http://103.99.128.19:8080/xmlui/handle/123456789/113 Thesis published in Dept. of Chemistry Sat, 14 Nov 2026 12:14:14 GMT 2026-11-14T12:14:14Z http://103.99.128.19:8080/xmlui/handle/123456789/612 REMOVAL OF EMERGING CONTAMINANTS FROM URBAN WATER SYSTEMS BY USING TiO2 COATED CuWO4 NANOCATALYST Rahman, Md. Mahfujur The growing presence of antibiotics in urban water systems poses serious risks to environmental and human health. This thesis presents a comprehensive approach to remove ciprofloxacin (CIP), a widely used and persistent antibiotic, using a TiO₂- coated CuWO₄ (CuWO₄@TiO₂) core-shell nanocatalyst. The nanomaterial was synthesized via a two-step hydrothermal method and thoroughly characterized using FTIR, XRD, FESEM, XPS, and BET techniques, confirming its core-shell architecture, surface properties, and active sites. Batch adsorption experiments, optimized through Response Surface Methodology (RSM), demonstrated over 99% CIP removal under neutral pH conditions with optimal parameters including 10 mg/L initial CIP concentration, 300 mg/L adsorbent dose, and 40 minutes of contact time. The adsorption process followed the Langmuir isotherm and pseudo-secondorder kinetic models, with a maximum theoretical adsorption capacity of 109.58 mg/g. The material showed strong reusability, retaining high removal efficiency after five adsorption–desorption cycles. Complementing the experimental study, a multilayer perceptron (MLP) neural network model was developed using experimental data to predict CIP removal efficiency. Hyperparameter tuning via Bayesian and Random Search, coupled with Particle Swarm Optimization (PSO), yielded highly accurate predictions, with R² values up to 0.9985 for training and R² 0.9856 for testing. Feature importance analysis identified contact time and adsorbent dosage as the most influential factors. This work provides a robust and transparent machine learning-integrated framework for optimizing nanomaterialbased antibiotic removal, contributing to the advancement of sustainable water treatment technologies. A Master of Engineering (M.Engg) Thesis in Chemistry Department at Chittagong University of Engineering and Technology (CUET). Sun, 12 Oct 2025 00:00:00 GMT http://103.99.128.19:8080/xmlui/handle/123456789/612 2025-10-12T00:00:00Z http://103.99.128.19:8080/xmlui/handle/123456789/610 ASSESSMENT OF SEASONAL HEAVY METAL POLLUTION AT THE ESTUARIES OF SOME SELECTED CANALS FEEDING THE RIVER KARNAPHULI Islam, Ariful; ID:, 14MCHEM011P The main goal of this study was to evaluate the sessional variation of heavy metals concentration in surface water and sediments at the estuaries of major cannals (locally known as khal) feeding to Karnaphuli river and their associated health risks. Additionally, some important physico-chemical parameters of surface water were also studied to assess the present environmental loads at the study points. Ten major khals, which serve as the natural drainage to the Karnaphuli river were chosen for collecting the surface water and sediments samples; among them six from the Chattogram city side and four from the opposite side of Karnaphuli river. Concentrations of eight heavy metals, like Cu, Cr, Cd, Pb, Ni, Mn, As and Zn in surface water and sediment samples during the wet and dry seasons were determined using flame atomic absorption spectroscopy (FAAS). Beside these, some important physico-chemical parameters, such as temperature, pH, DO, BOD, COD, TDS, EC, salinity and hardness of surface water were measured using portable multi-analyzer and standard methods, where applicable. Some of the studied parameters at some locations showed higher values than the limits recommended by WHO, especially in the dry season. The values of all parameters, except temperature were cosideably higher in the wet season than in dry season. The average concentrations of Cu, Cr, Cd, Pb, Ni, Mn, As and Zn in surface water samples during wet were found 57.48 ± 7.07, 52.79 ± 5.63, 14.94 ± 3.15, 52.15 ± 5.41, 34.34 ± 3.89, 64.90 ± 10.31, 9.40 ± 1.55 and 60.37 ± 6.77 µg/L and in dry season the concentrations were 65.24 ± 9.40, 62.50 ± 6.52, 22.20 ± 4.41, 72.24 ± 9.14, 38.28 ± 5.34, 69.90 ± 11.13, 15.03 ± 3.53 and 75.03 ± 9.78 µg/L respectively. Again, the average concentrations of those heavy metals in surface sediments samples were 38.84 ± 3.50, 46.92 ± 3.84, 2.18 ± 0.42, 42.98 ± 3.97, 43.39 ± 3.55, 1.34 ± 0.19 and 91.93 ± 7.72 mg/kg in wet season and 51.13 ± 2.88, 59.23 ± 1.65, 2.52 ± 0.14, 61.05 ± 4.09, vi 49.66 ± 5.70, 58.55 ± 8.112, 21 ± 0.74 and 104.44 ± 5.02 mg/kg respectively in dry season. The average concentration of Cu, Cr, Cd, Pb and Ni in sediments were found higher than the limit recommended by USEPA, 2019. However, the study also found that the concentration of heavy metals in both water and sediment samples were found higher in the dry season than that of wet season at most of the locations. The metal pollution index (MPI) shows that water of all the studied feeding khals are highly polluted in both wet and dry seasons. Potential carcinogenic and non carcinogenic health risks through dermal contact were found within the acceptable limit recommended by USEPA for lifetime exposure to the surface water. Most of the environmental indices calculated, like enrichment factor (EF), degree of contamination (Cd), pollution load index (PLI), geoaccumulation index (Igeo), potential ecological index (PERI) and nemerow pollution index (PN) for heavy metals in surface sediments showed no potential risk; although the contamination factor (CF) and modified contamination degree (mCd) indicate that the sediments of the studied khals became moderately and highly contaminated respectively with heavy metals. Pearson’s correlation coefficient was applied to find out the association between pollutants in the investigated samples. The results showed that physiochemical parameters of surface water, and concentration of heavy metals in surface water and sediments are influenced by seasonal water flows. Moreover, heavy metals showed variation from one location to others, and it was considerably higher in the industrial sites than that of municipal waste discharge sites. The obtained comprehensive data for physico-chemical parameters of surface water, and toxic heavy metals in the surface water and sediments at the estuaries of studied khals feeding to Karnaphuli river may help the policy maker for making effective legislation to minimize the ecological risks of the river through proper monitoring, controlling and protection. A Master of Philosophy (M.Phil.) thesis submitted to the Department of Chemistry, Chittagong University of Engineering and Technology (CUET). Wed, 30 Jul 2025 00:00:00 GMT http://103.99.128.19:8080/xmlui/handle/123456789/610 2025-07-30T00:00:00Z http://103.99.128.19:8080/xmlui/handle/123456789/600 ISOLATION OF MUCILAGE FROM THE FRUITS OF Momordica charantia AND INVESTIGATION OF ITS PHARMACOLOGICAL PROPERTIES Chowdhury, Tahamina Momtaz; ID:, 19MSCHEM005F Momordica charantia is a plant belonging to the Cucurbitaceae family, also known as ‘Bitter gourd’, and ‘Usta’ in bangle. It contains alkaloids, insulin-like polypeptides, and charantin, a combination of steroidal sapogenins. It is an effective hypoglycemic agent. Momordica charantia is the most common plant used in alternate medicines as an anti-diabetic agent. Metformin hydrochloride is derived from the class of compounds from biguanide family, is an oral anti-hyperglycemic agent and is widely used as an anti-diabetic drug in the treatment of non-insulin-dependent diabetes mellitus (NIDDM). The action of Metformin is the alteration of the energy metabolism of the cell. By blocking hepatic gluconeogenesis and glucagon's action, metformin has its predominant effect of lowering blood glucose levels. Metformin has 50-60% bioavailability and 1.5–4.5 hours for plasma half-life. Initial dose (800 mg) required in orally once a day .Therefore, in the case of higher diabetes, higher doses are required, there is a need to take this medicine 2–3 times in a day. In the current study, the mucilage isolated from Momordica charantia fruits and used in the tablets formulations as a binding agent. Different phytochemical test of isolated mucilage showed that only carbohydrates is present in it. We have designed nine