REMOVAL OF SOME SUBSTITUTED PHENOLS BY ACTIVATED CARBON OBTAINED FROM AGRICULTURAL WASTE

Equilibrium removal of phenol (P), m-,p-Cresol (Cr), 2-chlorophenol (2-CP), 4-nitrophenol (4-NP), 2,4-dichlorophenol (2,4-DCP), and 2,4-dinitrophenol (2,4-DNP) was tested by adsorption onto activated carbon prepared from apricot stone shells by chemical treatment with H3PO4. Disubstituted phenols are adsorbed in larger amounts than monosubstituted ones. No clear correlation seems to hold between the amount removed and texture characteristics of the sorbent. Uptake of phenols increases in the order P, Cr<2-CP<4-NP<2,4-DNP<2,4-DCP, which correlates well with respective increase in molecular dimensions and acidity and decrease in solubility of the sorbates. Abnormality shown by 2,4-DNP as a drop in its removal, is due to strong adsorption at the entrace or inside certain pores thus limiting further diffusion of solute molecules and/or probable molecular sieve effect.