Microwave/H2O2 efficiency in pentachlorophenol removal from aqueous solutions.

Abstract

Pentachlorophenol (PCP) is one of the most fungicides and pesticides. Acute and chronic poisoning from PCP may be occurred by dermal absorption, and respiration or ingestion. With respect to health and environmental effects of PCP, many methods were considered regarding its removal. Microwave assisted other methods are environmental friendly, safety, and economical method, consequently, in this study; microwave assisted with hydrogen peroxide (MW/H2O2) was used for PCP removal from aquatic solutions. The possible of PCP removal was considered by application of a modified domestic microwave. PCP removal rate was considered under different factors such as H2O2 dose (0.01, 0.02, 0.1, 0.2, 0.3 mol/L), PCP concentration (100,200, 300, 400, 500, 750, 1000 mg/L), pH (3, 7, 11), energy intensity (180,450, 600 W), COD (344 mg/L), and scavenger testes (0.02 mol/L from each of Tert- butyl alcohol (TBA), NaCl, NaHCO3, and Na2CO3). The concentration changes of PCP were determined using spectrophotometer and HPLC spectra, respectively. The best PCP removal was obtained in condition of pH 11, 0.2 mol/L H2O2, and 600 W energy intensity. Moreover, COD removal in this condition was 83%. Results obtained from radical scavengers indicated that OH° had only an initiator role, and had not a dominant role, and order reaction was in first order. The results of microwave/H2O2 application showed that this process is suitable for removal of PCP and other chlorinated organic compounds in alkaline pH.