Gas-bubbled nano zero-valent iron process for high concentration arsenate removal

• Published in: Journal of hazardous materials 2011-02, Vol.186 (2-3), p.2123-2128
• Main Authors: Tanboonchuy, Visanu, Hsu, Jia-Chin, Grisdanurak, Nurak, Liao, Chih-Hsiang
• Format: Article
• Language: English
• Subjects: Adjustment; air; Algorithms; Applied sciences; Arsenate; Arsenates; Arsenates - isolation & purification; Arsenic; Bubbling; Carbon dioxide; Carbon Dioxide - chemistry; chemical speciation; Deuterium Oxide - chemistry; dissolved oxygen; Exact sciences and technology; Gas bubbling; Gases; Groundwater; Groundwaters; Hydrogen-Ion Concentration; Iron; Iron - chemistry; Kinetics; Microscopy, Electron, Transmission; Nano-scale iron; Nanocomposites; Nanomaterials; Nanostructure; Natural water pollution; Pollution; Solutions; Water Pollutants, Chemical - isolation & purification; Water Supply - analysis; Water treatment and pollution
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2010.12.125

In this study, batch experiments were performed to investigate a novel process for high concentration arsenate removal in the presence of air and/or CO2 bubbling. The pretreatment step, CO2 bubbling at 300mL/min for 5min, was taken to adjust the solution pH to an acidic environment, followed by air bubbling at 300mL/min for 10min to increase dissolved oxygen in the solution. In the treatment period, the nano-scale zero-valent iron was applied to remove aqueous arsenate of 3000μg/L, while the treatment system was continuously bubbled by 300mL/min of air. Such a process resulted in outstanding performance in arsenate removal. Furthermore, in the field groundwater application, the arsenate removal rate for the proposed process was 5 times faster than the rate measured when the system was pretreated by acidic chemical species only.