Журнал биоремедиации и биодеградации

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Batch Equilibrium and Kinetic Studies of Simultaneous Adsorption and Biodegradation of Naphthalene by Orange Peels ImmobilizedPseudomonas aeruginosa NCIB 950

Samuel E. Agarry and Mujidat O. Aremu

The batch simultaneous adsorption and biodegradation (SAB) of naphthalene in synthetic naphthalene waste water by orange peels immobilized Pseudomonas aeruginosa NCIB 950 has been studied under different process conditions. Different orange peels particle sizes (0.125, 0.178 and 0.422 mm) were used as adsorbent and support matrix for the batch equilibrium adsorption-biodegradation studies; while different initial naphthalene concentrations (10 – 50 mg/l) and pH (5, 7 and 9) were used for the batch kinetic studies. The results of the batch equilibrium adsorption-biodegradation studies revealed 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 naphthalene degradation sorbent systems were well fitted to the three adsorption models with Redlich-Peterson adsorption isotherm having the best fit. The adsorption-biodegradation kinetic data obtained at different initial naphthalene concentrations and pH showed that the adsorption-biodegradation capacity of orange peels immobilized P. aeruginosa increased with increase in initial naphthalene concentration and pH. The kinetic data were analyzed using Lagergren pseudo-first order, Elovich and intra particle diffusion rate equations. The rate equations fitting showed that the adsorption- biodegradation kinetic data generally fitted the three 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. Adsorption studies have also been done separately to compare the efficiency of SAB over adsorption. Therefore, orange 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.