Application of optimized large surface area date stone (Phoenix dactylifera) activated carbon for rhodamin B removal from aqueous solution: Box-Behnken design approach

摘要

Box-Behnken model of response surface methodology was used to study the effect of adsorption process parameters for Rhodamine B (RhB) removal from aqueous solution through optimized large surface area date stone activated carbon. The set experiments with three input parameters such as time (10-600 min), adsorbent dosage (0.5-10 g/L) and temperature (25-50 degrees C) were considered for statistical significance. The adequate relation was found between the input variables and response (removal percentage of RhB) and Fisher values (F-values) along with P-values suggesting the significance of various term coefficients. At an optimum adsorbent dose of 0.53 g/L, time 593 min and temperature 46.20 degrees C, the adsorption capacity of 210 mg/g was attained with maximum desirability. The negative values of Gibb's free energy (Delta G) predicted spontaneity and feasibility of adsorption; whereas, positive Enthalpy change (Delta H) confirmed endothermic adsorption of RhB onto optimised large surface area date stone activated carbons (OLSADS-AC). The adsorption data were found to be the best fit on the Langmuir model supporting monolayer type of adsorption of RhB with maximum monolayer layer adsorption capacity of 196.08 mg/g.