Search Results (5)

Boehmite is an aluminum oxyhydroxide (AlO(OH)) and one of bauxite’s main mineral phases. This mineral is highly valued as an important source of aluminum for the metallurgical industry. However, the formation of synthetic boehmite has been observed in water treatment when aluminum anodes are used for electrocoagulation. This boehmite occurs in flocs that capture impurities from the water, but removing these flocs is a slow process. Therefore, the froth-flotation method was employed in the present study to float synthetic boehmite. This was achieved by evaluating the particle size of synthetic boehmite, generating microbubbles, and using an anionic collector system in a novel experimental setup. The results show that the surfactants sodium dodecyl sulfate (SDS) and potassium oleate (PO) favor the recovery of synthetic boehmite in different particle sizes, with the particle size favored related to the bubble size generated. It was noted that increasing the SDS concentration enabled the microbubbles to recover up to 95% of boehmite particles with diameters of less than 30 microns. Full article

A coagulation treatment is a separation technology widely used in industries as a pre-treatment step to remove the dissolved organic matter in wastewater. However, the type of coagulant, the optimized dose, and the treatment cost associated with various commercially employed coagulants must be investigated for the treatment of oil and gas produced water. In this study, five widely employed coagulants—ferric chloride, aluminum potassium sulphate, chitosan, sodium sulfide, and magnesium oxide—were tested for the treatment of actual complex oilfield-generated produced water. Water quality parameters such as the total suspended solids (TSS), total dissolved solids (TDS), turbidity, salinity, and pH were assessed for a better understanding of different coagulant activities against the produced water treatment. All the coagulants were efficient for the treatment of produced water. The findings of this study showed that ferric chloride led to the best removal of total solids (74.25%) of all water quality parameters, with treatment costs of USD 4 per m⁻³ of produced water. The results from this study contribute to the environmentally friendly, broader, and cost-effective application of a coagulation treatment to produced water. Full article

The environmental impact and availability of ingredients are vital for the new generation of rocket propellants. In this context, several novel composite propellants were prepared based on the “greener” oxidizer phase-stabilized ammonium nitrate (PSAN), a micronized aluminum–magnesium alloy fuel, iron oxide powder burn rate modifier, triethylene glycol dinitrate (TEGDN) energetic plasticizer and a polyurethane (PU) binder. The novelty of this study is brought by the innovative procedure of synthesizing and combining the constituents of these heterogeneous compositions to obtain high-performance “eco-friendly” rocket propellants. The polymorphism shortcomings brought by ammonium nitrate in these energetic formulations have been solved by its co-crystallization with potassium salts (potassium nitrate, potassium chromate, potassium dichromate, potassium sulphate, potassium chlorate and potassium perchlorate). Polyester–polyol blends, resulting from recycled post-consumer polyethylene terephthalate (PET) glycolysis, were utilized for the synthesis of the polyurethane binder, especially designed for this type of application. To adjust the energetic output and tailor the mechanical properties of the propellant, the energetic plasticizer TEGDN was also involved. The performance and safety characteristics of the novel composites were evaluated through various analytical techniques (TGA, DTA, XRD) and specific tests (rate of combustion, heat of combustion, specific volume, chemical stability, sensitivity to thermal, impact and friction stimuli), according to NATO standards, providing promising preliminary results for further ballistics investigations. Full article

Winter fog is a complex issue affecting human health and is responsible for higher numbers of traffic accidents in North India, which is further aggravated due to atmospheric pollutants. An indigenous glass-plate fog collector was used to collect fog water from December 2020 to February 2021. Thirty samples of fog water were collected from the rooftop of an academic building at Guru Nanak Dev University, Amritsar, in order to study the chemistry of fog water. The studied parameters were pH, electrical conductivity (EC), sodium (Na⁺), calcium (Ca²⁺), magnesium (Mg²⁺), potassium (K⁺) sulphate (SO₄²⁻), nitrate (NO₃⁻), chloride (Cl⁻), aluminum (Al), lead (Pb) and zinc (Zn). The average values were as follows: pH (4.6–7.5), EC (135 µS/cm), SO₄²⁻ (77.5 ppm), Cl⁻ (9.9 ppm), NO₃⁻ (9.3 ppm), Ca²⁺ (8.1 ppm), Mg²⁺ (2.0 ppm), K⁺ (2.0 ppm), Na⁺ (1.6 ppm), Zn (218 ppb), Al (60.8 ppb) and Pb (8.8 ppb). Cation–anion balance was used to assess the data’s reliability. The enrichment factor (EF) was utilized to distinguish between crustal and anthropogenic sources. SO₄²⁻, NO₃⁻, Cl⁻ and K⁺ originated from anthropogenic sources, whereas Mg²⁺ and Na⁺ came from crustal sources. The molar ratio of sulphate to nitrate was 10.6, which indicates a greater contribution from the combustion of fossil fuels and stack emissions. Ionic species were subjected to principal component analysis (PCA) as a dimensionality reduction approach and to group species with comparable behavior. Three principal components (PC) that together accounted for 77.5 percent of the total variance were identified by PCA. Backward trajectory analysis of air masses was performed to determine their origin, and two major clusters explained 89 percent of the contribution of air masses, primarily from the north-east and north directions. To gain a comprehensive understanding of fog water, a global perspective on pH, EC and ionic species is considered. Full article

A Microbial Fuel Cell (MFC) is a process in which a microorganism respires and captures the electrons that normally passes through the electron transport system of the organism and produces electricity. This work intends to present the different operating parameters affecting the efficiency of a Microbial Fuel Cell (MFC) process. To study the performance of the process, various materials for the cathode and anode rods with similar size and chape including, copper, aluminum, carbon cloth, steel and brass were considered to determine the combination that leads to the best results. Moreover, different oxidizing agents such as Copper Sulphate and Potassium Hexacyanoferrate were considered. Furthermore, the effects of shapes, sizes and distance between electrodes on the current and voltage were investigated. The power outputs between electrochemical and microbial cells were recorded. In addition, the power, whether expressed as voltage or current, was measured at different conditions and different cell combinations. The power is directly related to the area, volume of the bacterial solution and supplying air and stirring. Full article