 2013; explored the associated determinants of inner-annual spatiotemporal variation laws of SUHII, and did the prediction; and accurately estimated the effects of urbanization on variations in observed temperatures in region scale in China from 1977 to 2014. The main finding are as follows. (1) Larger annual mean daytime SUHII occurred in humid-hot southern China, or humid-cold northeastern China, while the smallest in the arid and semi-arid northeastern China. The strongest SUHII mainly occurred in most cities in the Yangtze River Delta and coastal areas of Taiwan. The season order for SUHII was summer > spring > autumn > winter in temperate regions except in northwestern China. While the SUHII was obviously larger in rainy season than dry season in tropical region. However, no significance difference existed between two seasons within the rainy or dry period. During daytime, the maximum SUHII mostly occurred in summer in each region, while the minimum in winter. The spatiotemporal variation degree was generally lesser for the SUHII during nighttime than during daytime. The seasonal variation laws were complex for nighttime SUHII. The annual SUHII was higher in northern China than southern. The maximum and minmum values occurred in the northwestern region and subtropic region in southern China, respectively. A certain cold island phenemon existed during nighttime. The maximum SUHII was almost significantly positive correlated with the minimum during daytime, nighttime and all-day in all environmental regions in the whole year and four seasons. This relationship was strongest and weakest during the nighttime and all-day, respectively. Moreover, the significant correlation did not exit or was weak for the daytime and nighttime range of SUHII. What’s more, the daytime SUHII was also insignificantly correlated with nightime SUHII in 50% cases. (2) The LST in overwhelming majority or most reference villiages did not changed significantly from 2003 to 2013 in China. The LST that have significantly changed showed obvious spatial agglomeration and spatial variation laws. In summer, except the LST in some reference villiages in Xinjiang significantly decreased during daytime, the others did not change significantly or was with significant positive change. The amplitudes were most 0.0 – 0.1 °C (yr-1 ). Some of them were 0.2 – 0.5 °C (yr-1 ). By contrast, the LST of reference villiages mainly did not change significantly or was with significant negative change, especially for some reference villiages in northeastern and northcentral regions, with the amlitudes of -0.4 – -0.1 °C (yr-1) in most cases. In autumn, the significant change rates were mainly negative, with the amlitudes of -0.4 - -0.1 °C (yr-1 ) in most cases. The laws were a little complicated. Note the variation rates were most -1.0 - -0.5 °C (yr-1 ) in some reference villiages in southcentral parts in northeastern region during daytime. The spatiotemporal variation laws of LST in cities were closely related with them in the corroponding reference villiages. During daytime, the differences were quite small between the spatiotemporal vartiations of LST in cities and their corresponding reference villiages. The largest differences occurred in summer. Not only the number of cities obviously increased whose mean LST significantly changed with positive rates, but also the variation rates obviously turned larger. In spring, the variation rates increased, especially for cities in the middle and lower reaches of Changjiang River. During nighttime, a certain differences exsited for the variation laws of LST between the cities and their corronponding reference villiages. The urbanization promoted the increase of LST. The overwhelming majority or most SUHII did not change significantly. But during the nighttime, the proportion with significant change of SUHII was obviously larger than of the LST of both the cities and reference villiages. The SUHII that have significantly changed showed obvious spatial agglomeration and spatial variation laws. The annual mean values of daytime and nighttime SUHII that significantly changed were 0.03± 0.11 and 0.05± 0.03 °C (yr-1 ), respectively. During daytime, the interannual variation of SUHII showed obviously seasonal laws. In summer, not only the variation rates but also the scope with significant varation were obviously the largest. Spring was the next and in which the variation rates were mainly positive. Then autumn. The varation was weakest in winter, when the varation rates in northcentral were even negative. During nighttime, the varation of SUHII was with less seasonal fluctuation. The varation rates almost unchanged, were most 0.0 – 0.1 °C (yr-1 ). (3) More significant partial relationships existed during nightime than during daytime between SUHII and both the difference between cities and villages for the night lights and difference between cities and villages for the built intensity (ΔBI). Moreover, the relationships between SUHII and ΔBI