Photocatalytic Degradation Of Rhodamine B And Chlortetracycline Hydrochloride In Wastewater By Kaolinite-Based Composites

A large number of organic pollutants exist in wastewater,which poses a serious threat to human health and natural environment,and has attracted widespread attention all over the world.However,because traditional sewage treatment technology is still unable to efficiently remove organic pollutants in wastewater,resulting in organic pollutants such as dyes and antibiotics in tap water.Among many sustainable and economical organic pollutant removal methods,photocatalysis technology and advanced oxidation technology are highly expected for their green,energy saving and high efficiency.In recent years,kaolinite-based composites have become one of the rapidly developing materials in the field of photocatalysis.Due to its large surface area,adjustable porous structure and abundant active sites,kaolinite-based composites have become the focus of attention due to its ability to efficiently degrade organic pollutants.In this paper,the kaolinite-based composite material as the research object,through the structural characterization and performance test,the kaolinite-based composite material degradation performance and mechanism of organic pollutants.The main research results are as follows:（1）BiOI/kaolinite photocatalyst with high efficiency was synthesized by a simple hydrothermal method.The crystal structure,chemical composition,morphology and photoelectric chemical properties of the samples were characterized.BiOI/Kaolinite composites were found to have the best catalytic activity,with a photocatalytic degradation rate of about 90%for Rhodamine B（Rh B）within 120 min,which was attributed to its stronger adsorption capacity and higher charge separation efficiency.The results show that BiOI/Kaolinite nanocomposite is an efficient and promising catalyst for wastewater treatment.（2）The MnFe₂O₄/coal-bearing strata kaolinite（MnFe₂O₄/CK）composite was prepared by hydrothermal method.The degradation rate of aureomycin hydrochloride（CTC·HCl）reached 85.1%within 60 min under the double action of light and peroxydisulfate（PDS）.Radical capture experiments and electron paramagnetic resonance analysis showed that active free radicals（h⁺and^·O₂^–）were the main ways to degrade CTC·HCl.In addition,MnFe₂O₄/CK composites show good stability and reusability in the cyclic experiments and degradation experiments of different pollutants.（3）La₂Ti₂O₇/acid-modified coal-bearing strata kaolinite（La₂Ti₂O₇/AK）composite was successfully synthesized by hydrothermal method.It was found that the composite can enhance the selective adsorption and photocatalytic degradation of complex wastewater.The adsorption rate of La₂Ti₂O₇/AK for CTC·HCl is 79.81%.Moreover,La₂Ti₂O₇/AK showed excellent adsorption capacity for CTC·HCl in a wide p H range.In addition,La₂Ti₂O₇/AK has excellent photocatalytic degradation effect,and the removal efficiency of CTC·HCl can reach 88.61%.La₂Ti₂O₇/AK can be used repeatedly to treat the wastewater containing CTC·HCl,with less loss of adsorption and photodegradation properties,and has good stability and reusability.Based on the above research results,this paper provides a new idea for the synthesis of kaolinite-based composites and their application in efficient and green treatment of dyes and antibiotics in wastewater.