Effect Of Ageing On Adsorption Of Pollutants On Mixed Biochar

Heavy metals and antibiotics are ubiquitous in the environment,seriously endangering human health.Biochar as a green carbonized material have presented an excellent sorbent for heavy metals and antibiotics.In practice,raw materials from the same source are usually not well separated and often used as a whole to prepared mixed biochar through pyrolysis.But current research mainly focuses on the adsorption performance of the biochar prepared from a single biomass and ignores the influence of the effect of mixed biomass.In addition,it should be emphasized that when biochar is exposed in the field,the physicochemical properties will be affected by geochemical weathering process called as "ageing" and further affect the adsorption behavior.The long-term ageing effects on mixed biochar was lack that is crucial for evaluating the long-term environment performance of mixed biochar in actual use,and warranted to precisely evaluateCorn cob and corn stalk as two of the most common biomasses were selected as raw materials to prepare biochar.Considering that raw materials from the same source often cannot be separated well,the biochars derived from mixed corn cob and corn stalk in five alternative proportions(1:0,3:1,1:1,1:3,0:1)were prepared at three alternative peak temperatures(350,500,650?).The 5%H2O2 method were used to simulate ageing effect on different biochar.The multifarious characterization methods and adsorption batch experiments of Cu2+and antibiotic sulfapyridine(SPY)were used on different biochar to systematically investigate the effects of mixed raw material proportion,pyrolysis temperature and ageing on the physicochemical properties and adsorption capacity of biocharThe results showed that(1)mixed biochar derived from higher corn stalk proportion,with higher yield and more ash content,exhibited stronger adsorption capacities of Cu2+ and SPY;(2)the precipitation could be the predominant mechanism involved in Cu2+ adsorption by fresh and aged biochar.The adsorption of SPY was controlled by ?-? EDA interactions and H-bonding interactions;(3)The pyrolysis temperature is another important parameter to enhance the adsorption capacities;(4)Ageing treatment could increase the adsorption capacity of SPY in all biochar,but inhibited the adsorption capacity of Cu2+,except for low-temperature biochar;(5)The adsorption of Cu2+and SPY by fresh and aged biochar was significantly affected by the pH value.The increasing pH enhanced the adsorption capacity of biochar to Cu2+,but inhibited SPY.(6)The mixed biochar C1S3-650 had a strong stability,maintained a high adsorption capacity of pollutants before and after aging,and was less affected by the environmental pH value,so it has a good utilization value.These findings suggest us to consider the effect of mixed raw materials on immobilization of environmental pollutant and long-term effect should be considered when use biochar as an amendment for contaminated sites.