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Keywords:

  • adsorption;
  • chlorophenols;
  • deprotonation;
  • polyvinyl pyrrolidone;
  • protonation

Abstract

Widely used as insecticides, fungicides, and disinfectants and regarded as having relatively high toxicities, chlorophenols are a group of organic contaminants whose solubility and sorptive properties on different substrates vary greatly with solution pH. In this study, the feasibility and applicability of using cross-linked polyvinyl pyrrolidone (PVP XL) polymers to adsorb and remove chlorophenols from water under different pH conditions were investigated. The adsorption of chlorophenols on PVP XL was instantaneous and followed a linear sorption isotherm under the tested concentrations from 0.05 to 10 mg L–1, suggesting a partitioning mechanism. The chlorophenol adsorption increased as the degree of chlorination, thus the octanol–water partitioning coefficient, increased. A decrease in contaminant distribution coefficients with an increase in solution pH suggested that the deprotonated species had a weaker affinity for PVP XL surfaces than their protonated counterparts. The free energy of adsorption of 2,3,4,6-tetrachlorophenol (TeCP) on PVP XL was negative, suggesting a spontaneous adsorption. The negative enthalpy values of TeCP adsorption on PVP XL indicated an exothermic process. The results from this study show that PVP XL could be a viable alternative for the adsorption of chlorinated phenols in aqueous media as a remediation tool. The instantaneous adsorption will make PVP XL a possible choice for ultra filtration to remove chlorophenols from water. © 2010 American Institute of Chemical Engineers Environ Prog, 2011