Materials Science Forum Vol. 1008

Abstract: In this paper, an experimental work studies the principal operating parameters of a proposed desalination process using air humidification-dehumidification method. The major objective of this work is to determine the humid air behavior through the desalination system. Different operating conditions including the effect of the water temperature at the entry to the humidifier, the ratio of the mass of water to the air, the air/water flow rate, and cooling water at entry the dehumidifier on the desalination performance were studied. The results show that the freshwater increases with increasing the water temperature at the inlet of the humidifier, the ratio of the mass of water to air, and cooling water flow rate in the dehumidifier. Cooling water outlet temperature at the condenser increases with increasing the water temperature at humidifier inlet. Also, it decreases as increasing cooling water flow rate while the ratio of the mass of water to air achieves the highest productivity and gained output ratio (GOR). The achieved mass ratio (MR) is 4.5 and the mass flow rate of air is 0.8 kg/min.

Abstract: In this study, commercially available bare stainless steel 304 was investigated as a working electrode in urea electrooxidation in alkaline solution using different electrochemical techniques like cyclic voltammetry (CV) and linear sweep voltammetry (LSV). The electrode stability was also investigated by the constant potential electrolysis test. Different concentrations of KOH (0.5-4 M) were employed to study the electrooxidation of urea solution with concentration of 0.33 M. An anodic peak current density of 34.82mA/cm² was obtained at 473 mV versus Ag/AgCl reference electrode in urea solution at KOH concentration of 4 M. Stainless steel properties such as corrosion resistance, low cost in addition to its catalytic activity make it an ideal anodic electrocatalyst for electrooxidation of urea-rich wastewater.

Abstract: The rate of removal of heavy metal Copper ion (Cu ²⁺) from synthetic wastewater was studied using an ion exchange resin and pulsation technique. Variables examined were initial concentration of (Cu ²⁺), ratio of mass of resin to solution liquid volume, frequency, amplitude and geometry of the disc responsible for the pulsation motion. The results were presented mathematically by using the dimensionless analysis and the mass transfer correlation was obtained also Langmuir and Freundlich adsorption isotherms were examined where the date fits Freundlich adsorption isotherms more than Langmuir adsorption isotherms. It is concluded that percentage of (Cu ²⁺) removal decreases as initial concentration of (Cu ²⁺) presented increases and increases with contact time, frequency (rpm), amplitudes and mass of resin per unit volume of solution.

Abstract: Excess sludge generated from wastewater treatment plants (WWTPs) can cause negative impacts on human health, water bodies, aquatic plants, and soil quality. However, the produced sludge could be appropriately managed to obtain various economic and environmental benefits. One of the feasible and practical options of sludge management is the synthesize of biochar via oxygen-limited pyrolysis. The use of biochar adsorbent for pollutant removal offers various advantages such as high adsorption capability, low operating and chemical costs, no production of toxins. Hence, this study addresses the applications of sewage sludge-derived biochar for industrial wastewater treatment. The methods of sludge collection, drying, pulverization, and pyrolysis are illustrated. Biochar characterization methods (SEM, EDX, XRD, and FTIR analyses) and mechanisms of the adsorption process are described. The sludge-derived biochar could be used as an adsorptive material for industrial effluent treatment. Recommendations for future studies that could enhance the adsorption capacity of biochar and modified-biochar are given.

Abstract: Granular activated carbon (GAC) is utilized as an adsorbent for the malachite green (MG) dye removal from aqueous solutions. The GAC was characterized by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) to realize the GAC chemical and physical features effects on the adsorption efficiency. Batch adsorption processes were carried out with different variables like pH, GAC dose, initial MG concentration and time. The response surface methodology (RSM) was used to design the experiments, model the adsorption process, optimize the operating conditions and predict the response. A 2⁴ full factorial central composite design (CCD) was performed for the experimental design and the analysis of the results. Analysis of variance (ANOVA) was employed to determine the significance of the factors and explore the interaction between the various experimental parameters. An empirical model was derived to correlate the experimental results and predict the behavior of the GAC for the adsorption process. The model showed a good agreement with the experimental results of R² = 0.9968 and evidenced that the optimum operating parameters are pH 10, 2 g GAC/L, 200 mg/L of MG initial concentration and 113 min adsorption time for complete removal of MG.

Abstract: PANI was prepared in-house, characterized and utilized in the sorption of calcium, magnesium, iron, and copper in aqueous solution. The objective of this research was to evaluate adsorption of metals in mono and multi-metal in aqueous solutions onto PANI. Literature has it that, there is no record for competitive sorption of metals by PANI. The characterization of the prepared PANI confirmed with other literature that it was the Emeraldine PANI that was prepared. The results obtained after the multi metal adsorption experiment showed that PANI has a good performance in the removal of copper, iron, calcium, and magnesium, and can be credited to its' large surface area since it is a nanomaterial. Testing for the selectivity showed that the prepared nanoPANI adsorbed 95.2% of lead, 93.8% of copper and 75.8% of the iron in the single metal system.

Abstract: Aviation industry is considered one of the contributors to atmospheric CO₂emissions. It is forced to cut off carbon dioxide emission starting 2020. Current trends in bio-jet production involve mega projects with million dollars of investments. In this study, bio-jet fuel production by blending bio-diesel with traditional jet fuel at different concentrations of bio-diesel (5, 10, 15, 20 vol. %) was investigated. This blending technique will reduce bio-jet production cost compared to other bio-jet techniques. Bio-diesel was originally produced by the transesterification of non-edible vegetable oil (renewable sources), so, its blend with jet fuel will has a reduced carbon foot print. The blend was tested to ensure that the end product will meet the ASTM D1655 international specifications for Jet A-1 and Jet A and can be used in aircrafts.Available data on biodiesel blending with jet fuel in the literature is not consistent, there are many contradictory results. Hence, more investigations are required using locally available feedstocks. The main physicochemical properties for Jet A-1 and Jet A according to ASTM D1655 were tested to check if the blend will be compatible with existing turbojet engine systems. Different tests were conducted; vacuum distillation, smoke point, kinematic viscosity, density, flash point, total acidity and freezing point. In addition, heating value of the blend was calculated. The result was then compared with calculated value using blending indices available in the literature. Blending indices were able to predict the laboratory measured specifications for the studied blends.It was found that only 5% bio-diesel- 95% jet fuel blend (B5) meets ASTM standard for Jet A. Hence, biodiesel can be safely used as a blend with fossil-based jet for a concentration of up to 5% without any change in the ASTM specifications. Freezing point is the most important constrain for this blending technique. Higher blends of biodiesel will cause the bio-jet blend to fail ASTM specifications. In general, blending technique will reduce the cost impact that may have been incurred due to change in infrastructure when using other production techniques.