organic contaminants
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2022 ◽  
Vol 423 ◽  
pp. 126991
Author(s):  
Yang Zong ◽  
Hua Zhang ◽  
Yufei Shao ◽  
Wenjie Ji ◽  
Yunqiao Zeng ◽  
...  

2022 ◽  
Vol 429 ◽  
pp. 132495
Author(s):  
Fu-Xue Wang ◽  
Chong-Chen Wang ◽  
Xuedong Du ◽  
Yang Li ◽  
Fei Wang ◽  
...  

2022 ◽  
Vol 34 (1) ◽  
Author(s):  
Adewumi Olufemi Oluwole ◽  
Olatunde Stephen Olatunji

Abstract Background Pharmaceuticals is one of the groups of contaminants of emerging concern that are resistant to decomposition or removal by most of the existing water and wastewater treatment procedures, hence the need to develop techniques to facilitate the removals of this group of organic contaminants from water systems. In this study, needle-like SnO2 nanoparticles was synthesised and loaded on exfoliated g-C3N4 nanosheet through a hydrothermal method, for use as sensitive visible light induce-photocatalyst for the decomposition of tetracycline in aqueous systems. The synthesised composites was characterized and analysed for the nature of the heterojunction between the SnO2 nanoparticle and g-C3N4 nanosheet using microscopic and spectroscopic techniques. Results The composites were of improved surface properties and enhanced visible-light absorption. The synthesised SnO2/g-C3N4 nanocomposites with various amounts of SnO2 (10–50 mg), employed in the degradation of tetracycline under visible light irradiation, were of good degradation efficiency. The degradation efficiencies of tetracycline by 1 wt.%, 2 wt.%, 3 wt.% and 5 wt.% SnO2/g-C3N4 photocatalyst were 81.54%, 90.57%, 95.90% and 92.15% as compared to g-C3N4 and SnO2 with 40.92% and 51.32% degradation efficiencies. The synergistic interaction between the needle-like SnO2 and exfoliated g-C3N4 nanosheet promoted the separation of photogenerated electron holes pairs, which enhanced their migration rate between SnO2 and g-C3N4 heterojunction, thereby facilitating the degradation of tetracycline. The ·O2− was noted to be the major reactive species in the photocatalytic of the 3 wt.% SnO2/g-C3N4 nanocomposite. Conclusion The fabricated SnO2 nanoparticles anchored on exfoliated g-C3N4 showed good performance for the decomposition of tetracycline in water, with possible application on other pharmaceuticals having same moiety (similar chemical structures).


2022 ◽  
Vol 9 ◽  
Author(s):  
Maja Nipen ◽  
Rolf David Vogt ◽  
Pernilla Bohlin-Nizzetto ◽  
Katrine Borgå ◽  
Eliezer Brown Mwakalapa ◽  
...  

Temporal trends of industrial organic contaminants can show how environmental burdens respond to changes in production, regulation, and other anthropogenic and environmental factors. Numerous studies have documented such trends from the Northern Hemisphere, while there is very limited data in the literature from sub-Saharan Africa. We hypothesized that the temporal trends of legacy and contemporary industrial contaminants in sub-Saharan Africa could greatly differ from the regions in which many of these chemicals were initially produced and more extensively used. For this purpose, a dated sediment core covering six decades from a floodplain system in urban Dar es Salaam, Tanzania, was analysed. The samples were analysed for selected legacy persistent organic pollutants (POPs) [polychlorinated biphenyls (PCBs) and polybrominated biphenyl ethers (PBDEs)] and chemicals of emerging concern (CECs) [alternative brominated flame retardants (aBFRs), chlorinated paraffins (CPs), and dechloranes]. All groups of chemicals showed a steep increase in concentrations towards the uppermost sediment layers reflecting the more recent years. Concentrations of the individual compound groups in surface sediment were found in the order CPs >> aBFRs ∼ ∑25PBDEs > dechloranes ∼ ∑32PCBs. Time trends for the individual compounds and compound groups differed, with ∑32PCBs showing presence in sediments since at least the early 1960s, while some CECs first occurred in sediments corresponding to the last decade. Investigations into potential drivers for the observed trends showed that socioeconomic factors related to growth in population, economy, and waste generation have contributed to increasing concentrations of PBDEs, aBFRs, CPs, and Dechlorane Plus. Further monitoring of temporal trends of industrial organic contaminants in urban areas in the Global South is recommended.


2022 ◽  
Author(s):  
Dongdong Guo ◽  
Yong Wan ◽  
Jiangshan Li ◽  
Ruiqi Liu ◽  
Lei Liu ◽  
...  

Abstract Modified bentonites for anti–seepage system application has been attracting global attentions. At the same time, the performances of modified bentonite containing retardation barrier exposed to organic–heavy metal pollutants have not been fully reported. In this study, the adsorption performances (one of the key evaluation indicators of retardation barrier) of nine kinds of commonly used modified bentonites on multiple contaminants were comparatively investigated. The X–ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) analyses were also performed to unravel the adsorption mechanisms. Results show that the adsorption of modified bentonites on phenol and Pb(II) follows the order of SB–16 > PVA > CTAB > APAM > CTAB + PAC > PAC > CPAM > CTAB + PAC > CTAB + CPAM + APAM. Among all the samples, the bentonite modified with SB–16 showed the highest adsorption capacities for phenol and Pb(II). The surfactant molecules inserted in the interlayer space of montmorillonite increase the substrate spacing, which changes the structural properties of the bentonite from hydrophilic to hydrophobic and increases the adsorption of organic contaminants. On the other hand, the polymer has functional groups such as hydroxyl and carboxyl that can form a spatial three–dimensional cross–linking structure on the bentonite surface, providing more adsorption sites for heavy metal ions. These findings indicate the potential industrial applications of modified bentonite in a contaminant barrier system.


2022 ◽  
Author(s):  
Feng Min ◽  
Zhengqing Wei ◽  
Zhen Yu ◽  
Yu-Ting Xiao ◽  
Shien Guo ◽  
...  

Both efficient charge separation and sufficiently exposed active sites are critical limiting for solar-driven organic contaminants degradation. Herein, we describe a hierarchical heterojunction photocatalyst fabricated by in situ growth of...


Author(s):  
Lei Dong ◽  
Pin Xie ◽  
Xin Zhang ◽  
Junlian Qiao ◽  
Dandan Rao ◽  
...  
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