REMOVAL OF NAPHTHALENE FROM SYNTHETIC WASTEWATER BY SIMULTANEOUS ADSORPTION-BIODEGRADATION (SAB) USING BACTERIA IMMOBILIZED SNAIL SHELL
REMOVAL OF NAPHTHALENE FROM SYNTHETIC WASTEWATER BY SIMULTANEOUS ADSORPTION-BIODEGRADATION (SAB) USING BACTERIA IMMOBILIZED SNAIL SHELL
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Date
2018-09
Authors
AINA, Oluwatoyin Emmanuel
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Abstract
This study investigated the use of snail (Achatina achatina) shell; an alternative adsorbent to natural matrices (such as polyvinyl alcohol and polyurethane) and agricultural wastes (such as sugarcane bagasse, orange peels, spent tea leaves, corn cobs and cotton seed hull) as a carrier to immobilize Pseudomonas putida and Bacillus subtilis for the degradation of naphthalene in synthetic wastewater. The hydrocarbon-degrading bacteria (HDB) used for the study were isolated from a refinery effluent and were further cultured in a nutrient medium. Naphthalene concentrations of 10, 20, 30, 40 and 50 mg/dm3 were studied at constant temperature of 30 oC, pH of 5, 7 and 9 and adsorbent dosage of 2, 3 and 5 g for 72 hours in batch mode. The naphthalene concentrations were determined using UV-spectrophotometer (Agilent CARY 300, USA) and the products of the degradation were determined using Fourier Transform Infra-red spectroscopy (CARY 630, USA) to assess the adsorption and simultaneous adsorption-biodegradation capacity and equilibrium. The results showed that optimal adsorption and biodegradation occurred at naphthalene concentration of 50 mg/dm3 and adsorbent dosage of 2 g. For the effect of pH, optimal adsorption took place at basic pH of 9, while the optimal biodegradation occurred at neutral pH of 7. The ranges of the percentage removal for the Pseudomonas putida and Bacillus subtilis immobilized on treated snail shell were: 73.23 - 82.12 % and 66.33 - 76.79 % respectively while on untreated snail shell were: 63.26 - 73.11 % and 60.17 – 74.46 % respectively. These values were significantly higher (P<0.05) than the values obtained from the adsorption of naphthalene which ranges were: 50.62 – 65.20 % and 57.05 – 67.10 % respectively for untreated and treated snail shell. The results of the equilibrium study indicated favourable adsorption and biodegradation, the R2 values obtained were: 0.9933,
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0.9997, 1.0000, 0.9973, 0.9947 and 1.0000. This indicated that the sorbent systems were well fitted to both the Langmuir and the Freundlich models. Therefore, snail shell can be employed as low-cost adsorbent and solid support matrix for the immobilization of microorganisms for the remediation of hydrocarbon contaminants.
Description
A DISSERTATION SUBMITTED TO THE SCHOOL OF POSTGRADUATE STUDIES,
AHMADU BELLO UNIVERSITY, ZARIA
IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE AWARD OF MASTER OF SCIENCE DEGREE IN ANALYTICAL CHEMISTRY DEPARTMENT OF CHEMISTRY, FACULTY OF PHYSICAL SCIENCES AHMADU BELLO UNIVERSITY, ZARIA NIGERIA
Keywords
REMOVAL OF NAPHTHALENE,, SYNTHETIC WASTEWATER,, SIMULTANEOUS ADSORPTION-BIODEGRADATION (SAB),, BACTERIA,, SNAIL SHELL,