Cleaner Engineering and Technology最新文献

The environmental impact is a strong incentive for the development of upcycling processes for textile waste. However, toxic chemicals may occur in both brand-new textiles and post-consumer garments, and the chemical transfer in such routes is important to investigate. The present study applied non-target screening and quantification with liquid chromatography/mass spectrometry to follow the fate of hazardous chemicals from post-consumer polycotton garments to a new material, cellulose nanocrystals, in a chemical upcycling utilizing strongly acidic conditions. The majority of hazardous chemicals detected within the process were found to be transferred to a residual of polyester material and not to the enriched cellulose. However, phthalates were found to be mainly attached to the cellulose nanocrystals. The detected total concentration, in this case, was below 5 μg/g, at least 200 times lower than the limit set by the European Union. This indicates the importance of monitoring and controlling the phthalate content in the starting material of the process, i.e., the post-consumer garments. The chemical release into the process waste effluent could be estimated based on water solubility data for chemicals under the applied conditions. Three compounds, the water-repellent substance perfluorooctanesulfonic acid and the dyes Crystal Violet and Victoria Pure Blue, were almost entirely transferred into the process waste effluent. Although the levels detected were very low in the present pilot process, their presence eventually indicates the need for wastewater purification at further upscaling, depending on the exposure and dose in relation to toxicological relevant thresholds.

This study aims to evaluate the potential of polyethylene glycol (PEG 6000), a recycled material, as an additive to improve unfired clay bricks. By proposing a sustainable alternative to traditional methods potentially linked to medical waste. This research explores the physicochemical, mechanical and thermal properties of unfired clay bricks modified by different contents of PEG 6000 (0%, 1%, 3%, 7%, 15% and 20% by weight) according to the standard NM 13.1 0.0442005. The testing methods comply with recognized building sector standards (Belgian NBN EN 771-3+A1 and American ASTM C675-17). The clay used was extracted from Berrechid city and it is identified as kaolinite and some trace of illite, which has non-swelling properties. The incorporation of PEG 6000 into the unfired clay bricks has notably reduced the porosity rate from 3.91 % to 1.21 %, an improvement of 69 % compared to the reference sample, leading to a decrease in the rate of capillary water absorption. The bulk density of the bricks has slightly decreased to 1670.07 kg/m³, which still allowed them to be classified as light bricks. The incorporation of 7% of PEG 6000 increased compressive strength and flexural strength up to 15.98 MPa and 0.959 KN respectively, an improvement of 63.23 % compared to the reference sample, making them suitable for the construction of interior and exterior walls according to the standard NBN EN 771-3+A1. However, thermal conductivity and specific heat capacity have been improved by 42.22 % compared to the reference sample, reaching 0.26 W/m.K and 0.89 kJ/kg.K respectively. Optimization showed that 7% of PEG 6000 is the optimal percentage for manufacturing high-performance bricks, taking into account all properties studied previously. Moreover, the simulations carried out by the TRANSYS software suggest significant energy gains in terms of insulation, achieving up to 58.33% energy savings. In essence, this research demonstrates the potential of PEG 6000 as a sustainable additive for unfired clay bricks, offering improved properties and promising energy efficiency benefits.

One of the main challenges in ethanol production within alcohol industries is the management of vinasse, a voluminous and highly toxic waste. This demands the search for alternatives for its reprocessing and disposal since its release into the environment results in soil and water pollution, leading to an unhealthy environment, ecological imbalances, and harm to wildlife. Given the relevance of this issue, the main objective of this study was to research patents in leading databases focused on vinasse treatment. The results were then correlated with an analysis of publications on vinasse application in new products and processes from January 1990 to December 2021. Additionally, we conducted a research profile analysis using three software tools (VOSViewer, CiteSpace, and CitNetExplorer) to extract citation networks, identify the main research groups, and comprehend the evolution of vinasse-related research over time. The results showed that most frequent applications are: i) biofuel production; ii) treatment; iii) recovery of organic compounds; iv) enzymatic hydrolysis; v) bioremediation; vi) fertilizer. With this, articles were searched for the investigation of innovations in the sugar-cane ethanol production chain. Most articles focus on the treatment of vinasse using microorganisms, in addition to the reuse of this effluent as a fertilizer. Thus, this study contributes to the presentation of the main works in the field and the literature regarding the use of vinasse and pointing out the current challenges to be overcome.

