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  • Randolph Jonsson posted an update 3 days, 7 hours ago

    The removal mechanisms, including adsorption kinetics, isotherms, thermodynamics, and electrostatic and hydrophobic interactions between polyurethane adsorbents and pollutants are discussed. In addition, regeneration, recycling and disposal of spent polyurethane adsorbents are reported. Finally, key knowledge gaps on synthesis, characterization, industrial applications, life cycle analysis, and potential health risks of polyurethane adsorbents are discussed.We evaluate the isolated and combined effects of glyphosate and its by-product aminomethylphosphonic acid (AMPA) and the potential of the aquatic macrophyte Salvinia molesta to remove these chemicals from contaminated water. Plants were exposed to environmentally relevant concentrations of glyphosate (0, 20, 40, 60, 80 and 100 µg l-1) or AMPA (0, 10, 20, 30, 40 and 50 µg l-1) for seven days. Then, based on the effective concentrations of glyphosate found to reduce photosynthetic rates by 10% (EC10) and 50% (EC50), the plants were exposed to combinations of 0, 16 and 63.5 µg glyphosate l-1 and 0, 5, 15, 25 µg AMPA l-1. The EC(10) and EC(50) were lower for AMPA (6.1 µg l-1 and 28.4 µg l-1 respectively) than for glyphosate (16 and 63.5 µg glyphosate l-1 respectively). When occurring together, the deleterious effects of those chemicals to plants increased. S. molesta plants removed up to 74.15% of glyphosate and 71.34% of AMPA from culture water. Due to its high removal efficiency, S. molesta can be used in phytoremediation programs. It will be important to evaluate the combined effects of glyphosate and AMPA in any toxicological studies of the herbicide.The deep removal of quinoline from coking wastewater is a prerequisite for reducing its potential threat to environmental safety. Therefore, it is urgent to develop advanced materials for efficient removal of quinoline in wastewater. In this work, a nitrogen-doped hollow carbon nanosphere/graphene composite aerogel (HCNS/NGA) was prepared by in-situ reduction self-assembly strategy, in which HCNS prevents the agglomeration of graphene oxide (GO) nanosheets, and a special sphere-sheet mutual support structure is formed to ensure the structural stability. As-prepared HCNS/NGA exhibits large specific surface area, hierarchical pore structure, and excellent conductivity. Large cavity inside and hierarchically porous structure that primarily consists of micropores, resulting in high quinoline adsorption performance (138.37 ± 2.58 mg g-1 at 298 K). Furthermore, in a fixed-bed column adsorption system, the partition coefficient at 10% breakthrough reaches up to 35.19 mg g-1 μM-1. selleck screening library More importantly, HCNS/NGA, as a conductive monolithic sorbent, can realize easy solid-liquid separation, as well as efficient regeneration in situ by electrochemically assisted regeneration. After ten regeneration cycles, the adsorption capacity retention is 91.54%. In short, as an efficient adsorbent, HCNS/NGA has an enormous application potential in wastewater treatment.Removal of toxic Cr (VI) from aqueous solutions using silicon-based adsorbents has been widely investigated. Meanwhile, contradictory between highly dispersed active Cr species and high Cr loading over commercial Cr-based catalyst was inevitable. In this work, amino-assisted electrostatic adsorption from toxic Cr (VI) treatment was developed to prepare highly dispersed Cr oxides catalysts supported on MCM-41. The Cr loading was as high as 15 wt%, and structure characters of the catalysts were well-reserved. As a result, electrostatic adsorption and subsequent complexation from negatively charged Cr (VI) species and positively charged ammonium groups made a positive contribution to the appearance of highly dispersed mono Cr species, which gave rise to improved non-oxidative propane dehydrogenation (PDH) activity. In contrast, the agglomeration of Cr species and lower PDH activity were observed on the sample synthesized using the traditional wet impregnation method. Besides, the transformation of Cr (VI) to active Cr (III) sites over the catalyst was proved by the designed in-situ H2-TPR, ex-situ UV-vis and Raman spectra results. This procedure reflects a new avenue of green chemistry, which can recycle waste Cr adsorbents as efficient PDH catalysts.Azoles are an emerging class of contaminants with a growing ubiquitous presence in the environment. This study investigates the aerobic microbial degradation of four azoles, pyrazole (PA), 1,2,4-triazole (TA), benzotriazole (BTA) and 5-methylbenzotriazole (5-MBTA), with return activated sludge and microbial enrichment cultures. Slow degradation of PA was observed in the presence of glucose and NH4+ with a peak degradation rate of 0.5 mg d-1 gVSS-1. TA was found to be highly persistent, with no significant degradation observed in 6-8 months under any incubation condition. In contrast, the benzotriazoles were readily degraded at faster rates in all incubation conditions. The degradation rates observed for BTA and 5-MBTA, when provided as the sole substrates, were 8.1 and 16.5 mg d-1 gVSS-1, respectively. Two enrichment cultures, one degrading BTA and the other degrading 5-MBTA, were developed from the activated sludge. Mass balance studies revealed complete mineralization of 5-MBTA and partial breakdown of BTA by the enrichment cultures. Nocardioides sp. and Pandoraea pnomenusa were the most abundant bacteria in the BTA and 5-MBTA degrading enrichment cultures, respectively. The research shows large differences in the biodegradability of various azoles, ranging from complete mineralization of 5-MBTA to complete persistence for TA.The fate of antibiotics and their impact on antibiotic resistance genes (ARGs) and microbial communities are far from clear in wetlands. The fate and impact of tetracycline (TC) on the nutrient degradation of wetlands and epiphytic microbes were investigated. This study showed that after TC spiking, 99.7% of TC were removed from the surface water of wetlands containing Vallisneria spiralis within 4 days post-treatment. TC spiking impaired the nutrient removal capacity and disrupted epiphytic microbial community structure while enhancing the abundance of 11 ARGs subtypes, including tetracycline resistance genes, tetX, tetM, tetO, tetQ, tetS, and tet36. TC decreased bacterial biodiversity but amplified the relative abundance of Proteobacteria and Firmicutes by 4% and 61%, respectively, and increased eukaryotic diversity. 16 metabolic pathways including Carbohydrate, Energy, Amino acid, ‘cofactor and vitamins’ metabolisms were significantly (p less then 0.01) increased in TC treatment. Phylogenetic, functional prediction analysis indicated that Flavobacterium was positively related with xenobiotics, cell motility, ‘terpenoids and polyketides’ metabolism but negatively related to nucleotide metabolism, while Rhodobacter showed a reverse trend but positively related with nucleotide and ‘glycan biosynthesis’ and metabolism.

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