Adsorption of heavy metals from the aqueous solution using activated biomass from Ulva flexuosa

The removal of various highly toxic heavy metals from wastewater environment is an important task to improve environment. The biosorption potential of cadmium, cobalt and zinc was evaluated using Ulva flexuosa biomass. The impacts of adsorbent dosage, pH of the medium, contact time, and agitation speed were analyzed. The maximum biosorption potential was reached at pH 4.0, 0.4 g initial biosorbent dosage, contact time 40 min and 30 mg/L initial metal concentration for cadmium, while the other factors were similar to zinc, except 35 min contact time (p < 0.01). The optimum absorption was pH 4, 0.6% adsorbent dosage, after 30 min contact time with the heavy metals and 40 mg/L cobalt concentration. Heavy metal removal efficiency was 94.8 ± 3.3%, 87.5 ± 2.3%, and 90.8 ± 1.4%, for cadmium, cobalt, and zinc, respectively (p < 0.01). The Langmuir constant (R²) was 0.980 for cadmium, 0.838 for cobalt and it was 0.718 for zinc. The present results revealed that the selected acid modified biomass was highly suitable for the adsorption of metal ions such as, Cd²⁺, Co²⁺ and Zn²⁺. The present work revealed the potential application of algal biomass for the removal of various heavy metals from the environment.