A Mini-Review of Coupled Convection-Diffusion Equations in a Fixed-Bed Adsorption

Abstract

Environmental contamination triggered by dyes has gained global attention. Industrial effluent of dye in high concentration into the rivers must be reduced to minimise the harmful effect on the quality of water that threatens human health. The removal of dye from wastewater is a significant step in addressing the problem of dye emission which can be achieved through adsorption separation technologies. In the most adsorption process, the adsorbent is in contact with fluid in a fixed bed. The performance of adsorptive separation of dye can be predicted through a fixed bed mathematical model which consists of coupled partial differential equations for optimizing the design and operating conditions. This paper presents a mini-review of mathematical modelling of fixed-bed adsorption of dye. The discussions are limited to the used of single component-dye separation in, convection-diffusion equations coupled with Langmuir isotherm. Besides, the numerical methods used for solving the convection-diffusion equations are also discussed in this paper.