http://103.99.128.19:8080/xmlui/handle/123456789/113 Thesis published in Dept. of Chemistry 2026-04-19T10:32:25Z http://103.99.128.19:8080/xmlui/handle/123456789/520 Title: Chemical and biological studies on the polar fraction of the fruits of Cassia fistula Linn (Sonalu). Authors: Shil, Proshanta Abstract: The plant Cassia fistula is one the important medicinal plants of Bangladesh. It belongs to the family Fabaceae and genus Cassia. The plant Cassia fistula is locally known as Sonalu. It is a medium sized deciduous or semi-deciduous tree, 10 to 15 m tall with a straight trunk to 5 m in height and 1 m in diameter. The leaves are deep green, flowers are bright yellow in color. The fruit is a pendulous and cylindrical. It is black, glabrous and many seeded. Seeds are ovate, imbedded horizontally, dark colored pulp. This plant is used for the treatment of several diseases like skin diseases, abdomen pain, fever and leprosy etc. Different types of compounds like flavonoids, glycosides, alkaloids, steroids and amino acids have been reported from the plant of the genus Cassia. Anthraquinone glycosides, kaempferol, tannins and chromen were reported from Cassia fistula. The purpose of the present research work was a phytochemical investigation on the fruits of Cassia fistula for the isolation of bioactive secondary metabolites like alkaloid, flavonoid, and chromen as well as to determine their molecular structure. Fresh and matured fruits of Cassia fistula were collected from Sitakunda-Kumira hill region of Chittagong district during the month of December 2020. The dried powdered fruits (3 kg) were successively extracted with dichloromethane (DCM) and rectified sprite (RS). RS extract was concentrated to 250 ml and partitioned with CHCl3, EtOAC and n- butanol respectively. On the removal of the solvent CHCl3 extract gave a green Mass 31 g. Fractionation and purification of CHCl3 extract afforded three pure compounds, named as P1, P2 and P3. Compounds P1 and P2 showed remarkable antibacterial activities against gram-positive and gram-negative bacteria and compounds P3 exhibited significant antifungal activities against the fungi Aspergillus niger. Their structure of compounds were established as 2-(1ʹ, 7ʹ - dihydroxy-2ʹ, 6ʹ - dimethylheptyl)-4H- chromen-4-one (P1), (E)-2-(1ʹ, 11ʹ -dihy droxy-4ʹ, 9ʹ -dimethylundee-6ʹ -en-1ʹ -yl)-4H-chromen-4-one (P2) and 5ʹʹ[{(2R,3S,5R,6S)-3ʹʹ,4ʹʹ,5ʹʹ-trihydroxy-6ʹʹ(hydroxymethyl)tetrahydro-2H-pyran-2-yl}oxy]-5ʹʹʹ[{(2S, 3R, 5S,6R)-3ʹʹʹ,4ʹʹʹ,5ʹʹʹ-trihydroxy-6ʹʹʹ (hydroxymethyl) tetrahydro-2H-pyran-2-yl}oxy]-17-[{(E)-17,21,25 -trimethyldodee-15-en-15-yl}oxy]-2ʹ-(28ʹ,29ʹ,30ʹ-trimethlytridecyl)--9,10ʹ-bianthracene]-9, 10ʹ (9ʹH,10H)-dione (P3) Description: Thesis in Chemistry 2024-07-29T00:00:00Z http://103.99.128.19:8080/xmlui/handle/123456789/517 Title: SYNTHESIS OF BIODEGRADABLE METAL ADSORBENT BY GRAFT POLYMERIZATION ONTO COTTON FOR THE REMOVAL OF HEAVY METAL FROM INDUSTRIAL EFFLUENT Authors: KHAN, MD. SABUR AHAMMAD Abstract: Heavy metal containing industrial effluents represent a substantial hazard to the environment and human health. Heavy metal removal from wastewater is critical for mitigating its negative consequences. In this study, two noble biodegradable adsorbents were synthesized for the removal of heavy metals from contaminated water. The first absorbent poly(triethylamine methacrylate) (Cotton-g-PTEAMA) was prepared by grafting triethylamine (TEA) onto Cotton grafted poly(glycidyl methacrylate) (cotton-g-PGMA) to remove heavy metals namely Fe and Cr from industrial effluent. The successful synthesis of Cotton-g-PTEAMA was confirmed by Fourier-transform infrared spectroscopy (FTIR). The adsorption behaviour of Cotton-g-PTEAMA towards Fe and Cr from contaminated water were studied at different pH, times, and metal concentrations. The obtained data were fitted to different models of adsorption kinetics and adsorption isotherms. The adsorption rate of metals showed good fitting to the pseudo-first-order kinetic model for both Fe and Cr, and the adsorption reached equilibrium within 150 min. The isotherm studies indicated that the obtained data showed good fitting to the Freundlich model for Fe and Langmuir model for Cr. The maximum adsorption capacities of Fe and Cr for cotton-g-PTEAMA were found as 12.68, and 34.72 mg g–1, respectively. The second adsorbent cotton grafted poly(ethylenediamine methacrylate) (Cotton-g-PEDAMA) for the removal of heavy metals from wastewater was developed through functionalization of ethylene diamine (EDA) onto cotton-g-PGMA . The adsorption behaviour of cotton-g-PEDAMA towards Fe and Cr from contaminated water were also studied at different pH, times, and metal concentrations. The results showed that cotton-g-PEDAMA has an outstanding adsorption capability for Fe and Cr ions from contaminated water. The adsorption rate of metals showed good fitting to the pseudo-first-order kinetic viii model for both Fe and Cr, and the adsorption reached equilibrium within 120 min. The isotherm studies indicated that the obtained data showed good fitting to the Freundlich model for Fe and