Environmental Progress & Sustainable Energy最新文献

A free radical polymerization method was utilized to produce the pectin-based hydrogel (PIACHs). This hydrogel was synthesized using pectin as the main component, using acrylamide and acrylic acid as monomers, and itaconic acid as a crosslinking agent. Three distinct grades of pectin-based hydrogel (PIACHs) were produced by varying the itaconic acid content. Thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy, gel permeation chromatography (GPC), scanning electron microscope (SEM), point of zero charge (ΔpHpzc) analysis, and x-ray diffraction (XRD) analysis methods were used to characterize the hydrogels. The PIACHs hydrogel was used for the removal of Cu²⁺ and Co²⁺ from aqueous solutions. The hydrogels showed an excellent maximum removal efficiency of 99.10% for Cu²⁺ ions and 97.13% for Co²⁺ ions. The Langmuir isotherm model agreed well with the experimental data, indicating monolayer adsorption. For Cu²⁺ and Co²⁺ ions, the highest adsorption capacities were 333.57 and 321.54 mg/g. The pseudo-second order model of the adsorption process was demonstrated by kinetic analysis, with rate constants of 0.9982 g/(mg min) for Cu²⁺ and 0.9972 g/(mg min) for Co²⁺. The regeneration experiments revealed that the hydrogel's adsorption capability remained stable throughout several adsorption–desorption cycles, with just a small decrease in efficiency to 88.39% for Cu²⁺ and 84.72% for Co²⁺.

Designing hybrid materials with tunable properties offers efficient solutions for wastewater purification. This work aims to develop chitosan-based hydrogels capable of effectively removing titan yellow (TY) dye from wastewater. A chitosan–zinc hydrogel (ChZn) adsorbent was prepared using a simple non-cumbersome wet-chemical method, and showed swift and effective removal of TY dye. A 22.1 mg dose of ChZn removed 68.2% of TY dye from its 10.0 mL solution of concentration 500 mg L⁻¹ at optimum pH ~ 6 within 25 min, demonstrating a capacity of 384.45 mg g⁻¹. By crosslinking ChZn with tannic acid, a new adsorbent (ChZnTA) was obtained. At optimized conditions of time (25 min) and strength (10.0 mL solution of 500 mg L⁻¹ TY dye), ChZnTA removed 97.5% of TY dye at pH ~ 7, offering a much higher capacity of 505.05 mg g⁻¹. The experimental data demonstrated that the adsorption process conformed to pseudo-second-order kinetics and was best described by the Freundlich isotherm, suggesting multilayer adsorption on a heterogeneous surface. The combined effect of hydrogen bonding, π-π stacking, van der Waals, and electrostatic interactions is suggestive of high adsorption capacities of the hydrogels. The desorption and regeneration tests confirmed the reusability of the materials, even after five consecutive cycles. ChZnTA and ChZn retained removal efficiencies of 59.9% and 35.3%, respectively. These findings underscore the potential of ChZnTA as a practical and highly effective adsorbent for sustainable water purification applications.

The circular economy (CE) promotes sustainable development through resource efficiency, waste reduction, and material reuse. While CE frameworks have been widely studied in developed countries, their application in developing countries faces challenges related to infrastructure, policies, and socio-economic conditions. This study utilizes systematic literature review (SLR), examining 110 peer-reviewed articles (2019–2024) through the PICOC framework and PRISMA methodology. The results show that India (14 publications) and China (10 publications) are the most active contributors for the topics among developing countries. Most studies focus on environmental indicators, while social dimensions such as informal sector engagement remain underexplored. Key barriers include data limitations, fragmented policies, and weak infrastructure. This review recommends the development of localized CE indicators that incorporate informal sector dynamics and policy harmonization. The novelty of this study lies in mapping CE index trends in developing countries and proposing an inclusive, context-sensitive framework for future CE assessment and policy formulation.

