Evalution Of Arsenic Removal Performance By Graphene/Iron-Based Material

Arsenic is a highly toxic protoplasmic poison, water arsenic pollution has become a worldwide environmental problem in recent years, arsenic removal in water has gotten wide attention. The adsorption method is effective in arsenic removal, so it is very important to research the high-absorbent material.This paper introduced three composite materials, which were prepared by magnetite, hematite and zero-valence iron loaded on the graphene, named graphene load magnetite (M-RGO), the graphene load hematite (H-RGO) and graphene load zero-valence iron (N-RGO) respectively, and materials preparation conditions and optimized by single factor experiments. Materials internal structure, crystalline structure, surface morphology and element distribution were analyzed by FTIR, XRD, XPS, SEM and EDX method. The arsenic removal performance, such as the adsorption kinetics, the adsorption isotherm, the initial concentration of arsenic, the appropriate pH range, the temperature and the resistance to co-existing ions were studied and compared. The mechanism of arsenic removal by three materials were studied preliminarily.The results showed that three hybrid materials as M-RGO、H-RGO and N-RGO were successfully made from graphene oxide with magnetite, hematite and zero-valence iron respectively. The adsorption of arsenic on three materials fit for pseudo-second-order kinetics equation, and the adsorption isotherm in accordance with Langmuir model, while the order of adsorption capacities was:N-RGO M-RGO H-RGO. Three materials had better adsorption of As (Ⅲ) under the condition of weak acid to neutral, the M-RGO and H-RGO materials were less influenced by the pH, and their pH range of adsorbing As (Ⅲ) was larger than that of N-RGO material. Three materials adsorbed As (Ⅲ) very well at temperature range30℃to40℃. In these three materials, N-RGO was affected by co-existing ions least, H-RGO was second, and M-RGO was affected most. Adsorption of arsenic with three materials were dominated by chemical adsorption combined physical adsorption, Fe and O elements constitute Fe-O functional group, this group with arsenic ions fromed complexes, and removed arsenic from water.