were stronger during nightime. The ΔEVI was commonly negatively partially correlated with daytime and nighttime SUHII. The ΔWSA was usually negatively partially correlated with night SUHII. During daytime, the relationship was complex. The IM or MAP was negative partially correlated with nighttime and positively with daytime SUHII in some cases, respectively. The MAT was positively partially correlated with nighttime SUHII in 40% cases. The ΔAOD was positively significantly related with nighttime and daytime SUHII in 56.00% and 48.00% cases. The correlation coefficients were obviously larger in arid and semi-arid northwestern China. Hoever, significant partial correlationships seldom existed, and with small partial coefficient. Although the UAS or TP was generally positively correlated with daytime and nighttime SUHII, significant partial correlation seldom existed. The ΔPD was positively partially correlated with nighttime SUHII in 32% cases, especially in southern China. In total, the explanation rates during daytime were larger than during nighttime in 72% cases. The largest and least was in summer day in humid cold northeaster China, and in southern China with the proportion of 63.84% and 10.44%, respectively. (4) Both the daytime and nighttime SUHII can be well predicted in the whole country and each environmental region in the whole year and four seasons in China, by adoping the Support Vector Machine based on Genetic Algorithm and using the driving indices that was significantly partially correlated with the SUHII. The prediction accuracy was always higher during nighttime than daytime. The RMSE ranged from 0.49 to 1.54 °C in national scale, while from 0.38 to 2.18 °C in regional scale. (5) Significant differences existed between the series of annual and four seasonal of mean minimum air tempeature (Tmin), mean maximum air tempeature (Tmax), and mean air tempeature (Tm) before and after homogenization. The Tmin was the most sensitive index to the change of observation system. The most adjusted amlitudes ranged from -1 to 1 °C, several absolute values of adjustments were larger than 1 °C, and the maximum adjusted value reached 7.84 °C. (6) China was divided to six regions with different rural temperature change trends from 1977 to 2014: I: Northeastern China and the Jiaodong Peninsula; II: Northern China and Middle Inner Mongolia; III: Northnorthwestern China, except for Northern Xinjiang; IV: Northern Xinjiang; V: the Qinghai - Tibet - Yunan Plateau and the Yangtze-Huaihe River Basin; and VI: Southern China. The rural temperature significantly increased in China, and the rates of annual Tmin, Tmax and Tm were 0.424, 0.339, and 0.352 °C (10 * yr-1 ), respectively. All maximum rates occurred in spring for Tmin, Tmax and Tm. The minimum rates occurred in summer for Tmax and Tm, as well as in winter for Tmin, which was 0.011 °C (10 * yr-1 ) less than in summer. Abrupt increases in Tmin, Tmax and Tm commonly occurred in China in recent decades, while a few abrupt decreases in recent years. (7) Significant correlations did not always exist between the temperature variation rates contributed by urbanization and three indices of urbanization intensity, and the correlation coefficients can be both positive or negative. The change in the area of the settelement ecosytem that was mainly compositional by impervious surfaces was the best related factor. Adopting the nighttime light data after calibration can overcome the saturation issue exsiting in the raw data, thus indicate the varation of urbanization intensity within cities. The percentage contributions of urbanization to annual Tmin, Tmax, and Tm were -0.08%, 0.21% and -0.09%, respectively in region scale in China from 1977 to 2014
A reduced TKTD model for standard acute toxicity testsof aquatic animals
No full text在常规的水生生物急性毒性检测和研究中，最常使用的毒性指标是半数致死 浓度 LC50。然而，该指标严重依赖试验周期，难以科学地比较不同物种之间的毒 性差异。并且，LC50仅为统计学、描述性指标，缺乏生物学涵义。而基于动态存 活模型的致死速率 Killing rate（Kk）不存在上述缺陷，可以作为科学的急性毒性 评价指标。 针对已有的 General Unified Threshold Model of Survival（GUTS）模型的不 足之处，本研究构建了简化的毒物代谢-毒物效应动力学（TKTD）存活模型，采 用 Markov Chain Monte Carlo（MCMC）方法作为最优化算法，用于评价参数 Kk 的可信程度。初步的研究结果表明，MCMC法拟合获得的致死速率 Kk能够可靠 地、稳健地表征急性毒性强度。并且，利用全部试验数据获得的模型参数还有： 主导速率常数 Kd可反映毒性物质的理化性质；无效应浓度 NEC表征不产生死亡 效应的阈值浓度，因此，研究结论具有更高的科学性。 通过设计不同的模拟试验，探讨了本模型的数据要求。结果表明，与标准的 急性毒性试验程序相比，可以减少试验浓度的数量，并且降低了对致死率试验数 据的要求。适用于 TKTD存活模型的最基本的试验设计如下：（1）试验周期内至 少 4次计数死亡动物数目；（2）每个浓度至少设置 2个平行，至少 20只试验动物； （3）试验期间，至少 2个浓度产生了 3个及以上不同的累计死亡率数据。 与以往的动态模型相比，简化 TKTD存活模型更加简便、易用，适用于常 规急性毒性检测和研究。并且，采用本模型可以进行科学的快速毒性检测。