REMOVAL OF CHLOROPHENOLS FROM WATER USING POLYVINYL PYRROLIDONE (PVP)

Chlorophenols belong to a type of organic contaminants whose solubility and sorptive properties on different substrates vary with solution pH. Under low pH they are present in water as protonated species such as chlorophenols. As the pH of water is higher than their Pka values they form deprotonated species such as chlorophenolates. Their toxicity generally increases with the degree of chlorination. Use of cross-linked polyvinyl pyrrolidone (PVP) polymers as the anti-leaching agents to selectively retain pesticides was patented by International Specialty Products (ISP). In this study we focused on testing the feasibility and applicability of using PVP to sorb and remove chlorophenols from water. Kinetic studies reveal that the sorption of chlorophenols on PVP is instantaneous. Equilibrium sorption studies showed that the sorption of protonated species followed a linear sorption isotherm, indicating a partitioning mechanism. As the solution pH increases, the contaminant distribution coefficients decreases, revealing that deprotonated species have a weaker affinity onto the PVP surfaces. In addition, the sorption increases as the degree of chlorination increases.