Native clay, MnFe2O4/clay composite and bio-composite efficiency for the removal of synthetic dye from synthetic solution: column versus batch adsorption studies

The Blue XGRRL dye removal efficiency native clay, MnFe2O4/clay composite, and biocomposite were studied. The adsorbent was characterized by X-ray diffraction and Fourier-transform infrared spectroscopy techniques. Affecting process variables, that is, temperature, pH, composite dose, initial concentration of dye and contact time were studied for enhanced dye removal. It was observed that pH 6-9, 0.05 g adsorbent dosage, 30 min contact time, 200 mg/L dye initial concentration at low temperature were the viable conditions for maximum adsorptive removal (49.93 mg/g) of dye. Langmuir isotherm along pseudo-second-order kinetic model fitted well to the dye adsorption data. Thermodynamic study revealed that the adsorption phenomenon was more viable at low temperatures as shown by lower Delta G degrees values. The Delta H degrees indicated the exothermic adsorption process of Blue XGRRL dye on to composites. Column bed height, Blue XGRRL dye initial concentration, and flow rate were studied in a column adsorption mode and it was observed that higher bed height, higher initial dye concentrations and low flow rates were observed to be more complimentary conditions for efficient adsorptive removal of dye in the column mode. Clay composite's efficiency was significantly higher vs. biocomposite that could be employed for the adsorptive removal of dyes from wastewater.