Preparation of iron-impregnated granular activated carbon for arsenic removal from drinking water.
Granular activated carbon (GAC) was impregnated with iron through a new multi-step procedure using ferrous chloride as the precursor for removing arsenic from drinking water. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) analysis demonstrated that the impregnated iron was distributed evenly on the internal surface of the GAC. Impregnated iron formed nano-size particles, and existed in both crystalline (akaganeite) and amorphous iron forms. Iron-impregnated GACs (Fe-GACs) were treated with sodium hydroxide to stabilize iron in GAC and impregnated iron was found very stable at the common pH range in water treatments. Synthetic arsenate-contaminated drinking water was used in isotherm tests to evaluate arsenic adsorption capacities and iron use efficiencies of Fe-GACs with iron contents ranging from 1.64% to 12.13% (by weight). Nonlinear regression was used to obtain unbiased estimates of Langmuir model parameters. The arsenic adsorption capacity of Fe-GAC increased significantly with impregnated iron up to 4.22% and then decreased with more impregnated iron. Fe-GACs synthesized in this study exhibited higher affinity for arsenate as compared with references in literature and shows great potential for real implementations.
Chang
Qigang
Q
Department of Civil Engineering, North Dakota State University, Fargo, ND 58105, USA; School of Resource and Environmental Engineering, East China University of Science and Technology, Shanghai 200237, China.
Lin
Wei
W
Department of Civil Engineering, North Dakota State University, Fargo, ND 58105, USA. Electronic address: wei.lin@ndsu.edu.
Ying
Wei-Chi
WC
School of Resource and Environmental Engineering, East China University of Science and Technology, Shanghai 200237, China.
D000327:Adsorption; D001151:Arsenic / Q000737:chemistry / Q000302:isolation & purification*; D002244:Carbon / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D008962:Models, Theoretical; D013057:Spectrum Analysis / Q000379:methods; D014881:Water Supply / Q000032:analysis*; D014965:X-Rays
D002244:Carbon; D007501:Iron; D001151:Arsenic