Synthesis of α-alumina developed from waste aluminium using precipitation technique

The heated aluminium containers were added to a solution of 8.0 M H2SO4 solution, which eventually yielded a solution of Al2(SO4)3 after a series of stepwise precipitation reactions. Al2(SO4)3 was presented in large quantities of H2SO4 in the white semi-fluid solution; there were some unreacted aluminium parts. The solution was subjected to filtration and then mixed with anion in a ratio of 2:3, this resulted in the formation of a white layer Al2(SO4)3•18H2O. Thereafter, Al2(SO4)3•18H2O was calcined in an electric oven for 2 h at various calcination temperatures (500, 700, 900, 1100, and 1300°C). The mixtures were heated and cooled at a rate of 10°C/min. XRD was employed to investigate variations in temperature and determination of elemental accumulation of alumina produced. Ah(SO4)3•18H2O was due to a series of aluminium compositions produced from dehydration. All transitions from low temperatures to aluminium phases were converted to high-temperature α-Al2O3. The results obtained from X-ray disintegration showed that the α-Al2O3 phase was obtained at a reaction temperature of about 1150°C and above

Absorption technology for upgrading biogas to biomethane

Industrial development in the modern era has been boosted through the extensive use of fossil fuels, which now is considered a critical issue for global warming and greenhouse gas emission. Frequent natural disasters, population migrations, and an imbalance of environmental conditions are the results of excessive use of fossil fuels as well. To cope with the global warming challenge, different methods to mitigate the increasing CO2 emissions such as carbon capture, storage, and conversion are introduced. Hence, all over the world, renewable energy sources are getting popular to meet the ongoing demand. According to a report by Murdock et al., the progress is not satisfactory for economic implications to achieve the goal by 2050. The same report stated that in 2018, renewable energy was only 11% of the total energy consumption around the globe. Biofuel emerges as an effective alternative to fossil fuels as it requires lower initial and operating costs and has a wide range of raw material selection. In 2012 the biogas energy consumption in the EU countries reached 29.5GW which reaches almost double within a decade and will reach 25% of the total fuel consumption in 2050. The high CO2 content in biogas reduces its calorific value and Wobbe index which hinders the optimal utilization of biogas. Therefore upgrading via different methods, the CO2 is reduced and instead of biogas, biomethane is produced which may be utilized in IC engines, power generation, and transportation. The scopes of biogas utilization have not been explored enough compared to the total global biogas production. Nevertheless, this industry is expanding, and as of 2016 according to the annual report of European Biogas Association (EBA), there are more than 503 biogas upgrading plants operating in Europe, up from 187 in 2011

Synthesis and applications of inverse vulcanized polysulfides from bio-crosslinkers

Elemental sulfur, an industrial by-product from petroleum industries worldwide, has drawn sufficient attention to researchers. The limited scope of application has caused a colossal surplus amount of elemental sulfur stacked in the open places. Several polysulfide synthesis processes, including condensation, free-radical process, and ionic copolymerization technique, were used but resulted in unstable products. A new polymerization technique, termed inverse vulcanization, has been introduced, which enabled different types of crosslinkers for polysulfide production and their scopes to explore numerous applications. The current paper concisely reviews the evolution and advances of using vegetable oils and plant extracts in inverse vulcanization to produce polysulfides. The alluring applications and properties have also been discussed briefly

Waste cooking palm oil as sustainable material for polysulfide synthesis : Characterization as a crosslinker for inverse vulcanization

Edible oils are becoming popular as crosslinkers to produce inverse vulcanized polysulfides. Waste palm cooking oil can be a suitable alternative as it is inexpensive and abundant in Malaysia. In the current work, the physicochemical properties were studied to analyze the potential of using waste palm cooking oil as a crosslinker. FTIR and GC-MS were done for molecular study, functional group analysis, and percentage of constituents. Data interpretation and comparison between fresh and waste palm cooking oil shows no significant structural and spectroscopic change. TGA was done to study the thermal stability and decomposition of both fresh and waste cooking oil. It is concluded that waste palm cooking oil can be a potential feedstock for inverse vulcanized polysulfides based on the experimental results

