Abstract:
Dye removal from industrial effluents has become a significant issue in recent years. In this
study Jackfruit (Artocarpus heterophyllus) seed activated carbon (JSAC) with zinc chloride
(ZnCl2) was used to investigate its potential as an adsorbent for the removal of two cationic
dyes, methylene blue (MB) and crystal violet (CV) from aqueous solution. The dried
Jackfruit seed powder/ZnCl2 mixture was put on a crucible placed in an electrical furnace for
carbonization. The heating rate of carbonization was 25 ºC/min and continues until the final
temperature of 550 oC was reached and it was kept at this temperature for 30 min. The
absorbance for MB and CV solution was obtained using UV-Vis spectrophotometer.
Experimental parameters such as contact time, medium pH, adsorbent dosage, dye
concentration and temperature were studied to explore their effects on the adsorption of
cationic dyes onto the adsorbent. Thermodynamics, isotherm models and kinetics were
applied on the experimental data in order to further understand the adsorption process and
mechanism. Kinetic studies of the data showed that the adsorption follows the pseudosecond-order kinetic model. Thermodynamic parameters, enthalpy change (∆H), entropy
change (∆S) and Gibbs free energy change (∆G) were also calculated for the uptake of MB
and CV. This parameter showed that adsorption on the surface of JSAC was feasible,
spontaneous in nature, and endothermic between temperatures of 25 and 45 oC. The
equilibrium data better fitted the Freundlich isotherm model for studying the adsorption
behavior of MB and CV by JSAC. Maximum adsorption capacity of JSAC was observed to
1.82 mg/g for MB and 2.39 mg/g for CV at 25 oC and 20 mg/L
