Sorption of Arsenic from Desalination Concentrate onto Drinking Water Treatment Solids: Operating Conditions and Kinetics

Abstract

Selective removal of arsenic from aqueous solutions with high salinity is required for safe disposal of the concentrate and protection of the environment. The use of drinking water treatment solids (DWTS) to remove arsenic from reverse osmosis (RO) concentrate was studied by batch sorption experiments. The impacts of solution chemistry, contact time, sorbent dosage, and arsenic concentration on sorption were investigated, and arsenic sorption kinetics and isotherms were modeled. The results indicated that DWTS were effective in removing arsenic from RO concentrate. The arsenic sorption process followed a pseudo-second-order kinetic model. Multilayer adsorption was simulated by Freundlich equation. The maximum sorption capacities were calculated to be 170 mg arsenic per gram of DWTS. Arsenic sorption was enhanced by surface precipitation onto the DWTS due to the high amount of calcium in the RO concentrate and the formation of ternary complexes between arsenic and natural organic matter (NOM) bound by the polyvalent cations in DWTS. The interactions between arsenic and NOM in the solid phase and aqueous phase exhibited two-sided effects on arsenic sorption onto DWTS. NOM in aqueous solution hindered the arsenic sorption onto DWTS, while the high organic matter content in solid DWTS phase enhanced arsenic sorption.

The Status of Arsenic Pollution in the Greek and Cyprus Environment: An Overview

“…Xu et al [98] applied batch sorption experiments to study the removal of As from aqueous solutions with high salinity. Drinking water treatment solids were used to remove As from reverse osmosis concentrates [98]. Each gm of solid derived from this treatment process is calculated to remove up to 170 mg of As [98].…”

“…Drinking water treatment solids were used to remove As from reverse osmosis concentrates [98]. Each gm of solid derived from this treatment process is calculated to remove up to 170 mg of As [98]. Khan et al [99] optimized the As removal process using central composite design based on response surface methodology.…”

Effects of phosphogypsum and water treatment residual application on key chemical and biological properties of clay soil and maize yield

“…Decreasing volatile NH 3 resulted in higher total N concentrations in poultry litter, thus resulting in a qualitative improvement in the waste production. Xu, Lin, Papelis, and Xu (2018) found that maximum sorption capacities of drinking water treatment solids to remove arsenic from reverse osmosis concentrate were 170 mg arsenic per gram of WTR.…”

Zeolite-Rich Composite Materials for Environmental Remediation: Arsenic Removal from Water

“…Due to both their low cost and a relatively operational ease, there is now a raising interest on sorption methods that seem to be the most promising way to remove arsenic from water sources [11]. Several materials have already been studied for the adsorption of arsenic from water, including metal-loaded coral limestone [12,13] hematite and feldspar, sandy soils [14], activated carbon [15][16][17][18], activated alumina [19,20], lanthanum-impregnated silica gel [21], hydrous zirconium oxide [22] and hydrous iron oxide [23] and zero valent iron [24,25]. Ohki et al [13] found an adsorption capability of 150 µg/g As(V) on coral limestone, while Xu et al [14] investigated the adsorption capacity of drinking water treatment solids (DWTS) in As(V) removal processes: at its best, DWTS adsorption capability was found to be 170 mg/g, although heavily affected by pH conditions.…”