Preparation Of Bismuth Based Composite Photocatalysts And Their Application Of Cr(Ⅵ) And Tetracycline Hydrochloride Remediation

With the implementation of various national water regulations and policies,the pollution of surface water has been effectively controlled,and the water quality has been greatly improved.Nevertheless,the issues of high energy consumption and secondary pollution have been existed in traditional water treatment processes,and their treatment capacity towards refractory chemicals is limited.Photocatalyisis uses clean and abundant renewable solar energy resources to stimulate the redox ability of semiconductors and degrade the contaminants,which presents great potential in the field of water remediation.Nowadays,the conventional photocatalysts have the shortcomes of low utilization of visible light and high electron-hole recombination rate during the reaction,severely limiting the practical application of photocatalytic technology.It is urgent to develop new photocatalysts with excellent performance.Herein,two kinds of bismuth based composite photocatalysts were prepared.They show good photocatalytic activity in terms of Cr（Ⅵ）photoreduction and TC-HCl degradation,thus providing new strategies for developing highly efficient photocatalysts.The specific research contents of this paper are as follows.1.Bi₂S₃ nanorod and NCDs were successfully prepared by sol-gel method and facile hydrothermal method,respectively.The NCDs were anchored on the surfaces of Bi₂S₃nanorods by reflux.Then,series of Bi₂S₃/NCDs/Au composites（BNAs）were synthesized by in situ chemical reduction of chloroauric acid.The structure and composition of BNAs were characterized by XRD、XPS、FT-IR、SEM and TEM.The diameter of Bi₂S₃nanorod is around 20nm.Au and NCDs with the size of 3 nm were uniformly loaded on the surfaces of Bi₂S₃.The photoreduction of Cr（Ⅵ）was performed using BNAs photocatalysts under visible light irradiation.The optimized BNA-2 presents the best photocatalytic activity,removing all of the Cr（Ⅵ）after 30 min of irradiation.The active free radical capture experiment was conducted for elucidation of the photocatalytic mechanism of ANBs.The photoinduced electrons played the main role in the removing of Cr（Ⅵ）.The photocatalytic performance of Bi₂S₃ was greatly improved by loading of double cocatalysts.2.TiC was prepared by chemical etching and ultrasonic stripping.Series of TiC/BiOI composites（TBs）were prepared by in-situ loading of Bi OI on the surface of TiC.The structure and composition of TBs were investigated by XRD,SEM and EDS,which confirmed the successful combination of TiC and Bi OI.The flower like Bi OI was homogenous growing on two dimensional TiC.The photodegradation towards tetracyclin HCl（TC-HCl）was performed using TBs photocatalysts under visible light irradiation.The optimized TBs displays the best photocatalytic activity,removing 92%of the TC-HCl upon120 min of irradiation.The active free radical capture experiment was conducted for elucidation of the photocatalytic mechanism of TBs.The photoinduced electrons played the main role in the degradition of TC-HCl.The combination with TiC greatly promoted the photocatalytic performance of Bi OI.In this paper,we successfully prepared two kinds of bismuth based composite photocatalytics,and their treatment effect and mechanism of Cr（Ⅵ）and TC-HCl were explored respectively.Which provided a positive significance for promoting the application of photocatalytic technology in wastewater treatment.