حانيه بورد

The entry of pollutants into the environment has intensified an‎d accelerated due to population growth an‎d the subsequent expansion of industries. Among the major water an‎d environmental pollutants are heavy metals, residual organic solvents, pharmaceuticals, pesticides, petroleum pollutants, fertilizers, radioactive waste, an‎d plastics, all of which pose a serious threat to aquatic ecosystems such as rivers, lakes, an‎d oceans. Therefore, the measurement of these pollutants is crucial for designing effective downstream actions. Various methods have been developed for pollutant measurement, among which adsorption-based techniques, utilizing an adsorbent, have gained significant attention. The identification an‎d synthesis of new materials have led to one of their first applications being the fabrication of adsorbents an‎d their use in pollutant measurement, especially for environmental contaminants. One such material, recently identified an‎d synthesized, is MXenes. These two-dimensional materials exhibit exceptional applicability an‎d unique properties such as environmental compatibility, high surface area, chemical stability, adequate adsorption capacity, an‎d hydro‎philicity. These properties make MXenes a promising can‎didate for effective adsorbent development in solid-phase extraction (SPE) methods. The objective of this dissertation is to synthesize various MXenes an‎d employ them in developing effective adsorbents for the extraction an‎d measurement of pollutants in environmental samples. In the first research study, to examine the effect of the adsorbent substrate structure on its performance, two materials, titanium carbide (TiC) an‎d MXene (Ti₃C₂), were investigated as substrates. A magnesium-aluminum layered double hydroxide (Mg-Al LDH) was synthesized an‎d deposited onto both substrates. The structure of these materials was analyzed using FT-IR, XRD, an‎d SEM techniques. Subsequently, key parameters affecting the adsorption an‎d desorption stages, including desorption solvent type, desorption solvent volume, adsorption an‎d desorption times, pH determination, an‎d salt effect, were examined an‎d optimized. After this stage, both materials were eva‎luated as adsorbents for BTEX aromatic hydrocarbons under identical optimal conditions. The obtained data showed that the adsorbent synthesized with Ti₃C₂ exhibited at least 42% an‎d at most 64% higher efficiency than the TiC-based adsorbent. This trend can be attributed to the differences in the physical an‎d chemical properties of the two adsorbents. The Ti₃C₂-based MXene adsorbent, due to its two-dimensional, layered structure, provided a significantly higher surface area an‎d easier surface accessibility for the adsorbed molecules, ultimately enhancing its adsorption capacity for these pollutants. Considering the results of the first study an‎d the demonstrated improvement in adsorbent efficiency through MXene application, in the second research study, we synthesized a novel MXene material enhanced with zinc-lanthanum layered double hydroxide (Zn-La LDH). The structure of this material was also analyzed using FTIR, SEM, an‎d XRD. This material was employed as an adsorbent for polycyclic aromatic hydrocarbons (PAHs) using a dispersive solid-phase extraction (DSPE) method in aquatic environmental samples, followed by their quantification. The results indicated a regression coefficient in the range of 0.9903 to 0.9993, with a limit of quantification (LOQ) between 0.02 an‎d 0.05 µg/L. Furthermore, the relative recovery of the proposed extraction method was within the acceptable range of 83.00% to 104.6%. The findings from this study demonstrate that the obtained quantification limit is lower than the permissible limit. Therefore, utilizing the high adsorption capability of the synthesized adsorbent, PAHs analysis can be performed using the GC-FID analytical instrument as a cost-effective alternative to the more expensive GC-MS technique.

روش استخراج فاز جامد پراكنده , تيتانيوم كاربيد (TiC) , مكسين (Ti3C2) , هيدروكسيد دولايه منيزيم-آلومنيوم (Mg-Al)

Dispersive Solid-Phase Extraction (DSPE) , Titanium Carbide (TiC) , MXene (Ti₃C₂) , ₂), Magnesium-Aluminum Layered Double Hydroxide (Mg-Al LDH)

Haniye Bourd

Roohollah Zare