Catalytic ozonation of pentachlorophenol in aqueous solutions using granular activated carbon

Ghorban Asgari,Ali Poormohammadi,Mohammad Ahmadian,Bahman Solimanzadeh,Fateme Samiee

doi:10.1007/s13201-014-0254-y

Abstract

The efficiency of granular activated carbon (GAC) was investigated in this study as a catalyst for the elimination of pentachlorophenol (PCP) from contaminated streams in a laboratory-scale semi-batch reactor. The influence of important parameters including solution pH (2–10), radical scavenger (tert-butanol, 0.04 mol/L), catalyst dosage (0.416–8.33 g/L), initial PCP concentration (100–1000 mg/L) and ozone flow rate (2.3–12 mg/min) was examined on the efficiency of the catalytic ozonation process (COP) in degradation and mineralization of PCP in aqueous solution. The experimental results showed that catalytic ozonation with GAC was most effective at pH of 8 with ozone flow rate of 12 mg/min and a GAC dosage of 2 g. Compared to the sole ozonation process (SOP), the removal levels of PCP and COP were, 98, and 79 %, respectively. The degradation rate of kinetics was also investigated. The results showed that using a GAC catalyst in the ozonation of PCP produced an 8.33-fold increase in rate kinetic compared to the SOP under optimum conditions. Tert-butanol alcohol (TBA) was used as a radical scavenger. The results demonstrated that COP was affected less by TBA than by SOP. These findings suggested that GAC acts as a suitable catalyst in COP to remove refractory pollutants from aqueous solution.

Highlights

These findings suggested that granular activated carbon (GAC) acts as a suitable catalyst in catalytic ozonation process (COP) to remove refractory pollutants from aqueous solution
At different pH points, the performance of COP was better in PCP removal than that of sole ozonation process (SOP), which explains the effect of pH on the properties of catalyst surface (Faria et al 2008; Li et al 2009) and on the ozone transfer from the gas phase to the liquid phase and ozone decomposition
This observation is consistent with the results of reactive red 198 removal in a COP with pistachio hull conducted by Moussavi et al In the current study, the maximum catalytic potential occurred at alkaline pH of 10 (Moussavi and Khosravi 2012)

Summary

Introduction

G. Asgari Social Determinants of Health Research Center (SDHRC), Department of Environmental Health Engineering, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran. F. Samiee Environmental Health Engineering, Department of Environmental Health Engineering, Faculty of Health, Hamadan University of Medical Sciences, Hamadan, Iran. M. Ahmadian School of Public Health, Kermanshah University of Medical Sciences, Kermanshah, Iran. Pentachlorophenol (PCP) is one of the hazardous pollutants extensively used in pesticides, herbicides and wood preservatives. This widespread application could lead to release of PCP into water sources (Oberg et al 1990). High levels of PCPs in aqueous environments may be toxic for, and it can reduce their removal efficiency by the biological processes. Advanced oxidation process (AOP) is a new technology used to treat industrial wastewater containing

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