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An Overview of the Advantages of Combining Photo- and Electrooxidation Processes in Actual Wastewater Treatment
No full textThe elimination of pollutants in real water and wastewater is a challenge for the successful application of electrooxidation processes (EOPs). The presence of inorganic salts in the reaction medium is of great relevance during EOPs, with active participation in the electrochemical reactions. A revision of the reported devices used in the decontamination and disinfection of real wastewater demonstrated the main drawbacks of efficiently removing pollutants. However, the combination of photocatalytic processes with electrochemical technologies has been explored to improve overall efficiency and reduce energy consumption. A wide variety of materials, mainly metals, polymers, carbon and graphite derivatives, oxides, and MOFs, as well as their combinations, have been applied to electrodes and photoactive coatings. The deposition of the active layer has been enriched with novel designs, including porous hierarchical growth and 3D printing. The use of powerful characterization techniques allows for the study of the composition, structure, surface, and photo- and electrochemical performance of the fabricated electrodes. The simultaneous optimization of the operating conditions, parameters, and reactors must be specifically defined according to each water matrix. This approach will increase the efficiency of the whole process and contribute to cost savings. Economic contributions have been revised to calculate the cost of wastewater treatment.This work was supported by the project TED2021-130809B-I00, funding by the Ministry of Science, Innovation, and Universities (MCIU)/Spanish State Research Agency (AEI)/10.13039/501100011033 and the “NextGenerationEU”/PRTR European Union Funds. LV thanks the MOPGA program for her fellowship.Peer reviewe
Reactivity of electron-deficient alkynes on gold nanoparticles
No full textPropiolates cyclotrimerize in the presence of catalytic amounts of gold nanoparticles to give aryl benzoates in high yields and with turnover frequencies of thousands per hour. Types of alkynes other than propiolates do not react, and, if molecular oxygen is present and dissociated by the gold nanoparticles, electron-rich arenes engage with the propiolate to form a new C-C bond. The activation of propiolates and electron-rich arenes to form C-C bonds, beyond gold-catalyzed Michael additions, constitutes a new example of how and where gold nanoparticles modify the electronic density of unsaturated C-C bonds and opens the door to future transformations. © 2013 American Chemical Society.A.L.-P. thanks CSIC for a contract. J.O.-M. thanks ITQ for a postgraduate scholarship. J.R.C.-A. and P.R.-M. thank MECD for the concession of a FPU contract. Financial support by the Severo Ochoa program and Consolider-Ingenio 2010 (proyecto MULTICAT) from MICIINN is acknowledged, and also the King Saud University. P.S. thanks European Union Seventh Framework programme (PIOF–GA–2009–253129)
Regioselective hydration of alkynes by iron(III) Lewis/Brønsted catalysis
No full textThe triflimide iron(III) salt [Fe(NTf 2) 3] promotes the direct hydration of terminal and internal alkynes with very good Markovnikov regioselectivities and high yields. The enhanced carbophilic Lewis acidity of the Fe III cation mediated by the weakly-coordinating triflimide anion is crucial for the catalytic activity. The iron(III) metal salt can be recycled in the form of the OPPh 3/[Fe(NTf 2) 3] system with similar activity and selectivity. However, spectroscopic and kinetic studies show that [Fe(NTf 2) 3] hydrolyzes under the reaction conditions and that catalytically less active BrAønsted species are formed, which points to a Lewis/Brønsted co-catalysis. This triflimide-based catalytic system is regioselective for the hydration of internal aryl-alkynes and opens the door to a new synthetic route to alkyl ketophenones. As a proof of concept, the synthesis of two antipsychotics Haloperidol and Melperone, with general butyrophenone-like structure, is shown. Just add water! The triflimide iron(III) salt [Fe(NTf 2) 3] promotes the direct hydration of terminal and internal alkynes with very good Markovnikov regioselectivities and high yields (see scheme). Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.The work has been supported by Consolider-Ingenio 2010 (proyecto MULTICAT), and PROMETEO from Generalitat Valenciana. J.R.C.A. thanks MCIINN for a pre-doctoral FPU fellowship. A.L.P. thanks ITQ for financial support. We thank Dr. J. A. Vidal-Moya for the EPR measurements.Peer reviewe
Copper(I)-catalyzed hydrophosphination of styrenes
No full textHydrophosphination of styrenes has been accomplished with metal salts for the first time. (CuOTf)2·toluene complex is the catalyst of choice, but CuCl can also be used. "In-situ" EPR and NMR studies suggest Cu(I) as the catalytically active metal species, giving exclusively the anti-Markovnikov product. Phosphine oxides or β-ketophosphine oxides can be prepared in one-pot by oxidation with molecular oxygen. © 2010 Elsevier B.V. All rights reserved.A. L.-P. thanks CSIC for a contract under the JAE-doctor program. J. R. C.-A. thanks MICINN for the concession of a FPU pre-doctoral fellowship. Financial support by the Consolider-Ingenio 2010 (proyecto MULTICAT) abd by the PLE2009 project from MCIINN are acknowledged
