Journal of Material Cycles and Waste Management最新文献

The growing need for sustainable energy storage solutions has driven the development of environmental friendly supercapacitors with materials made from renewable sources. This study investigates the production of high-performance supercapacitors using microcrystalline cellulose (MCC) derived from several waste paper sources, including office paper (OMCC), newspaper (NMCC), and corrugated boxes (CMCC). The extraction procedure involves acid hydrolysis, followed by hydrothermal synthesis of cellulose/reduced graphene oxide/zinc oxide (rGO–ZnO) composites to provide effective electrode materials. Although OMCC–rGO–ZnO had the smallest electrochemical active surface area (2.72 × 10⁷ cm²), it produced the highest specific capacitance (31.03 F g⁻¹), demonstrating the importance of surface chemistry, according to electrochemical analysis. NMCC-rGO-ZnO exhibited superior charge transfer with the lowest resistance (0.217 mΩ) and maximum conductivity (60.7 kS m⁻¹). CMCC–rGO–ZnO demonstrated exceptional cycling stability, retaining 96.5% capacity after 5,000 cycles. The findings underscore that performance is not solely governed by electrochemically active surface area but is profoundly affected by the intrinsic properties of the cellulose source. Subsequent research indicates a dominant electric double-layer capacitance behavior with minimal faradaic contributions. These findings clarify the significant impact of cellulose sources on supercapacitor performance, confirming waste paper as a feasible precursor for sustainable energy storage materials. The proposed method enhances renewable energy technologies while fostering environmental sustainability by utilizing paper waste in accordance with circular economy concepts. This research establishes a basis for the scalable manufacturing of environmentally sustainable supercapacitors while addressing global waste management challenges.

Phosphogypsum is an industrial waste, and it can be produced anhydrite to utilization. Some phosphogypsum impurities can be removed by flotation process. To detect the influence of flotation purification on anhydrite properties, anhydrites were prepared by calcining at different temperature from phosphogypsum, floated phosphogypsum and gypsum analytical reagent, respectively. The phase, superplasticizer dosage of normal consistency, setting time, whiteness, damp compressive strength and hydration rate of anhydrite were studied. The phase was mainly composed of anhydrite. The whiteness of anhydrite increased first and then decreased with the increase of calcination temperature. After phosphogypsum was treated by flotation process, the whiteness of anhydrite was significantly improved. With the increase of calcination temperature, the superplasticizer dosage decreased in all anhydrite. The setting time of all anhydrite prolonged first and then shortened with the increase of calcination temperature. After phosphogypsum was treated by flotation process, the setting time of the anhydrite prepared at 400–600 ℃ was significantly shortened, while the anhydrite prepared at 700–900℃ was slightly prolonged. The strength of anhydrite was significantly improved. After curing 28 days, the strength of anhydrite calcined at 600 ℃ for 2 h, was 49.01 MPa.

This study evaluates the feasibility of producing activated carbon from corncobs and oil palm empty fruit bunches (EPB) using the one step process (CAM). This method involves a single-step fast pyrolysis heating process at 500 °C with sodium acetate (NaCH₃COO) as the activating agent. A comprehensive techno-economic analysis was conducted, covering capital investment, raw material costs, fixed and variable costs, revenue, profit, cash flow, financial feasibility and sensitivity analysis. The study considers three production scenarios: activated carbon from corn cobs (AC-Corncob), empty palm oil bunches (AC-EPB), and a mixture of both (AC-mixed). AC-EPB is the most economically viable option in this model, with the highest NPV, ROI and the shortest PBP (8 months and 6 days). The highest BEP obtain form 9129 packages of AC-EPB, generating revenue of $19,970.69. The findings confirm that activated carbon production from EFB is more efficient and profitable compared to other raw materials. Sensitivity analysis results in determining the feasibility of maintaining a fixed product price while reducing sales volume but keeping quality constant indicate that the venture remains viable. This study provides valuable insights for industries looking to develop sustainable and cost-effective activated carbon production processes.

