Enhanced photodegradation of pentachlorophenol by single and mixed nonionic and anionic surfactants using graphene–TiO2 as catalyst

Zhang, Yaxin; He, Xin; Zeng, Guangming; Chen, Tan; Zhou, Zeyu; Wang, Hongtao; Lu, Wenjing

Enhanced photodegradation of pentachlorophenol by single and mixed nonionic and anionic surfactants using graphene–TiO2 as catalyst

2015

The photodegradation of pentachlorophenol (PCP) in a surfactant-containing (single and mixed) complex system using graphene–TiO₂ (GT) as catalyst was investigated. The objective was to better understand the behavior of surfactants in a GT catalysis system for its possible use in remediation technology of soil contaminated by hydrophobic organic compounds (HOCs). In a single-surfactant system, surfactant molecules aggregated on GT via hydrogen bonding and electrostatic force; nonideal mixing between nonionic and anionic surfactants rendered GT surface with mixed admicelles in a mixed surfactant system. Both effects helped incorporating PCP molecules into surfactant aggregates on catalyst surface. Hence, the targeted pollutants were rendered easily available to photo-yielded oxidative radicals, and photodegradation efficiency was significantly enhanced. Finally, real soil washing-photocatalysis trials proved that anionic–nonionic mixed surfactant soil washing coupled with graphene–TiO₂ photocatalysis can be one promising technology for HOC-polluted soil remediation.

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