Environmental Progress & Sustainable Energy最新文献

Alternate fuels are in high demand for current engines and such fuels are studied both property-wise and tested as fuel in the current engines. In current work, diesel engines are studied for higher blend Neem (Azadirachta indica) biodiesel (NB) as fuel, and fuel additives such as n-butanol and NiO nano additives are chosen. Experimentation was performed on the experimental stationary engine which is coupled to eddy current dynamometer for four test fuels under varying fuel injection timings. Four test fuels were chosen for experimental studies which are Diesel 90% (vol %) + n-butanol (10%), pure Neem biodiesel, NB 90% (vol %) + n-butanol (10%), and Neem Biodiesel 90% + 25 ppm of nickel oxide dissolved in solvent. The synthesis of nickel oxide nano additives was done using a homogenous grinding method and XRD, FESEM, and EDS characterization signifies the presence of NiO. The Neem biodiesel was derived from base catalytic process and was studied using Gas Chromatography and Mass Spectroscopy apparatus for its chemical composition. The experimentation results which were focused were on the energy, exergy derived, and expenditure at varying fuel injection timings. The exergy and energy usage were almost similar in nature and entropy produced during the chemical-to-mechanical energy transfer reduced with the advancement in fuel injection timing to 27° bTDC for Diesel 90% + Bt.10%, NB90 + Bt.10% and NB100 + 25 ppm of NiO by 2.2%, 2.9%, and 4.6% respectively. Also, the exergy destruction retarded when with advancement in fuel inlet timing to 27° bTDC by 2.1%, 3%, 6.2%, and 6.8% for the same fuels, respectively.

The fixation of nitrogen (N₂) from the air into ammonia (NH₃) and nitrate (NO₃⁻) is usually conducted using the Haber–Bosch process, which requires the raw material of hydrocarbons for hydrogen (H₂), which has a large amount of energy but produces high CO₂ emissions. An environmentally friendly and energy-saving alternative is the air plasma electrolysis method, which can be used to synthesize NH₃ and NO₃⁻ under ambient conditions. In this study, this method was used to inject air into the plasma zone in a K₂SO₄ electrolyte solution to produce N₂ fixation compounds. The results showed that the use of cathodic plasma promoted the formation of NH₃ but suppressed NO₃⁻ production. The optimal air injection rate was achieved at 0.6 L.min⁻¹ and an electrical power of 452 W, with a total fixed N₂ of 51.66 mmol. The highest formation of NO₃⁻ in cathodic plasma was obtained in 35 min, with a value of 29.92 mmol, and 2.57 mmol NH₃ was achieved at 60 min. The high concentration of H₂ gas, which is a by-product of this process, can contribute to increasing the use of Haber–Bosch green technology in the production of NH₃.

The metal smelting industry (MSI) is one of the major carbon emission sectors in China, and it is of great significance to clarify the mechanism and truth of the carbon effect of production relocation (PR) of MSI for reducing national carbon emissions. Based on this thinking and previous studies, we proposed two concepts of relative carbon emission effect (RCE) and absolute carbon emission effect (ACE) of PR, then developed models to explore the impact of PR of MSI (PRM) on national carbon emission between 30 provincial administrative units in China from 2007 to 2017. The study demonstrates that the PRM and its ACE and RCE is divergent across provinces and regions. Overall, the PRM is beneficial to national carbon reduction under both relative and absolute scenarios. Specifically, the transfer-in PRM of most provinces in central regions is beneficial to national carbon reduction, while the transfer-out PRM of many provinces in coastal areas has worst carbon leakage effect.

