The Aggregation and Dissolution of Citrate−Coated AgNPs in High Ammonia Nitrogen Wastewater and Sludge from UASB−Anammox Reactor

Jiachao Jiang, Xin Wang, Yuanyuan Zhang, Jiageng Zhang, Xiujun Gu, Shilong He, Shuo Duan, Jianli Ma, Lizhang Wang and Ping Luo
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Jiachao Jiang: School of Environment Science and Spatial Informatics, China University of Mining and Technology, 1 Daxue Road, Xuzhou 221116, China
Xin Wang: School of Environment Science and Spatial Informatics, China University of Mining and Technology, 1 Daxue Road, Xuzhou 221116, China
Yuanyuan Zhang: School of Environment Science and Spatial Informatics, China University of Mining and Technology, 1 Daxue Road, Xuzhou 221116, China
Jiageng Zhang: School of Environment Science and Spatial Informatics, China University of Mining and Technology, 1 Daxue Road, Xuzhou 221116, China
Xiujun Gu: School of Environment Science and Spatial Informatics, China University of Mining and Technology, 1 Daxue Road, Xuzhou 221116, China
Shilong He: School of Environment Science and Spatial Informatics, China University of Mining and Technology, 1 Daxue Road, Xuzhou 221116, China
Shuo Duan: Key Laboratory for Deep Processing of Major Grain and Oil of Ministry of Education, College of Food Science and Engineering, Wuhan Polytechnic University, Wuhan 430023, China
Jianli Ma: Solid Waste and Soil Environment Research Centre, Tianjin Academy of Eco–Environmental Sciences, Tianjin 300191, China
Lizhang Wang: School of Environment Science and Spatial Informatics, China University of Mining and Technology, 1 Daxue Road, Xuzhou 221116, China
Ping Luo: School of Environment Science and Spatial Informatics, China University of Mining and Technology, 1 Daxue Road, Xuzhou 221116, China

IJERPH, 2022, vol. 19, issue 15, 1-17

Abstract: Silver nanoparticles (AgNPs) are released into the sewage pipes and ultimately wastewater treatment plants during manufacturing, use, and end–life disposal. AgNPs in wastewater treatment plants aggregate or dissolve, and may affect the microbial community and subsequent pollutant removal efficiency. This study aims to quantitatively investigate the fate of AgNPs in synthetic high ammonia nitrogen wastewater (SW) and sludge from an up–flow anaerobic sludge blanket (UASB) anammox reactor using a nanoparticle tracking analysis (NTA), dynamic light scattering (DLS), transmission electron microscope (TEM), and atomic absorption spectroscopy (AAS). Results showed that 18.1 mM NH 4 + , 2.11 mM Mg 2+ in SW caused less negative zeta potential (ζ−potential, −18.4 vs. −37.4 mV), aggregation (388.8 vs. 21.5 nm), and settlement (80%) of citrate−coated AgNPs (cit−AgNPs) in 220 min. The presence of 18.5 mM Cl − in SW formed AgCl 2 − , AgCl (aq) and eventually promoted the dissolution (9.3%) of cit−AgNPs. Further exposure of SW−diluted AgNPs to sludge (42 mg L −1 humic acid) and induced a more negative ζ−potential (−22.2 vs. −18.4 mV) and smaller aggregates (313.4 vs. 388.8 nm) due to the steric and hindrance effect. The promoted Ag dissolution (34.4% vs. 9.3%) was also observed after the addition of sludge and the possible reason may be the production of Ag(NH 3 ) 2 + by the coexistence of HA from sludge and NH 4 + from SW. These findings on the fate of AgNPs can be used to explain why AgNPs had limited effects on the sludge−retained bacteria which are responsible for the anammox process.

Keywords: silver nanoparticles; aggregation; dissolution; sludge; high ammonia nitrogen wastewater (search for similar items in EconPapers)
JEL-codes: I I1 I3 Q Q5 (search for similar items in EconPapers)
Date: 2022
References: View complete reference list from CitEc
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