Adsorption efficiency of batik dye by modified Dialium cochinchinense activated carbon beads: kinetics and thermodynamics

Dialium cochinchinense seeds as local agricultural waste were used with two preparation methods to create new adsorbents: Dialium cochinchinense seed activated carbon (DCS-AC); and a bead form composite of poly(lactic acid)/Dialium cochinchinense seed powder activated carbon (PLA/ DCS-AC). The target was an eco-friendly, bio-degradable, inexpensive material for the treat-ment of wastewater from batik dyeing. Brunauer-Emmett-Teller surface area, scanning electron microscopy images, Fourier-transform infrared spectra, and the point of zero charge (pHpzc) were assessed. The effects of contact time, adsorbent dosage, pH, and temperature were examined and the Langmuir adsorption isotherm fit well. The calculated maximum adsorption capacities (qm) were 222.22 and 147.06 mg g-1 for DCS-AC and PLA/DCS-AC, respectively. The adsorption process was endothermic and spontaneous. Moreover, the desorption study confirmed that DCS-AC and PLA/DCS-AC can be regenerated. The batch adsorption of batik dye by DCS-AC and PLA/DCS-AC adsorbents appears an efficient approach to wastewater treatment.