1. Master Thesis
- Thesis topic: Effect of Rice husk activated Carbon modified by polyaniline (AC/PANI) on removal of pollutants from waste water
- Doi: https://doi.org/10.6840/cycu201800291
- Abstract:
The removal of pollutants( Methylene green dye, Copper, Zinc and Nickel) from the waste water using rice husk activated carbon modified by polyaniline was studied by different parameters such as: effect of contact time, effect of adsorbent amount, effect of pollutant concentration, kinetics adsorption, isotherm adsorption, effect of pH and also the morphology of the unmodified activated carbon and the activated carbon modified by polyaniline to explain clearly the behavior of the removal of those pollutants using activated carbon modified by polyaniline. The results of the experiment showed the adsorption at equilibrium time (240 minutes) for unmodified activated carbon with K2CO3 ratio 1:1 (AC1) was 91.50 % and the maximum sorption capacity of the sorbent was found to be 292.68 mg/g for methylene green dye at 28ºC and PH 7.0. The initial adsorbent amount of 0.2 g/L and the solution concentration was 50 ppm. Le equilibrium sorption data showed a good fit to Langmuir and Freundlich isotherm model. The effect of pH showed that at low pH, the unmodified activated carbons presented the best adsorption capacity, but the activated carbon modified by polyaniline had the highest adsorption capacity at high pH. The maximum adsorption capacity of Copper, Zinc and Nickel were 8.05 mg/g, 6.23 mg/g and 4.86 mg/g respectively and their removal efficiencies were 98.23 %, 74.8 % and 58.4 % respectively for the unmodified activated carbon with K2CO3 ratio 1:1.5 (AC2), with initial adsorbent amount of 0.6 g/L, heavy metals concentration of 5 ppm and the pH around 6. This study indicated that the kinetics studies showed the reactions did not follow the Pseudo first order model and the adsorption of heavy metals was not towards physisorption because the adsorption mechanism was very fast in the first 30 minutes and after that it became very slow and also presented an unsaturation behavior of adsorbent specially in the activated carbon modified by polyaniline. It might be due to the polymerization of aniline using 1 mole HCl that made the surface of activated carbon modified by polyaniline become more acid than the pure activated carbon (AC). The pseudo second order, intraparticle diffusion, freundlich isotherm and Langmuir isotherm showed that some adsorbents were in agreement and some did not. The SEM analysis showed the surface of the modified activated carbons by PANI(AC2/PANI) were smoother than the surface of unmodified activated carbon; this may be an explanation as to why the adsorption capacities of modified activated carbons were better than the unmodified activated carbon especially when the pH was higher.
Keywords: Aquaculture wastewater (AWW), Sand Filtration, Air Gap Membrane Distillation (AGMD), Adsorption
2. PhD Thesis
- Thesis topic: Novel Photocatalytic Applications for Degradation of Environmental Organic Pollutants under Visible/Solar light
- Doi: https://doi.org/10.6840/cycu202100261
- Abstract:
Environmental organic pollutants are generally toxic for human beings, animals and plants, and become a concerning issue for the world. This research focuses on new efficient photocatalytic applications for better degradation of different environmental organic pollutants such as Rhodamine B(RhB) dye, Acid Yellow 42(AY42) dye, Nitrogen Oxide (NO) gas, and Toluene gas under visible or solar light. In this study, the Bi2S3 catalyst was used and modified by three new companions (SnO2, MgO, and Lanthanum(La)) separately to synthesize SnO2/Bi2S3/BiOCl-Bi24O31Cl10, MgO/Bi2S3-BiOCl, and La/Bi2S3, respectively. The SnO2/Bi2S3/BiOCl-Bi24O31Cl10 catalyst was a strategic composite formed by the hydrothermal combination of 15% SnO2 and 85% Bi2S3 achieved an optimum photodegradation of 80.8% of RhB higher than pure Bi2S3(29.4%) and SnO2(0.1%) under visible light. The MgO/Bi2S3-BiOCl was synthesized via the co-precipitation method of 7% MgO and 93% Bi2S3 and showed a higher photodegradation around 74.61% of NO gas, which was better than pure Bi2S3(42.77%) and MgO (11.24%) under solar light. The presence of BiOCl as a heterojunction that usually forms between Bi2S3 and a precursor containing Cl ion was confirmed in the SnCl4.5H2O and MgCl2.6H2O in the water to form SnO2/Bi2S3/BiOCl-Bi24O31Cl10 and MgO/Bi2S3-BiOCl composites, respectively. The 3% La/Bi2S3 catalyst synthesized by the hydrothermal method and showed a better degradation efficiency of 92.1% of AY42 compared to the pure Bi2S3(46.7%). Besides, a photocatalytic module was also applied using 1% La-TiO2, which was synthesized by the sol-gel method, coated on the glass fiber cloth, and supported by activated carbon, reached a photodegradation of about 100% for toluene gas. Finally, the as-prepared catalysts were also analyzed by different characterization methods to confirm their formations and behavior in the degradation mechanism of the pollutants. Those new approaches materials for photocatalytic activities can serve as an inspiration for a lot of pieces of studies relating to photocatalysis technology in the future.
Keywords: Photocatalysis, SnO2/Bi2S3/BiOCl-Bi24O31Cl10, MgO/Bi2S3-BiOCl, La/Bi2S3, Photocatalytic module, La-TiO2, Environmental organic pollutants, Visible light, Solar light