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Feasibility of Using Drinking Water Treatment Residuals as a Novel Chlorpyrifos Adsorbent

Zhao, Yuanyuan, Wang, Changhui, Wendling, Laura A., Pei, Yuansheng
Journal of agricultural and food chemistry 2013 v.61 no.31 pp. 7446-7452
absorbents, adsorbents, chlorpyrifos, ionic strength, molecular weight, organic acids and salts, organic matter, pH, paddy soils, sorption, sorption isotherms, water treatment
Recent efforts have increasingly focused on the development of low-cost adsorbents for pesticide retention. In this work, the novel reuse of drinking water treatment residuals (WTRs), a nonhazardous ubiquitous byproduct, as an adsorbent for chlorpyrifos was investigated. Results showed that the kinetics and isothermal processes of chlorpyrifos sorption to WTRs were better described by a pseudo-second-order model and by the Freundlich equation, respectively. Moreover, compared with paddy soil and other documented absorbents, the WTRs exhibited a greater affinity for chlorpyrifos (log Kₒc = 4.76–4.90) and a higher chlorpyrifos sorption capacity (KF = 5967 mg¹–ⁿ·L·kg–¹) owing to the character and high content of organic matter. Further investigation demonstrated that the pH had a slight but statistically insignificant effect on chlorpyrifos sorption to WTRs; solution ionic strength and the presence of low molecular weight organic acids both resulted in concentration-dependent inhibition effects. Overall, these results confirmed the feasibility of using WTRs as a novel chlorpyrifos adsorbent.