Selective adsorption of heavy metal ions from aqueous solution by modified bagasse
Shuxin Huang, Jin Shan, Yi Wang, Jiequan Liu, Junxia Yu, Dong Liu, Ruan Chi
Abstract
Adsorption performances of heavy metal ions (Pb2+, Cu2+, Zn2+ and Cd2+) and the common co-ions of alkali and alkali earth metal ions (Mg2+, Ca2+ and K+) on phosphoric acid modified bagasse were investigated in single and multi-component systems, and selective removal of heavy metal ions from wastewater were studied under different sorbent dosage. Results showed that the maximum amount of Pb2+, Cu2+, Zn2+, Cd2+, Mg2+, Ca2+ and K+ adsorbed on the modified bagasse was 0.77, 0.64, 0.49, 0.69, 0.47, 0.67 and 0.09 mmol/g, respectively, which was much higher than the unmodified bagasse. Heavy metal ions and co-ions adsorption could complete within 60 min, and their kinetic curves fitted well by the pseudo-second order model. Competitive adsorption results showed the modified bagasse had much higher affinity toward heavy metal ions than co-ions due to their ion characteristic. Waste water treatment experiment showed that at the sorbent dosage of 0.015 g, removal efficiency of Pb2+, Cu2+, Cd2+ and Zn2+ was 94.53, 92.74, 70.46 and 83.30% while that of Mg2+, Ca2+ was only 6.64 and 4.75%, respectively, demonstrating that heavy metals could be removed selectively from wastewater by the modified sorbent. The as prepared sorbent had great potential in heavy metal wastewater treatment.