A new spent coffee grounds based biochar - Persulfate catalytic system for enhancement of urea removal in reclaimed water for ultrapure water production. (February 2022)

• Record Type: Journal Article
• Authors: Yang, Yuanying; Zhang, Xinbo; Ngo, Huu Hao; Guo, Wenshan; Li, Zening; Wang, Xiao; Zhang, Jianqing; Long, Tianwei
• Is Part Of: Chemosphere. Volume 288:Part 1(2022)
• Publication Date: 2022-02
• Subjects: Ultrapure water -- Urea -- Biochar -- Advanced oxidation processes -- Persulfate activation; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2021.132459
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: The demand for ultrapure water (UPW) in the semiconductor industry has increased in recent years, while the idea to use reclaimed water instead of tap water for UPW production has also attracted more attention. However, since urea concentration in reclaimed water is higher than that in tap water, UPW production has not been efficient. To resolve this problem, this study aims to develop a new spent coffee grounds based biochar (SCG-BC)/persulfate catalytic system as a pretreatment unit. The objective is to enhance urea removal from reclaimed water so that UPW production is more effective. In this study, the biochar used was prepared from spent coffee grounds with detailed characterization. Results strongly suggested that the urea removed by SCG-BC/persulfate catalytic system was very encouraging (up to 73%). The best possible dosages for SCG-BC and persulfate for urea removal were 0.2 and 2.0 g L −1, respectively. Furthermore, this system could remove urea effectively in a wide range of pH (3–10). Moreover, the characterizations of SCG-BC (graphite C, defective edges and functional groups, i.e. –OH, CO, carboxyl C–O) helped to activate persulfate in the catalytic process. OH and SO4 − were all involved in this process, while the SO4 − was the main radical for urea degradation. Graphical abstract: Image 1 Highlights: SCG-BC/persulfate system could effectively remove urea compared with SCG-BC alone. Persulfate and SCG-BC dosage affected the urea removal performance. SCG-BC with defective edges, graphite C and functional groups is beneficial. SCG-BC/persulfate system could be used in pretreatment stage for UPW production.