摘要
Biochars produced from crab shell(CSB),oak sawdust(OB),Jeru salem artichoke tuber(JAB) and sorghum grain(SB) displayed distinguishable adsorption-related characteristics,such as specific surface area(SSA),ash content and acidic oxygen-containing functional groups(AFGs),which linked to the biochar adsorption mechanisms of most pollutants.Herein,PO4^3-,Cd^2+,and nitrobenzene(NB) were employed for adsorption by these biochars to elucidate the dominant factors for the adsorption.Adsorption performance of the three pollutants onto these four biochars varied considerably,as exemplified by the excellent adsorption of PO4^3- and Cd^2+ onto CSB(225.3 and 116.0 mg/g,respectively) as compared with onto the other three biochars(4.2-37.1 mg/g for P043-and 9.7-41.0 mg/g for Cd^2+).OB displayed the best adsorption of NB(72.0 mg/g),followed by SB(39.5 mg/g),JAB(31.1 mg/g),and CSB(23.6 mg/g).The kinetics and isotherm adsorption assessments couple with material characterization suggested that the sorption of selected pollutants on biochars was attributed to the multiple mechanisms involved,including coprecipitation,chemical bonds,cation exchange,physical absorption,and complexation.Further path analysis suggested that AFGs and ash content in biochars were more important than SSA with regards to pollutant removal,especially,with ash playing a crucial role in the removal of Cd2+ and PO43-,and AFGs being mainly re s ponsible for NB adsorption.These findings might offer guidance on the preparation or modification of biochar with a targeted function for pollutant removal through an understanding the dominant factors.
Biochars produced from crab shell（CSB）,oak sawdust（OB）,Jeru salem artichoke tuber（JAB） and sorghum grain（SB） displayed distinguishable adsorption-related characteristics,such as specific surface area（SSA）,ash content and acidic oxygen-containing functional groups（AFGs）,which linked to the biochar adsorption mechanisms of most pollutants.Herein,PO43-,Cd2+,and nitrobenzene（NB） were employed for adsorption by these biochars to elucidate the dominant factors for the adsorption.Adsorption performance of the three pollutants onto these four biochars varied considerably,as exemplified by the excellent adsorption of PO43- and Cd2+ onto CSB（225.3 and 116.0 mg/g,respectively） as compared with onto the other three biochars(4.2-37.1 mg/g for P043-and 9.7-41.0 mg/g for Cd2+).OB displayed the best adsorption of NB（72.0 mg/g）,followed by SB（39.5 mg/g）,JAB（31.1 mg/g）,and CSB（23.6 mg/g）.The kinetics and isotherm adsorption assessments couple with material characterization suggested that the sorption of selected pollutants on biochars was attributed to the multiple mechanisms involved,including coprecipitation,chemical bonds,cation exchange,physical absorption,and complexation.Further path analysis suggested that AFGs and ash content in biochars were more important than SSA with regards to pollutant removal,especially,with ash playing a crucial role in the removal of Cd2+ and PO43-,and AFGs being mainly re s ponsible for NB adsorption.These findings might offer guidance on the preparation or modification of biochar with a targeted function for pollutant removal through an understanding the dominant factors.
基金
supported by the Department of Science and Technology of Sichuan Province (Nos.2017SZ0028,2017HH0047)