Langmuir model for Cr. The maximum adsorption capacities of Fe and Cr for cotton-g-PEDAMA were 44.27, and 174.4 mg g–1, respectively. Regeneration experiments indicated that the adsorbent maintained above 80% efficiency even after five adsorption/desorption cycles for both cotton-g-PTEAMA and cotton-g-PEDAMA. The adsorbent was effectively utilized to remove Fe and Cr from samples of industrial effluent. In comparison to existing treatment approaches, which frequently use non-biodegradable materials or expensive technology, the studied method shows potential as an eco-friendly option for heavy metal removal. By utilizing biodegradable materials, this study may contributes to resolve environmental problems connected with heavy metal pollution in industrial effluents. The findings may have consequences for long-term wastewater treatment practices, encouraging healthier water resources, and protecting human health. Description: An M.Phil. Thesis from the Department of Chemistry 2024-10-24T00:00:00Z http://103.99.128.19:8080/xmlui/handle/123456789/515 Title: Eco-Friendly and one pot synthesis of fluorescent carbon quantum dots from teak tree leaves through hydrothermal treatment. Authors: Barua, Jackson Abstract: This study describes the synthesis of environmentally friendly fluorescent carbon quantum dots (CQDs) derived from teak tree leaves (Tectona grandis) using a straightforward one-pot hydrothermal method. This method offers a sustainable approach to the synthesis of CQDs by utilizing renewable biomass resources. The synthesized CQDs exhibit nano-sized particles and possess strong fluorescence characteristics. Treatment with H2O2 facilitates the breakdown of the leaves structure and the formation of functional groups on their surface which enhanced their potential for the degrading hazardous chemical dyes like methylene blue (MB). The synthesized samples were extensively characterized using UV-Vis spectroscopy, photoluminescence spectroscopy, FTIR for functional group analysis, and Zeta potential measurements. Surface morphology and particle size were analyzed through TEM, SEM, EDX, and Histogram analysis. These CQDs demonstrate outstanding photocatalytic activity, achieving an impressive 98% degradation efficiency when exposed to visible light irradiation. Chemical oxygen demand (COD) analysis confirmed the high efficiency of photodegradation under visible light conditions. The combination of their eco-friendly synthesis method and superior photocatalytic performance underscores the potential of CQDs derived from teak as effective and sustainable materials for applications in environmental remediation. This research contributes to advancing the development of renewable nanomaterials for addressing environmental pollutants, suggesting a promising future for biomass-derived CQDs in various water treatment technologies and beyond. Description: Thesis in Chemistry 2024-07-24T00:00:00Z http://103.99.128.19:8080/xmlui/handle/123456789/494 Title: IMPACT OF SHIP BREAKING ACTIVITIES ON SOIL AND WATER QUALITY AT SITAKUNDA COASTAL AREA OF CHATTOGRAM Authors: Karim, Ahasanul Abstract: The Ship Breaking Area of Chattogram is one of the most ecologically effective regions in Bangladesh. It includes wealthy biodiversity that consists of numerous species that are endemic to this region. Physicochemical parameters and heavy metals in water and soil samples obtained from shipbreaking yards were measured to evaluate the potential ecological impact caused by these parameters. Here are the water quality parameters like temperature, EC, TDS, TSS, pH, DO, BOD, COD, salinity, oil, and turbidity. Temperature, pH, and BOD values were within the acceptable range, but TDS, EC, oil and grease, and turbidity were above the DoE's recommended standard level for surface water. Atomic absorption spectroscopy analysis was used to determine the presence of toxic metal contamination. Pb (avg. in Water: 0.46 mg/L; avg. in Soil: 52.55 mg/kg) > Cr(VI) (avg. in Water: 0.49 mg/L; avg. in Soil: 45.97 mg/kg) > As (avg. in Water: 0.205 mg/L; avg. in Soil: 6.99 mg/kg) > Cd (avg. in Water: 0.049 mg/L; avg. in Soil: 0.218 mg/kg). The levels of the harmful metals were higher than what was considered acceptable. Pb and Cr had no periodic effects, whereas As and Cd significantly varied (water and soil) with the times. The evaluation of the heavy metal pollution index showed that the study area had a critical score of water quality (HPI > 100). The average geo-accumulation index (Igeo) readings showed that the study area was very slightly polluted overall, with the exception of Cd. Also, all the ship-breaking region's sampling locations had pollution load indices ranging from 1.91 to 3.10, indicating that the soil there was heavily contaminated with heavy metals (PLI > 1). High levels of metal pollution in the study area suggest that it faces a high potential ecological risk index. According to this study, the shipbreaking site was moderately polluted with heavy metals and posed a risk to the ecosystem. Description: An M.Sc. Thesis from the Department of Chemistry 2023-12-13T00:00:00Z