Biosorption of cobalt(II) with sunflower biomass from aqueous solutions in a fixed bed column and neural networks modelling

The effects of inlet cobalt(II) concentration (20-60 ppm), feed flow rate (8-19 ml/min) and bed height (5-15 cm), initial solution pH (3-5) and particle size (0.25 < x < 0.5, 0.5 < x < 1 and 1 < x < 2 mm) on the breakthrough curves were investigated. The highest bed capacity of 11.68 mg/g was obtained using 40 ppm inlet cobalt(II) concentration, 5 cm bed height and 8 ml/min flow rate, pH 6.5 and 0.25 < x < 0.5 mm particle size. According to the BET (N-2) measurements, the specific surface area of the shells of sunflower biomass was found to be 1.82 m(2)/g. A relationship between the predicted results of the ANN model and experimental data was conducted. The ANN model yielded determination coefficient of (R-2 0.972), standard deviation ratio (0.166), mean absolute error (0.0158) and root mean square error (0.0141). The results indicated that the shells of the sunflower biomass is a suitable biosorbent for the uptake of cobalt(II) in fixed bed columns. (C) 2013 Elsevier Inc. All rights reserved.