اصلاح سطح بسترهاي كربني به‌منظور حذف فلزات سنگين و ذخيره‌سازي انرژي و بررسي نظري توليد هيدروژن از متيل سيكلوهگزان

This doctoral dissertation, with the aim of providing scientific an‎d sustainable solutions to address key global environmental an‎d energy challenges, focuses on the molecular an‎d surface engineering of advanced carbon/organic compounds an‎d substrates. The first study demonstrates the preparation of a reusable magnetic adsorbent through dopamine functionalization with ethylenediaminetetraacetic anhydride an‎d its polymerization on the surface of magnetic carbon nanotubes (EDTA@PD-CNT/Fe3O4). The synthesized adsorbent was characterized using XRD, FT-IR, zeta potential, FE-SEM, EDS, BET, TGA, DTA, an‎d VSM techniques. The adsorbent was employed for the removal of lead an‎d cadmium ions from aqueous solutions. The adsorption process was optimized by tuning key parameters such as pH, adsorbent dosage, contact time, an‎d initial ion concentration. Thermodynamic parameters an‎d adsorption kinetics were investigated for both ions. Experimental data analysis revealed that the Langmuir isotherm provided the best fit, while the adsorption kinetics followed a pseudo-second-order model. Thermodynamic data indicated that the adsorption process on EDTA@PD-CNT/Fe3O4 is spontaneous an‎d endothermic; the maximum adsorption capacities for Cd2+ an‎d Pb2+ were 204.45 mg/g an‎d 376.48 mg/g, respectively. In the second project, the specific surface area of carbon fiber felt (CF) was first increased from approximately 2 m2/g to 675 m2/g using KOH an‎d chemical etching. Subsequently, MIL-101(Fe)-NH2 was synthesized in situ on the activated carbon fiber felt (ACF) via a hydrothermal method without the use of binders. The synthesized electrode was characterized using XRD, FT-IR, FE-SEM, EDS, BET, TGA, DTA, an‎d Raman techniques. The performance of the ACF@MIL-NH2 electrode as the working electrode in a three-electrode system was eva‎luated using electrochemical techniques, including cyclic voltammetry (CV) an‎d galvanostatic charge/discharge (GCD). A calomel electrode served as the reference, platinum as the counter electrode, an‎d 1 M aqueous potassium hydroxide as the electrolyte. Preliminary results showed that this electrode delivers a volumetric capacitance of up to 2.79 F/cm3 in 1 M aqueous KOH electrolyte. Liquid organic hydrogen carriers (LOHCs) are promising systems for hydrogen storage, an‎d methylcyclohexane (MCH) is commonly used as a model compound due to its high hydrogen content. The third study, using density functional theory (DFT), investigates the effect of -NH2 an‎d -NO2 functional groups at the 4-position of methylcyclohexane on the dehydrogenation reaction over a Pt13 cluster. The results showed that thermodynamic analysis indicates improved favorability for both 4-methylcyclohexylamine (MCA) an‎d 1-methyl-4-nitrocyclohexane (MNC) compared to MCH, with similar trends observed for enthalpy changes. However, kinetic analysis revealed higher activation energies (Ea) for MCA an‎d MCH than for MNC, attributed to electronic effects an‎d changes in adsorption configurations, resulting in slower reaction rates. Reaction coordinate analysis identified the second step as the rate-determining step for MCH an‎d MCA, whereas the third step was rate-determining for MNC.

عليرضا نجفي چرمهيني , مهران غياثي

محمد ديناري , حسين فرخ پور , عباس رحمتي