Study On Preparation Of Biological Activated Carbon Based On Steel Slag-modified And Evaluation Of Its Formaldehyde Degradation Performance

As people’s requirements for indoor air quality are getting higher and higher,indoor formaldehyde emissions are also strictly controlled.As a common porous material with excellent adsorption performance,activated carbon is usually used in the treatment of indoor air pollutants,but activated carbon also has problems such as short service life,secondary pollution of the indoor environment,and spontaneous combustion.As a kind of industrial waste slag,steel slag has a large amount of accumulation,but its comprehensive utilization rate is low.In view of the above problems,considering the safe utilization of solid waste resources,it provides a reference for the preparation of steel slag-based bio-activated carbon with efficient formaldehyde degradation and flame retardant properties by effectively utilizing steel slag and walnut shells.In this study,steel slag and waste walnut shells were used as raw materials.First,the preparation of different steel slag powder was studied,and the grinding aid mechanism of steel slag grinding aid was analyzed.Then,the steel slag-based biological activated carbon was prepared by using steel slag powder to modify the waste walnut shell,the chemical composition of steel slag powder,the particle size distribution of steel slag powder and pore structure of steel slag-based biological active carbon on its formaldehyde degradation performance were explored,In addition,the differences in the flame retardancy of different ratios were investigated.Finally,the effect of chemical composition and particle size distribution of steel slag powder on its formaldehyde degradation performance was evaluated by the improved grey correlation method,and the reliability of the method was verified by comparing with the experimental results.The main research contents of this paper are as follows:（1）Research on the preparation of different steel slag powder and the mechanism of grinding aid.Different steel slag powder were prepared by steel slag composite grinding aids,and the chemical composition,particle size distribution and grinding-aid mechanism of different steel slag powder were studied.It was found that the steel slag composite grinding aid had good grinding effects on thermal powered slag I and II,electric furnace slag and wind-broken slag powder,,and the obtained steel slag powder meet the requirements of modification and preparation of biological activated carbon.（2）Research on the properties and action mechanism of steel slag-based biological activated carbon.The formaldehyde degradation performance was tested by the environmental test chamber method,the chemical composition of steel slag powder,the particle size distribution of steel slag powder and pore structure of steel slag-based biological active carbon were measured by XRF,LPSA and BET,furthermore effects of them on degradation performance of formaldehyde by use of slag-based biological activated carbon,in addition,its ignition point was tested to study the flame retardant performance of steel slag-based bio-activated carbon,so as to reveal its formaldehyde degradation and flame retardant mechanism.It was found that the prepared the steel slag-based bio-activated carbon show good formaldehyde degradation;and the formaldehyde degradation rate was 57.5%after 10 h;when the grinding time of the electric furnace slag was 90 min,and the amount of the electric furnace slag powder was 20 g.The steel slag-based bio-activated carbon modified by electric furnace slag powder has the best flame retardant performance,and its ignition points are 441℃,486℃and 480℃respectively.（3）Evaluation of formaldehyde degradation performance of steel slag-based biological activated carbon.The grey correlation analysis method was used as the main method,and the entropy weight and the coefficient of variation method were introduced to calculate the weighted correlation degree of the chemical composition and particle structure distribution of the steel slag powder on its formaldehyde degradation performance.The findings were consistent with the experimental method conclusions.The synergistic effect of adsorption degradation and catalytic degradation possessed by Al₂O₃,Fe₂O₃and Mn O is the main reason for the improved performance of the steel slag-based bio-activated carbon in degrading formaldehyde;improving the uniformity of particle size distribution of electric furnace slag powder can help improve its formaldehyde degradation performance;the pore volume and specific surface area were reduced,its formaldehyde degradation performance would not be reduced.The results show that the evaluation method is effective.