Enhanced adsorbability and photocatalytic activity of TiO2-graphene composite for polycyclic aromatic hydrocarbons removal in aqueous phase

• Published in: Colloids and surfaces, B, Biointerfaces B, Biointerfaces, 2017-02, Vol.150, p.68-77
• Main Authors: Bai, Hongzhen, Zhou, Jun, Zhang, Hongjian, Tang, Guping
• Format: Article
• Language: English
• Subjects: Adsorption; PAHs; Photocatalysis; TiO2 graphene composite
• ISSN: 0927-7765; 1873-4367
• DOI: 10.1016/j.colsurfb.2016.11.017

[Display omitted] •A series of TiO2-graphene were synthesized via hydrothermal treatment.•The optimal graphene ratio in composite was investigated for PAHs removal.•PAH degradation pathways were described through intermediates identification. Photodegradation via titanium dioxide (TiO2) has been used to remove polycyclic aromatic hydrocarbons (PAHs) from environmental media broadly. In this study, a series of TiO2-graphene composites (P25-GR) with different GR weight ratios were synthesized via hydrothermal reaction of graphene oxide (GO) and P25. Their structures were characterized and the proprieties were tested in aqueous phase. Phenanthrene (PHE), fluoranthene (FLAN), and benzo[a]pyrene (BaP) were selected as models of PAHs. The experiment indicated that P25-2.5%GR exhibited enhancement in both adsorption and photodegradation, ∼80% of PAHs were removed after 2h photocatalysis. The influence of photodegradation rate was studied, including PAHs initial concentration and pH. Aromatic intermediates were identified during the reaction process and the degradation pathways were portrayed. This work explored the enhanced photocatalysis performance was attributed to the PAH-selective adsorbability and the strong electron transfer ability of the composite. The analysis of the degradation intermediates confirmed that the reaction proceeded with the formation of free radicals, leading to the gradual PAH mineralization.