Study On The Preparation Of Straw-sludge Biochar And Its Activation Of Persulfate

In recent years,people’s living standards have greatly improved,and the amount of domestic sewage produced has increased rapidly.Municipal sludge,as the largest solid waste produced in the sewage treatment process,has also increased its production.Improper treatment can cause damage to soil,water and even air.At the same time,my country produces a large amount of rice straw every year,but most of the rice straw treatment methods are return to the field for composting and direct incineration,which results in low resource utilization and pollutes the atmospheric environment.The preparation of activated carbon is an environmentally friendly treatment method for reuse of municipal sludge and rice straw.Persulfate(S₂O₈^2-)has the advantages of good stability,high solubility and wide p H application range.Activated by light,heat,ultraviolet,and transition metal ions can generate strong oxidant sulfate radicals（SO₄^-·）,which degrade pollutants.The activation methods such as light and heat require additional energy,while the transition metal ion activation has the problem of secondary gold contamination after the reaction.Therefore,this paper chooses municipal sludge and rice straw as raw materials,zinc chloride as the activator,and chemical activation method is used to prepare straw-sludge biochar,which is characterized and analyzed,and the straw-sludge biochar is activated by straw-sludge biochar.Sulfate,establish an oxidation system,degrade pollutants and analyze the impact of adding soil to the microbial community.The main conclusions are as follows:The optimal preparation conditions for preparing straw-sludge biochar by zinc chloride activation method are:activation temperature is 500℃,raw material mass ratio is 1:2,activation time is 1.5 h,liquid-solid ratio is 1.5,The degradation rate of methyl orange after activation of persulfate by the straw-sludge biochar prepared under this condition can reach99%;through the characterization of the biochar,it can be obtained:The surface of the biochar has a porous structure;The straw-sludge organism Compared with sludge activated carbon,charcoal has an increased specific surface area and an increased micropore specific surface area;Biochar contains a large amount of C,O,Zn,and Pb elements;The absorption peak of the prepared biochar is from-OH,C=C,C=O caused by stretching vibration.When the initial concentration of simulated methyl orange is 100mg/L,the dosage of persulfate is 1mmol,the p H is 5,and the dosage of biochar is 0.03g,the degradation rate of methyl orange is the highest and the activation is the most efficient.Through the free radical quenching experiment,it is concluded that when the p H value is lower than 7.0,the active free radicals are dominated by SO₄^-·.When the initial p H is greater than 7.0,the active free radicals are dominated by·OH.Bohem titration experiments show that the content of-COOH and-OH is the highest in the preparation under optimal conditions.When the simulated petroleum contaminated soil,the degradation time is 7 days,the initial temperature is 30℃and the p H is 6 when the degradation rate of petroleum hydrocarbons in the soil is the highest,which can reach 39.60%.The microbial diversity decreased when the biochar/persulfate oxidation system was added to the system,and the soil microbes that added biochar/persulfate increased after 30 days.At the phylum level,Proteobacteria,Actinobacteria,and Bacteroidota are the main microorganisms.Inhibits the growth of Proteobacteria and Bacteroidota when the biochar/persulfate oxidation system is just added,and has no effect on Actinobacteria;Proteobacteria is promoted after 30 days And the growth of Bacteroidota（Bacteroides）inhibited the growth of Actinobacteriota（Actinobacteriota）.At the genus level,Alcanivorax,Marinobacter,Aliifodinibius and Salinisphaera are the dominant genus.When the biochar/persulfate oxidation system was first added,it inhibited the growth of Alcanivorax,Marinobacter,Aliifodinibius and Salinisphaera;30 days later,it promoted the growth of Alcanivorax,Mariinobacter,Aliifodinibius and Salinisphaera.