Kinetics Study of Nickel (II) Ions Sorption by Thermally Treated Rice Husk

The utilization of agricultural wastes, in the original or modified form, as heavy metal ion sorbents has been widely investigated. In this paper, we report the results of our study on kinetics of Ni(II) ion sorption by thermally treated rice husk. The sorbent was prepared by heating the rice husk at 650°C for two hours. For the kinetic study, the solute sorbent contact periods were varied between 30 to 180 minutes, whereas, the other parameters (pH, initial concentration, temperature and adsorbent dosage) were kept constant. The results revealed that the sorption capacity increased with the increase of contact period. The sorption data were evaluated using pseudo-first order, pseudo-second order and intraparticle diffusion models. The rate constants of sorption and diffusion were also determined. The data were best fitted with pseudo-second order kinetics model sorption which indicates that the sorption of Ni(II) ion by this thermally treated rice husk is via chemisorption process.