Optimisation of malachite green dye removal on spent tea leaves bio-char using response surface methodology

In this study, spent tea leaves (STL) bio-char was investigated to adsorb malachite green dye in aqueous solution. The adsorption parameters were optimised by central composite design (CCD). Three independent process variables namely adsorbent dosage, initial dye concentration and contact time were selected as input parameters while the percentage of MG removal was considered as response. The most important effect on the bio-sorption performance was found to be the adsorbent dosage followed by the contact time. The optimum operating conditions for the removal of MG dye using STL bio-char were determined at 0.18 g adsorbent dosage, 46.92 mg/L of initial dye concentration and contact time of 56.16 minutes. At this optimum conditions, the percentage of MG removal up to 98.92% with desirability of 1.000. Thus, it can be concluded that STL bio-char can significantly be an alternative for the removal of MG dye from aqueous solution.