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Global warming due to the combustion of fossil fuels has a major concern today. Therefore, the photocatalytic CO2 reduction of valuable chemicals and fuels has become a hotly debated topic of study. This is due to the fact that this can simultaneously resolve the energy crisis and environmental issues. In this regard, a lot of research has gone into developing efficient photocatalysts for CO2 reduction. Lanthanum cobalt perovskite (LaCoO3) is one the semiconductors with catalytic capabilities, excellent stability, nontoxic, and low costs. The properties of LaCoO3 perovskite based on the use of transition metals such as lanthanum (La) and cobalt (Co) make it applicable for photocatalytic enhancement of photoactivity. This is due to its visible light activity, ability to trap electrons, rapid charge carrier mobility, and conductivity. LaCoO3 nanoparticles are synthesized through the hydrothermal technique. This study reveals that LaCoO3 nanoparticles synthesized by hydrothermal method have a larger surface area and narrow bandgaps, resulting in a greater adsorptive capacity, increased visible light excitation, and an increase in the number of active sites for photocatalytic CO2 reduction. The XRD, FTIR, and SEM was used to analyses the LaCoO3 nanocatalysts. After 4 h with a 0.05 g catalyst loading and (CO2 + water) as a reducing agent at normal temperature and pressure, the use of LaCoO3 resulted in CO and CH4 production rates of 110.4, and 28.5 mol g-1. The high selectivity toward CO was certainly related to a greater surface area with enhanced light absorption. The LaCoO3 photocatalyst was also investigated under a number of operating conditions, including photocatalyst loading, and reducing agents. Using three different catalyst loadings of 0.025, 0.05, and 0.1 g, the optimal catalyst loading was 0.05 g. Among the reducing agents, water favoured CO evolution, while the methanol-water system favoured CH4 production. Interestingly, stability studies demonstrated that the LaCoO3 perovskite behaved well and remained stable over numerous cycles without evident deterioration. Furthermore, a suggested photo-induced reaction mechanism was discussed. All of these results demonstrate that LaCoO3 perovskite photocatalysts are capable of efficiently producing solar fuels and can be utilized in solar energy-related applications.

Alkaline–surfactant–polymer (ASP) flooding, a recognized method for oil recovery, encounters limited use due to its expense. In addition, ASP’s best composition and injection sequence still remains uncertain today. This study explores conventional ASP flooding using PT SPR Langgak’s special surfactants, simulating Langgak oilfield conditions in Sumatra, Indonesia. By comparing the outcomes of this flooding technique with that of starch-assisted ASP performed in another study, the benefits of adding starch nanoparticles to flooding are evident. Nano-starch ASP increased oil recovery by 18.37%, 10.76%, and 10.37% for the three configurations investigated in this study. Water flooding preceded ASP flooding, and flooding operations were carried out at 60 °C. This study employed sodium hydroxide (NaOH), sodium carbonate (Na2CO3), and specialized surfactants from PT SPR. The adopted polymer is solely hydrolyzed polyacrylamide (HPAM) at 2000 ppm. Starch nanoparticles underwent comprehensive characterization and focused more on charge stability. Purple yam nanoparticles (PYNPs) exhibited remarkable stability at −36.33 mV, unlike cassava starch nanoparticles (CSNPs’) at −10.68 mV and HPAM’s at −27.13 mV. Surface properties affect interactions with fluids and rocks. Crystallinity, a crucial characterization, was assessed using Origin software 2019b. CSNPs showed 24.15% crystallinity, surpassing PYNPs’ 20.68%. Higher crystallinity benefits CSNPs’ thermal stability. The amorphous behavior found in PYNPs makes them less suitable if applied in harsh reservoirs. This research correlated with prior findings, reinforcing starch nanoparticles’ role in enhancing oil recovery. In summary, this study highlighted conventional ASP flooding using HPAM as the sole polymer and compared it with three formations that used two starch nanoparticles included with HPAM, assessing their impact on charge stability, crystallinity, and recovery rate to emphasize their importance in the oil recovery industry. Starch nanoparticles’ benefits and limitations guided further investigation in this study.

