M.Phil / MS Theses
Permanent URI for this collectionhttps://repository.cuilahore.edu.pk/handle/123456789/27
This collection archives the complete set of theses produced by students of the COMSATS University Islamabad, Lahore Campus.
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Item Source Apportionment of PM2.5 in Lahore: Chemical Mass Balance Modeling and Inter-Study variability Assessment(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2025) Muhammad Nabeel Khan; CIIT/FA23-RNE-04/LHR; Dr. Wajih Ur Rehman; LHR TP 10010Elevated concentrations of fine particulate matter (PM₂.₅) pose a serious public health risk in Lahore due to their ability to penetrate deep into the respiratory system. This thesis applies the U.S. Environmental Protection Agency Chemical Mass Balance receptor model (CMB v8.2) to apportion PM₂.₅ sources using three independent, chemically speciated datasets from Lahore: a winter campaign (February 2019), a year-long monthly study (2019), and paired summer–winter measurements (2022). U.S. EPA source profiles for gasoline and diesel vehicles, biomass burning, coal combustion, road/soil dust, industrial emissions, and secondary Sulfate and Nitrate were employed. Model performance was evaluated using standard diagnostics (R², χ², percent mass explained, t-statistics, and residuals). The winter 2019 analysis showed good model performance (R² = 0.72, χ² = 3.8), with dominant contributions from petrol vehicles (101 µg·m⁻³) and biomass burning (81 µg·m⁻³), along with substantial secondary Nitrate and Sulfate. Monthly CMB runs for 2019 yielded R² values between 0.73 and 0.87, indicating stable performance across seasons. Diesel vehicle emissions peaked during late autumn and winter, while petrol vehicle contributions increased in warmer months. Coal and industrial combustion, together with secondary inorganic aerosols, contributed persistently throughout the year. Seasonal analysis of 2022 data showed PM₂.₅ increasing from approximately 130 µg·m⁻³ in summer to 303 µg·m⁻³ in winter, with acceptable mass closure and statistically significant source contributions. Across all datasets, combustion-related sources—vehicular emissions, biomass burning, and coal combustion—along with seasonally enhanced secondary inorganic aerosols were the dominant contributors to PM₂.₅ in Lahore, while dust sources were more influential during pre-monsoon periods. These results provide higher source resolution than previous PMF/PCA studies and support targeted mitigation strategies focused on vehicle emissions, combustion sources, and precursor gas controlItem Development of Experimental Testing Facility for Performance Evaluation Triboelectric Nanogenerator Device(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2025) Muhammad Nafees ul Hussain; CIIT/SP24-RNE-005/LHR; Dr Maria Mustafa; LHR TP 10011The study of Triboelectric Nanogenerators (TENGs) a flexible system to harvest low-frequency mechanical energy has become more accelerated by the increasing global demand on sustainable energy. But variable performance reporting in the field is often occasioned by lack of standardized and uniform testing conditions. This gap is covered by creating an in-house testing laboratory that will be utilized to precisely describe and quantify the durability of TENG devices. The two main parts of the experimental setup are an Arduino-controlled solenoid system that can perform independent testing at constant contact forces (2 N) and various periods of time, and a Dynamic Load Applicator (DLA) that can perform uniform cyclic endurance testing between 50-550 rpm. High-performance TENGs were created by evaluating the facility utilizing a polyvinylidene fluoride (PVDF) matrix covered with sodium niobate (NaNbO3) and carbon black (CB).Hydrothermal methods were used to create NaNbO3, and solution-based processing was used to install the thin film. Numerical outputs of the experiements highlighted facility's capacity to capture high-resolution data. The results suggest that the solenoid system was able to separate voltage peaks of up to 23V for PVDF+CB-NaNbO₃ combinations, while the DLA achieved maximum open-circuit voltages of 50 V for PVDF+CB-NaNbO₃ compositions. Sensitivity was exhibited by microampere-level current responses, which were 5.84 µA for PVDF+CB-NaNbO₃ utilizing the DLA and 5.62 µA for PVDF+NaNbO₃ utilizing the push-pull system. This study delivers a reliable and scalable setup for systematic TENG performance analysis