Design parameters for the treatment of phenolic wastes by carbon columns (obtained from fertilizer waste material)

The waste slurry generated in fertilizer plants in India has been converted into a cheap carbonaceous adsorbent material. The practical applicability of this product has been investigated in the column operations and the mass transfer kinetic approach has been successfully used for the determination of various parameters necessary for designing a fixed bed adsorber. The value of breakthrough capacity is more than the batch capacity. The total time (t(x)) involved for the establishment of the primary adsorption zone (PAZ), the time (t(delta)) required for the movement of PAZ down its length, the fractional capacity (f), the length of (PAZ) primary adsorption zone (delta), and percentage saturation of column at break point have been evaluated for carbon columns for the removal of phenols viz., 2,4,6-trinitrophenol, 4-nitrophenol, 4-chlorophenol and 1.3-dihydroxpbenzene. Studies have also been performed for the recovery of phenols and chemical regeneration of the spent column. It was observed that 70 mL of 5% w/w NaOH or 50 mL of acetone are sufficient for almost complete desorption elf phenols. After regeneration with 1M HNO3 the sorption capacity of the column is almost the same as that of virgin adsorbent material. (C) 2000 Elsevier Science Ltd. All rights reserved.