Treatment of Pentachlorophenol by Integrating Biosorption and Photocatalytic Oxidation
Invited conference paper presented and published in conference proceedings


摘要In this study, the pentachlorophenol (PCP) removal efficiencies by adsorption onto Chitin A (crude chitin, 71% pure), Chitin B (91% pure), Chitosan (Chitin C) prepared from spent shrimp (Penaeus japonicas) shell, were compared. For all three biosorbents, higher amount of biosorbent gave higher removal efficiency (RE) but lower removal capacity (RC) as more binding sites are available for PCP. The biosorption was biphasic with the first rapid step followed by slow adsorption, and the apparent-equilibrium was achieved at 60 min. The PCP removal was enhanced by lowering pH since neutral PCP was favorable for absorption. In addition, the higher temperature regressed the biosorption efficiency and it indicated that the adsorption was exothermic. The binding sites of Chitin B and Chitin C reached saturation in the range of PCP concentrations of 5-300 mg/L, but this phenomenon was not apparent in Chitin A. Langmuir isotherm could well- described the PCP adsorption by three biosorbents. With Chitin A showed the highest capacity and affinity for PCP, followed by Chitin C and Chitin B. Therefore, Chitin A was chosen for the following integrated system study since it had the higher efficiency and more economic for the treatment process, comparing with the other two biosorbents.

In the integrated treatment study, photocatalytic oxidation (PCO) was employed after the biosorption. Complete PCP removal was achieved after 4 h UV irradiation, in 100 mL solution with 6.7 mM of H2O2 and 200 mg/L of TiO2, while Chitin A was resistant to PCO and showed no change in chitin content, functional groups and biosorption efficiency. The photocatalytic degradation intermediates of PCP were identified as 2,3,5,6-tetrachlorohydroquinone (TeHQ) and 2,3,5,6-tetrachlorophenol (C6H2Cl4O) by gas chromatography/mass spectrometry (GC/MS) analysis. In addition, the toxicity of sample was monitored by the solid-phase Microtox® test, which showed decreasing along the irradiation time. Therefore, the combination of biosorption and PCO treatment was feasible for PCP remediation.
著者Chan Suk Mei, Wang Wanjun, Wong Po Keung
會議名稱The 33rd International Conference of the Society for Environmental Geochemistry and Health
關鍵詞Photocatalytic, Biosorption, Pentachlorophenol

上次更新時間 2018-23-05 於 13:04