Adsorption of p-Nitrophenol, Phenol and Aniline on Organoclays
Date Issued
2005
Date
2005
Author(s)
Huang, Shih-Chang
DOI
zh-TW
Abstract
p-Nitrophenol（PNP）, phenol（PNL）and aniline（ANL）are major pollutants in natural environments. Due to its polarity, natural clay surface is unable to adsorb hydrophobic pollutants. Swelling clays (i.e. Smectites ) intercalated by quaternary ammonium with long alkyl-chain or other functional groups, turning hydrophilic surface into hydrophobic, hence adsorbing organic pollutants.
This study used four organoclays（Cloisite®10A, Cloisite®15A, Cloisite®30B, Cloisite®93A）as adsorbents to adsorb PNP, PNL and ANL The modifier of organoclays 10 A, 15 A, 30 B and 93 A are quaternary. ammoniums with functional group 2M2HT, 2MBHT, MT2EtOT, M2HT respectively.（M：methyl,. B: bezene, H: hydrogenatedtallow, T: tallow, EtOT：bis-2-hydroxyethyl）
Before the adsorption, the results of X-ray diffraction （XRD）showed the d-spacing of 10 A、15 A、30 B and 93 A are 19.76、27.64、19.34 and 26.43 nm respectively. After the adsorption showed the d-spacing of clays 15 A and 93 A are greater than before .IR spectra of clays showed the bands at 2918.2 cm-1 and 2852 cm-1 were C-H groups of quaternary amine.
In order to determine concentrations of PNP, PNL and ANL, the UV-VIS spectroscopy is used with wavelength 317 nm, 210 nm and 230 nm. The best weight of adsorbents for adsorption isotherms is 50 mg, and the adsorptive capabilities are 15 A, 10 A better than 30 B and 93 A.
The sorption data fitted with Frundlich isotherm equation for these organoclays, R2 are between 0.77 and 0.99. The best description for adsorption kinetics data is pseudo first order equation, R2 are between 0.84 and 0.99. The comparisons of three sorbates, adsorbed capacity is PNP＞PNL＞ANL.
At various of pH （pH 4, pH 7）, these adsorbents showed the same result as pH was not adjusted, adsorbability is 15 A>10 A>30 B>93 A. To compare the influence of different pH on the same organoclay, adsorptive effect is pH 7>pH 4>pH 10,except 93 A , which has better effect at pH 4.15 A is less sensitive for the change of pH.
After adsorption of PNP and PNL, IR spectra showed the transmittance exist at wavenumber 2340 cm-1 for all these organoclays caused by the expand of bonded O-H. It is speculated that O-H of PNP and PNL gradually move into the interlayer of organoclays and the chemical interaction between both has taken place. Comparing with the spectra of ANL, there is no significant band appeared after adsorption.
Subjects
有機黏土
有機修飾物
對硝基酚
酚
苯胺
吸附
四級銨鹽
organoclay
organic modifier
p-nitrophenol
phenol
aniline adsorption
quaternary ammonium
SDGs
Type
thesis
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