Increasing demand for road construction materials has led to a search for innovative solutions to limit costs and conserve natural resources. Establishing efficient motorway networks is crucial for a nation's economic progress, necessitating the exploration of alternatives to natural materials. Recycling, a method commonly applied to waste reduction, is gaining traction in civil engineering. It diminishes resource demand, limits energy expenses, and repurposes waste that would otherwise occupy landfills. Soil stabilization, a key component of road construction, aims to enhance soil’s load-bearing capacity. This process mitigates undesirable properties and decreases permeability, making soils more suitable for road infrastructure. This article presents laboratory findings on the application of sewage sludge (SS) in soil stabilization, aiming to determine the optimal SS percentage for effective stabilization. The study utilized sewage sludge alongside fly ash and blast furnace slag using NaOH as a stabilization agent, which triggers the geopolymerization effect, investigating different mix ratios and curing times. The results showed strength development and properties suitable for road construction. The study provides a significant contribution to the potential reuse of sewage sludge and its incorporation into road stabilization processes.

The dairy industry is striving to reduce its environmental impact, with a particular focus on sustainable sludge management. A decision-making tool has been developed for Uruguayan dairy companies to optimize sludge management processes. This tool was created by proposing a superstructure and employing mathematical programming, allowing for a comprehensive evaluation of various operational alternatives. The tool evaluated various options, including dewatering, drying, and final disposal. The most cost-effective solution identified was the use of geotextile bags for dewatering, followed by drying and combustion. This alternative proved to be 20% cheaper than the baseline method and also provided a valorization alternative of the waste as a fuel. The tool’s utility was demonstrated through sensitivity analyses.

To enhance the tool’s accuracy, an experimental study was conducted to assess sludge dewaterability under pressure. Samples of sludge with varying origins and compositions were analyzed, revealing significant differences in the minimum moisture percentage achieved, despite similarities in the general shape of the curves. These findings enable a better selection of dewatering technologies based on the specific characteristics of each sludge, contributing to more efficient and sustainable management of dairy industry waste.

We have applied four different agricultural waste biomass supplements at 2.5 and 5.0 t ha-1 in this experiment. Buckwheat stover biomass (BWB) had the lowest microbial biomass carbon content, while rice straw biomass (RSB), soybean stover biomass (SSB), and millets biomass (MTB) had the highest. Exception for rice biomass, where dehydrogenase activity dropped, the dehydrogenase activity in each biochar treatment and control increased noticeably as the number of incubation days increased. In comparison to the control, the application of biomass to the soil raised the levels of acid phosphatase. At 5.0 t ha-1, the greatest alkaline phosphatase levels were detected in SSB and were 24.88, 29.83, 37.73, 68.22, and 82.78 at 1, 7, 30, 60, and 90 days of incubation, respectively. The addition of biomass residue increased soil protease enzyme activity, possibly as a result of increased inorganic nitrogen accessibility. Greater biomass concentrations were boosted more than lower ones, as seen by the greater biological indicator at 5.0 t/ha biomass incorporation rate compared to 2.5 t/ha. The study clearly shows that adding biomass from crop waste to soils may have a great potential for enhancing enzyme activities, which are crucial markers of soil quality and, in turn, biogeochemical cycles.

With rapid urbanization and economic growth, municipal solid waste (MSW) management has become a vital sector for reducing carbon emissions and advancing the circular economy. However, existing studies often overlook the life-cycle carbon emissions and recycling benefits of complex waste treatment processes. Thus, an innovative carbon footprint analysis framework was developed to evaluate treatment processes for various waste compositions, with case studies conducted in five major economies. The current carbon footprints of MSW treatment are quantified as 77.51 Mt CO₂-eq (China), 89.47 Mt CO₂-eq (the U.S.), 23.26 Mt CO₂-eq (the EU), – 5.57 Mt CO₂-eq (Japan), and 34.84 Mt CO₂-eq (India). The key contributors include landfill (LF) methane emissions from organic components, fossil CO₂ emissions from incineration (INC), and offsets from generated electricity. Scenario analysis reveals that future waste growth driven by economic development would contribute nearly three times the emission increase. While, grid decarbonization causes a 14.7% rebound effect due to diminished offset of energy recovery treatments. In addition, enhanced recycling reduces direct GHG emissions from incineration and increases the offsets, resulting in a 94% reduction in total carbon footprint of waste disposal. This research provides a robust quantitative basis for policymakers to design carbon–neutral roadmaps, highlighting the transformative potential of sustainable waste management in the transition to a low-carbon, circular economy.