The continued burning of fossil fuels since the beginning of the last century led to higher emissions of greenhouse gases and thus leads to global warming. Microalgae are one of the most important sources of green hydrocarbons because this type of algae has a high percentage of lipids and has rapid growth, consumes the carbon dioxide in large quantities. Besides, the cultivation of these types of algae does not require arable land. This review aims to explain the suitability of microalgae as a biofuel source depending on the fat content, morphology, and other parameters and their effect on the conversion processes of microalgae oil into biofuels by different zeolite catalytic reactions. It also discusses in detail the major chemical processes that convert microalgae oil to chemical products. This review sheds light on one of the most important groups of microalgae (Chlorella vulgaris microalgae). This review includes a historical overview and a comprehensive description of the structure needed to develop this type of algae. The most important methods of production, their advantages and disadvantages are also deliberated in this work. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

The free convection of Cu-water nanofluid is simulated and investigated inside a square heat exchanger chamber in the presence of MHD magnetic field. The Buongiorno model with the effects of Brownian and thermophoresis motion is considered to nanoparticles distribution inside the chamber. The geometry consists of a square chamber with two cylinders on the right and left sides as heater and cooler in order to create the buoyancy force, respectively. These cylinders represent hot and cold pipes, and the walls of the chamber are heat and mass insulation. the FVM with SIMPLE algorithm are used for velocity and pressure coupling. In current two-phase simulation, the effects of Rayleigh number, Hartmann number, inclination angle of chamber and volume fraction on streamline contours, isothermal lines, Lorentz force lines, nanoparticle distribution and Nusselt number are investigated. By modeling the motion of nanoparticles and evaluating it, a nanoparticle transport zone was observed. The diffusion effects of thermophoresis were significant in this zone. The nanoparticles were thrown from the hot cylinder to the cold cylinder. The application of a magnetic field enlarged the nanoparticle transport zone. However, increasing the Rayleigh number and decreasing the inclination angle of the enclosure caused the nanoparticles to disperse evenly.

The aim of this study is numerically to investigate the effects of local thermal non-equilibrium porous media on the melting process of paraffin with the melting temperature33°C. The geometry consists of a half-cylinder containing paraffin with a uniform constant temperature and an insulating wall. Also, Darcy model and buoyant force due to density changes are considered in this simulation. The effects of the presence of aluminum foam with porosity ε=0.8,and0.95 and difference temperature ΔT=5,10,and15 have been studied on the melting fraction of PCM, temperature and streamlines contours and heat flux of cylinder's surface. The observations show that enhancement of porosity 0.8 to 0.9 increases the volume of PCM 11.7%, and reduces time of melting process 30.8% for ΔT=15. Moreover, increment of ΔT=5to15 leads to decrease time of melting process 71.8% when porosity is 0.95.

Due to their high lipid content, microalgae are one of the most significant sources of green hydrocarbons, which might help lessen the world’s need for fossil fuels. Many zeolite-based catalysts are quickly deactivated by coke production and have a short lifetime. In this study, a bimetallic Lanthanum-Cerium (La-Ce)-modified HZSM-5 zeolite catalyst was synthesized through an impregnation method and was tested for the conversion of hydrolyzed oil into oxygen-free hydrocarbon fuels of high energy content. Initially, hydrolyzed oil (HO), the byproduct of the transesterification process, was obtained by the reaction of crude oil derived from Chlorella vulgaris microalgae and a methanol. Various catalysts were produced, screened, and evaluated for their ability to convert algal HO into hydrocarbons and other valuable compounds in a batch reactor. The performance of HZSM-5 was systematically tested in view of La-Ce loaded on conversion, yield, and selectivity. NH3-TPD analysis showed that the total acidity of the La-Ce-modified zeolites was lower than that of the pure HZSM-5 catalyst. TGA testing revealed that including the rare earth elements La and Ce in the HZSM-5 catalyst lowered the catalyst propensity for producing coke deposits. The acid sites necessary for algal HO conversion were improved by putting La and Ce into HZSM-5 zeolite at various loading percentages. The maximum hydrocarbon yield (42.963%), the highest HHV (34.362 MJ/Kg), and the highest DOD% (62.191%) were all achieved by the (7.5%La-2.5%Ce)/HZSM-5 catalyst, which was synthesized in this work. For comparison, the hydrocarbon yield for the parent HZSM-5 was 21.838%, the HHV was (33.230 MJ/Kg), and the DOD% was 44.235%. In conclusion, La and Ce-loading on the parent HZSM-5 may be responsible for the observed alterations in textural properties; nevertheless, there is no clear correlation between the physical features and the hydrocarbon yield (%). The principal effect of La and Ce modifying the parent HZSM-5 zeolite was to modify the acidic sites needed to enhance the conversion (%) of the algal HO during the catalytic deoxygenation process, which in turn raised the hydrocarbon yield (%) and increased the HHV and DOD%.

