Preparation Of Novel Rectorite/Sludge Derived Biochar Composites And Investigation Of Its Adsorption/Catalysis Property

With the acceleration of ubbanization and improvement of life quality,disposal and utilization of municipal sewage sludge are a growing concern.Pyrolysis is a cost-effective and clean disposal method.Sludge disposal and production of reused sludge derived biochar can be achieved.However,wide application of biochar is restricted due to relatively low properties.Application of low cost and convenient method to enhance the property of sludge derived biochar is crucial.Rectorite is a kind of lamellar clay mineral,because of its large specific area and strong cation exchange capacity,rectorite has good adsorption property.In this work,rectorite and sludge biomass are mixed and then pyrolyzed and carbonized to prepare rectorite/sludge derived biochar composites with relatively good properties.Then functional material is loaded on the surface to enhance its property and broaden its application.A series of rectorite/sludge derived biochar based composite materials have been succefully prepared.The specific research contents and conclusions are as follows:(1)The rectorite/sludge derived biochar composites and Mn O₂ modified rectorite/sludge derived biochar composites have been fabricated and characterized.Results indicated that lamellar rectorite is dispersed on the surface of sludge derived biochar.After modification of Mn O₂,amorphous and porous Mn O₂disperse on the surface of the composites.The surface of the composites is rich in surface functional groups and the BET surface area and total pore volume of the composites are higher than that of the pristine composites.(2)The rectorite/sludge derived biochar composites and Mn O₂ modified rectorite/sludge derived biochar composites are used to adsorb Pb(II)and Cd(II)in aqueous solution.The majority adsorption capacity of Pb(II)and Cd(II)onto the modified composites are 96.2mg g^-1and 27.7mg g^-1,far higher than the pristine composites.Batch adsorption experiemnts show that the adsorption kinetics and isotherms of Pb(II)and Cd(II)onto the modified composites fitted well with Elovich kinetic model and Langmiur isotherm model.The adsorption of Pb(II)and Cd(II)onto the modified composites is a highly p H-dependent process.The adsorption thermodynamic shows that the adsorption of Pb(II)and Cd(II)onto the modified composites is spontaneous,endothermic in nature and randomness increased process.(3)The rectorite/sludge derived biochar composites supported Cu Fe₂O₄ have been fabricated and characterized.Results indicated that Cu Fe₂O₄ have an irregular polyhedral shape and evenly dispersed on the surface of rectorite/sludge derived biochar composites.Crystalline analysis,surface functional group analysis and surface element valence analysis further confirm that Cu Fe₂O₄ is successfully fabricated and loaded on the surface of rectorite/sludge derived biochar composites.The pore size analysis of the composites indicates that the composites are mostly mesoporous,which is beneficial to the interaction between the catalyst and the substrate during the catalytic reaction.(4)The rctorite/sludge biochar composites supported Cu Fe2O4 is used as catalyst to investigate its activation performance of persulfate(PS)to degrade Acid Orange 7(AO7).Results indicated that when the concentration of PS and catalyst is 2mmol L^-1 and 0.4g L^-1 respectively,the degradation efficiency is above 80%.The influencing factors experiment and free radical quenching experiment have been conducted,SO₄^·-plays a vital role in the degradation process,O₂^·-may also take part in the degradation process.Therefore,the rectorite/sludge derived biochar composites supported Cu Fe₂O₄ is a novel and high-efficiency catalyst.