Broadening of the optimal pH range for reactive dye biosorption by chemical modification of surface functional groups of Corynebacterium glutamicum biomass

Biosorption has been demonstrated to be a useful alternative to conventional treatment systems for the removal of dyes from dilute aqueous solution. This study deals with a renewable, low cost biosorbent derived from waste biomass of Corynebacterium glutamicum. The biosorbent has been proved to have higher (or comparable) capacity of dye uptake than conventional sorbents like activated carbons and ion-exchange resins. This study focuses on the underlying mechanisms on dye binding to the biosorbent. The binding sites were identified to be primary amine groups present in the biomass. Chemical modification of the biomass, FTIR and potentiometric titration studies revealed that carboxyl and phosphate groups play a role in repulsion of dye molecules, which inhibits the dye binding. Based on the biosorption mechanism, the performance of biosorbent could be enhanced by the removal of inhibitory carboxyl groups from the biomass for practical application of the biosorbents.