Adsorption of cadmium ions by wheat bran treated with pectinase

In this study, we investigated the surface properties of raw wheat bran (R-WB) and wheat bran treated with Pectinase PL (P-WB) to evaluating its efficacy for removal of cadmium from waste water. The concentration of cadmium ions adsorbed by them was evaluated. The concentration of carboxyl groups of R-WB (3.56 mmol/g) was greater than that of P-WB (2.11 mmol/g), which indicated that the pectin of R-WB was broken down, resulting in a decrease in the concentration of carboxyl groups due to the enzyme treatment. From the scanning electron microscope (SEM) images of P-WB, the pores were newly generated with enzyme treatment. The concentration of cadmium ions adsorbed onto R-WB was greater than that of cadmium ions adsorbed onto P-WB. These results show that the adsorption mechanism of cadmium ions onto R-WB and P-WB depends on the carboxyl groups of pectin.