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一种固体废弃物制备盐碱土壤改良剂的新工艺
No full text本发明结合我国废弃生物质和磷石膏资源丰富的优势以及我国土壤盐碱化严重的现状,确立了一种适用于废弃生物质和磷石膏制备环境友好的盐碱土壤改良剂的新工艺。本工艺将废弃生物质与一定量磷石膏混合后在一定的条件下进行水热处理,离心固液分离得到所述的盐碱土壤改良剂。本发明的土壤改良剂制备工艺简单、可再生、成本低,可显著降低土壤的盐碱化程度,提高土壤肥力。本发明的改良剂通过废弃生物质和磷石膏制备,在高效改良盐碱土壤的同时实现了废弃生物质和磷石膏的清洁资源化利用
一种利用气固流化床干式清洗废旧塑料的方法
No full text本发明提供一种利用气固流化床干式清洗废弃塑料的方法,具体包括前处理、调理、清洗、分离、流化介质净化与循环利用五个工序。其特点是：利用气流给床层以曳力使床料流化,施加搅拌,使废弃塑料在气固介质的流化床中与气固两相介质充分接触,在摩擦、撞击、挥发、吸附及流化传质的共同作用下,使废弃塑料表面的各种杂质得到有效去除,流化介质经热处理后可以循环利用。该方法可以清洗出应对多种用途的再生塑料材料,可有效去除顽固印刷杂质
一种水热炭基重金属污染土壤原位修复剂及其制备方法
No full text本发明结合我国土壤重金属污染严重及农村废弃生物质数量巨大的现状,确立了一种适用于以废弃生物质为原材料制备环境友好的水热炭基重金属污染土壤原位修复剂的新工艺,包括以下步骤：1)废弃生物质水热处理转化为水热炭；2)水热炭中加入一定量的生石灰充分混合即得。本发明利用废弃生物质制备的水热炭基重金属污染土壤原位修复剂可以同时实现土壤中多种重金属的高效原位钝化,有效阻断重金属进入作物的路径；同时该修复剂具有绿色、环保、价格低廉等特点
具有抗HIV#1活性的Ritonavir硒唑衍生物及合成方法
No full text通过将Ritonavir分子中的噻唑环换成硒唑环,并对噻唑环取代基进行结构改造,我们获得了一些具有良好抗HIV#1生物活性的Ritonavir硒唑类似物。其特征在于该方法包括下列步骤：通式I中,X＝O,S#or#Se；Y＝N,CH；R1＝H,alkyl,aromatic；R2＝H,alkyl,aromatic
Seasonal and diurnal variations of BTEX compounds in the semi-urban environment of Orleans, France
No full textAtmospheric concentrations of BTEX (benzene, toluene, ethylbenzene and xylene) were measured at a semi urban site in Orleans, France, from October 2010 to August 2011. Air samples were collected by multi-bed adsorbent tubes. The BTEX concentrations were determined by thermal desorption-gas chromatography-mass spectrometry detector (TD-GC-MSD) technique. The average concentrations of the total measured BTEX during spring, summer, autumn and winter were 724.2, 337.4, 6823, 823.0 ppt, respectively. Maximal values for their diurnal variations usually happened during rush hours in the morning and late afternoon, and the minimal values in the daytime usually happened in around noontime. The diurnal variation of BTEX in four seasons and the correlations between BTEX and NO indicated that vehicular exhaust might be the primary source of BTEX. Benzene was found in relatively high levels and the B/T ratio was significant high in spring, indicating an irregular emission source of benzene other than traffic-related emissions. (C) 2016 Published by Elsevier B.V
Addition of conductive particles to improve the performance of activated carbon air-cathodes in microbial fuel cells
No full textActivated carbon (AC) is an inexpensive and sustainable catalyst for oxygen reduction in air-cathodes of microbial fuel cells (MFCs), but its electrical conductivity is relatively poor. To improve cathode performance, five different more conductive materials were added to AC: three carbon materials (carbon black, mesoporous carbon, and carbon nanotubes), and two metal powders (inexpensive copper and inert gold). Carbon-based particles improved maximum power densities by 6-14% compared to plain AC due to reduced charge transfer resistance. Copper powder had reduced performance, likely due to toxicity effects on the anode bacteria, while gold particles were similar to plain AC. Heat treated AC mixed with carbon black produced the highest power density of 1900 +/- 76 mW m(-2), 41% higher than the widely used Pt air-cathode (1350 +/- 55 mW m(-2)). The use of inexpensive carbon black with heat treatment was therefore the most effective and economical approach for improving cathode performance in MFCs
An alumina-supported silver catalyst with high water tolerance for H-2 assisted C3H6-SCR of NOx
No full textWater vapor is typically present in diesel engine exhausts, and thus the design of catalysts with high water-tolerance is highly desired. The addition of water vapor was shown to have quite different influences on the activity of Ag/Al2O3 catalysts with different Ag loadings during the H-2-assistedC(3)H(6)-SCR of NOx (H-2-C3H6-SCR). The 2 wt% Ag/Al2O3 catalyst showed the best activity for H2-C3H6-SCR, with excellent water resistance over the whole temperature range. An enhancement in NOx conversion was observed after water vapor was introduced, particularly at low temperatures. Over this catalyst, kinetic studies confirmed that H2O addition did not change the apparent activation energy for NOx reduction, while it increased the reaction order of C3 H-6 from -0.62 to 0.73. This result indicated that the reaction pathway for NOx reduction was hardly changed by the introduction of water vapor, while a poisoning effect related to C3H6 oxidation was decreased. In situ DRIFTS studies and DFT calculations revealed that water vapor significantly inhibits the formation of inert formate during the H2-C3H6-SCR process, and thus more sites are available for the formation of active enolic species and acetates, finally leading to increased activity for 2 wt% Ag/Al2O3 in NOx reduction. (C) 2017 Elsevier B.V. All rights reserved
