Environmental Progress & Sustainable Energy最新文献

The reutilization of municipal solid waste incineration (MSWI) fly ash is a prominent area of research. This study focused on creating fly ash porous plate filler (FAPPF) by using techniques, such as water extraction, milling, component adjustment, and sintering. The produced FAPPF was then used to cultivate a biofilm for wastewater treatment. The key parameters included a two-stage water extraction process with a 5:1 liquid-to-solid ratio; milling for 1, 2, and 4 h; component adjustment using waste glass powder, milled fly ash, palygorskite powder, and peanut shell powder at a 7:1:1:1 mass ratio; and sintering temperatures ranging from 700 to 1000°C. For the biofilm cultivation and treatment, this study employed semisimulated sewage in a sequencing biofilm batch reactor system. The results revealed the FAPPF had no heavy metal leaching, with a porosity of 48.53%–54.68%. Approximately 90% of its composition was derived from waste materials. Furthermore, scanning electron microscopy microanalysis revealed an internally stable liquid-phase sintering structure. Finally, a mature biofilm developed in 21 days, achieving maximum removal rates of 95.48% for chemical oxygen demand and 78.4% for ammonia nitrogen. This article confirms the sustainable recycling potential of MSWI fly ash.

Adsorption-focused technologies for atmospheric water harvesting is of great importance. Most of the available systems in the literature use glass as a condenser, which gets heated up. This restricts vapor condensation to harvest less water and hampers the system's scalability. The effectiveness of the proposed solar atmospheric water harvesting system, which uses an air-to-air fin-tube heat exchanger to condense the vapors, is experimentally evaluated in this work. In order to assess the system's effectiveness using a water-to-air fin-tube heat exchanger, a comparison study is also carried out. The experimental setup consists of evacuated tube solar air heater having 8.46 m² area and 15 kg silica gel adsorbent. The performance metrics for comparison include adsorption & regeneration rate, thermal, overall and exergy efficiency, along with economic analyses. The system harvests 1890 mL/day of water using air-to-air heat exchanger at cost of 0.19 $/l, achieving thermal, overall & exergy efficiencies of 21.66%, 2.24%, and 6.51%, respectively. On the other hand, the water-to-air heat exchanger based system harvests maximum of 2680 mL/day of water at a cost of 0.14 $/l, achieving thermal, overall & exergy efficiencies of 25.65%, 3.34%, and 9.13%, respectively. Moreover, the produced water is confirmed to be safe for consumption.

This research article presents an investigation conducted through a numerical model to analyze the influence of various operational parameters on the performance of solid oxide fuel cells (SOFCs). The parameters studied include operating temperature, current density, pressure, steam-to-carbon ratio, and fuel utilization. The electrochemical model employed the Butler-Volmer equation, Fick's model, and Ohm's law to calculate concentration, activation, and ohmic losses. The primary focus was on evaluating the generated power and electrical efficiency as performance metrics. The study revealed that increasing operating temperature and pressure resulted in higher power generation and specific optimum points were identified for optimal SOFC operation. Notably, the highest power generated was 812 kW, achieved at an operating temperature of 950 K and a current density of 18100 A/m². Additionally, decreasing the fuel utilization factor to 55% at 15250 A/m² led to a power output of 706 kW. Similarly, at a current density of 17150 A/m² and a pressure of 400 kPa, the fuel cell generated about 780 kW of power. Furthermore, the research demonstrated that reducing the steam-to-carbon ratio increased power generation, with an optimum power output of 704 kW achieved at a current density of 16000 A/m² and a low steam-to-carbon ratio. Notably, this point also showcased the improved electrical efficiency of the solid oxide fuel cell. Overall, this study underscores the significance of specific operational factors that significantly impact SOFC performance. By comprehending these parameters, it becomes possible to enhance the utilization of solid oxide fuel cells across various applications.

