Improvement of cadmium ion removal by base treatment of jumper fiber

摘要

Juniper is a small-diameter underutilized lignocellulosic material. We evaluated the efficacy of base-treated juniper fiber (BTJF) for cadmium (Cd~(2+)) sorption and the viability of juniper fiber as a sorbent for removing Cd~(2+) from water. Fourier transform infrared spectroscopy analysis indicated that carboxylate ion is a major functional group responsible for Cd~(2+) sorption. The apparent ideal sodium hydroxide concentration for base treatment is approximately 0.5M. A batch sorption isotherm test showed that equilibrium sorption data were better represented by the Langmuir model than the Freundlich model. After base treatment, the maximum Cd~(2+) sorption loading, Q_(max), was greatly improved (9.18-29.54mg/g), despite a decrease in specific surface area. A pseudo-second-order kinetic model fitted well for the sorption of Cd~(2+) onto BTJF. Initial metal ion concentration and treatment alkalinity were found to be major parameters influencing the kinetics of the sorption reaction. As a result of its strong ability to bind cadmium and its faster kinetics in low concentration, BTJF could be an inexpensive and efficient sorbent for removing heavy metals from stormwater runoff.