This study presents a modified passive single-slope solar still (MPSS) with a hanging wick and copper cooling coil to enhance productivity for sustainable groundwater desalination. In this study, the performance of MPSS is compared in terms of energy, exergy, economic, exergoeconomic, and environmental perspectives at the same climate conditions. Results show that annual freshwater production in MPSS increased by 41% compared to SPSS by enhancing free wet surface area to evaporate water. The highest energy and exergy efficiencies of MPSS are 23.84% and 2.98%, respectively. The cost per liter (CPL) of productive fresh water was significantly lower for MPSS (US$0.0139) than SPSS (US$0.0198) and MPSS achieved a higher exergoeconomic parameter of 0.77 kWh/US$ as compared to SPSS. MPSS using wick demonstrated the highest net CO₂ mitigation of 19.03 tonnes with corresponding carbon credits worth US$ 609.08. MPSS using wick demonstrated superior performance in terms of energy and exergy perspectives than SPSS. The novelty of this work lies in the integration of a hanging wet wick and copper cooling coil with a passive arrangement, significantly enhancing evaporation, yield, energy efficiency, and cost-effectiveness—offering a promising solution for decentralized groundwater purification in water-scarce regions.

Cupola furnace slag (CFS) poses significant challenges for casting industrialists, who must navigate the complexities of its disposal to maintain operational efficiency and environmental responsibility. This study aims to investigate and implement the reuse of CFS in the construction industry which in turn creates a new method for solid waste management. This study clarifies the mechanical and durability properties of concrete that contains CFS-coarse-aggregates (CCA) and cupola-fine-aggregates (CFA), which are natural fine and coarse aggregate substitutes. To accomplish this, compressive strength, split tensile strength, water penetration, impact resistance, surface abrasion loss, and rapid chloride penetration tests were conducted. In M30 grade concrete, the experimental procedures involved varying degrees of weight replacement (0% to 40%) of natural fine-aggregate (FA) and natural coarse-aggregates (CA) with CFA and CCA, respectively. The experimental findings revealed that compressive strength increased with up to 20% replacement of FA, but decreased afterward. Conversely, compressive strength decreased with the replacement of CA, though up to 30%, replacement still met M30 grade concrete requirements. A leachability test was conducted to detect toxic and heavy materials in CFS. SEM, EDX and XRD techniques were also employed. Replacing FA and CA with CFA and CCA, respectively, proved economically beneficial compared to standard concrete.

Solar energy has been a clean and renewable resource that offers a promising solution for water harvesting. Herein, a double slope solar still (DSSS) unified with an external condenser and internal heater was fabricated and tested to enhance freshwater production rates under Malaysian climate conditions. The integrated model was designed to operate both day and night, and its productivity was compared with that of a passive still. The study outcomes revealed that the average increment in the daily production rate of the active still was 56% during the daytime and 510% during the nighttime compared to the passive one. When calculating the cumulative production rates over the five days of the field experiment, the active still demonstrated a notable increase in productivity, reaching approximately 159% as compared to the passive one. This resulted in total production rates of 34.14 and 13.20 kg/m² from the active and passive stills, respectively. Compared to the passive still, the active still had a lower relative humidity due to the external condenser. Additionally, the factors such as water and ambient temperatures and solar radiation intensity significantly impact daily distillate output at which strong correlations were observed between these parameters. Finally, the product water demonstrates a significant improvement in desalinated water quality, meeting safety standards outlined by the World Health Organization (WHO).

The valorization of eggshell waste as a sustainable biofiller offers a promising approach to improve the mechanical properties of biocomposites while addressing environmental concerns. In addition to reducing landfill accumulation, eggshell powder, which is high in calcium carbonate, also acts as a functional hybrid reinforcement in composites made of polymers. At the same time, cigarette butts are the most common litter in the world. They release dangerous pollutants, including hydrogen cyanide, acetaldehydes, heavy metals, and polycyclic aromatic hydrocarbons, which linger in the environment and seriously endanger both aquatic and terrestrial life. Using duck eggshell powder (DEP) as a bio filler, the mechanical behavior of vinyl ester composites reinforced with silane-treated palm fruit fibers (STP) and smoked cigarette filter fibers (CFF) is optimized in this study. Compression molding was used to create hybrid composites with different eggshell powder loadings (0%, 2%, and 4%). The Criteria Importance through Inter-Criteria Correlation (CRITIC) method and the Evaluation Based on Distance from Average Solution (EDAS) methodology were used in an integrated multi-criteria decision-making (MCDM) framework to identify the best formulation. With a tensile strength of 49.71 MPa, flexural strength of 37.88 MPa, and impact strength of 38.67 J/m, the CP9 composite (CFF 40 weight percent + STP 40 weight percent + eggshell powder 2 weight percent) outperformed the other manufactured samples in terms of mechanical qualities. The experimental findings and hybrid optimization analysis verify that eggshell-incorporated bio-composites, especially CP9, exhibit improved mechanical performance and have a great deal of promise for environmentally friendly, sustainable applications.

