Keywords: metal removal, equilibrium studies, macrophytes, isotherms, protonated macrophyte biomass, nickel, citric acid, Hydrilla Verticillata, biosorption, adsorption
Uptake of Ni (II) from aqueous solutions using protonated macrophyte biomass - equilibrium studies
The removal of Ni (II) from aqueous solutions using citric acid activated Hydrilla Verticillata biomass has been studied under batch conditions. The biosorbent characteristics were studied. Batch experiments were performed to study the biosorption of Ni (II) with respect to the effect of operating parameters like initial pH, adsorbent dosage, initial metal concentration, contact time and temperature. The adsorption of Ni (II) increased with increase in contact timer and reached equilibrium at 180 min. The maximum removal efficiency was attained at pH 5.0. The uptake capacity was found to decrease with increase in temperature confirming the exothermic nature of sorption process. The equilibrium data was fitted to three isotherms namely Langmuir, Freundlich and Temkin isotherms. Langmuir model provided the best correlation (R² > 0.98) for the biosorption of Ni (II) by the selected sorbent and the monolayer biosorption capacity was found to be 11.9 mg g−1.