Polysulfide: Sorbent made from waste cooking palm oil for petroleum refinery wastewater

Refinery industries produces almost 1.6 times wastewater compared to the petroleum products. Heavy metals and oily compounds are considered as most dangerous pollutants. Adsorption is the easiest and most effective method to treat the refinery wastewater. Polysulfides are cost effective and easy to produce in industrial scale. Waste cooking palm oil is the crosslinking monomer of polysulfide. It is abundant and itself hazardous. Elemental sulfur which is a by-product is abundant as well

Recovery of waste cooking palm oil as a crosslinker for inverse vulcanized adsorbent to remove iron (Fe3+) ions

Gas and oil reservoirs around the world leave megatons of unused elemental sulfur as industrial byproducts which has been successfully used in inverse vulcanization. We reported the successful application of inverse vulcanized porous adsorbent from waste cooking palm oil (WCO) to remove ferric (Fe3+) ions. Sodium chloride (NaCl) acted as a porogen to get the porous polysulfide. The removal of Fe3+ was observed through the atomic absorption spectroscopic (AAS) technique. The effects of pH (3,7, and 11) and initial concentration (35, 40, 45 mg/L) of Fe3+ solution, and dosage (10, 15, and 20 g/100mL) on Fe3+ adsorption were studied to determine the best removal condition. Later, fixing the best parameters (pH 3, 40 mg/L, 20 g/100mL), Langmuir and Freundlich equations were used to study the adsorption isotherm. Adsorption kinetics were described using linear and nonlinear pseudo-first and second-order reactions. The Freundlich isothermal model and linear pseudo- second-order kinetics fit best for the removal process. The comparison between the pre and post-adsorption analyses using FTIR, SEM-EDX, and the isothermal model confirmed the physisorption of Fe3+. The current study concluded with some further scopes of the adsorbent for diverse removal applications

Synthesis of alumina from aluminium can waste to be applied as catalyst support for biodiesel production

Abundant of aluminum beverage cans are normally discarded after use have caused considerable land pollution and environmental problems. This research is therefore aimed to synthesize alumina from aluminum can waste which is one of the most common kind of waste. The objective of this research is to synthesize and characterize alumina produced from aluminum can waste, and to be applied as catalyst support in the biodiesel production. In this study, the alumina from aluminum can waste was produced via Sol-gel method by varying the aging time. Characterization of alumina was performed by using FTIR, XRD, BET, and SEM-EDX. The synthesized alumina was used as catalyst support for potassium nitrate catalyst to be applied in biodiesel production by using transesterification reaction of cooking oil. The biodiesel produced was analyzed by using gas chromatography-mass spectrometry (GCMS) and FTIR. The experimental results revealed that the alumina powder synthesized at room temperature have high surface area which are suitable to be used as catalyst support of producing biodiesel. In conclusion, it has been demonstrated that it is possible to produce alumina from aluminum can waste that can be used as catalyst support for biodiesel production. From the GCMS and FTIR results, it was proven that biodiesel is produced

Greener photocatalysts : Hydroxyapatite derived from waste mussel shells for the photocatalytic degradation of a model azo dye wastewater

