Study On Hydrothermal Preparation And Modification Of Zinc Sulfide Nanomaterials And Their Use For Photocatalytic Degradation Of Rhodamine B In Wastewater

In order to meet people's demand for fabric color and performance,textile printing and dyeing industry has to use more synthetic dyes to replace natural dyes,and use more complex processes and treatment agents,but the pollution to the environment has exceeded the capacity of environmental self-healing and become one of the main sources of environmental pollution.In order to alleviate the pollution of textile printing and dyeing to the environment,people are actively exploring efficient,environmental protection,energy-saving of technology of degrading dying wastewater.Zinc sulfide(ZnS),as a pHotocatalyst,has a wide application prospect in the pHotodegradation of organic pollutants in wastewater due to its large specific surface area,safe and stable pHotochemistry.In this paper,the influence of preparation conditions on the performance of ZnS was studied.At the same time,the existing defects were modified and rhodamine B dye was used as organic pollutant to study the pHotocatalytic degradation performance of ZnSIn this paper,ZnS was synthesized by hydrothermal method,and the effects of surfactant,reaction temperature and reaction time on the structure and properties of ZnS were studied.It is found that CTAB can help the growth and aggregation of ZnS crystals,but the excess CTAB can increase the size of ZnS particles.With the increase of reaction temperature and holding time,the size of ZnS particles will also increase.When the reaction temperature is 120?,the holding time is 12 hours and the ratio of SDS and CTAB is 1:2,the pHotodegradation performance of ZnS is better.In the aspect of ZnS modification,in this paper,two methods are used:doping Ni2+and in-situ growth of polymer matrix.In the study of Ni2+ doped ZnS,it is found that Ni2+ with smaller ion radius can enter the ZnS lattice to replace some Zn2+with larger ion radius.The doping of Ni2+can make ZnS produce intermediate energy level between valence band and conduction band,which can effectively capture pHotogenerated electrons.At the same time,the reduction of band gap width can improve the quantum efficiency and enhance the pHotocatalytic degradation performance.However,excessive Ni2+ will make the lattice defects become the composite centers of carriers,which will reduce the lifetime of pHotogenerated electron hole pairs.When the content of Ni2+is 7%(the mole ratio of Ni atom to Zn atom),the pHotocatalytic degradation performance is the best,and the degradation rate of organic dye wastewater can reach 97%.The in-situ growth of polymer matrix is one of the effective methods for the composite of inorganic particles and polymer.In this paper,PAN nanofiber membrane with good morpHology and small diameter obtained by electrospinning technology is used as polymer matrix.Firstly,the prepared nanofiber membrane was dipped into the mixed aqueous solution of zinc acetate dihydrate and thioacetamide,and the Zn2+was uniformly distributed on the fiber by ultrasonic for 30 minutes by the complexation of polymer functional groups with metal ions,then the ZnS/PAN nanocomposites were obtained by reaction in the closed hydrothermal environment.The size of ZnS particles grown in situ by polymer is smaller and the dispersion is better,which can avoid the agglomeration of ZnS nanomaterials.The corrosion resistance of polymer can also improve the corrosion resistance of ZnS and the recyclability of ZnS.In addition,the composite with PAN nano fiber membrane can make organic wastewater no longer need to be stirred,so as to save cost.