Application of Amberlite XAD-7HP resin impregnated with Aliquat 336 for the removal of Reactive Blue - 13 dye: Batch and fixed-bed column studies

Abstract

Adsorption studies were performed in both batch and column mode for the removal of Reactive Blue-13 (RB-13) dye using Amberlite XAD-7HP resin impregnated with Aliquat 336. In batch mode, the effect of adsorbent dosage (1–4 g/L), initial dye concentrations (50–100 mg/L) at various temperatures (293–333 K), pH (2–12), contact time (0–60 min), and ionic strength of salt (NaCl & Na2SO4: 1–50 mg/L) solution were studied. The Langmuir isotherm showed the best-fitted correlation for the equilibrium data at all temperatures. Adsorption kinetics followed both the pseudo-second-order (RRB2 = 0.997) and Elovich model (RRB2 = 0.998). The average values of ΔGo, ΔHo, and ΔSo were found to be -30.828 kJ/mol, −68.07 kJ/mol, and −98.19 kJ/mol, respectively, showing that the adsorption process is exothermic, feasible and spontaneous. 4 g/L of impregnated resin gave effective removal (∼99 %) of RB-13 dye (50 mg/L) within 60 min, and change in solution pH did not affect removal percent significantly. The resin could be regenerated up to 2 cycles. In fixed bed column studies, the bed height (2–4 cm), flow rate (2.5–5 mL/min), initial dye concentration (20–50 mg/L) and bed temperature (303–323 K) were changed to see their effect. All breakthrough curves were well fitted by Thomas model. A column with 0.1127 m ID, 0.0199 m height and 0.066 kg impregnated resin will be sufficient to treat 10,000 L/day of RB-13 dye solution.