Fixed-bed column studies on the removal of Fe 3+ and neural network modelling

The sorption potential of the particles of ignimbrite to uptake Fe 3+ ions from an aqueous solution was investigated using a fixed-bed sorption column. The effects of inlet Fe 3+ concentration (20–75 mg L −1 ), feed flow rate (5–15 mL min −1 ) and bed height (5–20 cm), initial solution pH (1.7–4) and particle size (0.25–0.5, 0.5–1 and 1–2 mm) on the breakthrough characteristics of the sorption system were investigated. The experimental and neural network sorption capacities of the sorbent at different particle sizes (0.25–0.5, 0.5–1, and 1–2 mm) were determined as 3.26, 3.75, 2.12, 2.98 and 1.46, 1.39 mg g −1 , respectively. The highest experimental and theoretical bed capacities were obtained to be 3.65 and 3.29 mg g −1 at inlet Fe o 3+ concentration of 75 mg L −1 , bed height of 5 cm and flow rate of 5 mL min −1 , pH of 4 and particle size of 0.25–0.5 mm. The ANN model yielded determination coefficient was 0.980 and the root mean square error was 0.65.