Environmental Progress & Sustainable Energy最新文献

Polymers and biopolymers have gained significance due to their applicability and use in industry reducing the negative impact of polymers based on petroleum. A possible solution for the conventional polymer's biodegradability is bio-composites, which contain natural fibers or aggregates such as microalgae. Hence, microalgae biomass has a promising application to address the biodegradability issue of conventional polymers. In this study, Chlorella vulgaris biomass was mixed with pectin for control samples with glycerol as plasticizer. The mixture microalgae-pectin-glycerol, and the addition of pine needles was used to evaluate the tensile strength and compression of the bio-composite. This bio-composite showed a higher Young's modulus of 95.66 MPa for blend C2 and a higher strength with 20% of pectin concentration in the mixture. Additionally, the pine needle addition did not have a low effect between the compression results. On the other hand, analysis on elasticity showed that the full recovery of the bio-composite happened after 10 min in all the blends. Also, the bio-composite showed a slow release of nitrogen and phosphorous after 5 days of water addition, indicating an effective slow release for blend B for both nutrients. Water uptake capacity and loss of soluble material was studied using pullulan, chitosan, and cetyltrimethylammonium bromide additives. These cationic surfactants demonstrated their potential for reduction of water solubility of the bio-composite.

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.