batch tablets containing 500 mg of Metformin HCl with different compositions of mucilage (1%, 2.5%, 5%, and 10%) for 800 mg of each tablet. The pre-compressional and post-compressional pharmacological properties of different formulated granules and tablets are evaluated. The granules showed good to excellent flow properties based on the values of bulk density, tap density, carr’s index, hausner's ratio and angle of repose. The weight of the tablets is close to the standard and shown good hardness properties. Among all the formulations, the tablets batches of formulation 4 (F4) and formulation 8 (F8) have good disintegration properties. From in vitro dissolution profile analysis, formulation batch F 4 composed of 10% mucilage and F-8 composed of 10% mucilage along with 10 % starch, released 40.8% and 31.63% of the drug, respectively in 60 minutes. Drug Release Kinetics Study showed that F4 showed the first-order release kinetics and F-8 showed the zero order and the Higuchi-s release kinetics. Hence, mucilage from Momordica charantia can be used as excipients or tablet binders for low cost, available, nontoxic in pharmaceutical tablet formulations. A Master of Science (M.Sc) Thesis in Chemistry Department at Chittagong University of Engineering and Technology (CUET). Thu, 29 May 2025 00:00:00 GMT http://103.99.128.19:8080/xmlui/handle/123456789/600 2025-05-29T00:00:00Z http://103.99.128.19:8080/xmlui/handle/123456789/584 VISIBLE- LIGHT DRIVEN PHOTOCATALYTIC DEGRADATION OF ORGANIC POLLUTANTS OVER CuWO4@TiO2 NANOCOMPOSITE: A COMBINED EXPERIMENTAL AND THEORITICAL STUDIES Dutta, Keya Rani; ID:, MSCHEM014F With the growing presence of organic pollutants like methylene blue (MB) in wastewater, there are significant concerns for both the environment and public health, highlighting the urgent need for the development of effective remediation strategies. This study addressed the urgent need for effective remediation strategies for organic pollutants, specifically methylene blue (MB), in wastewater by synthesizing and evaluating a CuWO₄@TiO₂ nanocomposite photocatalyst. A comprehensive characterization using UV-Vis diffuse reflectance spectroscopy (DRS), field emission scanning electron microscopy (FESEM), X ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET) surface area analysis, electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV) was conducted to assess the nanocomposite's structural, morphological, and electrochemical properties. Density functional theory (DFT) calculations provided insights into the photocatalytic mechanism, particularly the most stable Ti/Cu@CuWO₄ interface configuration. To enhance predictive modeling for MB degradation, ten machine learning (ML) algorithms, including AdaBoost, Bagging, CatBoost, Decision Tree, Extra Trees, Gradient Boosting, HistGradientBoosting, LightGBM, Random Forest, and XGBoost, were evaluated based on coefficient of determination (R²), mean square error (MSE), root mean square error (RMSE), mean absolute error (MAE), and median absolute error (MedAE). Among this HistGradientBoosting model demonstrating exceptional performance, achieving an R² of 0.9998 in training and 0.9915 in testing, along with low error metrics. Experimental validation under optimal conditions (200 mg/L catalyst, 150 mW/cm² light intensity, 88.6 min reaction time) confirmed a 98.5% MB degradation efficiency, closely aligning with the ML-predicted 98.99%. The nanocomposite exhibited significantly higher catalytic activity as compared to individual CuWO₄ and TiO₂, with rate constants of 0.0302 min⁻¹ for the nanocomposite, 0.0197 min⁻¹ for CuWO₄, and 0.0167 min⁻¹ for TiO₂. Scavenger experiments revealed the order of active species in the degradation process as O₂•⁻ > HO• > ¹O₂ > e⁻ > h⁺, this research emphasizing the combined effectiveness of experimental, computational, and machine learning methods in optimizing photocatalytic water treatment processes. A Master of Science (M.Sc) Thesis in Chemistry Department at Chittagong University of Engineering and Technology (CUET). Wed, 30 Apr 2025 00:00:00 GMT http://103.99.128.19:8080/xmlui/handle/123456789/584 2025-04-30T00:00:00Z