Low-carbon cementitious materials: Scale-up potential, environmental impact and barriers
No full textThe construction industry's heavy reliance on ordinary Portland cement (OPC) significantly contributes to global carbon emissions, accounting for 7–9 % of CO2 emissions. This paper reviews low-carbon cementitious materials (LCCMs) as sustainable alternatives to OPC. Key LCCMs examined include supplementary cementitious materials (SCMs), limestone calcined clay cements (LC3), alkali-activated materials (AAMs), belite-rich Portland cements (BRPCs), ye’elimite-rich cements (YRCs), and non-hydraulic carbonatable binders (CBs). The paper examines the reaction mechanisms, hydration products, and properties of these materials, whereas scalability potential, cost, environmental impact, barriers, and research gaps are also highlighted. LC3 demonstrates high scalability potential due to its similarities with OPC, cost-effectiveness, and the abundant availability of raw materials. Environmentally, AAMs offer the most significant impact reduction, achieving a 40–75 % decrease compared to OPC, followed by LC3 (∼40 %), CBs (∼37 %), YRC (∼20–25 %), and BRPC (∼10 %). However, the costs of AAMs, YRC, and CBs may be higher than OPC and other LCCMs. Technical challenges and research gaps for LCCMs include low reactivity of SCMs, low early-age strength, prolonged setting times, availability of suitable activators, finding compatible superplasticizers, and a lack of long-term performance studies, which shall be further explored in the future. Existing infrastructure may not be adaptable for the new LCCMs, which may require a significant initial investment. Policy barriers are also significant, as updating standards is linked with the satisfactory long-term performance of LCCMs and is hindered by the dominance of OPC market. There is a need of enhanced collaboration efforts among researchers, industry, and policymakers to overcome these technical, economic, and policy barriers, paving the way for sustainable construction practices.The authors would like to acknowledge the start-up financial support received from PolyU, UGC (P0046103) and Innovation and Technology Fund - Guangdong-Hong Kong Technology Cooperation Funding Scheme (GHP/144/21GD).CCUS technology also faces several barriers from the economic perspective. Production cost of CO 2 is changed according to process selection, characteristics of exhaust stream and captured CO 2 volume, hence, demanding significant financial investment for operating and capital cost. Moreover, skilled workforce is required for management of CCUS facilities. CCUS technologies are not matured and lack robustness particularly in term of economic feasibility, and large-scale implementation is uncertain at this stage. Other economic barriers especially in developing and underdeveloped countries may include the uncertain carbon pricing, lack of incentives and financial support from regulatory bodies, high energy consumption demand and financial risks. It requires combination of financial incentives along with supportive government policies and ongoing research and development efforts to mitigate these economic barriers. Moreover, international collaboration and sharing of knowledge could be helpful to spread the adaptation of CCUS technologies worldwide.Peer reviewe
Key concepts and a world-wide look at plant recruitment networks
Get PDF25 páginas.- 6 figuras.- 4 tablas.- 175 referenciasPlant–plant interactions are major determinants of the dynamics of terrestrial ecosystems. There is a long tradition in the study of these interactions, their mechanisms and their consequences using experimental, observational and theoretical approaches. Empirical studies overwhelmingly focus at the level of species pairs or small sets of species. Although empirical data on these interactions at the community level are scarce, such studies have gained pace in the last decade. Studying plant–plant interactions at the community level requires knowledge of which species interact with which others, so an ecological networks approach must be incorporated into the basic toolbox of plant community ecology. The concept of recruitment networks (RNs) provides an integrative framework and new insights for many topics in the field of plant community ecology. RNs synthesise the set of canopy–recruit interactions in a local plant assemblage. Canopy–recruit interactions describe which (“canopy”) species allow the recruitment of other species in their vicinity and how. Here we critically review basic concepts of ecological network theory as they apply to RNs. We use RecruitNet, a recently published worldwide data set of canopy–recruit interactions, to describe RN patterns emerging at the interaction, species, and community levels, and relate them to different abiotic gradients. Our results show that RNs can be sampled with high accuracy. The studies included in RecruitNet show a very high mean network completeness (95%), indicating that undetected canopy–recruit pairs must be few and occur very infrequently. Across 351,064 canopy–recruit pairs analysed, the effect of the interaction on recruitment was neutral in an average of 69% of the interactions per community, but the remaining interactions were positive (i.e. facilitative) five times more often than negative (i.e. competitive), and positive interactions had twice the strength of negative ones. Moreover, the frequency and strength of facilitation increases along a climatic