Complete oxidation of formaldehyde at room temperature over an Al-rich Beta zeolite supported platinum catalyst
No full textFor human health and environmental protection, removal of formaldehyde (HCHO) has become a hot topic, and completely catalytic oxidation at room temperature has been identified as one of the efficient routes for solving this problem. Recently, it has been reported that zeolite-supported Pt catalysts are active for HCHO oxidation at low temperatures, but they are still unable to completely oxidize HCHO at room temperature. To enhance the activity, it has been suggested to increase the Pt dispersion and acidic density in the zeolite-supported Pt catalysts. We therefore chose Al-rich Beta as a zeolite support because abundant aluminum species in the zeolite framework are advantageous for increasing acidic density through ion-exchange of protons and for improving Pt metal dispersion through the metal-zeolite interaction by increasing the negative charge of the zeolite framework with positively charged metal ions. As we expected, the Al-rich Beta zeolite supported platinum catalyst is very active, giving complete oxidation of HCHO at room temperature. To the best of our knowledge, this is the first time the complete oxidation of HCHO at room temperature over a zeolite-supported noble metal catalyst has been realized. In addition to its extraordinary activity, this catalyst is also very stable and selective. The strategy of designing zeolite-supported noble metal catalysts might offer an alternative way to develop highly efficient heterogeneous catalysts for the removal of air pollutants. (C) 2017 Published by Elsevier B.V
Does residual H2O2 result in inhibitory effect on enhanced anaerobic digestion of sludge pretreated by microwave-H2O2 pretreatment process?
No full textThis study investigated the effects of residual H2O2 on hydrolysis-acidification and methanogenesis stages of anaerobic digestion after microwave-H2O2 (MW-H2O2) pretreatment of waste activated sludge (WAS). Results showed that high sludge solubilization at 35-45 % was achieved after pretreatment, while large amounts of residual H2O2 remained and refractory compounds were thus generated with high dosage of H2O2 (0.6 g H2O2/g total solids (TS), 1.0 g H2O2/g TS) pretreatment. The residual H2O2 not only inhibited hydrolysis-acidification stage mildly, such as hydrolase activity, but also had acute toxic effect on methanogens, resulting in long lag phase, low methane yield rate, and no increase of cumulative methane production during the 30-day BMP tests. When the low dosage of H2O2 at 0.2 g H2O2/g TS was used in MW-H2O2 pretreatment, sludge anaerobic digestion was significantly enhanced. The cumulative methane production increased by 29.02 %, but still with a lag phase of 1.0 day. With removing the residual H2O2 by catalase, the initial lag phase of hydrolysis-acidification stage decreased from 1.0 to 0.5 day
Optimization of MBR hydrodynamics for cake layer fouling control through CFD simulation and RSM design
No full textMembrane fouling is an important issue for membrane bioreactor (MBR) operation. This paper aims at the investigation and the controlling of reversible membrane fouling due to cake layer formation and foulants deposition by optimizing MBR hydrodynamics through the combination of computational fluid dynamics (CFD) and design of experiment (DOE). The model was validated by comparing simulations with measurements of liquid velocity and dissolved oxygen (DO) concentration in a lab-scale submerged MBR. The results demonstrated that the sludge concentration is the most influencing for responses including shear stress, particle deposition propensity (PDP), sludge viscosity and strain rate. A medium sludge concentration of 8820 mg L (1) is optimal for the reduction of reversible fouling in this submerged MBR. The bubble diameter is more decisive than air flowrate for membrane shear stress due to its role in sludge viscosity. The optimal bubble diameter was at around 4.8 mm for both of shear stress and PDP. (C) 2016 Elsevier Ltd. All rights reserved