As an indicator used in acute toxicity testing, median lethal concentration LC50 heavily depends on test duration, and was less mechanistic and biologically relevant. However, killing rate Kk derived from dynamic model is free from these drawbacks, so that it would be a more scientific measurement of acute toxicity. To assess the reliability of Kk, a reduced TKTD model of survival was created and optimized with MCMC method. The preliminary results showed that Kk might be a reliable and robust indicator of acute toxicity. Moreover, this model has two other parameters: dominant rate constant Kd, NEC. Kd may indicate some physicochemical properties of a toxicant, and NEC stands for no effect concentration of lethal effect. Therefore, the results utilized all test data were more reliable and scientific. Different simulated tests were set up to explore data requirements of this model. The results showed less data were required of numbers of concentrations and partial mortalities. The basic experiment design for this method was: (1) at least 4 counts of dead individuals through test duration; (2) at least 2 parallels and 20 animals for each treatment; (3) at least 3 different cumulative mortalities in a minimum of 2 treatments. In a summary, killing rate Kk might be a reliable measurement of acute toxicity, and this reduced TKTD model could be applied in routine acute toxicity studies and in some repaid toxicity testing
Study on the Technology and Management System of Eco-environmental Internet of Things ——a case study of Xianghe Segment of China's Grand Canal
No full text随着我国城市化水平的快速提升，生态环境问题呈现出显著的区域性、复合 性和长期性特征，而我国区域生态环境变化的监测与管理一直缺乏长期有效的平 台，迫切需要一种覆盖范围广阔、监测手段多样、采样频率高的生态环境区域化 监管手段。采用物联网技术提高区域生态环境的监测、管理和应急处置能力，将 有利于区域的可持续发展。 本研究基于生态学、环境学、可持续发展等基础理论，将理论与实际工程建 设相结合，开展生态环境物联网的理论与技术研究并应用于实践。主要研究内容 包括生态环境物联网技术体系架构与标准体系、生态环境物联网管理技术体系和 实践案例应用三个方面。 （1）本研究在传统物联网三层结构（即感知层、传输层和应用层）的基础 上，开展生态环境物联网系统架构的顶层设计，提出了包含感知硬件基础、感知 设备选型和感知节点布设的感知层分层设计架构，包含信息传输、信息存储和信 息安全的网络传输层分层设计架构，应用支撑和主要应用专项的应用层分层设计 架构。根据上述技术体系架构，从各分层应包含的元素着手，归纳出了各分层应 该包含的功能、指标、技术、设备等要求，形成标准体系。 （2）本研究创新性的针对生态环境物联网开展管理技术体系构建。针对生 态环境物联网布设过程中的共性问题，提出了公共管理技术的要求；根据生态环 境物联网的不同功能（感知、调控、参与和展示），提出对应不同功能应用阶段 的共性管理技术体系，即感知管理体系、调控管理体系、公众参与管理体系和展 示管理体系。为了评价生态环境物联网管理的效果，构建了生态环境物联网管理 综合评价指标体系，从生态环境物联网高效运行、生态环境物联网多要素感知、 生态环境物联网调控区域生态环境、公众的环境参与体验和展示效果 6个方面综 合评价生态环境物联网管理的效果。 （3）本研究在北运河香河段开展了生态环境物联网系统的实践研究，建成 了多个生态环境物联网子系统，包括公共管理技术子系统、感知管理子系统、调 控管理子系统、参与管理子系统和展示管理子系统。构建了北运河香河段生态环 境物联网环境管理体系框架，并提出了相应的环境管理对策。 研究认为，物联网应用于生态环境保护领域是信息技术发展到一定阶段的必 然结果，也是生态环境领域信息化的必然趋势。生态环境物联网可以提供区域生 态环境监测与管理的新方法，通过快速、连续、大覆盖地监测生态环境关键指标， 评估区域生态环境的现状和发展趋势，达到快速全面反映生态环境问题的目的； 通过生态环境物联网管理技术体系，理论与技术上拓展了物联网在生态环境领域 的应用研究与实践；通过在典型区域开展生态环境物联网试点示范应用，为区域 开发过程中的生态环境保护与管理提供技术支持，进而保障区域生态安全，实现 区域的可持续发展。With the significant raise of urbanization level, eco-environmental problems present a regional, complicated and persistent character, but there has been lacking a long-term effective platform to monitor and manage the eco-environment changes. Therefore, it is imperative that regional eco-environment supervision should be provided with broader and diversified monitoring means with higher sampling frequency. It is conductive to regional sustainable development by promoting the capacity of regional eco-environmental supervision, management, and emergency response based on Eco-Environmental Internet of Things (EEIoT) technology. This research investigated the theory and technology of EEIoT on the basis of ecology, environmental science, and sustainable development, and then put the basic theory into engineering practices. The contents of this research included three parts: technical framework of EEIoT, management framework of EEIoT, and engineering practices of EEIoT. (1) In this research, the top layer of EEIoT system architecture was designed on the basis of traditional IoT structure that included perception layer, transport layer and application layer. In this system design, the hierarchical architecture of perception layer included hardware underpinnings, equipment selection and node deployment; the hierarchical architecture of transport layer included information transmission, information storage, and information security; the hierarchical architecture of application layer included practice supporting and special applications. According to the technical architecture and elements of every layer components, the demand of function, index, technology, and equipment in each layer was generalized. These demands formed standardization system finally. (2) This research for the first time provided the technology management framework of EEIoT. The research proposed the requirement of management techniques of EEIoT based on the common issues of the EEIoT practice, and the framework of management techniques of EEIoT in different application stages of EEIoT based on the different functions of EEIoT (sensation, regulation, participation and demonstration), which included the management system of sensation, regulation, public participation and demonstration. In order to evaluate the effects of the management of EEIoT, a comprehensive evaluation index system was developed. The effects of EEIoT management were comprehensively evaluated from six aspects, including effective functioning of EEIoT, multi-element perception of EEIoT, regulation of regional eco-environment, environmental public participation experience and display effect. (3) In this study, an empirical analysis of EEIoT system was carried out for Xianghe Segment of