Preparation Of Rectorite/sludge Composited Biochar Materials And The Performance And Mechanisms Of Their Adsorption/catalysis

Clay minerals and carbon materials have received extensive attention in the fields of catalysis and environmental governance.Among them,rectorite and biochar are considered as ideal carriers for supporting metal/metal oxide nanoparticles because of their excellent properties.O n the one hand,rectorite（REC）is conducive to improving the dispersion and stability of the loaded nanoparticles by its high specific surface area.The synergistic effect between rectorite and metal oxides provides good performance of composite materials.On the other hand,domestic sewage sludge,as a waste,has not been used reasonably and effectively for a long time,which causing multiple problems such as environmental pollution and waste of resources.The use of sludge as a cheap raw material to prepare high-efficiency biochar（SDBC）adsorbents and catalyst carriers for the removal of polluted wastewater is the current research hotspot.This study combines the industrial background of rectorite,sewage sludge biocha and metal oxides,a noval series of rectorite/sludge composited biochar materials（RSDBC）have been succefully synthesized and characterized with several techniques.In addition,a var iety of functional mater ials were loaded on RSDBC to improve the performance and broaden the application fields.The catalytic degradation performance of composite materials for dyeing wastewater and the adsorption performance for heavy metals in water were investigated.Specific research results includ ing:（1）Preparation and characterization of rectorite sludge biochar composites（RSDBC）.The adsoption properties of composites for Pb（Ⅱ）and Cd（II）in water were investigated.The results of adsorption experiments show that the prepared RSDBC composites have better adsorption performance for heavy metals than single rectorite and slud ge biochar.The adsorption of RSDBC composites on Pb（Ⅱ）and Cd（II）can be fitted by pseudo-second-order kinetic model and Langmuir isotherm model.The maximum adsorption capacit ies of RSDBC for Pb（Ⅱ）and Cd（II）were 30.91 mg/g and 15.86 mg/g,respectively.（2）Preparation and characterization of manganese dioxide-supported rectorite sludge biochar composites（MnO₂@RSDBC）.The adsoption properties of composites for Pb（Ⅱ）and Cd（II）in water were investigated.Adsorption experiments show that the adsorptio n of MnO₂@RSDBC composites on Pb（Ⅱ）and Cd（II）can be fitted by pseudo-second-order kinetic model and Langmuir isotherm model.The adsorption process is greatly affected by p H.The adsorption processes of MnO₂@RSDBC for Pb（Ⅱ）and Cd（II）are spontaneous endothermic processes,and the degree of chaos increases.The maximum adsorption capacities of MnO₂@RSDBC for Pb（Ⅱ）and Cd（II）were 111.41 mg/g and 46.21 mg/g,respectively.Loaded MnO₂ greatly improved the adsorption performance of RSDBC for heavy metals.（3）A spinel copper ferrite supported rectorite sludge biochar nanocomposite（C u Fe₂O₄@RSDBC）was prepared and characterized,and the degradation of acid orange 7（AO7）by activated persulfate PS was explored.The catalytic experiment results show that the degradation of AO7 by C u Fe₂O₄@RSDBC is in accordance with the pseudo first-order kinetic model.The degradation efficiency of composite activated persulfate system for AO7was closed to 94%.A variety of intermediate products were detected and correspond ing degradation routes were drawn.Sulfate radicals played a major role in the degradation of AO7.（4）A zinc oxide-supported rectorite sludge biochar nanocomposite（ZnO@RSDBC）was prepared and characterized,and the photocatalytic and PS activation performance of the composite and the degradation of AO7 were investigated.The experimental results show that the degradation of AO7 by ZnO@RSDBC nanocomposites fit the Langmuir-Hinshelwood kinetic model,and the degradation efficiency of AO7 by photocatalytic/PS activation system of composites reaches 96%.The degradation pathway was analyzed.Free radical competition experiments show that h_vb are the main active substances in the reaction system.（5）The photocatalytic/PS activation performance of RSDBC composite,MnO₂@RSDBC composite,CuFe₂O₄@RSDBC nanocomposite and ZnO@RSDBC nanocomposite for treatment of organic dye in textile wastewater were discussed.The results show that ZnO@RSDBC has the best catalytic treatment effect and the decolorization efficiency of AO7 was closed to 95%.The main components of the textile wastewater and the changes before and after the reaction were identified.The results show tha t the composite has a good degradation effect on the main dye components in the textile wastewater.Especially,the efficiency of organic dyes with simple structure and low molecular weight is more remarkable.