This paper deals with the investigation of N identical compound parabolic concentrator evacuated tubular collector included single slope solar desalting unit (N-CPC-ETC-SSU) by incorporating energy metrics for solving contemporary issue of water scarcity in the society. It will contribute to the sustainable development of society and recede the dependency on fossil fuels, too. The energy metrics investigation is important for energy system because it talks about the feasibility of the system. The methodology consists of getting fundamental equations from energy balance equations. All fundamental equations with relevant data are fed to the code developed in MATLAB followed by the computation of overall energy and exergy. All types of climatic situations have been considered for the analysis. Data required for the same are accessed from IMD, Pune, India. The energy payback period, energy production factor, and life cycle conversion efficiency for N-CPC-ETC-SSU have been calculated at eight number of collectors, 0.012 mass flow rate and 0.14 m water depth. Results of N-CPC-ETC-SSU have been compared with results of SSU included with ETCs. Concludingly, energy payback period is lower by 6.41%, energy production factor is higher by 6.25% and exergy-based life cycle conversion efficiency is higher by 96.39% for N-CPC-ETC-SSU than N-ETC-SSU.

Water supply challenges are caused by population growth, industrialization, as well as the scarcity of freshwater resources. Low-grade waste heat-driven seawater desalination technologies may improve the water-energy nexus issues of desalination systems by different configurations. The data envelopment analysis is used to determine the best final decision to achieve a better comparison of different parameters. The optimal configuration of low-grade waste heat driven seawater desalination is studied using flue gas waste heat in heat recovery boilers of an industrial oil refinery. Nine different types of multistage flash and multi-effect distillation (MED) desalination plants have been considered. The results show that the multistage flash brine recirculation may produce more desalinated water while the multi-effect distillation with three stages (3-stage MED) has the best payback period. Using 3-stage MED with a production of approximately 19,630 kg/h of water from 5.3 MW exhaust gas is more suitable for this design. Thus, the proposed strategy guides us toward the best decisions to configure low-grade waste heat-driven desalination plants for better design considering rigorous simulations for the plants. Moreover, this framework enables us to consider different criteria of technical, economic, and environmental issues for optimal configuration.

In this investigation, we assessed the efficacy of an indirect-type solar drying system that utilized skewers and rack arrangements, comparing it to a conventional drying cabinet equipped with trays for dehydrating bitter gourd slices. We examined the influence of pretreatment methods and loading quantities on the solar drying process for bitter gourd slices in both configurations. The drying behavior of various combinations was scrutinized, and the physicochemical attributes of the dried bitter gourd samples, including total phenolic content, total flavonoid content, total chlorophyll content, antioxidant capacity, ascorbic acid content, and color, were analyzed. Rehydration characteristics, such as rehydration ratio, coefficient of rehydration, percent water in the rehydrated sample, and hardness of the rehydrated sample, were also determined. The bitter gourd slices achieved a final moisture content of 6.84%–8.27% wb after drying from an initial range of 88%–90% wb, within a total elapsed time of 28–55 h. The solar drying cabinet utilizing skewers exhibited enhanced efficiency, featuring reduced drying time and superior product quality compared to the tray-equipped drying cabinet. This improved performance is ascribed to enhanced hot air circulation over the produce surface, facilitated by the uniform spacing between skewers on racks within the drying chamber.

The government of India has mainly focused on waste management, environment protection acts, and control of energy demand, which will lead to the development of a clean and green India. Nowadays most of the drinking water is getting polluted due to the harmful gases released by well-renowned industries mining operations, alloy industries, and dye industries. The presence of more amounts of heavy metals in drinking water leads to a rise in chemical levels than the constrained level in the environment, inside a human body, and any living being. Protection of the environment through the recovery of heavy metals from waste effluents through a chemical activation process using bio-derived activated carbons as adsorbents is one of the known strategies in the current decade that can be adopted. The application of these heavy metals as catalysts in the synthesis of biodiesel from nonedible oils through an ultrasound (US)-assisted process is one of the emerging strategies that will help in the reduction of energy demand. In the current review, the recovery of heavy metals from the waste effluents through a conventional chemical activation process and their applications as catalysts in the US-assisted synthesis of biodiesel from nonedible oils is discussed.