China’s Grand Canal. A number of subsystems of EEIoT were established, including public management technology subsystem, perceptual management subsystem, control and management subsystem, participation management subsystem, and presentation management subsystem. Based on this, a system framework of EEIoT management in Xianghe Segment of China’s Grand Canal was constructed, and corresponding environmental management countermeasures were proposed. The research considered that the application of Internet of Things in the field of ecological environment protection is the inevitable result of the development of information technology to a certain degree. EEIoT is the inevitable trend of informatization in the field of eco-environment. EEIoT can provide a new method of regional eco-environment monitoring and management. It can obtain comprehensive ecological and environmental situation of a certain region quickly, by means of key eco-environment indicator monitoring network and subsequent assessment of regional eco-environment status quo and development trend. Through the research of EEIoT management technology system, the applications of the Internet of Things in the field of ecological environment were expanded theoretically and technologically. Through the applications of EEIoT in a demonstration area, it will technical support to the eco-environment protection and management during regional development processes, and thus to protect the regional ecological security and to achieve regional sustainable development
A Dissertation Submitted to University of Chinese Academy of Sciences For the Post-doctor Research Report
No full text研究表明，生物难于处理的污染物通常具有化学稳定性高, 难以被常规氧化剂完全矿化的特点, 这就要求所采用的化学氧化剂必须具有足够的氧化能力, 因而促进了以产生氢氧自由基为主要特点的高级氧化技术(AOPs)的迅速发展。在过去的30年，针对高级氧化技术在大气和水体污染物处理的研究及应用已经取得了长足的发展。作为AOPs技术的一种，使用UV照射和二氧化钛(TiO2)的光催化氧化(PCO) 在水处理领域显示出显著的优势。光催化氧化技术的组成部分大致可分为与光能产生协同作用的光催化剂、给催化剂提供光能的光波段和产生光催化氧化反应的反应场，其中的每一个组成部分可延伸为一个崭新的研究领域。因此，针对光催化体系中的各组成部分进行交叉研究，有助于探索并设计光催化处理污水的新方法。围绕这一思路，本研究开展了光催化材料的研制和基于CFD的光反应器优化，取得的成果如下：
（1）为了克服微孔和介孔分子筛的局限性，应用微-介孔复合材料是一种简单高效且环保的方法，可以改善介孔分子筛的水热稳定性，同时提供大量的活性位点。本研究结合SBA-15介孔材料与ZSM-5的活性位点，通过后合成法在水热硅质材料上合成出不同ZSM-5(38)质量比例的(Xg)ZSM-5-SBA-15复合材料，随后使用溶胶-凝胶方法将不同质量的二氧化钛沉积在复合材料的表面及孔洞之中。制备材料(XmL)TiO2/ZSM-5-SBA-15的光催化性能通过对水溶液中甲基橙(Methyl Orange(MO))的吸附与光催化性能进行表征，并与粉末状TiO2进行了比较。
（2）针对内循环气升式反应器，建立了三相流(气-液-固)模型，通过优化反应器内导流筒的结构、气含率、固含率以及流体循环速度等参数，提升固体光催化剂在反应器中的均匀混合效果，并提高小颗粒催化剂在反应结束之后的回收率。
（3）针对UV/H2O2AOPs处理污水中毒性和难降解有机污染物技术，通过CFD方法，建立了耦合水动力、UV辐射和化学反应动力学过程的数值模型，提高了催化剂停留时间和混合效果，并通过水中毒性和难降解有机污染物的降解效率进行了验证。
（4）基于CFD开发了能够深入分析适用于水处理的VUV/UV技术的数值模型。模型结合了水动力学、组分传输和化学反应动力学模块，可模拟反应器中辐射强度分布，并基于模型结果讨论了VUV/UV光反应器中不同化学组分的反应途径。Previous studies indicated that the pollutants which are not effective for biological treatment are usually chemically stable and difficult to be completely mineralized by conventional oxidizers. This requires that the employed chemical oxidizers should have sufficient oxidizing ability, which promotes the rapid development of advanced oxidation technology (AOPs) charactered as the production of hydroxyl free radicals. In the past 30 years, the research and application of advanced oxidation technology in the treatment of air and water pollutants have achieved great process. As one type of AOPs, the photocatalytic oxidation (PCO) method using UV irradiation and titanium dioxide (TiO2) shows a significant advantage in the field of water treatment. The PCO technology generally includes three components, which are photocatalysts that work synergistically with light energy, optical wavebands that provide light energy to the catalyst, and reaction fields or reactors that produce photocatalytic oxidation reactions. Each of the components can be extendedinto a new research field. Therefore, the cross-study of the various components of the photocatalytic system is helpful to explore and design a new method of photocatalytic treatment of sewage. Based on this idea, the research carried out the development of photocatalytic materials and the optimization of photoreactor based on CFD, the obtained achievements are listed as following:
(1) In order to overcome the limitations of microporous and mesoporous molecular sieves, the post-synthesis method was used to synthesize the micro-mesoporous composite, which not only improved the hydrothermal stability of the mesoporous molecular sieve, but also provided a large number of active sites. In this study, (Xg) ZSM-5-SBA-15 composites were prepared by using SBA-15 mesoporous materials and ZSM-5 (38) microporous materials at different mass ratios. As well, different quality of titanium dioxide (TiO2) was loaded on the surface and in the pores of (Xg) ZSM-5-SBA-15 composite via sol-gel method to prepare (XmL)TiO2/ZSM-5-SBA-15 photocatalyst. The photocatalyst loaded with 0.4 mL of TiO2 showed the best catalytic effect based on the morphology and structure analysis of prepared new material and the testing results of adsorption and photocatalytic performance of methyl orange (MO) dye in aqueous solutions.
