Experimental and Modeling Investigation of Arsenate Adsorption on Synthetic

Arsenic is an environmental contaminant of worldwide concern due its high toxicity and presence in groundwater aquifers. Adsorption of arsenic onto metal-oxides is an important phenomenon that locally controls the transport of arsenic in groundwater systems. In this study, we have investigated adsorption of arsenic(V) onto iron (goethite) coated sands. We also developed novel methods to scale the adsorption models. The study is divided into three phases: (i) In the first phase, we developed a scalable surface complexation modeling framework for predicting arsenic(V) adsorption onto various types of iron (goethite) coated sands. We first synthesized four different types of goethite-coated sands with iron content varying by nearly an order of magnitude and generated adsorption isotherms and pH edges for these four sands. We then used experimental data from one of the sands to develop a surface complexation model for the sand. We then scaled the surface complexation model developed for the sand, based on measured surface site density values, to predict adsorption onto th