Remediation of wastewaters from chlorophenol using agricultural wastes as adsorbents: adsorption, kinetics and chemical evaluation

Phenolic compounds are mixtures of phenol derivatives which are produced from several industries including biocides, pharmaceuticals and coal production. Phenolics are considered the major contaminants in industrialized wastewater. Therefore, treatment of wastewater polluted by phenolics is mandatory previously to discharge in order to protect the environment. Among the numerous procedures reported for remediation of industrial wastewater from phenolics; adsorption technology was the best method from the effectiveness and economical point of view. In this study, three agricultural wastes produced in huge amounts were evaluated in remediation of wastewater contaminated by 2-chlorophenol. The studied agricultural wastes were water hyacinth, palm leaf, and banana peel. The adsorption process parameters were determined including temperature, pH, amount of adsorbents, concentration of pollutant, and treatment time. The process followed Freundlich adsorption isotherm and pseudo-second-order kinetic model. Boyd model showed that the adsorption mechanism of chlorophenol on the surface of the different adsorbents was occurred via film diffusion mechanism. The obtained adsorption capacities at the equilibrium conditions were 288.1, 290.3, and 388.9 mg/g for water hyacinth, palm leaf, and banana peel, respectively. The spectroscopic evaluation showed the physical interaction between the chlorophenol molecules and the different functional groups on the studied adsorbents. Banana peel showed the highest adsorption efficiency, which was related to the abundance and types of the bioactive compounds in its chemical structure.