To mitigate selenium (Se) stress in Cyphomandra betacea, the effects of salicylic acid (SA) on the growth and Se absorption of C. betacea seedlings under Se stress were investigated in this study through a pot experiment. SA was found to enhance the biomass of various organs in C. betacea seedlings, with the optimal concentration being 150 mg/L. Compared to control, the concentration of 150 mg/L SA resulted in a 52.55% increase in root biomass and a 37.68% increase in shoot biomass. Additionally, SA was found to increase the levels of photosynthetic pigments, net photosynthetic rate, transpiration rate, stomatal conductance, and intercellular CO₂ concentration of C. betacea seedlings. SA also led to an increase in the antioxidant enzyme activity and soluble protein content of C. betacea seedlings. Furthermore, SA increased the Se contents in various organs of C. betacea seedlings, with the most effective concentration being 150 mg/L. At this concentration, the contents of root Se and shoot Se increased by 29.74% and 30.69%, respectively, compared to control. Correlation and gray relational analyses indicated that the chlorophyll b content, net photosynthetic rate, and shoot biomass were the most closely related to the shoot Se content. In conclusion, SA can effectively mitigate Se stress in C. betacea, and promote its growth and Se absorption, with the most effective concentration being 150 mg/L.

Rapid urbanization in the Nordic region has intensified municipal solid waste (MSW) accumulation, straining waste management systems and contributing to ecosystem pollution through expanded transportation and industrial activities. This study investigates the effects of waste recycling, MSW, environmental taxes, and urbanization on the ecological footprint in the Nordic countries from 1995 to 2021. Employing second-generation unit root tests, slope homogeneity analysis, and panel cointegration tests, followed by quantile regression, the results reveal that economic growth, MSW, and urbanization increase the ecological footprint, while higher recycling rates reduce it. Environmental taxes exert a mitigating effect on the ecological footprint primarily at higher quantiles. Robustness checks using Driscoll-Kraay standard errors (DKSE), panel-corrected standard errors (PCSE), and system generalized method of moments (GMM) confirm these findings. Dumitrescu-Hurlin (D-H) causality tests indicate bidirectional relationships between MSW and the ecological footprint, recycling rates and the ecological footprint, and urbanization and the ecological footprint. These insights provide valuable guidance for policymakers advancing sustainable development goals (SDGs) in the Nordic region.

This study addresses key research gaps in diesel engine-based combined heat and power (CHP) systems by presenting the very first overall Energy, Exergy, Economic, and Environmental (4E) investigation of compression ratio optimization. Unlike previous research, this research uniquely demonstrates that optimization of the in-built compression ratio in diesel-CHP systems can alone result in significant efficiency, economic, and environmental improvements. This novel 4E analysis and optimization approach opens up a new design pathway via quantification of multi-objective trade-offs of compression ratio modulation, thereby advancing CHP system design beyond peripheral retrofits. It has been demonstrated that raising the compression ratio (14:25) elevates engine power output by 44% and recoverable heat, to as much as 89.5% CHP efficiency. These advantages are realized, however, at severe costs: 6.8% more exergy destruction and 10.3% less carbon emission savings (CDER). To mitigate these trade-offs, a novel multi-objective genetic algorithm framework was developed with normalized objectives. Optimization returns cr = 20.11 as the Pareto-optimal solution, trading off 89.13% CHP efficiency, 0.2469 $/kWh energy cost, moderated exergy destruction (44.7 kJ/kg), and sustainable CDER (0.2389). Above all, the Pareto frontier delineates actionable design regimes: sustainability-focused applications favor cr = 14–18.89 (high emission reduction), while efficiency-focused systems operate at cr = 20.11–25 (peak η_CHP).