Piotr M. Słomkiewicz

Determination of the Adsorption Equilibrium of Alcohols and Alkenes on a Sulphonated Styrene–Divinylbenzene Copolymer

The adsorption equilibrium constants of the alcohols: methanol, ethanol and propan-1-ol, and of the alkenes: 2-methylpropene, 2-methylbut-1-ene, 2-methylbut-2-ene, 2-methylpent-1-ene, 2-methylpent-2-ene and 2-methylhex-2-ene, onto the sulphonated styrene–divinylbenzene copolymer Amberlyst 15 were determined by inverse gas chromatography. During the adsorption measurements, catalytic reactions such as dehydration of the alcohols as well as isomerization and dimerization of the alkenes were controlled to see whether or not they occurred on the surface of Amberlyst 15. The physical integrity of the adsorption equilibrium constants determined experimentally for the alkenes was verified by calculation of their adsorption enthalpies and the use of Boudarts rules.

Adsorption Equilibria of Linear Alkenes onto a Sulphonated Styrene-Divinylbenzene Copolymer

The adsorption equilibrium constants of the alkenes propene, but-1-ene, pent-1-ene, hex-1-ene and hept-1-ene onto the sulphonated styrene-divinylbenzene copolymer Amberlyst 15 were determined by inverse gas chromatography. During the adsorption measurements, catalytic reactions such as the isomerization and oligomerization of alkenes were controlled to see whether or not they occurred on the surface of Amberlyst 15. The physical integrity of the adsorption equilibrium constants determined experimentally for the alkenes was verified by calculation of their adsorption enthalpies and the use of Boudarts rules. The effect of the number of carbon atoms in the alkene molecule on the increase in the adsorption enthalpy onto the sulphonated Amberlyst 15 copolymer was determined.

EFFECT OF TEMPERATURE ON HALLOYSITE ACID TREATMENT FOR EFFICIENT CHLOROANILINE REMOVAL FROM AQUEOUS SOLUTIONS

Monochloroanilines and dichloroanilines are important reagents or chemical intermediates in the production of dyes, pharmaceuticals, and agricultural chemicals. These toxic compounds have a large tendency to accumulate in the environment and a low natural biodegradability, so improved methods to remove or sequester them are needed. Halloysite is used as an efficient adsorbent to remove toxic compounds, such as aniline, from aqueous solutions. The purpose of this study was to evaluate whether acid-activated halloysites from the “Dunino” (Poland) strip mine could be effective in the removal of not just aniline but also of its chloro-substituted forms from aqueous solutions. The composition, structure, and morphology of activated halloysites were characterized using the following methods: wavelength dispersive X-ray fluorescence analysis (WDXRF), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), Fourier-transform infrared spectroscopy (FTIR), and N2 adsorption-desorption analysis. The acidactivated halloysites had an increased ability to remove aniline and chloroanilines from aqueous solutions as the acid activation temperature was increased. This suggests that the acid activation temperature is an important factor that influences the ability of acid activated halloysites to adsorb aromatic amines (anilines) from water. The efficiency of aniline and chloroaniline removal by halloysite activated at 80°C reached maximum levels, especially for the removal of aniline and 4-chloroaniline. The adsorption isotherm data were best described by the Langmuir adsorption model. The values of the Langmuir adsorption constants were calculated using the inverse liquid chromatography method.

Determination of Adsorption Equations for Chloro Derivatives of Aniline on Halloysite Adsorbents Using Inverse Liquid Chromatography

Chloro derivatives of aniline are commonly used in the production of dyes, pharmaceuticals, and agricultural agents. They are toxic compounds with a large accumulation ability and low natural biodegradability. Halloysite is known as an efficient adsorbent of toxic compounds, such as phenols or herbicides, from wastewater. Inverse LC was applied to measure the adsorption of aniline and 2-chloroaniline (2-CA), 3-chloroaniline (3-CA), and 4-chloroaniline (4-CA) on halloysite adsorbents. A peak division (PD) method was used to determine a Langmuir equation in accordance with the adsorption measurement results. The values of adsorption equilibrium constants and enthalpy were determined and compared by breakthrough curve and PD methods. The physical sense of the calculated adsorption enthalpy values was checked by applying Boudarts entropy criteria. Of note, adsorption enthalpy values for halloysite adsorbents decreased in the following order: aniline > 4-CA > 2-CA > 3-CA.