Rhodamine-B dye removal using aliquat-336 modified amberlite XAD-4 resin in fixed-bed columns in series

The present work reports studies on the effective removal of Rhodamine-B (RhB) using Aliquat-336 modified Amberlite XAD-4 resin in the fixed-bed columns in series. The effect of flow rate (Q = 2 to 6 mL·min^-1), bed height (h = 3.5 to 7 cm) and initial RhB dye concentration (C_in = 10 to 20 mg·L^-1) was studied. When a single column was used, 93% RhB dye was removed in 3 h at Q = 2 mL·min^-1, C_in = 10 mg·L^-1, and h = 7 cm. When three columns in series were used, almost 100% dye was removed until 80 h. The maximum breakthrough time (142 h) and saturation time (244 h) were found by keeping Q = 2 mL·min^-1, h = 7 cm of each column and C_in = 10 mg·L^-1. Mathematical modeling of the breakthrough curves was done by using Yoon-Nelson, Clark, Wolborska, and pore diffusion models. The Clark model best fitted the experimental data. The possible interaction mechanism between Aliquat-336 and RhB dye was proposed. The column was regenerated in continuous mode using 1 M HCl solution and maintaining a flow rate of 2 mL·min^-1.