This paper presents a novel approach for upgrading utility systems by integrating absorption cooling systems using R-curve analysis. The key contributions include a comprehensive methodology for drawing the R-curve, determining priority paths, and optimizing the system without additional capital costs; a step-by-step case study illustrating the process of integrating two absorption chillers and analyzing their impact on cogeneration efficiency and the R-curve; equations for calculating cogeneration efficiency and power efficiency for different turbine paths to prioritize the most efficient paths; and findings revealing that integrating absorption chillers can significantly impact system performance, potentially increasing or decreasing cogeneration efficiency depending on the specific system. The proposed approach enables engineers to optimize utility systems by leveraging existing equipment and integrating absorption cooling efficiently, with the R-curve analysis providing a powerful tool for visualizing and optimizing the system to achieve the best balance of power, cooling, and heating. The findings demonstrate that careful analysis and optimization of the utility system using R-curve techniques can unlock significant energy savings and emissions reductions by prioritizing the most efficient turbine paths and integrating absorption cooling optimally.

Transportation is one of the sectors with the highest CO₂ emissions, accounting for 23% globally and significantly contributing to climate change. To address this challenge, the authorities have proposed new stringent policies that lead to decarbonization. From this perspective, this work proposes a multi-scenario analysis for the electrification of a fleet of private users. The scenarios differ on the type of charging mode adopted: slow charging (charging modes 1 and 2) and fast charging (charging modes 3 and 4). The model aims to identify the percentage of potential users who can shift from Internal Combustion Engine (ICE) to Electric Vehicles (EVs) in different scenarios. Furthermore, the model will highlight the average expenditure of users for charging, highlighting how the cost of energy could be a driver for the electrification of the sector. Finally, the model will allow us to evaluate the savings of up to 220 tons of CO₂/year thanks to the electrification of the sector with Long Range vehicles, in best case scenario. The use of a multi-scenario analysis allowed several possible electrification solutions to be explored, highlighting the strengths and weaknesses of the charging mode used, supported by quantitative results. This data-driven approach allows us to identify optimal locations for public charging stations in region of northern Italy region, where the data was sourced, which will help to encourage the switch to EVs.

The critical necessity of decreasing energy consumption and environmental effects is vital in various facets of urban life, particularly in urban waste management. This research aimed to evaluate the energy flow, CExD, and Life Cycle of a composting system for Municipal Solid Waste (MSW) in Tehran province, Iran. The initial phase entailed assessing the energy flow and effectiveness of the composting system, while the subsequent phase focused on enhancing energy efficiency through the application of Data Envelopment Analysis (DEA) to determine an optimal energy consumption strategy for conserving energy and reducing environmental impacts in Tehran's MSW composting system. Over a 90-day period, the analysis of energy usage revealed an energy input and output of 417.30 GJ (8500 t MSW)⁻¹, with 227.02 GJ (8500 t MSW)⁻¹ linked to transportation and 190.28 GJ (8500 t MSW)⁻¹ related to composting activities. The overall energy consumption in the composting system was determined to be 6424.77 GJ (8500 t MSW)⁻¹. By applying DEA optimization, energy savings of 14.45 GJ (8500 t MSW)⁻¹ were accomplished in the composting process, with a significant reduction in electricity usage contributing to these savings. The environmental impact of the energy consumption patterns identified by DEA was notably lower compared to current energy practices. The most notable decrease in impact was observed in the Photochemical Oxidation category. By following the energy usage pattern recommended by DEA, the Global Warming Potential impact reduced by 500 kg CO₂ eq. per 8500 t MSW. Additionally, the optimization of energy use through DEA led to a decrease in fossil energy resource depletion by around 4 GJ (8500 t MSW)⁻¹ in the composting process.

This study focuses on the sustainable utilization of Quinoa plant components, particularly its leaves, as a waste agricultural material for natural dyeing applications. Two distinct Quinoa genotypes, Titicaca and Giza, were selected for their natural dyeing properties. UV-VIS absorption spectra of Quinoa colorant extracts provided insights into their chemical composition, revealing distinctive peaks indicative of betalains (400–450 nm), chlorophyll (600–650 nm), carotenoids (400–500 nm), and aromatic amino acids (250–280 nm). Wool samples dyed with different plant parts such as flowers, leaves, and stalks exhibited distinct yellow hue, with leaves demonstrating the highest color strength. Metal mordants such as iron (II) sulphate, copper sulphate, and tin (II) chloride influenced color outcomes, highlighting their role in tailoring final appearance. Fastness properties of dyed wool samples were evaluated, with leaves showing moderate staining resistance and good light fastness. Additionally, antibacterial properties of leaves of Giza Quinoa variety were assessed, showing promising activity against Staphylococcus aureus. The antibacterial properties of fabrics dyed with the leaf extract by mordanting method with different metal salt mordants, particularly Fe, Cr, and Cu, exhibited significant enhancement. These results highlight the multifaceted benefits of Quinoa plant components in sustainable natural dyeing and textile applications, emphasizing their potential for eco-friendly practices in the textile industry.

