Complexes of Cu(ii) with triethanolamine (TEA) are widely used in aqueous precursor solutions of Cu-based catalysts and metal oxides such as YBaCuO superconductors. An outstanding question is whether such complexes are multinuclear in solution. Here, we use various spectroscopic techniques to unmistakably prove the existence of such multimers. Firstly, we introduce an original approach based on NMR spectroscopy and the Evans method that establishes the existence of multimers in aqueous solution at pH 4 and higher, and allows precise monitoring of the formation of these complexes with increasing pH. Secondly, we use extended X-ray absorption fine structure (EXAFS) spectroscopy to show that a Cu-Cu interaction exists at pH 9.5, which is not observed in acidic (pH 2) solutions. Finally, NMRD measurements reveal additional structural information regarding the multinuclear complexes. Knowledge concerning the nature of Cu(ii)-TEA complexes in solution is of great relevance in view of the design of speciation models to predict the stability of copper triethanolamine-based precursor solutions.
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http://dx.doi.org/10.1039/c7dt04146b | DOI Listing |
Dalton Trans
December 2024
Environmental Engineering Division, Department of Civil Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721302, India.
Aquatic biota and human health are seriously threatened by the dramatic rise in antibiotics in environmental matrices. In this regard, the present study aims to improve knowledge of the combined effects of heterojunction design and defect engineering on the photocatalytic degradation of pharmaceuticals in aqueous matrices. Advantageously, the positioning of the valence band (VB) and conduction band (CB) levels of S@g-CN, being higher than those of BiMoO, demonstrates the feasibility of forming a type-II heterojunction between these materials.
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December 2024
North China Electric Power University, College of Environmental Science and Engineering, CHINA.
Although Pb-based metal halide perovskites (MHPs) have excellent photoelectric characteristics, their toxicity remains a limiting factor for their widespread application. In the paper, a series of CsCuClxBr3-x (x = 1, 2, 3) MHP microcrystals were developed and their hydrogen evolution performance in ethanol and HX (X = Cl, Br) was also studied. Among them, CsCuCl3 microcrystals exhibit high hydrogen evolution performance in both HX and ethanol, attributed to their longest average lifetime and suitable band structure.
View Article and Find Full Text PDFInorg Chem
December 2024
State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing, Jiangsu 210023, China.
In this study, we employed classical molecular dynamics (CMD) and first-principles molecular dynamics (FPMD) simulations to investigate the speciation of uranyl in carbonate-rich hydrothermal solutions. The association constants (log) of uranyl carbonate complexes were derived from the potential of mean forces (PMFs) obtained from CMD simulations, and the acid constants (ps) of uranyl aqua ions were calculated using the FPMD-based vertical energy gap method. The results showed that uranyl ions could form stable mono- and bi-carbonate complexes at elevated temperatures and that uranyl aqua ions strongly hydrolyzed in neutral solutions at temperatures exceeding 473 K.
View Article and Find Full Text PDFACS Omega
December 2024
Institute of Chemistry and Technology of Environmental Protection, Faculty of Chemistry, Brno University of Technology, Purkyňova 118, 612 00 Brno, Czech Republic.
The escalating global water scarcity demands innovative solutions, one of which is hydroponic vegetable cultivation systems that increasingly use reclaimed wastewater. Nevertheless, even treated wastewater may still harbor various emerging organic contaminants, including pharmaceuticals. This study aimed to comprehensively assess the impact of pharmaceuticals, focusing on bioconcentration factors (BCFs), translocation factors (TFs), pharmaceutical persistence in aqueous environment, ecotoxicological end points, and associated environmental and health risks.
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December 2024
Department of Petroleum Engineering, King Fahd University of Petroleum & Minerals, Dhahran 34464, Saudi Arabia.
In chemical-enhanced oil recovery (cEOR), surfactants are widely used but face significant stability challenges in high-salinity brine, where they often degrade or precipitate. Existing methods, such as adding cosurfactants, offer limited compatibility with anionic surfactants and raise economic concerns, creating a need for more robust solutions. This study introduces a novel approach to enhance the stability of anionic surfactants in extreme salinity conditions by incorporating silicon dioxide (SiO) nanoparticles (NPs).
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