N-nitrosodiphenylamine (NDPhA) is soluble in water and highly toxic. Exposure to NDPhA even at low concentrations for a long period can cause several health effects. Hence the removal of NDPhA from aqueous samples using a widely abundant and economical adsorbent is highly challenging. In this study, a highly efficient, eco-friendly, and low-cost adsorbent was derived from the dead leaves of Halodule uninervis seagrass (SG) without any chemical modifications. The derived adsorbent was characterized and investigated for the removal of NDPhA from aqueous solutions. The effects of solution pH, contact time, adsorbent dosage, and adsorbate concentration were studied and optimized. The SG adsorbent showed a significant removal efficiency of 83% for NDPhA from wastewater solution using 1 g L⁻¹ adsorbent. The maximum adsorption capacity for SG was found to be 64.84 mg g⁻¹ at neutral pH and room temperature. The adsorption isotherm results fitted with the Langmuir model and followed pseudo-second-order kinetics. From the thermodynamic parameters, it has been found that the adsorption of NDPhA onto SG adsorbent is favorable, endothermic, and the chemical adsorption mechanism is predominant. This study indicated that SG adsorbent is reusable and can be easily regenerated and reused at least three times with a slight decrease in its removal efficiency.

Arthrospira has the ability to tolerate effluents from domestic to farm wastewater. Food leachate coming from fruits and vegetables can be toxic in water discharge due to high dissolved oxygen and nutrient demands. Thus, pretreatment is required before passing through wastewater treatment plants, which generates higher costs and contamination in water bodies. In this work, leachate from fruits and vegetables was used in different percentages to produce Arthrospira maxima using airlift-type bioreactors with continuous air flow, two photoperiods, and two inoculums. The treatment with 3% leachate (T1) reached 5.23 g/L after 16 days, while the control reached 3.81 g/L (T0). An optimization of the biomass production was carried out seeking to use the maximum percentage of the leachate, resulting in the best treatment of 9% of leachate (T8) achieving 4.88 g/L. After optimization, three cell disruption methods were applied to the obtained biomass, quantifying amino acids and hydrolysis grade (GH), being the ultrasonication treatment the most important reaching 80% GH and a concentration of 25 mg/g of amino acids, while the unbroken biomass contain 13 mg/g. The Arthrospira maxima species is an algae that can be widely used as a bioremediation method, since it managed to reduce the concentrations of COD and orthophosphates, in addition to containing some of the nutrients that plants require for their development, given that plants require amino acids. During its growth, it is proposed to apply the biomass generated from leachates as a plant biostimulant.

Solar panels' efficiency is highly affected by high-operating temperatures, especially in semi-arid and arid regions. This outdoor experimental study aimed to enhance the energy performance of the photovoltaic module by integrating two fans at the outlet of the thermal/photovoltaic hybrid system to ensure forced ventilation. The work novelty depending on achieving low energy consumption by DC fans, so that there is a proportional relationship between the intensity of solar radiation and the energy produced and consumed. The influence of the reduced temperature, operating temperature, and solar radiation intensity on the energy performance of the photovoltaic/thermal hybrid system was analyzed experimentally. The obtained results showed an improvement in electrical and overall efficiency of the new hybrid system by about 4% and 60%, respectively, compared to the conventional photovoltaic module. On the contrary, a decrease in the temperature of the PV module installed in the hybrid system was measured by about 9°C, compared to the conventional photovoltaic module. In addition to the effectiveness of the new technology air cooling proposed at the lowest consumption cost, the thermal energy generated from the proposed system can be invested in solar drying and building applications.

Desalination can provide additional water resources in water-stressed zones and also in zones suffering from water pollution or insufficient/overexploited groundwater. This study carried out the energy and exergy assessments of a multi-effect desalination unit driven by a gas turbine based on the specific exergy cost (SPECO) approach. The chemical exergies of brine and seawater are explicitly considered (most studies consider the same specific heat for input seawater and output brine). In addition, the enthalpy of each flow of the desalination unit is considered according to its salt concentration (results are then compared to the constant specific heat model). The highest exergy rates of fuel and product are obtained at the combustion chamber, and its exergy efficiency is 67.83%. The lowest exergy efficiencies were obtained at the condenser, followed by the first effect of the desalination unit, and the heat recovery steam generator. The overall exergy efficiency of the multi-effect distillation unit is 21.49%. Regarding exergy destruction, as expected, the highest rate was obtained at the combustion chamber, which contributed with 41% to the overall exergy destruction, followed by the regenerator and heat recovery steam generator, with contributions of 16% and 11%, respectively, to overall exergy destruction.

