Object

Abstract:

In this PhD thesis, carbon haloysite composites were synthesized, in which the carbon template was halloysite of various morphology, and the carbon precursor was microcrystalline cellulose. Two methods of synthesis of carbon haloysite composites were used: the method of impregnation of halloysite in a cellulose solution (the cellulose was previously dissolved in the Cross Bewan reagent) and the method of dry grinding of halloysite and cellulose. The composites were pyrolysed at two temperatures: 500˚C and 800˚C. The obtained carbon halloysite composites were characterized by the following methods: scanning electron microscopy with energy dispersion spectroscopy (SEM/EDS analysis), X ray powder diffraction (XRPD), low temperature nitrogen adsorption, Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, determination of oxygen functional groups by the Boehm method, determination of the point of zero charge (pHPZC) and inverse gas chromatography (IGC). The obtained carbon haloysite composites were used as adsorbents of triclosan, chloroxylenol and chlorophene from water using adsorption measurements in a static system. The influence of the type of adsorbent, its mass, pH and temperature of the environment was checked. The kinetic models of the pseudo first, pseudo second and the Weber Morris intramolecular diffusion model were fitted to the obtained experimental data. Adsorption isotherm models: Freundlich, Langmuir (one center), Langmuir (multi center), Temkin and Dubinin Radushkevich were fitted to the experimental data. Adsorption measurements in a dynamic system were performed in order to determine adsorption equilibrium constants and adsorption capacities. The adsorption equilibrium constants were determined by the peak division (PD) method, and the adsorption capacities by the breakthrough curve (BC) method. Based on the SEM/EDS analysis, the presence of carbon on the halloysite surface was confirmed. On the basis of X ray diffraction and Raman spectroscopy, the presence of crystalline carbon in carbon halloysite composites was confirmed. The HNT m 800 composite has the highest content of crystalline carbon. The FTIR spectra allowed to confirm the change in the structure of the carbon haloysite composites compared to the unmodified halloysite and indicate the highest strength of carbon bonding with the halloysite in the case of the HNT m 800 composite. Based on Boehm's method the highest content of carbonyl functional groups was found. Values of point of zero charge indicate that in an environment with pH ~ 6, the surface of the composites has a positive charge. The HNT m 800 composite is also characterized by the highest value of adsorption free energy and a high ratio of the basic constant to the acid constant (Kb/Ka), which determines the adsorption process.
Based on the adsorption measurements in the static system, it was found that the best adsorbent of triclosan, chloroxylenol and chlorophene was the HNT m 800 composite. The removal efficiency of these compounds from water was the highest at pH ~ 6. The adsorption process of triclosan, chloroxylenol and chlorophene onto HNT m 800 composite is effective, and the desorption proceeds to a small extent, which means that these compounds are permanently adsorbed. The adsorption process of triclosan, chloroxylenol and chlorophene follows the pseudo second kinetic model. The adsorption rate constants increased in the following order: chloroxylenol < chlorophene < triclosan. Adsorption of these compounds takes place according to the Langmuir multi center model and the adsorption equilibrium constants increase in the order: chloroxylenol < chlorophene < triclosan. Adsorption of triclosan, chloroxylenol and chlorophene in the dynamic system also occurs according to the Langmuir multi center model. The adsorption measurements in the dynamic system (ILC) differed slightly from those obtained using the static method, but they confirmed the sequence of changes in the adsorption equilibrium constants, which increase in the following order: chloroxylenol < chlorophene < triclosan.

Additional notes:

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Identifier:

oai:bibliotekacyfrowa.ujk.edu.pl:10052

Computer catalogue:

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Language:

pol

Degree name:

doktor

Date obtained:

26.10.2023

Degree grantor:

Uniwersytet Jana Kochanowskiego w Kielcach

Supervisor:

Słomkiewicz, Piotr M.

Reviewer:

Kyzioł-Komosińska, Joanna ; Włodarczyk-Makuła, Maria Alfreda ; Rajca, Mariola

Field:

Dziedzina nauk ścisłych i przyrodniczych

Scientific disciplines:

Nauki chemiczne

Faculty:

Wydział Nauk Ścisłych i Przyrodniczych

Type:

rozprawa doktorska

Access rights:

tylko w Oddziale Informacji Naukowej

Publication status:

niepublikowana