Adsorption of o-, m- and p-nitrophenols onto organically modified bentonites.
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 (d(001)) of the HDTMA-B and PEG-B were found to be 38.71 m(2)g(-1), 69.04 m(2)g(-1) and 21.96 Å, 15.17 Å, 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. R(L) 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.
Forensic Medicine Foundation, Felek Street, No 45, 06300 Kecioren, Ankara, Turkey. hkoyuncu@yyu.edu.tr
Hülya
H
Koyuncu
Nuray
N
Yıldız
Uğur
U
Salgın
Fatmanur
F
Köroğlu
Ayla
A
Calımlı
D000327:Adsorption; D001546:Bentonite / Q000737:chemistry*; D000077286:Cetrimonium; D002593:Cetrimonium Compounds / Q000737:chemistry; D009596:Nitrophenols / Q000737:chemistry*; D010316:Particle Size; D011092:Polyethylene Glycols / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D013818:Thermogravimetry; D014961:X-Ray Diffraction
D002593:Cetrimonium Compounds; D009596:Nitrophenols; D001546:Bentonite; D011092:Polyethylene Glycols; D000077286:Cetrimonium