Effective adsorption of nickel (II) with Ulva lactuca dried biomass: isotherms, kinetics and mechanisms

摘要

This study aimed to evaluate the Ni~(2+)ions adsorption capability of Ulva lactuca . The isotherms, kinetics and mechanisms for the adsorption of Ni~(2+)from aqueous solution by Ulva lactuca were also investigated. Influencing factors including initial pH, initial Ni~(2+)concentration, biomass, contact time were examined. The results indicate that the maximum Ni~(2+)adsorption capacity of 38.28 mg/g was obtained at pH 5, initial Ni~(2+)concentration 250 mg/L, biomass dosage 0.5 g/L and contact time 30 min. The adsorption can be well fitted with Langmuir isotherm, and the kinetics were well described by the pseudo-second-order model. The parameters of thermodynamics verified that Ni~(2+)adsorption on Ulva lactuca was a spontaneous and endothermic process. Analyses of FT-IR, SEM-EDS and XPS indicate that carboxyl and hydroxyl groups on the surface of biomass are involved in Ni~(2+)adsorption. The dried biomass of Ulva lactuca can be a cost-effective and eco-friendly adsorbent for the removal of Ni~(2+)from wastewater.