Full Length Research Paper

Equilibrium and continuous flow studies on the sorption of Congo Red using ethylenediamine modified rice hulls

Siew-Teng Ong¹*, Eng Hooi Tay², Sie-Tiong Ha¹, Weng-Nam Lee² and Pei-Sin Keng³

¹Department of Chemical Science, Faculty of Science, Engineering and Technology, Universiti Tunku Abdul Rahman, Jln Universiti, Bandar Barat, 31900 Kampar, Perak, Malaysia.

²Department of Science, Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jln Genting Kelang, Setapak, 53300 Kuala Lumpur, Malaysia.

³Department of Pharmaceutical Chemistry, International Medical University, No.126, Jalan 19/155B, Bukit Jalil, 57000 Kuala Lumpur, Malaysia.

*Corresponding author. E-mail: ongst@utar.edu.my.

Accepted 23 September, 2009.

   Abstract

The effectiveness of using ethylenediamine rice hulls (EDA-RH) to remove Congo Red (CR) from synthetic dye solution was carried out in batch and column experiments under various experimental conditions. Surface morphology analysis was carried out also using atomic force microscopy (AFM). The experimental data obtained at different initial dye concentrations fitted well to pseudo-second order kinetic model. Application of Langmuir isotherm indicated that maximum sorption capacity of EDA-RH for CR was enhanced by 2-fold as compared to natural rice hulls. Column studies revealed that the breakthrough curves of CR followed the typical S shape of packed-bed systems and it was bed-depth and influent-concentration dependent. The BDST model was used to predict the bed-depth service time data at different bed depths. A plot of BDST at 50% breakthrough yielded a straight line that, however, does not pass through the origin. 

Key words: Sorption, ethylenediamine rice hulls, Congo Red, batch study, column study.