Development of Poly(acrylic acid)-Modified Bacterial Biomass As a High-Performance Biosorbent for Removal of Cd(II) from Aqueous Solution

Anionic polymer, poly(acrylic acid) (PAA), was chemically attached onto the surface of Corynebacterium glutamicum biomass in order to introduce plenty of binding sites for cationic metals. In addition, to reinforce the mechanical strength of PAA-modified biomass (PAAB), it was cross-linked with glutaraldehyde (GA), referred as PAAB-G. Cd(II) was chosen as a model cationic pollutant in this work. FTIR and SEM were used to characterize PAAB-G. pH edge experiments revealed that Cd(II) biosorption was favored at pH 6. According to the Langmuir model, PAAB-G recorded the maximum Cd(II) uptake of 139.8 mg g^-1, with 3.2 times enhancement comparing that for raw biomass. Kinetic experiments showed that equilibrium was quickly obtained within 10 and 30 min for the raw biomass and PAAB-G, respectively. Desorption studies indicated that Cd-loaded PAAB-G could be easily eluted by adjusting water solution to pH 2.0. Therefore, this simple and cost-effective method for surface modification can be considered as a promising design tool for developing a high-performance biosorbent for removal of cationic metals from aqueous solution.