Thin films of titanium dioxide (TiO2) were prepared through sol-gel routes and dip-coating technique, employing titanium isopropoxide (TTIP) in 2-propanol as precursor, and three stabilizing agents i.e. diethanolamine (DEA), lactic acid, and citric acid. The optical properties, crystallinity, and morphology of the samples were evaluated using UV-Visible (UV-Vis) Spectrophotometry analysis, X-Ray Diffraction (XRD) analysis, and Scanning Electron microscope (SEM). Homogeneous crack-free thin films with uniform size were obtained. All the samples showed the formation of anatase phase TiO2 with no impurities. It was found that TiO2 with all samples has excellent photocatalytic performance on methylene blue degradation.
Aims: In this research work the viability of producing silicon carbide reinforced aluminium composite using indigenous casting technology has been investigated.
Place and Duration of Study: AfDB Lab, African University of Science and Technology, Abuja between August 2018 and September 2019.
Methodology: The materials used are aluminum alloy 6063 of the following composition: Al -98.5%, Mg -0.51%, Si-0.46%, silicon carbide of particle size 30 µm, and sodium tetra borate (borax) as a wetting agent. In order to produce the composite, the following steps were taken: 6%, 9%, 12%, and 15% volume fractions of Silicon carbide of 1 kg, 1.2kg, 1.5 kg, and 1.6 kg respectively of aluminium alloy 6063 ingots were weighed and preheated to 450°C with simultaneous dehydration of the borax at 250°C. The alloy 6063 was charged into the diesel fire furnace, heated above the liquidus at 750±50°C and then the temperature was allowed to drop to the semi-solid state at about 600°C. The preheated Silicon carbide and dehydrated borax mixture was charge in the ratio 2:1 into the semi-solid alloy and was manually stirred using a preheated stirrer. The composite temperature was raised back to above the liquidus at 750±50°C and automatic stirring was done for 10 minutes using an electric motor with a speed of 300rpm. The molten composite at about 700°C was poured into a green sand mold with graphite coated cavities and the composites solidified into a trapezoidal cross-sectional bar.
Results: It was observed that in terms of weight there is practically little or no difference between the indigenously produced composite and the ones produced by standard technology. The hardness properties of the composite increases with increase in the volume percent of silicon carbide.
Conclusion: Diesel fired crucible furnace can be used to produce quality aluminium silicon carbide composite from locally sourced materials and equipment.
This research work focused on extracting dye from the surface of dyed polyester fabric and also investigates the effect of exposing the extracted dye solution to diffused light and changes in temperature which are common processes in dry cleaning industries. This is to establish the stability of the extracted dye in non aqueous solvents. Two commonly used dry cleaning solvents- perchloroethylene (PCE) and tetrachloromethane (TCM) were used to extract disperse blue 1 dye from the surface of dyed polyester fabric obtained from a previous work. The storage stability of the extracted dye at room temperature in diffused light as well as thermal stability at 20°C, 30°C and 50°C in the two solvents is reported. The daily visual check on the colour of the extracted dye solution on exposure to diffused light for a period of 14 days was found to be stable for 5 days in PCE while it lasted for 9 days in TCM before fading. Spectrophotometry analysis of the extracted dye solution was found to be thermally stable in TCM at the various temperatures used for the experiment relative to PCE where concentration of the extracted dye was found to decrease. The results obtained therefore serves as useful standard for choosing suitable solvents during dry cleaning of dyed fabrics to prevent adverse effects on the aesthetic nature of the fabric surface dye.
The adsorption of lead (II) ions from fertilizer wastewater using Acid Modified Eggshell (AMES) as adsorbents was studied. The effects of process parameters such as temperature, contact time, pH and adsorbent dosage on the adsorption of Lead (II) ions from fertilizer industrial waste water were investigated. FTIR spectrum was employed to investigate the functional groups present in the egg shell before and after modification. Scanning Electron Microscope (SEM) was used to study the surface morphology of the egg shell before and after modification. Kinetic and isotherm model of the best fit for the data was investigated using the established models. FTIR characterization revealed that some functional groups disappeared while new ones appeared after modification indicating effective modification. SEM analysis revealed that the microporous spaced increased after modification. The process factors considered significantly affected the rate of lead ion adsorption. Batch adsorption studies demonstrated that the highest percentage of 94.6% of lead ion was removed at a dosage of 40 mg of adsorbent per 100 ml of effluent after 60mins at a pH of 5 with optimum temperature of 45°C. The adsorption isotherm suggested a good fit of the experimental data into Temkin models with 0.998 as the R2 value. Second order kinetic model was found to be the best fit for the adsorption data. Thermodynamic studies revealed that the adsorption of lead ion onto activated egg shell is endothermic with entropy and enthalpy value as 0.025 kJ/mol.k and 15.96 kJ/mol, respectively. Results obtained showed that acid modified egg shell is a good adsorbent for the removal of lead ion from wastewater.
Environmental protection, public health, physical capital, and natural state, maintaining biological diversity and fragile ecosystems balance, waste management, etc. are just some of the current issues facing humanity. Waste management and hence their degree of recycling have different valences from one country to another, in Romania, registering notable efforts to develop viable strategies for sustainable development and integrated waste management, especially of the industrial and household waste. The purpose of this paper is to highlight the remarkable results of the activity of industrial pollution protection, recycling, and the use of wood waste as a raw material in products with an efficient recovery, due to the increasing concerns for use of secondary energy resources.
