| Summary: | The ability of corncob (Zea mays) to remove iron contained in acidic mine drains (AMD) from coal in laboratory-scale packed bed reactors was evaluated. The tests had an effluent filtering phase, through the bed, at a flow rate of 5 mL×min-1 and a column wash, with distilled water, in order to remove weakly adsorbed material. The variables evaluated were: (i) modification of the corncob with sodium hydroxide (NaOH) or citric acid (C₆H₈O₇) and (ii) iron concentration in the AMD of 500 ppm, 1,000 ppm and 2,000 ppm. At the same time, trials were performed at the same conditions, but, with washes of distilled water to the corncob, each 400 mL of filtered AMD, in order to avoid saturation of the system. The treated effluent was monitored every 80 min through pH and iron measurements (atomic absorption spectroscopy). The biomasses were physicochemically characterized at the beginning and at the end of the process using FTIR. Overall, the pH of AMD played an key role in the metal removal capacity and better iron removal percentages are obtained using NaOH modified marlo, including sporadic washes during the process.
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