Alternative alkaline activators have become necessary to advance geopolymer concrete due to the high carbon emissions and cost associated with traditional activators. Therefore, waste-derived alkaline activators are a way forward from the environmental and economic viewpoint. However, knowledge of the strength and durability of geopolymer concrete using waste-derived activators remains highly limited. This study investigates the compressive strength and durability analysis of geopolymer concrete manufactured with rice husk ash (RHA) derived alkaline activator, an alternative that solves both carbon emissions and cost concerns. Fly ash (FA) and ground granulated blast furnace slag (GGBS) are employed as source materials with varying proportions. The results reveal that the mix containing 60% FA and 40% GGBS reached the highest 28-day compressive strength of 39.1 MPa. Durability test results indicate a reduction in strength under acid exposure, while an increment in strength is noted under sulfate attack. In addition, all specimens exhibit very low sorptivity values that suggest better resistance to water penetration. The findings offer vital insights into the alternative alkaline activators in manufacturing geopolymer concrete thereby underscoring their potential.

This study aimed to develop life cycle greenhouse gas (GHG) emission factors for biogasification processes targeting food waste, sewage sludge, and livestock manure in South Korea. The system boundary encompassed pretreatment, anaerobic digestion, biogas utilization, and digestate treatment. Within this boundary, four scenarios were evaluated using life cycle assessment (LCA): a conventional biogas process (Scenario I), biogas utilization for power generation (Scenario II), application of the ANAMMOX process in wastewater treatment (Scenario III), and a combination of both strategies (Scenario IV). To ensure comprehensive comparisons, two functional units were considered: 1 ton of substrate input and 1 Nm³ of biogas produced. The results showed that GHG emissions per ton of substrate were substantially reduced for food waste and sewage sludge in Scenario II, by 99.1% and 70.2%, respectively. In Scenario III, sewage sludge and livestock manure achieved moderate reductions of 12.9% and 13.9% through the application of the ANAMMOX process. When evaluated based on energy output, biogasification exhibited higher GHG emissions than LNG, but significantly lower emissions compared to grid electricity. Overall, these findings suggest that electricity generation from biogas, rather than biogas production alone, offers a more promising pathway for achieving low-carbon goals in organic waste management.

The possibility of using marble waste (MARWAS) slurry as the raw material for synthesizing precipitated calcium carbonate (PCC) with desired shapes pertinent to its application as a filler in handmade papermaking was investigated in this study. Aiming to utilize a waste material for synthesizing a useful product, the MARWAS slurry was converted into CaCl₂ and subsequently carbonated in the presence of NH₃ in a bubble column reactor to synthesize submicron PCC particles. The synthesized PCC products were cubic-, rosette-, and spherical-shaped monodispersed particles of average size 188, 750, and 785 nm, respectively. The physical, mechanical, and optical properties of filler-loaded papers were also determined. The maximum filler retention of 87.95% was obtained with 20% loading of the rosette particles. For the same, tear strength increased by 31%, but burst strength remained unchanged compared to unloaded papers. However, the improvements in the optical properties of the filler-loaded papers were higher with the cubic and spherical particles than with the rosette type. An economic feasibility study made at 15% filler loading, the maximum level usually applied in Indian paper products showed that the product cost gets reduced by 29.6% if PCC made from MARWAS slurry is used instead of TiO₂.

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