Merits and limitations of TiO2-based photocatalytic pretreatment of soils impacted by crude oil for expediting bioremediation

作     者：Yu Yang Hassan Javed Danning Zhang Deyi Li Roopa Kamath Kevin McVey Kanwartej Sra Pedro J.J. Alvarez 

作者机构：Department of Civil and Environmental Engineering Rice University Houston TX 77005 USA Department of Chemistry Rice University Houston TX 77005 USA Department of Civil and Environmental Engineering Tongji University Shanghai 200092 China Chevron Energy Technology Company Houston TX 77002 USA 

出 版 物：《Frontiers of Chemical Science and Engineering》 (化学科学与工程前沿（英文版）)

年 卷 期：2017年第11卷第3期

页      面：387-394页

核心收录：

学科分类：083002[工学-环境工程] 0830[工学-环境科学与工程（可授工学、理学、农学学位）] 081705[工学-工业催化] 08[工学] 0817[工学-化学工程与技术] 0703[理学-化学] 

基　　金：supported by Chevron Energy Technology Company. 

主　　题：ZiO2 pretreatment bioremediation total petroleum hydrocarbons ultraviolet 

摘      要：Heavy hydrocarbons （HHCs） in soils impacted by crude oil spills are generally recalcitrant to biodegrada- tion due to their low bioavailability and complex chemical structure. In this study, soils were pretreated with varying concentrations of ultraviolet radiation A （UVA） or ultraviolet radiation C （UVC） activated titanium dioxide （TiO2） （1%-5%） under varying moisture conditions （0%- 300% water holding capacity （WHC）） to enhance biodegradation of HCCs and shorten remediation time- frames. We demonstrate that pretreatment of impacted soils with UVC-activated TiO2 in soil slurries could enhance bioremediation of HHCs. Total petroleum hydrocarbon （TPH） removal after 24 h exposure to UVC （254 nm and 4.8 mW/cm2） was （19.15：1.6）% in slurries with 300% WHC and 5 wt-% TiO2. TPH removal was non-selective in the C15-C36 range and increased with moisture content and TiO2 concentration. In a 10-d bioremediation test, TPH removal in treated soil increased to （26.05：0.9）%, compared to （15.45：0.8）% for controls without photo- catalytic pre-treatment. Enhanced biodegradation was also confirmed by respirometry. This suggests that addition of UVC-activated TiO2 to soil slurries can transform recalcitrant hydrocarbons into more bioavailable and biodegradable byproducts and increase the rate of subsequent biodegradation. However, similar results were not observed for soils pretreated with UVA activated TiO2. This suggests that activation of TiO2 by sunlight and direct addition of TiO2 to unsaturated soils within landfarming setting may not be a feasible approach. Nevertheless, less than 1% of UVA （7.5 mW/cm2） or UVC （1.4 mW/cm2） penetrated beyond 0.3 cm soil depth, indicating that limited light penetration through soil would hinder the ability of TiO2 to enhance soil bioremediation under land farming conditions.