The exploitation and utilization of Traditional Chinese medicine have annually produced 30 million tons of waste residues including Radix Angelica Dahurica residue (RAR), which raised environmental concerns. Meantime, the non-steroidal anti-inflammatory drug of ibuprofen (IBP) is an emerging contaminant in the aquatic environment, annually producing up to 9000 tons in China. After extracting the active substance, RAR is prepared as activated carbon (AC) for the purification of IBP wastewater. Two kinds AC modified without (RAR-AC) and with phosphoric acid (M-RAR-AC) were characterized by FT-IR, TG, BET and SEM. The phosphoric acid activation contributed to the high BET surface area (564.9914 m² g⁻¹) and large total pore volume (0.4894 cm³ g⁻¹). M-RAR-AC showed 7.7 folds (15 min) and 2.7 folds (30 min) higher extent of IBP removal compared to commercial activated carbon (C-AC). The enhancement of IBP removal with M-RAR-AC was investigated further by varying initial pollutant concentration, absorbent dosage, temperature, pH and rotating speed. Especially, temperature nearly has no effect on IBP removal by M-RAR-AC. Isotherm and kinetic studies suggested IBP was adsorbed on the heterogeneous surface in multilayer form and chemisorption played the dominant role in IBP removal. IBP removal of 93.3 ± 0.1% and 64.2 ± 2.8% was achieved for first and fifth cycle, respectively. The IBP removal on M-RAR-AC may be accomplished by a variety of interactions such as electrostatic attraction, pore-filling, hydrogen bonding, and π-π interaction. These findings provide new insights into the utilization of RAR for preparing AC and highlight the potential applications for treating industrial wastewater.

The study aimed to investigate the use of SrO/TiO₂ nano-catalysts in the one-pot production of valuable products (such as fatty acid methyl esters, oxygenates, hydrocarbons, and aromatics) from Chlorella vulgaris microalgae through a supercritical process. The research focused on examining the impact of the factors, the SrO to TiO₂ ratio, preparation method, and calcination temperature on the catalytic performance. Two calcination temperatures (600°C and 850°C), two Sr:Ti molar ratios (1 and 2), and two catalyst preparation methods (photochemical and impregnation) were considered. The catalysts were characterized using Scanning electron microscopy, transmission electron microscope, x-ray crystallography, and Brunauer-Emmett-Teller techniques. The evaluation of catalyst performance primarily focused on the production of value-added products, particularly fatty acid methyl esters (FAMEs). The results indicated that the catalyst prepared using the photochemical method with a Sr:Ti molar ratio of 2 and calcined at 850°C exhibited superior performance in terms of FAMEs and oxygenates production. It was demonstrated that the catalyst prepared using the photochemical method with higher Sr:Ti ratio had better performances in the production of biodiesel.

The goal of this study is to optimize and examine the effect of different rim angles and focus lengths on the performance of a solar parabolic dish. To achieve these goals, a solar parabolic dish concentrator was constructed with different focus point positions and tested under the climatic conditions of the Upper Egypt region in Qena city, with the location of (Latitude: 26.16°, Longitude: 32.71°). The preliminary experimental days started on 18th and lasted on 20th of September 2022, and the tested rim angles were 70°, 80°, and 60°. The results showed that the performance of the proposed solar parabolic dish concentrator was enhanced when the rim angle was between 60° and 70°, otherwise, the performance was regressed when the rim angle was between 70° and 80°. To optimize the rim angle, another available rim angle was selected to increase the performance of the solar dish fixed at 65°, and this angle was tested on 21st of September 2022. The results demonstrated that the thermal efficiency of the solar parabolic dish with rim angle of 65° was higher than that of 70°, 80°, and 60°, and the recorded thermal efficiency reached up to 79.5%, 39.4%, 5.84%, and 28.4%, respectively, under the tested rim angles.