Research On The Preparation Of Special-shaped ZnO,TiO₂ Loading Ag/AgCl Photocatalysts And Their Graphene Hydrogel Composite

In modern industrial production,printing and dyeing wastewater has brought great pressure on the environment.Organic dye pollutants not only damage the ecological environment,but also endanger human life and health.Solving the problem of the treatment of printing and dyeing wastewater in factories is an urgent problem to be solved.Photocatalytic degradation and adsorption are important methods for treating printing and dyeing wastewater.There are commercially available photocatalysts and adsorbents,such as P25,and activated carbon,but most of them have low adsorption cycle performance and low photocatalytic degradation efficiency.This study mainly focused on the above problems.ZnO tetrapods and TiO2 nanosheet crystals were first loaded with Ag/AgCl with the aid of the adhesion and reducibility of polydopamine to synthesize a highly efficient composite photocatalyst,which was then compounded into the self-assembly process of graphene to develop composite hydrogel with both absorbability and photocatalytic degradation.The main research content is as follows:(1)Firstly,ZnO tetrapod is prepared,the Ag/AgCl was loaded on its surface by a mild dopamine self polymerization process to expand the light response range of the composite photocatalyst.By adjusting the pH value,the self polymerization and reduction degree were controlled,and then the composition,morphology and dispersion of Ag/AgCl were regulated.Finally,Ag/AgCl/ZnO composites with excellent photocatalytic activity and stability were prepared.With xenon lamp irradiation for 20 min,the degradation of rhodamine B reached 90%.After four recycling tests,the degradation remained stable without the slightest sign of reduction.(2)Secondly,through the process of H+ exchanging and alkylamine intercalation,TiO2 nanosheets can be obtained.TiO2 nanosheets were modified by polydopamine,which was used as a medium to further load Ag/AgCl.Finally,polydopamin-modified TiO2 nanosheet crystals and Ag/AgCl/TiO2 composite photocatalyst materials with certain adsorption and photocatalytic properties were prepared.With xenon lamp irradiation for 100 min,the degradation of rhodamine B reached 95%.(3)Thirdly,ZnO tetrapods and TiO2 nanosheets awere combined with graphene to form three-dimensional network structure by self-assembly.ZnO-GOH and TiO2-GOH composite hydrogels with excellent adsorption and degradation properties were prepared.Gel formation mechanism,adsorption and cycling properties were further analyzed.The integrated adsorption and photodegradation of rhodamine B by ZnO-GOH is more than 85%,and the integrated adsorption and photodegradation of rhodamine B by TiO2-GOH is as high as 98%.(4)Finally,In order to improve the catalytic degradation performance of the composite graphene-based hydrogels,the preparation and exploration of ZnO-GOH and TiO2-GOH composite hydrogels loaded with Ag/AgCl were carried out,and the Ag/AgCl/ZnO-GOH and Ag/AgCl/TiO2-GOH composite hydrogels with certain adsorption and degradation properties were prepared.