Chlorella sorokiniana immobilized on the biomatrix of vegetable sponge of Luffa cylindrica: a new system to remove cadmium from contaminated aqueous medium

A new sorption system of microalgal cells immobilized on the biostructural matrix of Luffa cylindrica for sequestering cadmium is reported. Free and immobilized Chlorella sorokiniana removed cadmium from 10 mg l−1 solution at the efficiency of 92.7% and 97.9% respectively. Maximum cadmium sorption was observed to be 39.2 mg g−1 at equilibrium (Ceq) of 112.8 mg l−1 by immobilized microalgal biomass as compared to 33.5 mg g−1 at Ceq of 116.5 mg l−1 by free biomass from initial concentration of 150 mg l−1. In continuous liquid flow column, the cadmium sorption capacity of immobilized C. sorokiniana was 192 mg g−1, which was 73.2% of the total metal passed in 51.5 l. Metal desorption with 0.1 M HCl was 100% and the desorbed immobilized system was reusable with a similar efficiency in the subsequent cycle.