Removal of Pb (II) from Aqueous Solution by a Pectin-Producing Alga, <i>Penium margaritaceum</i>, Immobilized on Filter Paper

Lead (Pb) pollution from local mines and industrial use increases risks for human, animal, and plant health. Pectin is an effective chelator of Pb, and it has been shown that a unicellular green alga, Penium margaritaceum, synthesizes pectin in the cell wall. In this study, the ability of P. margaritaceum to remove Pb from an aqueous solution was investigated. Energy dispersive X-ray spectroscopy revealed that two strains of P. margaritaceum accumulated Pb on the cell surface. Hence, P. margaritaceum cells were immobilized on cellulose filter paper. The immobilized algal cells were soaked in 1.0 mg/L Pb solution with gentle shaking for 8 h, and Pb in the solution and on the filter paper was measured by flame atomic absorption spectrometry. The immobilized algal cells continuously decreased the Pb concentration to less than 0.5 mg/L and recovered 31.8–32.7% of added Pb. The specific decrease in Pb and increase in Ca were observed in the presence of 1.0 mg/L each of Ca, Mg, Na, and K. Fourier transform infrared spectra suggested that the carboxylic acid group would be responsible for the adsorption of Pb. This study is the first to demonstrate the effectiveness of the immobilized P. margaritaceum cell in removing Pb from aqueous solutions with simple solid–liquid separation