Microalgae is one of the most important sources of green hydrocarbons because it contains a high percentage of lipids and is likely to reduce reliance on fossil fuels. Several zeolite-based catalysts have a short lifetime due to coke-formation deactivation. In this study, a lanthanum-modified HZSM-5 zeolite catalyst for the conversion of crude oil into non-oxygenated compounds (hydrocarbons) and oxygenated compounds has been investigated. The crude oil of Chlorella Vulgaris microalgae was extracted using Soxhlet and converted into hydrolyzed oil (HO) through a transesterification reaction. The experiments were conducted in a batch reactor (300 °C, 1000 rpm, 7 bar of N2, the catalyst to the algal HO ratio of 15% (wt.%) and 6 h). The results were organized into three groups: product yield, chemical composition, and carbon number distribution. The liquid products were investigated, including their elemental composition, higher heating value (HHV), atomic ratios of O/C and H/C, and degree of deoxygenation (DOD%). The loading of lanthanum into HZSM-5 zeolite with different loading percentages enhanced the acid sites needed for the algal HO conversion. Among all the synthesized catalysts, 10%La/HZSM-5 produced the highest conversion of the algal HO, the highest yield of hydrocarbons, the highest HHV, and the highest DOD%; those were 100%, 36.88%, 34.16 MJ/kg, and 56.11%, respectively. The enhanced catalytic conversion was due to the presence of lanthanum, which alters the active sites for the desired reactions of catalytic deoxygenation. The main effect of the modification of the parent HZSM-5 zeolite with lanthanum led to adjusting the acidic sites needed to increase the conversion (%) of the algal HO in the catalytic deoxygenation process and thus increase the hydrocarbon yield (%), which in turn led to an increase in the HHV and DOD%. The proposed La-based zeolite composite is promising for different energy applications due to its unique benefits compared to other expensive and less-stable catalysts.

Despite the extensive research into the catalytic uses of zeolite-based catalysts, these catalysts have a limited useful lifetime because of the deactivating effect of coke production. This study looks at the use of Cerium (Ce) loaded HZSM-5 zeolite catalysts in the hydrocarbon and oxygenated chemical conversion from Chlorella Vulgaris microalgae crude oil. Characterization of structure, morphology, and crystallinity was performed after the catalysts were manufactured using the impregnation technique. Soxhlet extraction was carried out to extract the crude oil of microalgae. Transesterification reaction was used to produce algal hydrolyzed oil (HO), and the resulting HO was put to use in a batch reactor at 300 °C, 1000 rpm, 7 bars of nitrogen pressure, a catalyst to the algal HO ratio of 15% (wt. %), and a retention time of 6 h. To determine which Ce-loaded HZSM-5 catalysts would be most effective in converting algal HO into non-oxygenated molecules (hydrocarbons), we conducted a series of tests. Liquid product characteristics were analyzed for elemental composition, higher heating value (HHV), atomic ratios of O/C and H/C, and degree of deoxygenation (DOD%). Results were categorized into three groups: product yield, chemical composition, and carbon number distribution. When Cerium was added to HZSM-5 zeolite at varying loading percentages, the zeolite’s acid sites became more effective in facilitating the algal HO conversion. The results showed that 10%Ce/HZSM-5 had the greatest conversion of the algal HO, the yield of hydrocarbons, HHV, and DOD% (98.2%, 30%, 34.05 MJ/Kg, and 51.44%, respectively) among all the synthesized catalysts in this research. In conclusion, the physical changes seen in the textural characteristics may be attributed to Cerium-loading on the parent HZSM-5; nevertheless, there is no direct association between the physical features and the hydrocarbons yield (%). The primary impact of Cerium alteration of the parent HZSM-5 zeolite was to change the acidic sites required to boost the conversion (%) of the algal HO in the catalytic deoxygenation process, which in turn increased the hydrocarbons yield (%), which in turn increased the HHV and DOD%.

Plastic waste from film packaging is one of the major threats to environmental sustainability. The problem can be reduced by using a biodegradable raw material such as starch to replace the non-biodegradable petroleum-based plastic. However, starch is highly hydrophilic and brittle, which needs to be modified to improve these drawbacks. In this research, a mixture of tapioca starch (S) and glycerol (G) was crosslinked with citric acid (CA) at different ratios (0, 0.4, 0.6, 0.8, 1.0 wt% of dry basis). Effects of CA contents on the degree of crosslinking, thermal stability, and tensile properties were investigated. The sample that contained 0.6 wt% CA showed the highest degree of crosslinking (i.e. 56 %), good thermal stability, high modulus (10 MPa) and tensile strength (0.16 MPa), and low elongation at break (161 %) when compared with other samples. Samples that have higher CA contents (i.e. 0.8 wt% and 1.0 wt%) experienced the acid hydrolysis on the crosslinking site, reducing the degree of crosslinking, thermal stabilities, and tensile properties.

Highly reducible Ni/TiO2 modified ZnTiO3 composite was synthesized through hydrothermal approach and tested through phenol steam reforming (PSR) for hydrogen production. The activity tests were conducted in a continuous flow reactor to determine the effect of bi metal modified ZnTiO3 support on PSR reaction. Ni/TiO2 modified ZnTiO3 composite is a promising reforming catalyst for H2 production and can be further employed in cleaner energy production and other environmental applications.

