جلسه دفاعیه رساله دکتری آقای ایاد سامی عبود
| تاریخ ارسال: 1401/4/26 |
دفاعیه دکتری در دانشکده شیمی
آقای ایاد سامی عبود دانشجوی دکتری شیمی، در تاریخ ۱۴۰۱/۰۴/۲۸از رساله دکتری خود تحت عنوان" عنوان لاتین : Synthesis of Alginate-based Nanocomposite beads as an efficient adsorbent for removal of Lead, Arsenic and Cadmium from water "
با راهنمایی خانم دکتر ملاحسینی و آقای دکتر علی غفاری نژاد دفاع خواهدکرد.
استاد راهنمای اول: خانم دکتر ملاحسینی
استاد راهنمای دوم: آقای دکتر علی غفاری نژاد
هیات داوران: دکتر فرزانه شمیرانی، دکتر حجت اله کاظمی قهفرخی، دکتر روح اله زارع دورابی و دکتر محبوبه ربانی
این جلسه ساعت ۱۶ روز سه شنبه ۲۸ تیرماه ۱۴۰۱ در سامانه جلسات مجازی دانشکده شیمی برگزار خواهد شد.
چکیده :
In this study, two novel modified microbeads were synthesized and used as adsorbents. The first one was based on metformin (Met), the Met-GO
Alg, which was composed of graphene oxide (GO) and alginate beads (Alg) and applied to the removal of arsenic and lead ions from aqueous media. The second one, sulfonated magnetic nanoparticle caged alginate microbeads (S.MNPsAlg) was developed for enhanced removal of cadmium and lead ions from water. The adsorbents were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX) techniques. The effect of solution pH, adsorbent dosage, contact time, temperature, and co-existing ions were studied and optimized. The arsenic (As۳+ & As۳+), lead (Pb۲+), and cadmium (Cd۲+) adsorption nature were adopted with various isotherms, kinetics, and thermodynamic models. Hence, for Pb۲+ removal with Met-GOAlg, the adsorption kinetic process is fit with the pseudo-second-order model (R۲ > ۰.۹۷) with ۹۵% removal efficiency. The adsorption isotherm is well fit to the Freundlich model (R۲ > ۰.۹۹) with the maximum adsorption capacity of ۳۷۰ mg. g-۱. Overall, Met-GOAlg nanocomposite revealed good efficiency, applicability, and ۵ times reusability. For arsenic (As۳+ & As۳+) removal with Met-GOAlg, the experimental process validated with isotherm modes, the results are perfumed that the Langmuir model (R۲ > ۰.۹۹) is better fitted to adsorption data than the Freundlich mode. The adsorption rate was studied and kinetics models followed a pseudo-second-order (R۲>۰.۹۹) and adsorption reached to be equilibrium at ۱۲۰ min for As۳+ and As۳+ ions. The maximum adsorption capacity obtained was ۶۴.۱ and ۸۴.۵ mg. g-۱ for As(III) and As(V), respectively. The removal efficiency obtained was ۸۱% for As(III) and ۹۲% for As(V), respectively. Beads were successfully regenerated by using NaOH solution and reused for multiple cycles. By entrapping graphene oxide and metformin there was enhanced removal achieved for As(III) and As(V) in aqueous media. For Cd۲+ and Pb۲+ removal with S.MNPsAlg, the removal efficiencies were reported to be over ۹۵%, under the best experimental condition. The process is fitted well to the Langmuir model and the maximum adsorption capacity obtained was ۸۵ mg. g-۱ and ۳۷ mg. g-۱ for Cd(II) and Pb(II) ions respectively. The as-prepared S.MNPsAlg is easy to prepare and effective in the uptake of Cd(II) and Pb(II) ions with a physisorption mechanism, which adsorption rate is limited with the pseudo-second-order model. The adsorbent lost less than ۵% of its removal efficiency in five adsorption-desorption cycles.
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