(2) A three-phase flow (gas-liquid-solid) model was established for the internal recycle airlift reactor. By optimizing the structure of draft tube in the reactor and parameters such as gas content, solid content and fluid circulation velocity, the gas and liquid can be well separated in the bottom zone of the reactor increasing the mixing performance in the reactor at the ratio of r/R = 0.4 and the gas velocity of Ug = 0.5m/s. In this way, the uniform mixing effect of the solid photocatalyst in the reactor is improved, and the recovery efficiency of the small particle of catalyst after the reaction is improved as well.
(3) As the technology of UV/H2O2 AOPs is for treating the toxic and refractory organic pollutants in sewage, a numerical model of coupling hydrodynamic, UV radiation and chemical reaction kinetics was established based on the CFD method to simulate the hydrodynamic phenomenon and the chemical reaction process in the designed photocatalytic cyclone reactor. In the hydrodynamic analysis of the new reactor, it was found that the velocity of the fluid is maximized at the inlet and then decreases until the outlet which still provides rotational force for the reaction mixture in the reactor to provide hybrid power and prolong the residence time for different flow rates. Finally, the continuous experiment of degradation of methylene blue by the desgined reactor verified that the simulation was consistent with the experimental results.
(4) A numerical model based on CFD was developed to further analyze the VUV/UV technology which is suitable for water treatment. The model combines the hydrodynamics, the component transport model and the chemical reaction kinetic module to simulate the distribution of radiation intensity and the hydrodynamics in the reactor. Based on the modelling results, the reaction pathway of different chemical components in the VUV/UV photoreactor was discussed. In the hydrodynamic analysis, it is found that the fluid at the inlet rised to the outlet along the wall of the reactor in a pusher flow and then flows downward along the surface of the light source in complete mixing for different flow rates. Finally, the continuous experiment of degradation of methylene blue by the designed reactor verified that the simulation was consistent with the experimental results
Coupling of elements and mechanisms ofmicrobial Fe(III) reductionbased on the principle of thermodynamics
No full text微生物驱动着生物圈很多关键的过程和元素的氧化还原循环，改变着地表化 学环境。微生物在自然生态系统中对物质和能量转化所起的重要作用已引起广泛 关注。而热力学原理为预测反应能否自发，反应是否可能参与到微生物活动中， 物质与环境之间的能量交换以及微生物反应在环境中的分布提供了基本框架，也 成为微生物反应机制研究的理论基础。理解特定环境中微生物主导的过程必须理 解微生物代谢能量。 铁在土壤和沉积环境中都很丰富，主要以二价铁和三价铁的固态铁矿形式存 在。土壤和沉积物中微生物驱动的二价铁和三价铁矿物的氧化还原显著影响很多 其它元素的地球化学循环，与温室效应、有机污染和重金属污染等多种环境问题 密切相关。因此理解微生物驱动的铁循环有极其重要的意义。虽然人们已经对微 生物驱动的铁还原展开深入的研究，但目前微生物铁还原机制和途径仍然存在很 多未知。微生物在中酸性条件下的铁还原机制已有大量报道，但在碱性条件下微 生物铁还原机制还鲜有研究。 本论文从热力学出发，对环境微生物活动中涉及的最主要的几种元素的耦合 反应进行了研究，评估微生物在不同pH 下铁还原的能力，通过细菌培养实验探 究碱性环境中微生物铁还原的主要机制。论文的主要研究内容如下： （1）厌氧环境中厌氧微生物催化各种氧化还原反应，驱动着元素的地球化 学循环。厌氧微生物从催化氧化还原反应捕获能量以维持生长。这些微生物驱动 的氧化还原反应的热力学可行性由基于环境条件的产出能量所控制。不同的氧化 还原反应会按照热力学梯度从高产能到低产能顺序进行。氧化还原反应的热力学 能量影响各种厌氧生态系统中微生物氧化还原反应的分布和元素的循环转化。在 本研究中我们将厌氧微生物驱动的C、N、Fe 和S 之间的耦合反应与它们的热力 学可行性联系到一起。结果表明环境中已证实的微生物氧化还原反应的存在和分 布与它们的热力学可行性较为一致，热力学原理为氧化还原反应的存在和分布提 供了理论依据。因此，利用热力学原理来探究微生物驱动的元素耦合具有重要意 义。 （2）微生物胞外铁氧化物还原在很多生物地球化学循环中起重要作用。近 中性环境中已提出几种微生物铁还原机制，但在碱性条件下微生物铁还原的途径 还鲜有研究。在本研究中我们利用AQDS 作为腐殖质醌基组分的代表物质，探 究腐殖质在碱性条件下对铁还原的潜在作用。基于热力学计算，我们预测，在碱 性条件下三价铁（氢）氧化物的微生物酶还原热力学可行，但十分微弱。在微生物培养实验中，Shewanella oneidensis MR-1 和Geobacter sulfurreducens PCA 以及 水稻土富集菌混合培养具有较弱还原水铁矿的能力，S0 或AQDS 的存在均显著 促进了铁氧化物的还原。在碱性条件下AQDS 作为电子穿梭体促进铁还原的能 力高于元素硫(S0)。这些结果表明碱性条件下三价铁（氢）氧化物的微生物还原 可能是通过电子穿梭体介导的途径进行的。考虑到腐殖质有较强的电子穿梭能力 并且在环境中分布广泛，腐殖质介导的铁还原可能是碱性环境中微生物铁还原的 主导机制。