Green synthesis of reusable multifunctional γ-Fe2O3/bentonite modified by doped TiO2 hollow spherical nanocomposite for removal of BPA

Yiyun Cao; Guangzhu Zhou; Runsheng Zhou; Cuizhen Wang; Baorong Chi; Yue Wang; Chunyu Hua; Jun Qiu; Yuqin Jin; Sai Wu

doi:10.1016/j.scitotenv.2019.134669

Green synthesis of reusable multifunctional γ-Fe₂O₃/bentonite modified by doped TiO₂ hollow spherical nanocomposite for removal of BPA

Sci Total Environ. 2020 Mar 15:708:134669. doi: 10.1016/j.scitotenv.2019.134669. Epub 2019 Nov 23.

Authors

Yiyun Cao¹, Guangzhu Zhou², Runsheng Zhou¹, Cuizhen Wang¹, Baorong Chi¹, Yue Wang¹, Chunyu Hua¹, Jun Qiu¹, Yuqin Jin¹, Sai Wu¹

Affiliations

¹ College of Chemical and Environmental Engineering, Shandong University of Science and Technology, Qingdao, China.
² College of Chemical and Environmental Engineering, Shandong University of Science and Technology, Qingdao, China. Electronic address: zhouguangzhu@sdust.edu.cn.

PMID: 31796270
DOI: 10.1016/j.scitotenv.2019.134669

Abstract

Eco-friendly treatment of refractory pollutants in wastewater is still full of challenge in catalytic oxidation and adsorption. In this study, based on the concept of green chemistry, sulfur-doped titanium dioxide hollow spheres modified by surfactant loaded on magnetic bentonite (CST/γ-Fe₂O₃-BT) is synthesized in two steps, and bisphenol A (BPA) was chosen as the representative organic pollutant. These materials were characterized by means of XRD, FTIR, SEM, EDS, TEM, XPS, BET, and VSM techniques. The adsorption and photodegradation behavior of CST/γ-Fe₂O₃-BT were examined. The Langmuir isotherm exhibited a better fit with a maximum adsorption capacity of 77.36 mg/g. At pH 7, the reaction rate constant (k) of the BPA photocatalytic degradation by product was 0.00104 min^-1, and the adsorption equilibrium constant (K) was 0.04034L/mg. In addition, the composite can be recovered from the reaction mixture by applying an external magnetic field due to the existence of the superparamagnetic iron oxide nanoparticles in the construct. The recovered particles retained their catalytic activity which the catalytic activity of the material still reached 91% of the first catalytic experiment after 5 repetitive experiments. Results infer that the material has excellent reusability. Thus, CST/γ-Fe₂O₃-BT is a significant candidate for the treatment of recalcitrant organic pollutants in wastewater.

Keywords: Adsorption; Bentonite; Bisphenol A; Magnetic; Photocatalytic degradation; TiO(2).