Journal of Material Cycles and Waste Management最新文献

The recovery of graphite has been investigated mainly for black mass from spent Li-ion batteries. However, less research has been performed on the graphite recovery from spent Zn/C and alkaline batteries. Graphite is a critical raw material and it is necessary to search for new secondary sources to recover it. The main advance of this research is to study the application of froth flotation for the recovery of graphite from black mass of spent Zn/C and alkaline batteries. The effect of two thermal pre-treatment processes (roasting at 340ºC and pyrolysis at 600ºC) plus an attrition stage previous froth flotation have been analyzed. Experimental results showed that pyrolysis treatment of black mass from Zn/C and alkaline batteries allows greater selectivity of graphite versus Mn/Zn minerals. This may be due to a modification of the particle size do related to the removal of the finest ones, as well as a modification of the surface chemistry of the graphite and/or manganese oxides. In addition, the thermal treatment also modifies the mineralogical composition of the Mn oxides.

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This study quantified methane emissions from two Indonesian landfills—Griyomulyo and Sekoto—using four models: IPCC, LandGEM, Afvalzorg, and the Thailand Model. LandGEM and Thailand allowed full manual input of DOC, L₀, and k, making them suitable for Tier 2 use. In contrast, the IPCC model restricted input, limiting adaptability. Site-specific values—DOC (0.17 at Griyomulyo; 0.16 at Sekoto), L₀ (94.88 and 76.84 m³ CH₄/Mg), and k (0.006 and 0.055 yr⁻¹)—were used to improve reliability. In 2025, Griyomulyo’s modeled emissions ranged from 6,414.12 Mg/year (Thailand) to 9,952.37 Mg/year (Afvalzorg), while field measurements showed only 47.65 Mg/year, indicating substantial overestimation. Sekoto’s estimates ranged from 2,399.59 to 4,795.97 Mg/year. The average surface flux at Griyomulyo was 0.73 g/m²/h, slightly above global reference levels. IPCC and LandGEM showed the most significant deviations. A regional k value database was developed using Thompson’s rainfall-based equation, applying data from 164 stations across 38 provinces. Grouping analysis produced three climate zones (K1–K3) with average k values of 0.10, 0.06, and 0.08, aligning with IPCC defaults. This study demonstrates the value of integrating field data with adaptable models. It provides a practical foundation for establishing a nationally relevant methane inventory system in Indonesia, addressing data gaps and reporting needs.

The sustainability of rural waste management in China calls for a sound payment system. The Chinese government proposed the implementation of the pay-as-you-throw (PAYT) system in rural areas in 2018. Through the lens of theory of reasoned action, this study empirically examines the PAYT system's implementation effects based upon the survey data of 716 rural households Xiangtan and Zhuzhou, Hunan Province, China. Propensity score matching (PSM) is employed in the analysis. The results show that, at current stage, the PAYT system significantly enhances farmers' satisfaction with rural waste management services by 0.747, their environmental awareness by 0.855 and their willingness to participate in waste sorting by 1.066. Although the policy has generated these positive outcomes, its impact on measurable waste reduction remains statistically insignificant due to challenges in policy enforcement, farmers' attitudes, and insufficient infrastructure. The implementation of the PAYT system better aligns with the evolving needs of farmers in the new era. Notably, it proves particularly effective in improving environmental concern and waste-sorting intentions among farmers with low prior awareness of waste management. Furthermore, the system significantly enhances waste management satisfaction and environmental attention among relatively disadvantaged rural households. These findings confirm the positive effects of implementing waste treatment fee systems in rural China, broadening the perspective of existing research on rural waste governance. The study provides theoretical and empirical support for establishing sustainable waste management mechanisms in other regions of China and developing countries, contributing to the goal of achieving ecologically livable rural environments.

