Akademik Veri Yönetim Sistemi
Journal of Hazardous Materials, cilt.185, sa.2-3, ss.1332-1339, 2011 (SCI-Expanded, Scopus)
Experiments were conducted on the adsorption characteristics of o-, m- and p-nitrophenols by organically modified bentonites at different temperatures. Two organobentonites (HDTMA-B and PEG-B) were synthesized using hexadecyltrimethylammonium bromide (HDTMABr) and poly(ethylene glycol) butyl ether (PEG). Synthesized HDTMA-B and PEG-B were characterized by XRD, FTIR and DTA-TG analyses and their specific surface area, particle size and pore size distributions were determined. BET surface areas and basal spacings (d001) of the HDTMA-B and PEG-B were found to be 38.71m2g-1, 69.04m2g-1 and 21.96Å, 15.17Å, respectively. Increased adsorption with temperature indicates that the process is endothermic for o-nitrophenol. On the other hand m- and p-nitrophenols exhibited lower rates of adsorption at higher temperatures suggesting a regular exothermic process taking place. Results were analyzed according to the Langmuir, Freundlich and Dubinin-Redushkevich (D-R) isotherm equations using linearized correlation coefficient at different temperatures. RL separation factors for Langmuir and the n values for Freundlich isotherms showed that m- and p-nitrophenols are favorably adsorbed by HDTMA-B and, p-nitrophenol is favored by PEG-B. Adsorption of o-, m- and p-nitrophenols as single components or from their binary mixtures on HDTMA-B and, p-nitrophenol on PEG-B are all defined to be physical in nature. © 2010 Elsevier B.V.