Microbial activity drives many key processes and the redox cycle of elements in the biosphere, changing the surface chemical environment on earth. The important role of microbial mass and energy transformation in the nature has attracted increasing attention among researchers. The principle of thermodynamics provides a basic frame for predicting whether a reaction is spontaneous, whether the reaction may be involved in microbial activity, the extent of energy exchange between substrates and the environment, and the distribution of microbial processes in the environment and becomes a theoretical foundation for learning the mechanisms of microbial reactions. Learning the microbial energy metabolism is necessary for understanding redox processes dominated by microorganims in a particular environment. Iron (oxyhdr)oxides, mainly in the form of solid ferric and/or ferrous minerals, are abundant in both soil and sedimentary environments. Redox cycles of ferric and ferrous minerals driven by microorganisms in the soils and sediments significantly affect the geochemical cycles of many elements, and are closely linked to many environmental problems, including release of greenhouse gases, contamination of organic pollutants and heavy metals. Therefore, understanding the microbial iron cycle is of dramatic significance. Although many advanced technologies and methods have been developed for the researches about microbial Fe(III) reduction, the mechanisms and pathways for microbial iron reduction are still unclear. A lot of investigations have been made for mechanisms of microbial Fe(III) reduction under near neutral conditions. However, the mechanisms of microbial Fe(III) reduction under alkaline conditions are rarely investigated. In this paper, we investigated the coupling of elements which are importantly involved in microbial activities from the perspective of thermodynamics. We estimated the feasibility of enzymatic iron reduction at different pHs and explored the main mechanism of microbial iron reduction in alkaline environments through batch culture experiments. The main contents of this paper are as follows: (1) Anaerobic microorganisms catalyze diverse redox reactions in anoxic environments and drive elemental biogeochemical cycles on the earth. They capture energy released from these redox reactions to support growth. The thermodynam feasibility of these redox reactions driven by microbes is controlled by their energy yields depending on environmental conditions. Different redox reactions would proceed following a thermodynamic ladder, sequentially from the high energy yields towards the low energy yields. The energy released by redox reactions therefore affects the distribution of microbial redox reactions and transformation of elements in various anaerobic ecosystems. In this study, the distribution of the coupling reactions between C, N, Fe and S, the most important elements in microbially mediated redox reactions, was linked to their thermodynamic feasibility. The results indicate that there is good consistency between the existence and distribution of microbial redox reactions in the environment and their thermodynamic feasibility. The principle of thermodynamics provides a theoretical foundation for the existence and distribution of the redox reactions. Therefore it is important to explore the coupling of elements driven by microorganisms with the principle of thermodynamics. (2) Extracellular Fe(III) reduction plays important roles in a variety of biogeochemical processes. Several mechanisms have been proposed for microbial Fe(III) reduction in pH-neutral environments, but it has rarely been studied in alkaline conditions. AQDS was used as a representative of qinones within humic substances to investigate the potential role of humic substances on mediating microbial Fe(III) reduction in alkaline environments. Based on thermodynamic calculations, we predicted that the enzymatic reduction of Fe(III) (oxyhydr)oxides would be thermodynamically feasible under alkaline conditions although very weak. In our experiments, the reduction of Fe(III) was significantly increased by anaerobic inoculation of Shewanella oneidensis MR-1, Geobacter sulfurreducens PCA