Cu-Fe BIMETALLIC MATERIAL ON ARSENIC REMOVAL UNDER GAS-BUBBLING CONDITIONS

Abstract

Arsenic removal was investigated using nano X-Fe (bimetal) particles. Copper and nickel were selected as additional metals into NZVI. Under a batch condition with an initial concentration of 5000 µg/L of arsenic, pH of 7.0, nanoparticles of Cu-Fe showed higher arsenic treating efficiency over Ni-Fe and NZVI. The synthesis of Cu-Fe was further investigated via two kinds of synthesis techniques. One was an in-situ [(Cu-Fe)IS] and the other was impregnation [(Cu-Fe)IM]. Properties of both materials were characterized by SEM-EDX, TEM, BET, and XANES. The arsenic removal was carried out in CO2/O2 gas bubbling under the flow rate of 300 ml/min accommodating low pH and high DO condition. Copper loading varied from 2.5-30.0%wt was studied on both (Cu-Fe)IS and (Cu-Fe)IM, where 10%Cu loading under impregnation synthesis technique provided highly removal on both As(III) and As(V) in synthetic wastewater. The mechanism of arsenic removal on Cu-Fe was proposed. A mixture of As(III)-As(V) solution was tested and it was found that solution containing As(V) individually showed the faster in arsenic removal. Furthermore, the removal of arsenic species, including As(III) and As(V), in field groundwater and synthetic groundwater by (Cu-Fe)IM were tested. The presence of background species was observed significantly on arsenic removal. Concerning in kinetics of arsenic removal using (Cu-Fe)IM in gas bubbling system, it was well fit with pseudo-second order and pseudo-first order for As(III) and As(V), respectively. Rate constants were evaluated to be 0.0003 L∙(µg∙min)-1 for As(III), and 0.1489 min-1 for As(V). The proposed gas bubbling system was conducted in a continuous system for multiple additions of (Cu-Fe)IM, providing a beneficial outcome of arsenic treatment to meet a standard drinking limitation of 10 µg/L.