Development and evaluation of innovative iron-containing porous carbon adsorbents for arsenic removal

Abstract

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Two types of carbon based iron-containing adsorbents, As-GAC and FeOMC, were developed for arsenic removal from drinking water in this dissertation. Granular activated carbon-based iron-containing adsorbents (As-GAC) was developed by primarily using GAC as a supporting medium for ferric iron that was impregnated by ferrous chloride (FeCl2) treatment, followed by chemical oxidation. An ordered nano-structured adsorbent, iron-containing ordered mesoporous carbon (FeOMC) was synthesized and developed by involving in synthesis of ordered silica template SBA-15, in situ polymerization of mono acrylic acid (AA) in the silica template followed by carbonization and template removal to obtain ordered mesoporous carbon (OMC), and iron impregnation. Adsorbents were developed by optimizing the preparation conditions, including initial Fe concentration, oxidant type and dosage, and AC or OMC types, etc. and they were characterized by scanning electron microscope (SEM) and transmission electron microscope (TEM) with energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and nitrogen adsorption-desorption analyses, etc. The ability of adsorbents for arsenic removal was evaluated by both batch and column studies. Effects of ionic strength, pH, and other competing constituents on the arsenic removal were also studied in batch systems. Redox transformation and surface characteristics of carbon based adsorbents were investigated. Adsorption of arsenic on adsorbents was modeled by the surface complexation model.