Comparison of the effects and distribution of zinc oxide nanoparticles and zinc ions in activated sludge reactors

作者：Zhang, Dongqing^*; Trzcinski, Antoine P.; Oh, Hyun-Suk; Chew, Evelyn; Liu, Yu; Tan, Soon Keat; Ng, Wun Jern

来源：Journal of Environmental Science and Health - Part A: Toxic/Hazardous Substances & Environmental Engineering , 2017, 52(11): 1073-1081.

DOI：10.1080/10934529.2017.1338896

• Biosorption
• waste activated sludge
• zinc ions
• ZnO nanoparticles

Zinc Oxide nanoparticles (ZnO NPs) are being increasingly applied in the industry, which results inevitably in the release of these materials into the hydrosphere. In this study, simulated waste-activated sludge experiments were conducted to investigate the effects of Zinc Oxide NPs and to compare it with its ionic counterpart (as ZnSO4). It was found that even 1mg/L of ZnO NPs could have a small impact on COD and ammonia removal. Under 1, 10 and 50mg/L of ZnO NP exposure, the Chemical Oxygen Demand (COD) removal efficiencies decreased from 79.8% to 78.9%, 72.7% and 65.7%, respectively. The corresponding ammonium (NH4+ N) concentration in the effluent significantly (P<0.05) increased from 11.9mg/L (control) to 15.3, 20.9 and 28.5mg/L, respectively. Under equal Zn concentration, zinc ions were more toxic towards microorganisms compared to ZnO NPs. Under 50mg/L exposure, the effluent Zn level was 5.69mg/L, implying that ZnO NPs have a strong affinity for activated sludge. The capacity for adsorption of ZnO NPs onto activated sludge was found to be 2.3, 6.3, and 13.9mg/g MLSS at influent ZnO NP concentrations of 1.0, 10 and 50mg/L respectively, which were 1.74-, 2.13- and 2.05-fold more than under Zn ion exposure.

• 出版日期2017