Removal of heavy metals from aqueous solution by using mango biomass

Abstract

Biosorbent and unfertilizable flowering buds of mango plant, a local agrowaste in Multan, Pakistan known as battoor is used in this study. Efficacy of the biosorbent is tested in batch for Pb²⁺, Cu²⁺, Zn²⁺ and Ni²⁺ in single metal solution under control experimental conditions. The concentration of the biomass was 0.5 g. Metal ions were analyzed by atomic absorption spectrophotometer using its specific lamp for each metal at a specific wavelength. It was found that metal sorption increases when the equilibrium metal concentration is raised. Uptake sorption in single metal system (SMS) were 24.4 mg Pb²⁺, 22.506 mg Cu²⁺, 18.932 mg Zn²⁺ and 17.618 mg Ni²⁺ per gram for Mangifera sp. (mango) biomass at the highest experimental solution concentration, which is 150 mgl^-1. Removal of metal were 92% Pb²⁺, 86.84% Cu²⁺, 83.96% Zn²⁺, 82.29% Ni²⁺ for Mangifera sp. (mango) biomass at the lowest experimental solution concentration, that is, 25 mgl^-1. Biosorption equilibrium isotherms were plotted for the metal uptake q against the residual metal concentrations in solution. The q versus Cf sorption isotherm relationship was mathematically expressed by linear Langmuir and Freundlich models. The values of separation factor or equilibrium parameter between 0 and 1 indicate the favorable sorption for four tested metal on the biosorbent. Values of surface coverage approach nearly 1 with the increasing solution concentration which indicate the effectiveness of the biosorbent under invesigation.The nonliving biomass of Mangifera sp. present comparable biosorption capacity for Pb²⁺, Cu²⁺, Zn²⁺ and Ni²⁺ ions with other types (sources) of biosorbent materials found in previous literature. Efficiency of the biomass indicates that they are effective in removing metal ions from single metal solutions as well as other co-ions with the main metal of solution.

Key Words: Mangifera sp., biosorbent, intercationic, efficacy.