This paper demonstrates for the first time the feasibility of utilising waste mussel shells for the synthesis of hydroxyapatite, Ca10(PO4)6(OH)2 (denoted as HAP) to be used as a greener, renewable photocatalyst for recalcitrant wastewater remediation. HAP was synthesised from Perna canaliculus (green-lipped mussel) shells using a novel pyrolysis-wet slurry precipitation process. The physicochemical properties of the HAP were characterised using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The HAP produced was of comparable quality to commercial (Sulzer Metco) HAP. The synthesised HAP had good photocatalytic activity, whereby methylene blue (a model textile wastewater compound) and its azo dye breakdown products were degraded with an initial rate of 2.5×10-8molL-1min-1. The overall azo dye degradation was nearly 54% within 6h and 62% within 24h in an oxygen saturated feed in a batch reactor using a HAP concentration of 2.0g/L, methylene blue concentration of 5mgL-1, UV irradiation wavelength of 254nm and a stirring speed of 300rpm. The kinetics were well described by three first order reactions in series, reflecting the reaction pathway from methylene blue to azo dye intermediates, then to smaller more highly oxidised intermediates and finally degradation of the recalcitrants. The final two steps of the reaction had significantly slower rates than the initial step (rates constants of 6.2×10-3min-1, 1.2×10-3min-1 and approximately (due to limited data points) 1.6×10-4min-1 for the first, second and third step respectively), which tie in with this mechanism, however it could also indicate that the reaction is either product inhibited and/or affected by catalyst deactivation. FTIR analysis of the post-reaction HAP revealed surface PO43- group loss. Since there is good photocatalytic activity with oxygen in limited and excess supply during the photoreaction, this indicates the possibility of lattice oxygen participation in the photocatalytic reaction, which needs to be characterised more fully. However, overall, these results indicate that the HAP derived from the mussel shells is a promising greener, renewable photocatalyst for the photocatalytic degradation of wastewater components

Green synthesis and photocatalytic insights A review of zinc oxide nanoparticles in wastewater treatment

Embracing sustainable practices like photocatalysis for wastewater management is more crucial than ever. Nanotechnology enhances the effectiveness of photocatalysis, and zinc oxide nanoparticles (ZnONPs) are considered as a promising photocatalyst with large bandgaps and exciton binding energy, which can be synthesized through green approaches. As wastewater treatment with ZnONPs is deemed self-limiting due to various synthesis approaches, a critical evaluation of its purported benefits is necessary. This review summarized current scientific findings based on both unmodified and modified ZnONPs, primarily synthesized using plant sources as reducing and capping agents. The study highlights areas requiring further research, with many plant extracts having been utilized for ZnONP synthesis. Additionally, various dopants, such as carbon derivatives, metal oxides, N-type semiconductors, and metals, have been employed to modify ZnONPs, enhancing their photocatalytic activity. Investigation into biosynthesized ZnONPs, particularly from plant extracts and waste materials, reveals their significant impact on nanoparticle characteristics, including size reduction and bandgap energy control. Secondary metabolites from plant extracts play crucial roles as stabilizing, reducing, and capping agents. The study highlights the superior effectiveness of modified ZnONPs in photocatalysis compared to unmodified counterparts. Integrating renewable, biodegradable resources in bioinspired ZnO-modified photocatalysts opens new opportunities in green technology, offering potential alternatives for water treatment that are cost-effective and environmentally friendly. The utilization of ZnONPs in photocatalysis, particularly when derived from sustainable sources and modified through eco-friendly approaches, presents a promising avenue for addressing global water purification challenges and contributing to a more sustainable future

Low-calcination temperature to synthesize a-alumina from aluminium waste can using sol-gel method

Many countries around the world are facing issues in managing solid waste materials; most of these wastes such as aluminium can are deposited to the landfills, leading to environmental pollution. Recycling is considered as an effective technique to manage the aluminium can waste since it can provide benefits in terms of energy savings, reduce volumes of waste and cost-effectiveness. In this article, it was desired to turn the aluminium can waste into α-Alumina using sol-gel method. Alumina exists in many crystalline structures which degenerate to the most stable hexagonal α-phase at high temperatures. α-Alumina (a-Al2O3) is the most stable crystalline structure widely used and studied as electronic packaging, corrosion resistance ceramics, high-temperature structural material, and translucent ceramics. FTIR, XRD, SEM-EDX, TGA, and BET were employed to investigate the properties of a-alumina. The experimental results obtained from this study demonstrates the possibility of producing alumina from an aluminium can waste with the exact surface area of 5.2105 m2/g, crystallite size at 132.50 nm and total weight loss of 2.71% at 900 C calcination temperature