Climate change presents urgent challenges that require simultaneous attention to environmental and economic dimensions. Addressing this global issue involves tackling its root causes and closely monitoring progress in energy transition efforts to formulate effective strategies. Understanding the complexities and opportunities of shifting toward low-carbon economies underscores the necessity for innovative sector-specific policies promoting sustainable energy practices and reducing air pollution. An insightful grasp of how energy transitions impact environmental sustainability is critical, highlighting sector-specific dynamics for informed policy and decision-making. This study employs a wavelet approach to explore the relationship between CO₂ emissions and renewable energy consumption, analyzing both aggregate and sector-specific metrics. This time-varying analysis offers a view of how this relationship evolves over time, providing valuable insights into the effectiveness and outcomes of sustainable energy strategies. Drawing on a dataset spanning from January 1989 to March 2022 in the United States, the research identifies coherence and co-movements across different frequencies and time dimensions. Results underscore the need to tailor energy strategies to sector-specific dynamics, particularly noting that despite the growing adoption of renewable energies in industrial and transportation sectors, their impact on reducing CO₂ emissions remains limited. However, the electric power sector shows a promising potential for reducing emissions through increased renewable energy integration.

A notable distinction in this research is the utilization of a new method for calculating critical heat flux (CHF) based on a Look-Up Table. The present study comprehensively investigates the effects of hybrid nanofluid, a type of passive heat transfer enhancement technique, on convection heat transfer coefficients and CHF. The study covers five different climates representing significant climate conditions in Iran, namely Bandar Abbas, Esfahan, Shiraz, Tehran, and Yazd, each with different solar irradiations. The nanoparticles considered in this study include silver, nickel, and aluminum, as well as Ag-Au hybrid nanofluid with volumetric concentrations of 0.1%, 0.3%, 0.5%, 1%, and 2%. The modeling results reveal that the heat transfer coefficient increases with the volumetric concentration of nanoparticles. According to the results, at the CHF point for 2 vol% Ag–Au hybrid nanofluid and Ag, Ni, and Al nanoparticles, the heat transfer coefficient shows an increase of 28%, 11.5%, 10.6%, and 4.9%, respectively, compared to the results for pure water in Shiraz. Despite the acceptable results and effective performance of 2 vol% Ag–Au hybrid nanofluid for a linear Fresnel reflector, economically, 2 vol% nickel nanoparticles are identified as the most suitable choice.

This research introduces a novel technique for transforming wastewater into renewable hydrogen gas using an innovative photoelectrode composed of CrO₃-Cr₂O₃/polypyrrole (Ppy), synthesized through a one-pot method. The photoelectrode is applied to split wastewater under different light conditions: darkness, white light, and monochromatic light. In the absence of light, the CrO₃-Cr₂O₃/Ppy photoelectrode produces a photocurrent density (J_ph) value of 0.54 mA cm⁻², which significantly increases to 0.78 mA cm⁻² under white light exposure. The J_ph values range from 0.68 to 0.76 mA cm⁻² at wavelengths between 730 and 340 nm, showcasing the photoelectrode's remarkable sensitivity. This sensitivity highlights the potential of the photoelectrode to efficiently capture light energy for applications in wastewater treatment and green hydrogen production. By utilizing wastewater as a renewable energy source and employing the CrO₃-Cr₂O₃/Ppy photoelectrode, this approach addresses environmental concerns and energy needs concurrently. The proposed prototype for a three-electrode cell aims to directly produce hydrogen gas from wastewater, with the ultimate goal of generating hydrogen suitable for industrial applications. This innovative solution not only addresses wastewater treatment but also transforms it into a valuable source of green energy, emphasizing the potential for positive environmental and energy-related advancements.