Predictability by Box-Behnken model for removal of chromium (VI) using Eclipta prostrata (Bhringraj) plant powder as an adsorbent

Abstract

The removal of hexavalent chromium ions from aqueous solutions using Eclipta prostrata (Bhringraj) plant powder was investigated using the batch adsorption technique. The contact time, pH, initial concentration of chromium (VI) ions and amount of adsorbent were optimized using the Box-Behnken experimental design in response surface methodology to study the effects and interactions of manipulated factors. The experimental data obtained were subjected to analysis of variance and fit with a quadratic model to relate the process parameters to chromium removal. The optimum conditions were found to be pH= 1.78, contact time = 4.31 h, adsorbent dosage = 12.51g/l and initial concentration = 250 mg/l. Confirmatory experiments performed to evaluate the accuracy of the prediction for optimal operating point yielded an adsorption efficiency of 96.69%, which is in a good agreement with the model prediction.

Keywords

• eclipta prostrata
• biosorption
• chromium (vi) ion
• bhringraj
• box-behnken design
• anova
• response surface methodology