The mill scale, a significant byproduct of the steel industry, has been utilized for the synthesis of red (hematite) and yellow (goethite) pigments with specific morphologies and chemistries for use in flexographic ink. In the recovery process, calcination temperatures of 750 °C and 900 °C, along with pH levels of acidic (YP-2) and alkaline (YP-12) conditions, resulted in two distinct shades of red and yellow pigments, respectively. Characterization of the morphologies and chemistries of the recycled pigments were conducted using X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), N2 adsorption–desorption analysis, and ultraviolet–visible spectroscopy (UV–Vis). The results indicated the spherical particles in YP-2, which demonstrated better optical density (O.D.) of the ink without altering the viscosity parameters. The FTIR, surface area and SEM analyses revealed a higher presence of non-stoichiometric hydroxyl groups with spherical morphology, higher pH stability, and specific surface area, leading to improve dispersibility in water-based ink for YP-2 pigment and decrease the band gap to 2.3 eV (from 2.7 eV for rod-shape in YP-12). A lower calcination temperature for the red pigment resulted in a narrower size distribution of particles, enhancing O.D. and producing desirable color properties in flexographic ink.

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Increasing waste generation and disposal through open dumping is a significant issue in developing countries. The widespread open dumping method causes numerous environmental impacts and instability in waste dumps. This study aims to investigate the shear strength of waste in controlled open dumps, mainly focusing on waste samples aged less than 1 year, fresh waste, and dried fresh waste. Direct shear tests were used to explore the effect of waste characteristics on shear strength, and electrical resistivity tomography measurements were used to investigate the relationship between geophysical parameters and shear strength. The shear test results reveal that the waste’s cohesion values, and friction angles are 1.32–32.55 kPa and 6.61–65.41°, respectively. Additionally, the electrical resistivity of the waste ranges from 31.19 to 1,335.63 Ω-m. Furthermore, this study reveals that the shear strength of waste aged less than 1 year is lower than that of fresh waste. This decrease in shear strength is attributed to the relative increase in plastics, rubber, leather, fibrous materials, and fine fractions in older waste samples. The increase in resistivity corresponds to an increased cohesion and friction angle. Using a combination of nappies and fibrous materials with resistivity could improve the accuracy of the prediction model, indicating a strong correlation. Overall, the results demonstrate that moisture content and unit weight influence shear strength. In addition, the heterogeneous nature of waste dumps presents challenges in accurately measuring shear strength behavior which could be potentially addressed by the use of another geophysical techniques and statistical analysis in the future.

This study has investigated the major barriers to the successful implementation of Construction and Demolition Waste (CDW) management and suggested effective strategies for managing CDW. This study used a mixed-method approach combining quantitative and qualitative techniques. It started by identifying major barriers through a literature review and an on-site preliminary survey. A questionnaire survey was constructed to identify the most prominent barriers, and the perceptions of respondents were analyzed using SPSS and the Relative Importance Index (RII) index. After that, face-to-face interviews were conducted among the construction experts to suggest effective policies to manage CDW. The interview results were analyzed using thematic analysis in NVivo software. The quantitative analysis has indicated that “Workers lack training in healthcare and waste handling (E6-RII 0.949),” “Insufficient attention given to waste reduction in building planning and design (I3-RII 0.948),” and “Difficulty in implementing existing regulations in practice (L2-RII 0.946)” are the most influential barriers. Furthermore, to eliminate those barriers and manage CDW effectively, the construction experts have indicated some strategies including regulatory enforcement, stakeholder collaboration, etc. This investigation aims to capture the overall waste reduction landscape and propose key waste management strategies tailored to the Bangladeshi construction sector.

Direct interspecies electron transfer (DIET) has emerged as a promising mechanism to enhance the efficiency of anaerobic digestion, particularly in systems challenged by high organic loading, ammonia toxicity, or volatile fatty acid (VFA) accumulation. This review synthesizes recent advances in the use of conductive materials to stimulate DIET, focusing on the comparative roles of metal- and carbon-based materials. Metal-based materials, including zero-valent iron, magnetite, and nickel, facilitate redox-mediated degradation and act as both conductive agents and micronutrients. Carbon-based materials, such as biochar and granular activated carbon, enhance stability by buffering pH and alleviating ammonia and VFA accumulation. Modified or composite materials, especially those at the nanoscale, often yield synergistic effects that strengthen electron transfer and improve methane production. Comparative evidence indicates that carbon-based materials generally increase methane yields by 30–50%, while metal-based materials can achieve improvements approaching 70%. Composites perform best, with methane yield gains of up to 65% and biogas productivity increases exceeding 60%. Key factors affecting DIET efficiency—including particle size, dosage, operating conditions, and substrate type—are also addressed. Finally, this review highlights future directions for optimizing material properties, improving reuse strategies, controlling metal toxicity, and validating scalability through pilot- and full-scale demonstrations.

