Removal of methylene blue from aqueous solution by rubber (Hevea brasiliensis) seed shell in a fixed-bed column

The present study investigated the dynamic sorption of methylene blue (MB) from solution using rubber seed shell (RSS) in a fixed-bed column. The process of sorption of MB from solution was analyzed using five different isotherm models (Langmuir, Freundlich, Temkin, Harkins-Jura, and Halsey isotherm equations), and the monolayer sorption capacity (82.64 mg/g) obtained from the Langmuir plot was compared with the bed depth service time (BDST) capacity (703.42 mgA) obtained from the BDST model plot. The effect of two process variables (RSS bed height and initial MB concentration) on the dynamic sorption of MB on RSS was studied using the breakthrough curve. The total time (t,) for the establishment of primary adsorption zone (PAZ), the time required for the movement of the PAZ down the length of the RSS bed (t3), the fractional capacity (f), and the length or depth of PAZ (3) were evaluated. The operating design of the fixed was altered using serial dynamic, sorption study, and the sensitivity of the RSS bed to drought was monitored when the Ci/Cf approached 0.5. The operational parameters of these variations were also estimated. The process variables were correlated with the BDST model, and a linear graph with high linear correlation (R-2 > 0.9) values was obtained (0.9944 and 1.0000 at T-b10 and T-b50 respectively). The results obtained from the correlation of the process variables with the BDST model were used to predict the effect of changing the process variables on the system by using the BDST approach. (C) 2008 Curtin University of Technology and John Wiley & Sons, Ltd.