Biosorption of zinc from aqueous solutions using biosolids

The potential to remove zinc from aqueous solutions through biosorption using biosolids was investigated. Batch experimental results showed that the biosorptive capacity of dry, unground biosolids was 0.564 mM/(g dry biosolids). Pretreatment of the biosolids, including drying and grinding, affected the sorptive potential of the biomass. Kinetic experiments showed that dilute zinc solutions reached equilibrium within 5 h, whereas equilibrium was not reached until 24 h for more concentrated solutions. The biosorptive capacities were dependent on zinc solution pH, with pH 4 being optimal. Infrared spectra analysis suggested that carboxyl functional groups are responsible for zinc uptake.