Characterization of upgraded hydrogel biochar from blended rice husk with coal fly ash

Abstract

Rice husk biochar (RB) blended with coal fly ash (CFA) is used as a material to develop hydrogel for heavy metal removal. This combination, namely hydrogel rice husk biochar-coal fly ash (HRB-CFA) composite is synthesized by embedding the biochar into acrylamide (AAM) as monomer, with N,N’-Methylenebisacrylamide (MBA) as crosslinker and ammonium persulfate (APS) as initiator. While activated carbon (AC) remains an expensive material, HRB-CFA is attracting great interest for its use in the absorption of organic contaminants due to its low material cost and importance as renewable source for securing future energy supply in the environmental system. Although the CFA does not have the surface area as high as AC, certain metallic components that are naturally present in the CFA can play the catalytic role in the removal of heavy metal from wastewater. The percentage of heavy metal removal is depends on the parameters that influence the sorption process; the effect of pH solution, dosage of adsorbent, initial concentration of solution, and contact time. The aim of this study is to characterize HRB-CFA by performing several analyses such as the Brunauer-Emmett-Teller (BET), thermogravimetric (TGA) and field emission scanning electron microscopy (FESEM) methods. The results obtained revealed that the best hydrogel ratio is 0.5:0.5 of blended RB and CFA, as proven by BET surface area, pore volume and pore size of 3.5392 m2/g, 0.00849 cm3/g and 90.566 Å, and the surface morphology showed an increase in porosity size.