Application of Non-Linear Kinetic and Isotherm Model for Investigation of Cod Removal from Tapioca Liquid Waste Onto Modified Lampung Natural Zeolite

Abstract

The experimental data analysis of tapioca liquid waste onto modified Lampung natural zeolite using non-linear regression models is limited. The adsorption data were analyzed with nine kinetic models (the pseudo-first-order, the pseudo-second-order, the intraparticle diffusion, fractional power, Bangham, Elovich, mixed-1.2-order, modification of pseudo-second-order, and Avrami) and eight isotherm models (Langmuir, Freundlich, Dubinin-Radushkevich, Sips, Redlich-Peterson, Toth, Liu, and Khan). The percentage of adsorption was decreased from 61.29% to 13.66% with increasing Chemical Oxygen Demand (COD) concentration 310 mg/L to 9450 mg/L. The result showed that the power model (R2: 0.98, X2: 0.137), Avrami (R2: 0.98, X2: 0.141), Bangham (R2: 0.98, X2: 0.145) and modified pseudo-second-order (R2: 0.98, X2: 0.147) can be recommended as the best fitted to experimental kinetic data. The Khan model (R2: 0.99961, X2: 0.03729) and Langmuir (R2: 0.99478, X2: 0.24902) was the most reliable for describing the isotherm model. Thus, the analysis of experimental adsorption data using a non-linear regression model is highly recommended.