ABSTRACT
This study was aimed to investigate the use of pineapple as a cheap, eco-friendly adsorbent and support matrix for the immobilization of microbial cell and for subsequent removal of phenol from waste water. The effects of initial phenol concentration, pH and adsorbent particle size on the simultaneous adsorption-biodegradation (SAB) of phenol were studied. The batch simultaneous adsorption and biodegradation (SAB) of phenol in simulated phenol waste water by pineapple peels immobilized Pseudomonas aeruginosa NCIB 950 has been studied with the use of glass bottles as bioreactors placed in a rotary mechanical shaker for 72 h. The results of the batch equilibrium adsorption-biodegradation studies showed that adsorption-biodegradation capacity decreased with increase in particle size. The equilibrium adsorption-biodegradation data were analyzed by the Langmuir, Freundlich and Redlich-Peterson models of adsorption. The results showed that the equilibrium data for phenol degradation sorbent systems were well fitted to the three adsorption models with Langmuir and Redlich-Peterson adsorption isotherms having the best fit. The adsorption-biodegradation kinetic data obtained at different initial phenol concentrations and pH showed that the adsorption-biodegradation capacity of the pineapple peels immobilized P. aeruginosa generally increased with increase in initial phenol concentration and pH. The kinetic data were analyzed using Lagergren pseudo-first order, pseudo second-order, Elovich and intraparticle diffusion rate equations. The rate equations fitting showed that the adsorption-biodegradation kinetic data generally fitted the four rate equations tested from which the rate constants and diffusion rate constants were estimated. However, the Lagergren pseudo first-order rate equation gave the best fit and, thus the process followed first-order rate kinetics. Therefore, pineapple peels being an agricultural waste product have the potential to be used as low-cost adsorbent and support matrix for microbial culture immobilization for the removal of organic pollutant from waste water.