Removal of heavy metals from aqueous solution by biochars derived from anaerobically digested biomass

• DOI: 10.1016/j.biortech.2012.01.072
• Publication Date: 2012-01-30T05:27:26Z
• Authors: Mandu Inyang; Bin Gao; Ying Yao; Yingwen Xue; Andrew R. Zimmerman; Pratap Pullammana...; Xinde Cao
• Keywords: Solutions; Kinetics; Metals, Heavy; 0211 other engineering and technologies; Water; Anaerobiosis; Biomass; 02 engineering and technology; 7. Clean energy; 6. Clean water

This study examined the ability of two biochars converted from anaerobically digested biomass to sorb heavy metals using a range of laboratory sorption and characterization experiments. Initial evaluation of DAWC (digested dairy waste biochar) and DWSBC (digested whole sugar beet biochar) showed that both biochars were effective in removing a mixture of four heavy metals (Pb(2 +), Cu(2+), Ni(2+), and Cd(2+)) from aqueous solutions. Compared to DAWC, DWSBC demonstrated a better ability to remove Ni and Cd. Further investigations of lead sorption by the two biochars indicated that the removal was mainly through a surface precipitation mechanism, which was confirmed by batch sorption experiments, mathematical modeling, and examinations of lead-laden biochars samples using SEM-EDS, XRD, and FTIR. The lead sorption capacity of the two biochars was close to or higher than 200mmol/kg, which is comparable to that of commercial activated carbons.