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This study introduces novel hybrid biocomposites by integrating natural fibers (hemp and abaca) with oil cake filler derived from agricultural waste, addressing the dual goals of sustainability and developing multifunctional composites with enhanced performance characteristics relative to conventional biobased materials. The biocomposites were fabricated by varying fiber content (10%, 15%, and 20% by weight) and oil cake filler proportions (2%, 4%, and 6% by weight). Mechanical properties, wear resistance, and moisture absorption behaviors were systematically evaluated. A composition of 10% fiber and 4% filler exhibited superior tensile strength (39.69 MPa), bending strength (59.21 MPa), and impact resistance (93.65 J/m). The novelty lies in the strategic integration of nano-sized oil cake filler with dual natural fibers (hemp and abaca) in an epoxy matrix, resulting in enhanced crystallinity, interfacial bonding, and combined improvements in mechanical, tribological, and moisture-resistant performance—distinguishing this system from previous single-fiber oil cake-based composites. This novel combination of natural fibers with nano-sized oil cake filler introduces a multi-functional reinforcement strategy. Unlike prior hemp or abaca-based systems, the filler enhances interfacial bonding and crystallinity while reducing hydrophilic behavior, offering a unique performance synergy in a fully biodegradable composite. This work demonstrates the potential of these biocomposites as eco-friendly alternatives for automotive, construction, and packaging industries, advancing the valorization of renewable resources and agricultural residues.

China’s hydrometallurgical zinc smelting industry, accounting for 80% of the total global zinc output, faces critical mercury waste challenges under the Minamata Convention on Mercury with 600–800 tons per year mercury input. Through a political, economic, social, and technological analysis, this study identifies massive-scale mercury waste generation driven by stringent emission standards and specialized removal technologies, focusing on the internal strengths and weaknesses as well as external opportunities and threats. Analytical results demonstrate strengths in China’s policy frameworks but reveal critical weaknesses in outdated regulatory standards and technical capacity for Category A waste management. Declining market demand for by-product mercury threatens circular economics, while international technical cooperation offers crucial pathways for mercury waste treatment technology upgrading and alignment with global environmentally sound management standards. Findings underscore the necessity to tighten material standards, advance mercury recycling technologies, and implement best environmental practices to ensure sustainable industry development.

Sustainable management of construction and demolition waste (CDW) has become a crucial aspect of the construction industry’s endeavor to reduce waste generation and promote resource conservation. This paper encompasses the recovery of CDW through recycled coarse aggregate (RCA) and recycled fine aggregate (RFA), different shortcomings and measures already taken for recycled aggregate (RA), and its application in various construction sectors. The RA offers benefits over natural aggregate (NA), reducing the cost of construction. It helps to mitigate excess carbon emissions and provides benefits such as waste reduction, resource conservation, and energy saving. The water absorption capacity of RCA and RFA exhibits higher values, 5.09% and 9.0% compared to natural coarse aggregate (NCA) and natural fine aggregate (NFA), 0.87% and 1.01%, respectively. The sp. gravity of RCA and RFA is a lower value of 2.41 and 2.34 vs. 2.68 and 2.64 for NCA and NFA, respectively. Physical and chemical treatment methods can improve the quality of RA by reducing water absorption capacity and increasing sp. gravity. Among all the treatment methods, pozzolanic slurry treatment is the most economical method. Recycle and reuse of RA in roads and structural applications are recommended for improved waste management.