aridity gradient worldwide, so the demography of plant communities is increasingly strongly dependent on facilitation as aridity increases. At network level, species can be ascribed to four functional types depending on their position in the network: core, satellite, strict transients and disturbance-dependent transients. This functional structure can allow a rough estimation of which species are more likely to persist. In RecruitNet communities, this functional structure most often departs from random null model expectation and could allow on average the persistence of 77% of the species in a local community. The functional structure of RNs also varies along the aridity gradient, but differently in shrubland than in forest communities. This variation suggests an increase in the probability of species persistence with aridity in forests, while such probability remains roughly constant along the gradient in shrublands. The different functional structure of RNs between forests and shrublands could contribute to explaining their co-occurrence as alternative stable states of the vegetation under the same climatic conditions. This review is not exhaustive of all the topics that can be addressed using the framework of RNs, but instead aims to present some of the interesting insights that it can bring to the field of plant community ecology. © 2024 The Author(s). Biological Reviews published by John Wiley & Sons Ltd on behalf of Cambridge Philosophical Society.During the writing of this study, the leading authors were supported by the following projects: J.M.A. and J.L.G. –project PGC2018-100966-B-I00 (Spanish Agencia Estatal deInvestigación, Ministerio de Ciencia e Innovación and European Union ERDF); M.V. – projects CIPROM/2021/63 (Generalitat Valenciana) and PID2020-113157GB-100 (Spanish Agencia Estatal de Investigación, Ministerio de Ciencia e Innovación); A.M.-N. – project TED2021-129926B-I00 (MCIN/AEI/10.13039/501100011033/European Union NextGenerationEU/PRTR).Peer reviewe
Intraguild interactions between the European badger and the Iberian lynx
No full text[Description of methods used for collection/generation of data] Camara traps.[Relationship between files, if important] Each file is a sequence of photos captured by camera tramps.Peer reviewe
Influence of DEIPA and TIPA on the hydration and microstructure of model cements
No full textThis study investigates the impact of diethanol-isopropanolamine (DEIPA) and triisopropanolamine (TIPA) on hydration kinetics, phase assemblage and microstructure of C3S and a model cement (which clinker only contains C3S and C3A) pastes. Results showed that DEIPA initially delayed C3S reaction, probably due to the formation of DEIPA-Ca2+ complexes that slow down the supersaturation required for the nucleation of hydrates and/or by adsorbing onto the hydrates. In contrast, TIPA did not significantly modify the hydration kinetics of both studied cementitious materials. Furthermore, DEIPA adsorbs onto Ca(OH)2 and has a relevant impact on the amount of portlandite and morphology and stoichiometry of C–S–H. In particular, DEIPA decreased the amount of portlandite and favored the formation of a C–S–H with a higher Ca/Si than the one formed in plain C3S pastes. DEIPA also favored the intermixing of portlandite and AFm phase with C–S–H in C3S pastes and model cement pastes, as well as the formation of greater plates of portlandite in the latter. In contrast, TIPA did not impact the C–S–H stoichoimetry and the amount of portlandite, but a higher intermixing of C–S–H with portlandite and AFm has been observed in both, C3S and model model cement, respectively. The observed low impact of DEIPA and TIPA on the reactivity of the C3A and the amount of early aluminate hydrates in model cements in comparison to previous studies done on Portland cement, highlights the relevance of the presence of Fe on the working mechanims of both alkanolamines and in particular on the enhancement of C4AF reactivity by the formation of Fe-amino complexes
Utilizing Ceramic Factory Waste to Produce Low-Cost Refractory Ceramics
No full textThe use of solid waste such as ceramic sludge, ceramic rollers, and magnesite was studied to obtain cheap refractory ceramics at temperatures of 1300 °C based on XRF, XRD SEM, EDX, bending strength, and dielectric properties. The prepared samples were examined. The results showed that the significant crystalline phases formed were mullite, spinel, and corundum. They also showed that mullite hindered the formation of cordierite and enhanced spinel formation. With increased cordierite content, the microstructure varied from fine grained to coarse grained. Bending strength increased with increasing mullite content and bulk density, ranging from 10.80 to 13.50 MPa. Bulk density increased with the increase in mullite content and sintering temperature and ranged from 1.99 to 1.94 g/cm, while the percentage of porosity and water absorption decreased and ranged from 29.40 to 38.83, respectively. To examine the effect of the produced phases on the dielectric characteristics, the permittivity (ε′), dielectric loss (ε″), and AC conductivity (σ) were measured in the frequency range of 10 Hz to 10 Hz. As the concentration of cordierite increased, there was a noticeable drop in ε′ from 35.6 to 8.2 and σ from 10 s/cm to around 10 s/cm and high values of resistivity from 10 cm/s to about 10 cm/s, suggesting that this material might be an excellent insulator.Peer reviewe