that is significant for the development of self-powered devices and sensing technologies.Item Surface Modification of Layered Double Hydroxides for Reinforcement in Nitrile Butadiene Rubber(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2025) Ahmad Ali; CIIT/SP22-RCH-002/LHR; Dr. Khaliq Majeed; LHR TP 10007This study examines the reinforcement of the nitrile butadiene rubber (NBR) composites with Zinc-aluminium layered double hydroxides (LDH) with sodium dodecyl sulfate (SDS) to enhance filler-matrix compatibility and mechanical properties. The pure LDH was prepared by the co-precipitation method, after which modification was done on the surface by the SDS, to enhance the hydrophobicity and interfacial contact with NBR. The successful intercalation of the SDS and increased basal spacing in the modified LDH were verified by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). Tensile tests on the modified and unmodified LDH-NBR composites showed that SDS modification had a significant enhanced dispersion behavior of the filler, which resulted in an enhancement of mechanisms. The force- elongation curves exhibited linear behavior to some elongation after which there was sudden material failure, which was regarded as tensile limits of the composite. Even though, the SDS-modified LDH-NBR composites exhibited better reinforcement than the unmodified systems, unexpected failure in higher elongations indicated that additional optimization is necessary in filler dispersion and bonding between phases. The study has given a valuable insight into the potential of SDS-modified LDH as a reinforcing agent in NBR composites, with future studies aiming to optimize the filler dispersion, investigate alternative methods of modification, and evaluate the long-term performance within different environmental conditions.Item Green & Sustainable Membranes for Efficient Bioethanol Purification via Pervaporation(Library Information Services COMSATS University Islamabad Lahore Campus, 2023-02-27) Abeera Naeem; SP22-RNE-002; Dr. Muhammad Yasin; LHR TP 8636Traditional membrane technologies, typically reliant on fossil-based polymers and hazardous solvents, pose significant environmental threats. To address these challenges, this study introduces an innovative approach: the development of hydrophobic mixed matrix membranes utilizing waste polyvinyl chloride (PVC) pipes and deep eutectic solvents (DES) based on thymol: urea as green additives. The research focuses on synthesizing two types of membranes: dense and asymmetrical. Each type is evaluated for its efficiency in terms of flux and selectivity. The asymmetric membranes undergo optimization processes, involving adjustments in polymer concentration, co-solvent use, and evaporation time, to enhance pervaporation performance. This optimization aims to achieve maximum ethanol flux and high separation factor. In contrast, the dense recycled PVC membranes exhibit comparable results to conventional polymeric membranes in terms of flux (1.98 kg/m2) and separation factor (16). Significantly, the incorporation of DES into the membrane matrix results in substantial performance improvements. The separation factor enhanced by approximately 125%, alongside a 36% increase in ethanol sorption capacity. Asymmetric membranes particularly demonstrate a higher potential in flux performance, reaching 5.12 kg/m2.hr, in contrast to dense membranes with a flux of 1.98 kg/m2.hr. These findings highlight the effectiveness of using recycled waste materials and DES in membrane fabrication. This approach not only enhances pervaporation performance but also aligns with the goals of green and sustainable membrane technology, offering a promising solution to environmental concerns in the field of membrane separation.Item Simulation-Based Development of Deep Eutectic Solvent-Driven Extractive Distillation for Butanol Separation(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2025) Shazam Ali; CUI/FA23-RCH-006/LHR; Dr. Muhammad Yasin; LHR TP 9671Overreliance on fossil fuels such as coal, oil, and natural gas has led to severe environmental and human health concerns due to greenhouse gas (GHG) emissions and resource depletion. These issues have triggered the world to find renewable and environmentally friendly energy resources. Among these biofuels, biobutanol is the most promising fuel, primarily produced through the microbial fermentation process, and is a key component of the acetone-butanol-ethanol (ABE) fermentation process. However, the industrial scalability of biobutanol production is constrained by its low concentration in fermentation broths and the challenges of separating it from water due to azeotrope formation. Conventional separation processes, such as distillation, are energy-intensive and economically unviable for biobutanol recovery. Hybrid extractive distillation using ionic liquids (ILs) as an entrainer has shown potential as an alternative, with notable success in the dehydration of biobutanol. However, the limitations of ILs, such as toxicity, non- biodegradability, and high costs, pose significant barriers to their widespread adoption. To address these issues, deep eutectic solvents (DES) have emerged as a promising alternative. DES offers superior advantages over ILs, such as biodegradability, lower costs, and simple preparation. Recent research highlights their potential for separating lower alcohol, including biobutanol. However, the selection of optimal DES and the development of an efficient dehydration process for biobutanol remain unexplored. In this study, three new ideal hydrophobic deep eutectic solvents (DESs) were used for the effective extraction of butanol from aqueous mixtures: Thymol: Octanol (1:1), Thymol: Diphenyl (1:1), and Thymol: Octadecanol (3:1) in Aspen Plus V14. The DESs were used as selective entrainers to improve butanol recovery in the extractive distillation process, especially in cases in which the presence of azeotropes makes conventional separation energy intensive. At the distillate outlet, the Thymol: Octadecanol (3:1) mixture produced the highest 87% butanol purity among the evaluated DESs, demonstrating better performance. A thorough exergy analysis was carried out to assess the (DL-Menthol: Decanoic acid) and (Thymol: Octadecanol) DES-based configuration's sustainability and thermodynamic efficiency in further detail. The Thymol: Octadecanol (3:1) system had the best exergy efficiency, extractor column (99.96%), pump (99.99%), distillation column (5.03%), and cooler (99.99%), with the least amount of exergy destruction, according to the data, showing its capability as a highly efficient and energy-efficient solvent for sustainable butanol recovery. This work enhances the advancement of more environmentally friendly options for the purification of biofuels by offering a systematic method to choosing and evaluating the use of DESs in extractive distillation processes.Item Graphitic Carbon Nitride (g-C3N4) based Photocatalytic membrane for enhanced Pharmaceutical Micropollutant Filtration and Degradation(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2025) MUHAMMAD FAIQ BUTT; CUI/SP23-RCH-005/LHR; Dr. Abdul Razzaq; LHR TP 9670In the 21st century, the world is facing major challenges in water quality and global climate change due to an exponential growth in human population, so green technology is the need of the time to mitigate climate change and to minimize further factors that play a vital role in climate pollution. So, a combination of two technologies emerges as a new technology for the treatment of wastewater. Graphitic carbon nitride (GCN) has been integrated into polyacrylonitrile (PAN) membranes via an immersion- precipitation phase-transition reaction. This addition enhances the structural and morphological investigations, showing that GCN nanoparticles are evenly distributed in the PAN matrix. Different performance tests and characterization techniques confirmed that as the content of GCN increased, the performance of highly concentrated GCN-PAN hybrid enhances such as 0.25wt.% GCN-PAN membrane became more hydrophilic and less prone to fouling. More so, GCN-PAN membranes displayed the function of photocatalysis. Regarding photocatalytic activity, different loadings of hybrid membranes are used. Continuous degradation of metformin under sunlight irradiation was performed using 0.25wt.% GCN-PAN with a degradation rate of metformin of 50%. The presence of photogenerated h+ is high, and reactive oxidative species proved that these are the ones that were the cause of the observed degradation of organics and bacterial inactivation. This study proves that the addition of GCN into polymeric membranes enhances the performance, like permeate flux, salt rejection, and antifouling, due to the hydrophilic properties exhibited by GCN. Finally, the hybrid 0.25wt.% GCN-PAN membrane under the exposure of sunlight degrades wastewater treatment performance.