Equilibrium kinetic and isotherm studies of dye colour adsorption on the banana peel

Abstract

Textile, paper, rubber, plastics, leather, cosmetics, pharmaceuticals, and food industries extensively employ dyes. This study aims to determine the best equilibrium kinetic and isotherm model of dye colour adsorption using waste adsorbent. Methylene blue (MB) is a dye colour contaminant that can be removed from wastewater via adsorption due to its ease of usage and cost-effectiveness. This study employed banana peels (BPs), a low-cost and waste adsorbent, to remove MB from synthetic wastewater. A series of batch equilibrium adsorption studies investigated the effect of different dosages of 0.05 to 0.4 grams, contact time of 15 to 150 minutes, and agitation speed of 150 rpm. BPs dosage is added from 0.05 g to 0.4 g in 100 ml of Methylene Blue solution. The concentration of MB in the samples was determined using a HACH DR2800 Spectrometer. According to the kinetic study analysis, the adsorption of MB followed a pseudo-second order kinetic with an R2 of 0.9934. Furthermore, the Freundlich model fit better than others based on the equilibrium isotherm investigation, with an R2 of 0.7688. As a result, BPs can be used as an alternative waste adsorbent media for extracting dye colours from industrial effluent.