Highly effective remediation of high-arsenic wastewater using red mud through formation of AlAsO4@silicate precipitate. (15th October 2021)

• Record Type: Journal Article
• Authors: Lu, Zhixu; Qi, Xianjin; Zhu, Xing; Li, Xuezhu; Li, Kongzhai; Wang, Hua
• Is Part Of: Environmental pollution. Volume 287(2021)
• Publication Date: 2021-10-15
• Subjects: Arsenic -- Wastewater -- Red mud -- Precipitation -- Stabilization; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2021.117484
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: High-arsenic wastewater derived from the metallurgical industry of nonferrous minerals is one of the most dangerous arsenic (As) sources that usually follow the emission of massive hazardous arsenic-bearing wastes. Considering the properties of red mud (RM), we propose an alternative and environmentally friendly method for the efficient remediation of high-arsenic wastewater using RM through formation of AlAsO4 @silicate precipitate, aiming at ''zero-emission of hazardous solid waste''. The results show nearly 100% of arsenic could be stepwisely removed from high-arsenic wastewater and reduce the arsenic concentration from 6100 mg/L to 40 μg/L using RM at room temperature. The highest arsenic removal capacity of RM reaches 101.5 mg/g at a RM-to-wastewater ratio of 40 g/L due to the superior arsenic adsorption and the co-precipitation of arsenate and Al 3+ to form insoluble aluminum arsenate. The silicate shell of arsenic-loaded RM created at an alkaline condition acts as an arsenic stabilizer, resulting in a leached arsenic concentration of 1.2 mg/L in TCLP tests. RM acts as a highly effective arsenic remover and stabilizer for the disposal of high-arsenic wastewater. It shows great potential for the remediation of wastewater containing heavy metals with varying concentrations to produce clean water available for industrial purpose. Graphical abstract: Synopsis: Arsenic in acidic wastewater is mainly removed by red mud (RM) in the form of aluminium arsenate. The As-loaded RM could be stabilized through the creation of As-loaded RM@silicate structured precipitate at alkaline condition. Image 1 Highlights: 100% removal efficiency of arsenic from high-arsenic wastewater using red mud. Arsenic capacity of red mud reaches 101.5 mg/g. Formation of environmentally stable arsenic-enriched RM@silicate precipitates.