Solmaz Saadat - Ph.D. of Civil and Environmental Eng., Dept. of Civil and Environmental Eng., Shiraz University
Fatemeh Azadi - Master student of Civil and Environmental Eng., Shiraz University
Ayoub Karimi-Jashni - Assist. Prof., Dept. of Civil and Environmental Eng., Shiraz University

Continuous adsorption experiments were performed in a fixed bed adsorption column to evaluate the performance of NaOH modified rice husk as a low-cost adsorbent for the removal of Ni(II) from aqueous solutions. The up flow column was operated at room temperature and the effects of experimental conditions, such as the inlet metal concentration, flow rate and bed depth, were studied and the corresponding breakthrough curves were obtained. The dynamics of the adsorption process were fitted by empirical models of Thomas and Adams-Bohart. Experimental data showed better fits to the Adams-Bohart model than the Thomas model. The breakthrough time increased from 2.5 to 5 h with increasing in bed depth from 10 to 30 cm. The sorption parameters were also affected by the inlet metal concentration and flow rate. Results indicate that NaOH modified rice husk can be used as an efficient adsorbent for Ni(II) removal.

Ni(II), Adsorption, Modified rice husk, Fixed bed column, Breakthrough curve