Effects of water chemistry and flow rate on arsenate removal by adsorption to an iron oxide-based sorbent

• Published in: Water research (Oxford) Vol. 42; no. 18; pp. 4629 - 4636
• Main Authors: Zeng, Hui, Arashiro, Maiko, Giammar, Daniel E.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01-11-2008; Elsevier
• Subjects: Adsorption; Applied sciences; arsenates; Arsenates - chemistry; Arsenates - isolation & purification; Arsenic; diffusion; drinking water; Drinking water treatment; Exact sciences and technology; Ferric Compounds - chemistry; groundwater contamination; hydrochemistry; Iron oxide sorbent; iron oxides; optimization; Other industrial wastes. Sewage sludge; Packed-bed column; pollutants; Pollution; Pore and surface diffusion Model (PSDM); Reproducibility of Results; simulation models; Wastes; water flow; Water Purification - methods; water treatment; Water treatment and pollution; Packed-bed column; Drinking water treatment; Iron oxide sorbent; Arsenic; Adsorption; Pore and surface diffusion Model (PSDM); Phosphates; Water treatment; Packed bed; Arsenates; Treatment efficiency; PSDM; Modeling; Pore and surface diffusion Model; Mass transfer; Operating conditions; Sorbent; Ultrapure water; Packed column; Breakthrough curve; Ground water
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/j.watres.2008.08.014

Arsenate removal from water using an iron oxide-based sorbent was investigated to determine the optimal operating conditions and the influence of water composition on treatment efficiency. The novel sorbent with a high surface area was studied in flow-through column experiments conducted at different flow rates to quantify the effect of empty bed contact time (EBCT) on treatment performance. Arsenic removal efficiency declined with decreasing EBCT. Arsenic breakthrough curves at different EBCT values were successfully simulated with a pore and surface diffusion model (PSDM). Surface diffusion was the dominant intraparticle mass transfer process. The effect of water composition on arsenic removal efficiency was evaluated by conducting experiments with ultrapure water, ultrapure water with either phosphate or silica, and a synthetic groundwater that contained both phosphate and silica. Silica was more inhibitory than phosphate, and the silica in synthetic groundwater controlled the arsenic removal efficiency.