Kinetic and thermodynamic studies of the adsorption of dye on to saccharum officinarum waste adsorbents

International Journal of Research and Scientific Innovation (IJRSI) | Volume VIII, Issue IV, April 2021 | ISSN 2321–2705

Kinetic and thermodynamic studies of the adsorption of dye on to saccharum officinarum waste adsorbents

Yunus, M.M.* and Garba, I. B.
Department of Chemistry, Yobe State University, Damaturu; Nigeria
Corresponding Author*

Abstract: This work investigated the potential use of activated carbon produced from saccharum officinarum waste as an adsorbent for the removal of dye stuff from aqueous solution. The activated carbon was impregnated using Orth-phosphoric acid for chemical activation. Some physicochemical parameters of the activated carbon studied include, pH, bulk density, ash and moisture content. Adsorption experiments were conducted at varying contact times, initial dye concentration and temperature. Adsorption equilibrium was achieved in less than 40 minutes of contact time. Adsorption of dyes increased with increasing temperature. Thermodynamic characteristics which include free energy, enthalpy and entropy values were assessed using van’t Hoff equation. Negative free energy and positive enthalpy values indicate the feasibility as well as endothermic nature of the adsorption event. Positive entropy suggests increased disorderliness at the solid/solution interface during adsorption process. The kinetic study shows that pseudo-second-order model is best fit for the experimental data obtained.

Keywords: Chemisorption, bulk density, saccharum, filtrate, kinetic model

I. INTRODUCTION

Dyes are colored ionizing aromatic and heterocyclic compounds which show affinity towards the substrate to which they arebeing applied. They are generally applied in solution/aqueous to textiles, hair, wood or food. Compositionally, they are aromatic compounds whose structures possess aryl rings (C6H5) that have delocalized electron systems (Abazied, 2016). Usually, they find relevance when used for decoration or aesthetical purposes. Substances known as dyes have found applications in textiles, paper, leather, cosmetics and pulp industries. The coloring agents disposed as waste from these industries constitute serious hazards to the environment. Effluents from industrial and domestic wastes even at low concentrations contribute immensely to the increase of contaminants in water bodies globally (Ali et al., 2016). Usually dyes have complex aromatic molecular structures that make them very stable and difficult to biodegrade. Many of them are toxic to some microorganisms and may cause the inhibition of their catalytic capabilities thus leading to serious problems to the ecological systems (Dijali et al., 2015 and Diouri, et al., 2015).Due to systematic accumulation of these pollutants and their increasing levels in the environment, a concern toward their regulation was aroused.

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