ABSTRACT
One of the problems facing leather industries is to come up with an efficient way of reducing the organic pollutant loads of their wastewaters. This research dissertation was aimed at the preparation and application of α-FeOOH and α-FeOOH-SiO2-Al2O3 catalysts for tannery effluent treatment using Fenton oxidation process. Effluent at the point of discharge from Mamuda tannery industry, Sharada phase III, Kano state, Nigeria, was collected and characterized as highly polluted tannery effluent that needs to be treated before discharge in to the environment.The α-FeOOH catalyst was prepared through the use of precipitation method, doped with silica and aluminain the ratio 50:2:1 and calcined at 600oC for 2 hours. The composite α-FeOOH-SiO2-Al2O3 catalyst wascharacterized using XRD and SEM analyses. The SEM images revealed a cluster of crystal particles indicating an orthorhombic crystal shape of α-FeOOH catalyst and the crystal particles become bigger and agglomerated. Furthermore, design expert 6.0.7 versionsoftware of response surface methodology (RSM) was employed using central composite design (CCD) to optimize Fenton oxidation of tannery effluent. Quadratic models were developed for the response variable (COD reduction) and were found to be significant for applyingα-FeOOH and α-FeOOH-SiO2-Al2O3 catalysts for tannery effluent treatment using Fenton oxidation process. The optimization of Fenton oxidation of tannery effluent was carried out using design expert 6.0.7 versionsoftware in order to achieve maximum COD reduction. The desired goal was set at target and at maximum and the optimum value of 68.57% COD reduction for applying α-FeOOH catalyst was predicted to be achieved by the design expert software at the optimal conditions of 30.00 mg/L catalyst loading, 900.00 mg/L peroxide dosage, 125.00mins reaction time and a pHof 3.00.While for applying α-FeOOH-SiO2-Al2O3 catalyst, 82.43% COD reduction was predicted to be achieved at optimal conditions of 50.00mg/L catalyst loading, 400.00mg/L peroxide viii dosage, 240.00mins reaction time and a pH of 7.00. Validation experiments were conducted based on the same optimal conditions stated in order to verify the accuracy and reliability of the optimized results predicted by the design expert software. The actual results of 65.93% and 79.29% COD reduction were obtained from validation experiments conducted for applying α-FeOOH andα-FeOOH-SiO2-Al2O3 catalysts which are in close agreement with the optimized results predicted confirming the accuracy of the model