or microbes enriched in a paddy soil respectively in the presence of S0 or AQDS. More Fe(III) minerals were reduced with AQDS as a soluble electron shuttle than that of element sulfur (S0) under the alkaline conditions. These results suggested that microbial reduction of Fe(III) (oxyhydr)oxides may proceed via a pathway mediated by electron shuttles under alkaline conditions. Considering the vast distribution of humic substances and its high ability as electron shuttles, we suggest that Fe(III) reduction mediated by humic substances may potentially be the dominant mechanism for Fe(III) reduction in alkaline environments
Environmental Behavior and Human Exposure of Cyclic Per- and Polyfluorinated alkyl Substances and Cl-PFESAs
No full text全氟和多氟化合物（Per- and polyfluoroalkyl substances，PFASs）的环境问
题一直是近几年的研究热点。它们在环境中广泛存在且不易被降解，并可对生物
和人体造成不良影响。因此，目前许多替代产品被大量生产和使用。这些替代产
品主要包括一些短链的 PFASs和结构中引入醚键和/或氯等杂原子的 PFASs；另
外，虽然一些 PFASs被大量生产和使用多年，但分析技术和科学研究的局限使
得它们一直未曾进入环境科学家的研究视野，近年来色谱质谱技术特别是高分辩
质谱的飞速发展和环境科学研究的不断深入使得它们的环境存在逐渐得以揭示。
我们将上述全氟和多氟化合物统称为新型 PFASs。目前环境科学界对新型 PFASs
的环境行为、生物富集和人体暴露的研究十分有限。本论文以环状 PFASs及其
异构体和氯代多氟醚磺酸（Cl-PFESAs）等新型 PFASs为对象，在建立起定性和
定量分析方法的基础上，研究它们在典型区域中的环境行为及人体暴露，论文主
要包括以下内容：
1、在目前常见 PFASs分析方法的基础上，综合优化常见 PFASs的样品前处
理、色谱分离和质谱检测方法，并对它们的异构体给予了高度关注，完善建立了
包括 Cl-PFESAs在内的多种 PFASs同时分析的方法，方法的检出限和加标回收
率等参数均满足要求，适用于环境水样、底泥和生物组织等实际样品的分析。
2、开展了北京首都机场周边环境中环状 PFASs及其异构体的识别分析、环
境行为和器官特异性的生物累积研究。利用高分辨的四级杆线性离子阱静电场轨
道阱质谱（Orbitrap MS）首次在环境和生物样品中识别分析了全氟乙基环己烷磺
酸（PFECHS）和全氟丙基环戊烷磺酸（PFPCPeS）的五种异构体的存在。地表
水和底泥中环状 PFASs的总浓度分别为 1.04 - 324 ng/L和<MLQ - 2.23 ng/g dw，
并且随着与首都机场人工湖距离的增加，其浓度均呈对数下降的趋势。PFECHS
和 PFPCPeS在鲫鱼的肝脏、肾脏、血液和鱼鳔均有较强的累积，生物富集因子
（Log BAFwhole‑body）平均值分别为 2.7和 1.9。该研究说明环状的特殊结构和磺
酸基的位置均对 PFASs的环境行为和生物累积具有明显影响。
3、系统研究了北京城区地表水中 Cl-PFESAs和常见 PFASs的污染现状、空
间分布和季节变化规律。于 2013年 10月到 2014年 9月分十次采集了北京城区
350个地表水样品，采样布点涵盖绝大多数北京城区河流和湖泊。分析结果表明，
PFBA和 PFPeA是浓度最高的 PFASs，平均浓度分别为 12.79 ng/L和 9.90 ng/L，
C8 Cl-PFESA是被检出的唯一 Cl-PFESAs，浓度范围在<MLQ到 6.93ng/L之间；
在污染的空间分布方面，北京北部和东部区域的∑ PFASs浓度偏高，但 C8
Cl-PFESA的浓度在全部采样点未发现显著性差异；∑PFASs和 C8 Cl-PFESA的
季节性变化表现出夏季浓度水平最高和冬季浓度水平最低的特点。
4、研究了石家庄普通人群 Cl-PFESAs和常见 PFASs的暴露水平、特征及主
要暴露途径。对石家庄市 439个普通人群血清样品的分析发现，C8 Cl-PFESA在
所有样品中均有检出，平均浓度为 2.70 ng/g（0.04 - 42.72 ng/g），占血清总 PFASs
浓度的 9.32%，且 C8 Cl-PFESA浓度与主要常见 PFASs浓度呈现一定的正相关
性（ρ > 0.194，p < 0.01）；与常见 PFASs相似，男性 C8 Cl-PFESA的浓度（n =
210；3.25 ng/g，0.08 - 24.34 ng/g）显著高于女性（n = 229；2.88 ng/g，0.04 - 42.72
ng/g；p < 0.05）；青年女性体内常见 PFASs和 C8 Cl-PFESA的浓度最低。此外，
通过食鱼的摄入可能是石家庄普通人群 Cl-PFESAs暴露的主要途径。
5、探讨了头发、指甲和尿液作为非侵入性生物监测介质对一些常见和新型
PFASs内暴露指示的有效性和可行性。结果表明，对受高浓度 PFASs暴露影响
的成对血清与指甲样品（n = 8）的分析发现 PFUnDA、PFHxS、PFOS和 C8
Cl-PFESA等发生了具有明显剂量依赖性的从血清到指甲的转移（ρ > 0.74，p <
0.05）；实际环境条件下的被动吸收模拟实验表明，56天的暴露仍未发现头发中
有 PFASs的明显吸收，说明可以基本排除实际空气环境直接暴露对头发和指甲
作为内暴露指示者的影响；综合分析PFOS和C8 Cl-PFESA在高低暴露人群血液、
尿液、头发和指甲中的浓度比值和转移关系，发现头发和指甲中 PFOS和 C8
Cl-PFESA浓度水平和人体内暴露存在可能的联系。另外，尿液样品可为血清样
品中无法检测到的短链 PFASs的内暴露提供证据。In recent years, a growing concern is of the environmental problem on per- and
polyfluoroalkyl substances (PFASs) due to their omnipresence, persistence and
bioaccumulation. Thus, a large number of substitute compounds have been widely
produced and used, which is collectively named emerging PFASs. They mainly
include PFASs with shorter-chain carbon or ether bonds added in the perfluoroalkyl
chain. However, limited studies reported environmental behavior, bioaccumulation
and human health effects of emerging PFASs. Here, we develop the analytical
methods for determination of two typical emegering PFASs, cyclic PFASs and
Cl-PFESAs, and investigate their environmental behavior, potential impacts on biota
and human. The main contents of this dissertation comprise the following five
sections:
Firstly, on the basis of the established analytical methods for legacy PFASs, the
pretreatment and HPLC-MS method were optimized and established for determining
cyclic PFASs isomers and Cl-PFESAs in various matrixes. The methods, with good
recoveries and repeatability, are appropriate for the detection of PFASs in real
samples.
