Preparation Of Biochar And Its Treatment Of Formaldehyde Pollution

Formaldehyde is a pollutant that has a great impact on the environment and human health,and has received much attention.At present,a lot of research has been done on the pollution treatment of formaldehyde,and some achievements have been made,but there are still many problems to be studied and improved,such as causing secondary pollution,high cost of treatment agent or energy consumption.From the perspective of waste recycling and reuse,this paper selects three different wastes as biomass materials（pork bone,corn cob,chicken manure）for high temperature treatment to obtain biochar and modify it.The modified biochar was studied for the adsorption treatment of formaldehyde pollutants,and the following conclusions were drawn:（1）Pork bone biochar PC0,PC0 impregnation and hydrogen peroxide were prepared by pyrolysis of pig bone.The modified biochar PC1 was prepared in the urea solution,and the modified pig bone charcoal was adsorbed and the PC2 was filtered.At the same time,the prepared biochar was characterized by FT-IR spectrophotometer,XRD and SEM.The characterization showed that the charcoal contained calcium,hydroxyl and phosphate groups.The characterization showed that PC1 had better affinity,higher porosity and ratio.Large surface area.The effects of four preparation conditions,such as impregnation ratio,immersion time,pyrolysis temperature and pyrolysis time,on the treatment performance of formaldehyde contaminated aqueous solution were studied.Orthogonal test analysis showed that the influencing factors of preparation conditions were:impregnation ratio>pyrolysis temperature>immersion time>pyrolysis time.The single factor experiment showed that the impregnation ratio was 1:1.5,the pyrolysis time was 2 h,the pyrolysis temperature was450°C,the adsorption time was the best when the immersion time was 4 h,and the saturated adsorption capacity of formaldehyde was 2.87 mg/g.（2）The modified corncob carbon was prepared by using corn cob as raw material,pretreated corn cob with a certain concentration of potassium permanganate solution and Fe³⁺to prepare modified corncob carbon.After filtration,COC2 was obtained.The structure,crystal form and morphology of COC0,COC1 and COC2 were characterized by FT-IR spectrophotometer,XRD,SEM and EDS.The characterization showed that the surface of COC1 was loaded with MnO₂ and Fe³⁺,and the structure of aerobic functional groups increased.The effects of potassium permanganate mass concentration,initial formaldehyde concentration,dosage and adsorption temperature on the treatment performance of formaldehyde contaminated aqueous solution were also studied.The single factor experimental analysis showed that the mass concentration of potassium permanganate was 2%,the initial concentration of formaldehyde was 40 mg/L,the dosage was 0.4 g,the adsorption temperature was 10°C,and the adsorption was 2.79 mg/g.The experimental design analysis of the response surface expert-design8.0 showed that the significance of the impact factor was:initial formaldehyde concentration>biochar dosage>adsorption temperature.（3）The biochar prepared by using chicken manure as raw material and modified by saturated sodium carbonate and saturated sodium hydrogen sulfite was prepared experimentally.Comparative analysis of the prepared materials showed that the carbon content and sodium content of the modified chicken charcoal increased,and there was also the introduction of S.The original elements,functional groups and pores in the chicken charcoal after adsorption are reduced or disappeared by the action of formaldehyde.The single factor adsorption formaldehyde test showed that when the pyrolysis temperature was450°C,the adsorption time was 5 h,the dosage was 0.5 g,and the initial concentration was30 mg/L.The treatment effect of chicken charcoal on formaldehyde contaminated aqueous solution was better,and the adsorption efficiency was 86.12%.The kinetic and thermodynamic analysis of the process of treating formaldehyde-contaminated aqueous solution can be obtained:the treatment process is applicable to the pseudo-second-order kinetic equation,and the treatment of formaldehyde-contaminated carbon in formaldehyde-contaminated aqueous solution is a synergistic effect of physical and chemical adsorption and spontaneous and endothermic The process has the adsorption characteristics of mesoporous adsorbents;the adsorption process indicates that it conforms to the Langmiur model,and the adsorption is mainly by monolayer adsorption.（4）By comparing the performance of the adsorption of formaldehyde on the prepared biochar,it can be seen that the modified biochar has a great improvement in the treatment performance of the formaldehyde-contaminated aqueous solution before the modification,and the unmodified The treatment performance of biochar on formaldehyde-infected aqueous solution:CHC0>PC0>COC0,CHC0 adsorption efficiency can reach 60.32%;the modified biochar has the best treatment performance for formaldehyde-infected aqueous solution PC1>CHC1>COC1,PC1 treatment efficiency is best It is 91.74%.