title: Studies on the optimum conditions using acid-washed zero-valent iron/aluminum mixtures in permeable reactive barriers for the removal of different heavy metal ions from wastewater.
abstract: The method of permeable reactive barriers (PRBs) is considered as one of the most practicable approaches in treating heavy metals contaminated surface and groundwater. The mixture of acid-washed zero-valent iron (ZVI) and zero-valent aluminum (ZVAl) as reactive medium in PRBs to treat heavy metal wastewater containing Cr(VI), Cd(2+), Ni(2+), Cu(2+), and Zn(2+) was investigated. The performance of column filled with the mixture of acid-washed ZVI and ZVAl was much better than the column filled with ZVI or ZVAl alone. At initial pH 5.4 and flow rates of 1.0 mL/min, the time that the removal efficiencies of Cr(VI), Cd(2+), Ni(2+), Cu(2+), and Zn(2+) were all above 99.5% can keep about 300 h using 80 g/40 g acid-washed ZVI/ZVAl when treating wastewater containing each heavy metal ions (Cr(VI), Cd(2+), Ni(2+), Cu(2+), and Zn(2+)) concentration of 20.0 mg/L. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) were used to characterize ZVI/ZVAl before and after reaction and the reaction mechanism of the heavy metal ions with ZVI/ZVAl was discussed.
authors.affiliation: School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China; South China Institute of Environmental Science, MEP, Guangzhou 510655, China.
authors.forename: Weijiang
authors.initials: W
authors.lastname: Han
authors.affiliation: School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China. Electronic address: fufenglian2006@163.com.
authors.forename: Fenglian
authors.initials: F
authors.lastname: Fu
authors.affiliation: School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China.
authors.forename: Zihang
authors.initials: Z
authors.lastname: Cheng
authors.affiliation: School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China.
authors.forename: Bing
authors.initials: B
authors.lastname: Tang
authors.affiliation: School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China.
authors.forename: Shijiao
authors.initials: S
authors.lastname: Wu
keywords: Acid washing; Heavy metal wastewater; Permeable reactive barriers (PRBs); Zero-valent aluminum (ZVAl); Zero-valent iron (ZVI)