Spent coffee ground as low-cost adsorbent for congo red dye removal from aqueous solution

Abstract

This study represents the utilisation of spent coffee ground to remove Congo red dye from aqueous solution. Congo red dye may cause adverse effect towards human and aquatic organism if present in water. This study investigated three parameters, adsorbent dosage (0.5, 1.25 and 2 g), initial dye concentration (10, 30 and 50 mg/L) and contact time (10, 35 and 60 min). Batch adsorption studies were carried out to study the effect of these parameters towards percentage of Congo red removal. Optimisation study was conducted using Response Surface Methodology (RSM) by employing Central Composite Design (CCD). Quadratic model was selected for the response. The highest percentage of Congo red removal obtained was 88.43% with operating conditions of 2 g adsorbent dosage, 50 mg/L initial dye concentration and 60 minutes contact time. Meanwhile, the percentage of CR removal that predicted by RSM was 89.17% with conditions of 1.87 g adsorbent dosage, 48.18 mg/L initial dye concentration and 57.96 minutes contact time with the desirability of 1. This study indicates that spent coffee ground could be employed as a low cost adsorbent for the removal of Congo red dye.