The current conventional process for recovering NH₄Cl from wastewater generated by organotin mercaptide-based polyvinyl chloride thermal stabilizer plants through evaporative crystallization is energy intensive and has not yet been discussed. Three energy-saving process variants, namely mechanical vapor recompression (MVR), double-effect evaporation (DEE), and thermal vapor recompression (TVR) processes, have been proposed and evaluated in terms of both technical and economic feasibility, treating the case as a cost-cutting project aimed to avoid off-site wastewater treatment costs. Comparative evaluation has also been carried out with the conventional (CON) process used as a reference. Under the studied conditions, the MVR, DEE, and TVR processes provided energy savings in the ranges of 60%–76%, 35%–43%, and 26%–37%, respectively, confirming that applying the three alternative processes for recovering NH₄Cl results in a significantly cleaner and more sustainable recovery process. Under typical conditions and with a plant capacity of 5000 kg/h, the MVR, DEE, and TVR processes required an additional investment of 2.3, 1.0, and 0.2 million USD, respectively, compared to the CON process. The revenue was primarily driven by cost savings due to the elimination of off-site wastewater treatment, which accounted for 86.9% of the total revenue. Sensitivity analysis showed that the off-site wastewater treatment cost was found to be the most influential factor on economic feasibility. When economic targets can be traded off, MVR process is highly recommended as an alternative to the conventional energy-intensive process. If economic feasibility comparable to the conventional process is still targeted, DEE and TVR are recommended. The results of this study dismiss concerns that cleaner processes would have a negative economic impact.

Global steel production, a major contributor to anthropogenic carbon dioxide, heavily relies on manganese, a key ingredient that significantly impacts the carbon footprint during the production of high-carbon ferromanganese. A single-step generation of low-carbon ferromanganese (LC-FeMn) from manganese ore in an electric arc furnace (EAF) was investigated. The theoretical and experimental investigations helped to balance the required and supplied energy. The process sustainability was predicted based on the enthalpy of the reaction. Pre-reduction of manganese ore decreased energy consumption in the smelting process and saved raw materials costs. The simulation studies revealed a significant effect of lime and silica on the slag-metal equilibrium. It further confirmed the best-reducing condition with the basicity 1.5–1.77 by smelting tests in EAF. Experimental results showed an optimal charge mixture comprising appropriate ratios of ore:SiMn:lime ratio, producing a standard-grade product. Simultaneous melting and smelting sensibly used the exothermic heat, consuming 410–880 kWh/ton, much lower than the international benchmark, i.e. approximately 2000 kWh/ton. The characterization of resulting slags corroborated the advantages of the manganese ore pre-reduction on the energy and reductant consumption, alloy grade, and slag characteristics. The present study's findings can potentially contribute to the ongoing low-carbon initiatives of steel.

In various cities/other urban settlements, buildings are replaced with newer stocks, ending many buildings' lives. Unfortunately, these buildings nearing or at end-of-useful lives are mostly not deconstructed; instead, they get demolished, resulting in waste generation and pollution, among other environmental concerns. Deconstruction supports closing the material loop in construction, facilitating reuse at end-of-life of the building; however, it is not always easy to assess the feasibility of deconstruction for existing buildings – deconstructability. For this purpose, this paper investigated critical factors that needed to be checked to make informed decisions about the deconstructability of buildings. These factors cover economic, social, environmental, legal, and technical dimensions. Based on the exploratory factor analysis (EFA) and confirmatory factor analysis (CFA), 31 significant drivers were identified. These drivers were classed into seven factors. The findings in this paper contribute to the practice of deconstruction, mainly supporting deconstructability decision-making and are helpful for deconstruction/demolition auditors, waste-management consultants and/or other stakeholders with waste minimisation goals, particularly for buildings nearing or at the end-of-useful lives.