Recovery elemental sulfur from calcium sulfide prepared by red gypsum in sulfuric acid wastewater treatment

Journal of Material Cycles and Waste Management - Red gypsum comes from TiO2 production industry by sulfate method, which comes from the low acidic liquid stream treatment using lime or limestone....     

Fabrication of PVA/GO Nanofiber Films by Electrospinning: Application for the Adsorption of Cu2+ and Organic Dyes

Journal of Polymers and the Environment - In recent years, the treatment of water pollution has been a challenging and far-reaching topic. In order to improve the adsorption performance of...     

A Highly Efficient Adsorbent Based on Starch-Graphene Oxide Architecture for Scavenging Aqueous Pb(II): Isotherms,Kinetics, Thermodynamics and Interaction Mechanism

Journal of Polymers and the Environment - Heavy metal pollution stems from the modern industry is a severe environmental problem. In this work, a highly efficient adsorbent based on starch-graphene...     

Influence of extracellular polymeric substances from activated sludge on the aggregation kinetics of silver and silver sulfide nanoparticles

• The NPs aggregation in the electrolyte solution is consistent with the DLVO theory. • In NaNO₃ and low Ca(NO₃)₂, EPS alleviates the NPs aggregation by steric repulsion. • In high Ca(NO₃)₂, EPS accelerates the NPs aggregation by exopolysaccharide bridging. • Ag₂S NPs have stronger stability compared with Cit-Ag NPs in aqueous systems. Extracellular polymeric substances (EPS) in activated sludge from wastewater treatment plants (WWTPs) could affect interactions between nanoparticles and alter their migration behavior. The influence mechanisms of silver nanoparticles (Ag NPs) and silver sulfide nanoparticles (Ag₂S NPs) aggregated by active EPS sludge were studied in monovalent or divalent cation solutions. The aggregation behaviors of the NPs without EPS followed the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. The counterions aggravated the aggregation of both NPs, and the divalent cation had a strong neutralizing effect due to the decrease in electrostatic repulsive force. Through extended DLVO (EDLVO) model analysis, in NaNO₃ and low-concentration Ca(NO₃)₂ (<10 mmol/L) solutions, EPS could alleviate the aggregation behaviors of Cit-Ag NPs and Ag₂S NPs due to the enhancement of steric repulsive forces. At high concentrations of Ca(NO₃)₂ (10‒100 mmol/L), exopolysaccharide macromolecules could promote the aggregation of Cit-Ag NPs and Ag₂S NPs by interparticle bridging. As the final transformation form of Ag NPs in water environments, Ag₂S NPs had better stability, possibly due to their small van der Waals forces and their strong steric repulsive forces. It is essential to elucidate the surface mechanisms between EPS and NPs to understand the different fates of metal-based and metal-sulfide NPs in WWTP systems.     

Mechanistic insight into the biofilm formation and process performance of a passive aeration ditch (PAD) for decentralized wastewater treatment

• A Passive Aeration Ditch was developed to treat decentralized wastewater. • A model was developed to describe the process performance. • A high C/N ratio facilitates microbial growth but nitrification deteriorates. • A high salinity decreases both organic and nitrogen contaminants removal. Decentralized wastewater containing elevated salinity is an emerging threat to the local environment and sanitation in remote coastal communities. Regarding the cost and treatment efficiencies, we propose a passive aeration ditch (PAD) using non-woven polyester fabric as a feasible bubbleless aerator and biofilm carrier for wastewater treatment. Consideration has been first given to PAD’s efficacy in treating saline decentralized wastewater, and then to the impact of chemical oxygen demand-to-nitrogen (C/N) ratio and salinity on biofilm formation. A multispecies model incorporating the salinity effect has been developed to depict the system performance and predict the microbial community. Results showed that the PAD system had great capacity for pollutants removal. The biofilm thickness increased at a higher C/N ratio because of the boost of aerobic heterotrophs and denitrifying bacteria, which consequently improved the COD and total nitrogen removal. However, this led to the deterioration of ammonia removal. Moreover, while a higher salinity benefited the biofilm growth, the contaminant removal efficiencies decreased because the salinity inhibited the activity of aerobic heterotrophs and reduced the abundance of nitrifying bacteria inside the biofilm. Based on the model simulation, feed water with salinity below 2% and C/N ratio in a range of 1 to 3 forms a biofilm that can reach relatively high organic matter and ammonia removal. These findings not only show the feasibility of PAD in treatment of saline decentralized wastewater, but also offer a systematic strategy to predict and optimize the process performance.     

Effects of exposure to environmental pollutants on mitochondrial DNA copy number: a meta-analysis

Environmental Science and Pollution Research - Exposure to environmental pollutants has been associated with alteration on relative levels of mitochondrial DNA copy number (mtDNAcn). However, the...     

Effect of ambient O3 on mortality due to circulatory and respiratory diseases in a high latitude city of northeast China

Environmental Science and Pollution Research - In recent years, O3 pollution had been worsening in China and became a major challenge for human health. To evaluate the O3 effects on circulatory and...     

Screening and application of Chlorella strains on biosequestration of the power plant exhaust gas evolutions of biomass growth and accumulation of toxic agents

Environmental Science and Pollution Research - To use microalgae for the biosequestration of carbon dioxide (CO2) emitted from the coal-fired power plants, the screening of high CO2 tolerant...     

Investigation of indole biodegradation by Cupriavidus sp. strain IDO with emphases on downstream biotransformation and indigo production

Environmental Science and Pollution Research - Indole, as a typical N-heterocyclic aromatic pollutant, poses risks to living things; however, indole-biotransformation mechanisms remain...     

SDG-oriented multi-scenario sustainable land-use simulation under the background of urban expansion

Environmental Science and Pollution Research - With the continuous improvement of urbanization level and the continuous expansion of city scale, there are some unreasonable land development and...