Secondly, identification, tissue distribution and bioaccumulation potential of
cyclic perfluorinated sulfonic acids isomers in Beijing international airport were
studied. Here, we investigated the presence of perfluoroethylenecyclohexane sulfonate
(PFECHS) isomers in environmental samples for the first time using a combination of
high resolution and tandem mass spectrometry (Orbitrap MS Fusion). Five distinct
peaks attributed to different isomers of PFECHS and perfluoropropylcyclopentane
sulfonate (PFPCPeS) were identified in environmental samples. The sum of PFECHS
and PFPCPeS isomers displayed logarithmically decreasing spatial trends in water
(1.04 - 324 ng/L) and sediment samples (<MLQ - 2.23 ng/g dw) with increasing
distance from Beijing international airport. PFECHS and PFPCPeS displayed the
highest accumulation in liver, kidney, blood and bladder and average whole body
bioaccumulation factors (Log BAFwhole-body) were estimated to be 2.7 and 1.9
respectively. Isomer-specific differences in the tissue/blood distribution ratios and
BAF whole-body indicate that ring structure and position of the sulfonic acid group affect
the bioaccumulation potential of cyclic perfluoroalkyl acids.
Thirdly, we investigated the occurrence, spatial distribution and seasonal variation
of PFASs, including Cl-PFESAs, in 350 urban river or lake water collected during
October 2013 and September 2014 (except the frozen period) in Beijing, China.
PFBA and PFPeA were predominant compounds with the average concentrations of
12.79 and 9.90 ng/L, respectively. As for Cl-PFESAs, only C8 Cl-PFESA could be
detected with the concentrations range at <MLQ - 6.93 ng/L. Significantly higher
concentrations of∑PFASs were observed in the northern and eastern regions than
ones in other regions of Beijing, while there were no significant differences for C8
Cl-PFESA among different sampling sites. The highest and lowest levels of∑PFASs
and C8 Cl-PFESA were both found in summer and winter. Additionally, risk
assessment indicated that PFOA, PFOS and C8 Cl-PFESA might pose low risk to
fish.
Fourthly, we investigated the levels of Cl-PFESAs and legacy PFASs in 439
serum samples of general population from Shijiazhuang and its main exposure
medium, such as dust, drinking water and freshwater fish to elucidate PFASs
composition and characteristic in human and its main exposure pathways. C8
Cl-PFESA could be detected in all serum samples, with a mean concentration of 2.70
ng/g, accounting for 9.32% of the total PFASs. Meanwhile, the strong correlations
were observed between C8 Cl-PFESA and principal legacy PFASs (ρ > 0.194; p <
0.01). Similar to legacy PFASs, C8 Cl-PFESA levels in male serum samples (3.25
ng/g) were significantly higher than those in female serum samples (2.88 ng/g; p <
0.05). The lowest concentrations of C8 Cl-PFESA and legacy PFASs were both
observed in the young female sub-population. Furthermore, based on the comparison
of estimated daily intake by different exposure routes, it was concluded that diet is the
primary source of Cl-PFESAs to general population in Shijiazhuang.
Finally, we investigated the validity and applications of using hair, nail and urine
samples for characterizing internal exposure to legacy and emerging PFASs.
Biomonitoring samples from 8 highly exposed individuals showed that PFHxS, PFOS,
C8 Cl-PFESA and PFUnDA were transferred from serum to nails in a dose dependent
manner (ρ > 0.74; p < 0.05). Passive uptake experiments demonstrated that only lower
than 6% of spiked PFASs were absorbed in hair and nail matrices from standard
solutions (10, 100 and 1000 ng/g). Meanwhile, no uptake of PFASs in hair occurred
over 56 days of contact with naturally contaminated indoor dust and air.
Measurements of PFOS and C8 Cl-PFESA in hair and nail samples in a background
exposed population displayed a plausible link to internal exposure by evaluation of
statistical correlations with urine measurements and comparison with transfer ratios
determined in highly exposed individuals