Study On The Treatment Of Phenol By Magnetic Biochar Fenton-Like Process In Water And The Promoting Effect Of Hydroxylamine Hydrochloride

Phenolic wastewater pollution is serious in China at present.In view of the shortcomings of traditional Fenton method,such as limited p H range,large Fe loss and poor mineralization ability,this study took phenol as the representative phenolic pollutant,and adopted magnetic biochar synthesized by straw biochar supported Fe₃O₄ as adsorbent and catalyst to catalysis the degradation of phenol by H₂O₂.The promoting effect of hydroxylamine hydrochloride（HAHC）on the system was investigated.This study of the preparation of magnetic biochar（BC-Fe₃O₄）is a straw biomass as a matrix,under the condition of low temperature oxygen pyrolysis to form contains pore structure and abundant surface functional groups of straw biochar,coprecipitation method adopted to assign a magnetic,and by comparing the different carbon iron quality ratio of magnetic system of biochar catalytic effect on the degradation of phenol,The preparation process of magnetic biochar was optimized.SEM,EDS,XRD,FTIR,VSM and XPS were used for analysis and observation.The results show that the prepared BC-Fe₃O₄ biochar has a uniform distribution of C and Fe,a Fe₃O₄ phase structure,-OH,C-O,C-H,C-C,C=O,C=C,Fe-O bond on the surface,a magnetic intensity of 13.50 emu/g,and a good stability at p H 3.0～12.Taking phenol concentration（20,50,100 mg/L）,BC-Fe₃O₄ dosage（0.5,1.0,1.5mg/L）,p H（3,5,no adjustment）as variables,orthogonal test with three factors and three levels and study results of BC-Fe₃O₄ adsorption effect on phenol in water:The maximum adsorption capacity of BC-Fe₃O₄ biochar for phenol is only 22.342 mg/g,and the adsorption effect of BC-Fe₃O₄ biochar for phenol is not ideal.Using BC-Fe₃O₄ as catalyst,the results of a series of studies on phenol degradation by magnetic biochar/H₂O₂ system under the control of single factor variable showed that the removal rate of phenol solution at 50 mg/L could reach 98%under the optimal reaction parameters.The removal rate of phenol was still higher than 97%after repeated use of BC-Fe₃O₄ for 5 times.The main free radicals of the reaction are·OH and HO₂·.At 120min,the mineralization rate of phenol was about 60%.In the study of degradation of phenol in BC-Fe₃O₄/H₂O₂/HAHC system with hydroxylamine hydrochloride（HAHC）,the optimal parameters are as follows:phenol concentration is 100 mg/L,material dosage is 0.5 g/L,H₂O₂ concentration and HAHC concentration are 10 m M,temperature is 298 K.At this time,the removal rate of phenol was about 98.5%.The degradation process of phenol conforms to the quasi-first order kinetic model,and the degradation requires low energy.The removal rate of phenol by BC-Fe₃O₄ was still higher than 90%after repeated use for 5 times.The phase structure of BC-Fe₃O₄ did not change significantly before and after the reaction.The Fe content decreased slightly and the properties were stable.The promoting effect of HAHC mainly comes from HAHC,which can accelerate the transformation of Fe³⁺to Fe²⁺,and can react with H₂O₂ to produce·OH,and improve the removal rate of phenol.In this paper,BC-Fe₃O₄ magnetic biochar was successfully prepared from straw,and BC-Fe₃O₄/H₂O₂ system on phenol degradation series of research results can provide reference for agricultural waste straw resource utilization way,as well as the degradation of phenol pollutants mechanism and effective removal of wastewater containing phenol industry provide certain theoretical support.