In this study, fabrication of single wall carbon nanotubes modified titanium dioxide (SWCNTs/TiO2) composite catalyst for selective and enhanced photocatalytic CO2 reduction to fuels has been investigated. The samples were synthesized by a modified one-pot sol-gel method and were characterized by X-ray diffraction (XRD), Scanning Electrons Microscopy (SEM) and Photoluminescence (PL) Spectroscopy. The pure anatase phase with reduced crystal size and hindered charges recombination was obtained by modifying TiO2 with SWCNTs. The performance of newly developed nano-catalyst was investigated for photo-induced CO2-hydrogen reduction under visible light irradiations. The products detected were CO, CH4 and CH3OH with appreciable amounts of C2-C3 hydrocarbons. The yield of CO as the main product over 5 wt% SWCNTs/TiO2 was 1,220 µmole g-cat.-1 h-1, a 5.35 times more than the pure TiO2 NPs. Similarly, yield of methanol of 23.4 µmole g-cat.-1 h-1 was detected, 6.5 folds the amount produced over the pure TiO2 NPs. The SWCNTs found to be efficient to enhance TiO2 activity due to its ability to capture visible light irradiations with proficient charges separations over the TiO2 surface. The higher interaction between SWCNTs/TiO2, efficient adsorption-desorption and hindered charges recombination rate promoted the photoactivity and products selectivity. The reaction mechanism to understand the role of SWCNTs in TiO2 for CO2-hydrogen conversion is also deliberated.

This study investigates fabrication of transparent conductive glass using fluorine-doped tin oxide (FTO) as a more affordable alternative to indium tin oxide (ITO) in photovoltaic applications. To enhance conductivity, a ZnO layer was deposited on FTO, followed by a Cu2O layer via electrodeposition. The synthesis parameters are varied to determine their effect on the reaction and to identify the optimal conditions. The characteristic of FTO/ZnO/Cu2O studied using XRD, SEM annexed with EDX, IV testing and visible light absorption spectroscopy to disclose its optoelectronic applications. The FTO layers were produced via spray pyrolysis, with optimal deposition achieved at 400 °C and efficiency value 0.0149 %, resulting in a dense, transparent structure. Meanwhile the efficiency of samples at temperatures of 350°C, 450°C, and 500°C are 0.0032 %, 0.0042 %, and 0.0037 %. From the efficiency results, the optimal thickness of the Cu2O layer was obtained at a duration of 30 min, which was 0.0380 %, while the other durations of 1 hour, 2 h, and 3 h were 0.0149 %, 0.0076 %, and 0.0056 %. The best efficiency was obtained at an optimum pH of 10 with a value of 0.0038 %, promoting crystal growth along the (111) plane. While at pH variations of 8, 9, 11, and 12, the efficiency values were 0.0016 %, 0.0083 %, 0.0083 %, and 0.0073 %, respectively. I-V testing of FTO/ZnO:Mg/ Cu2O with varying electrodeposition voltage show that the efficiency of samples at voltage 5 V, 10 V, 15 V, 20 V, and 0.0128, 0.0093, 0.0036, 0.0053 and 0.0383 %. The optimum conditions for fabricated the samples was achieved with a 30-minute electrodeposition duration at 25 V and pH 10, as confirmed through I-V testing. The study highlights the influence of pyrolysis temperature, electrodeposition time, and pH on the optical and electrical properties of the glass, with optimized conditions yielding improved photoresponse performance.

The synthesis of mesoporous Fe2O3/TiO2 heterostructures using a P123-Gelatin hybrid template has been investigated for enhanced photocatalytic degradation of methylene blue under visible light. The study focused on the effect of gelatin concentration on mesoporosity, iron content, particle size, and surface area of Fe2O3/TiO2. The results showed that the Fe2O3/TiO2 composites exhibited superior photocatalytic activity compared to individual TiO2 and Fe2O3. This enhancement was attributed to the optimized gelatin concentration, which increases mesoporosity and Fe2O3 incorporation, facilitating efficient electron transfer and photo-electron conversion for methylene blue oxidation. Additionally, a fuzzy logic analysis was conducted to correlate the physicochemical properties of the composites with their photocatalytic activities. This analysis identified iron loading and mesoporosity as theion dominant factors affecting photocatalytic efficiency, with a high correlation coefficient. The study concluded that mesoporous Fe2O3/TiO2 synthesized with the P123-Gelatin template significantly improves methylene blue degradation. This improvement is primarily due to the synergistic effect of large pore diameter and Fe3+/Ti4+ interaction. The fuzzy logic model provided accurate predictions, confirming the critical role of iron loading and mesoporosity in enhancing photocatalytic performance.