Theses and dissertations (Engineering and Built Environment)
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Item Improvement of scratch and abrasion resistance properties of automobile paint(2023) Mohanty, Debasmita; Kanny, Krishnan; Mohanty, SmitaThe automobile paint industry normally consumes petro-based feedstock as the raw material, which is non-renewable and emits a higher amount of volatile organic compound (VOC), that pollutes the environment. This study focuses on the use of ecofriendly castor oil (CO) as a substitute for petro-based feedstocks; while synthesizing polyurethane (PU)-based automobile coats. The novelty and objective of this work is paints derived from bio-based CO as a substitute for petro-based feedstocks.CO is a nonedible oil, hence it does not affect the food chain. Paints derived are with fewer VOCs, thus having a less detrimental effect on the environment and is cost-effective. Modified castor oil (CO) based polyurethane (PU)/nano-silica (NS)/titanium pigment (TP) hybrid coating with an organic-inorganic covalent bond was synthesized by the in-situ polymerization method. Aminopropyl tri-ethoxy silane (APTES) modified NS particles along with TP were added to the PU matrix at various wt. %. Thermal, mechanical, and chemical resistance properties of the coating samples were significantly enhanced with the addition of NS and TP. Char residue, Glass transition temperature, pencil hardness, Young’s modulus, water contact angle (WCA), crosssectional density, cross-cut tape adhesion %, abrasion % increased from 0.29%, - 24.5ºC, 2H, 251MPa, 77.61º, 0.16mol/m3 , 65±5%, 0.040% to 1.26%, 1.94ºC, 3H, 1199MPa, 88.89º, 2.4mol/m3 , 93±2% and 0.016% with addition of modified NS particles along with TP particles. Paint formulation with 0.5 wt% NS and 0.2 wt% TP was optimized to be applicable as an automobile base coat and its characteristic properties can be comparable with a commercial base coat (BC). An acrylate-PU/NS hybrid coating was developed, which was derived from CO-based polyol. CO was modified by employing a process that includes epoxidation, followed by transesterification, and acrylation to synthesize the required polyols, which is used for acrylate-PU paint synthesis via the in-situ polymerization process. Triallyl isocyanurate (TI) modified NS particles were incorporated with the paint matrix by the ultrasonication method to enhance the paint properties. Experimental findings revealed that with the incorporation of NS particles, char residue, Young’s modulus, abrasion resistance, and cross-cut adhesion % increased by 71.31%, 42%, 0.28%, and 5% respectively. Also, glass transition temperature, pencil hardness, nanoindentation depth, water contact angle (WCA), and cross-linking density were increased from -12.16 ºC, 2H, 3300 nm, 81.71 º, and 0.90 mol/m3 to 1.65 ºC, 3H, 2000 nm, 92.26 º, and 1.78 mol/m3 respectively. The UV-visibility spectra, haze, transmittance, and gloss parameter showed the enhanced optical properties of the paint samples. PU/NS composite coating developed showed equivalent properties as that of the commercial clear coat. Epoxy/PU composite applicable as automobile sealer was synthesized by the ultrasonication mixing process. TI-modified NS particles were incorporated into the blend to enhance the characteristic properties. Structural properties of the composite were studied using FTIR spectra. Char residue %, glass transition temperature, crosslinking density, and WCA were observed to increase from 3.10%, 50.60 °C, 0.98 mol/m3 , and 85.63 ° to 4.55%, 73.76 °C, 3.75 mol/m3 , and 91.45 ° respectively after incorporation of NS. The impact strength, tensile strength, and fracture toughness of the blend were studied to increase after NS reinforcement. The epoxy-PU/NS nanocomposite developed fulfilled the parameters of automobile sealer.Item Bioremediation of acid mine drainage and crude contaminated soils(2020-09) Anekwe, Ifeanyi Michael; Isa, Yusuf MakarfiPollution is one of the greatest ills plaguing the existence of the ecosystem which could lead to the annihilation of terrestrial and aquatic habitat if not remedied. Acid mine drainage (AMD) and crude oil are among the major land and water pollutants cause by industrial and human activities. The constant exploration, mining, and processing of mineral resources and prevalent use of petroleum products for economic purposes have contributed to contamination of soil and proximate water bodies which results in environmental degradation; thus, remediation becomes necessary. The treatment of AMD contaminated soils using the conventional methods has some room for improvement to meet the remediation purpose. Bioremediation technology provides a sustainable and eco-friendly approach to the treatment of contaminants. This study aims to evaluate the performance of different potential bioremediation techniques and conduct a comparative analysis of these methods for the treatment of AMD and crude oil-contaminated soils. The treatment approach for both pollutants comprises of soils separately contaminated with AMD and crude oil before the application of bioremediation techniques. For the biostimulation study, contaminated soils were amended with varying ratios of the brewery or municipal wastewaters (BWW and MWW), while the bioventing (BVT) treatment involved wastewater amendment and supply of atmospheric air from the vadose zone at 3L/min at 30 minutes intervals every 48 hours. The bacteria strain Pseudomonas aeruginosa ATCC 15442 used for the study which was inoculated at 5%(w/w) was cultured in two different media for respective treatments and wastewater was amended as an extra energy source for bioaugmentation (BAU) study while Bioattenuation (BAT) which received no amendment was used as a control treatment for the study. The treatments were conducted in plastic bioreactors under mesophilic conditions for 28 days and samples were collected from each treatment system on weekly basis to analyse for sulfate, heavy metals, and total petroleum hydrocarbon (TPH) reduction. The result of the study showed that the amendment of contaminated soils with wastewater increased alkalinity in the system which enhanced microbial activities for effective remediation which recorded 52.43 and 51.23% average TPH and metal removal efficiency for the BSTc treatment. Also, the combined application of bioremediation techniques was more effective than single application as the introduction of oxygen into the treatment system with wastewater amendment increased the TPH and metal removal efficiency by an average of 12.98 and 13.17% respectively but efforts to enhance sulfate removal by air-injection (BVTa) proved abortive with 17.20 and 14.67% removal efficiencies less than BSTa and BAUa respectively as sulfate-reducing bacteria thrive in an anaerobic environment. However, P. aeruginosa ATCC 15442 adopts the sorption process in the reduction of hydrocarbon and metal toxicity with 42.02 and 41.81% average removal efficiencies respectively and the amendment extra nutrient (wastewater) increased the removal efficiency of these pollutants by 25.24 and 16.23% respectively. The results of the study inferred that wastewater (BWW and MWW), air-injection and P. aeruginosa ATCC 15442 showed great potentials in the degradation and removal of TPH, metals and sulfate contaminants, hence, can serve as a viable strategy for the remediation of AMD and crude oil polluted soils while improving waste management and amelioration of pollution aftermath faced by communities involved in mining and oil production and/or processing. There is a need for optimization to ensure effective remediation while further study is required to validate large scale application.Item The development of a boom and skimmer for the recovery of oil spilt in waterways(1999) Candy, Robert Leonard; Walker, M.The two and a half billion dollars spent in cleaning up the Exxon Valdez spill in Prince William Sound is one of many indications of how seriously environmental damage is viewed today. Due to the massive problems encountered during spills, clean-ups remain time consuming and costly. Thus the aim of this study is to develop a more efficient method, which will be the design and development of an oil reclaimer to operate in moderate sea conditions. The feasibility of the concept will be evaluated against existing methods.