Biomodification of palm shell activated carbon using Aspergillus niger and Bacillus subtilis and its effect on the adsorption of lead ions from aqueous solutions

Abstract

Adsorption of lead ions from aqueous solutions using commercial untreated granular palm shell activated carbon (PSAC) and PSAC biomodified with Bacillus subtilis and Aspergillus niger biomass, respectively, was studied. The adsorption capacity of the three biosorbents was evaluated in batch adsorption experiments at pH 3 to 6; lead concentration varied between 20 to 300 mg/L. The PSAC-B. subtilis showed the highest uptake of lead at pH 6; it was followed by PSAC-A. niger and the original PSAC comprising 74, 72 and 65 mg Pb/g, respectively. The lowest removal of lead in the reversed order was observed at pH 3: 34, 37 and 40 mg Pb/g, respectively. The adsorption followed the pseudo-second reaction order for all biosorbents. High desorption efficiency (90%) was maintained in three consecutive cycles. The results show that the introduction of microbial biomass into the palm shell activated carbon matrix has potential to improve carbon’ sorption capacity towards lead ions.

Key words: Adsorption, lead, activated carbon, fungi, microorganisms, biosorbent.