Solid Waste Recycling Research Articles

Mechanical characteristics and microscopic mechanism of polypropylene fiber modified recycled road solid waste fine aggregate mortar

Recycled fine aggregate (RFA) is a recycled building material obtained by crushing and screening waste concrete, which is the main raw material for producing recycled aggregate mortar (RAM). However, due to the defects of RFA such as many cracks, high porosity and large fragmentation index, RAM has problems such as low compressive strength and poor flexural strength, which limits its large-scale application in mortar engineering. In this paper, a series of experiments were carried out to verify that the addition of polypropylene fiber (PPF) improves the mechanical strength of RAM. Four lengths (3mm, 6mm, 9mm, 12mm) and three dosages (0.3%, 0.6%, 0.9%) of PPF were added, and their effects on the compressive strength and flexural strength of RAM were studied. The test results show that the addition of PPF can improve the compressive strength and flexural strength of RAM and increase the toughness of RAM. The addition of PPF with 0.6% dosage and 12mm length can increase the compressive strength of RAM by 57% and the residual strength by 73%. The addition of PPF with 0.9% dosage and 12mm length can increase the flexural strength of RAM by 58% and the fracture energy by 163%. Scanning electron microscopy (SEM) results show that PPF can improve the microstructure of RAM. The effective bonding between the matrix and PPF is observed, which increases the mechanical strength of RAM. In addition, PPF is pulled out and broken, proving that PPF effectively plays its bridging and stretching role in the matrix. Moreover, a prediction model for the effect of PPF length and dosage on the compressive strength and flexural strength of RAM is proposed, which can provide theoretical basis for practical engineering and reference for related researches. This study proposes a negative carbon method for applying road solid waste to engineering mortar, which can provide theoretical basis for practical engineering and reference for related research.

Honeycombed pomegranate-like sludge ceramsite particles: Preparation with fly ash floating beads as the pore-forming template and performance optimization

Ceramsite used in construction and building are typically limited by high water absorption rates, the contradiction between lightweight and high strength, and severe performance fluctuations. This can be attributed to the fact that ceramsites are currently prepared by high-temperature sintering expansion, wherein viscosity and surface tension of the liquid phases shall perfectly match with the gas generation rate. On the other hand, sand washing sludge and fly ash are common solid wastes in construction and building and their environmentally friendly disposal are of great significance. In this study, honeycombed pomegranate-like sludge ceramsites with low density (packing density = 733.2–968.3 kg/m3), high strength (cylinder compressive strength = 11.2–18.8 MPa), and low water absorption rate (one-hour water absorption rate = 1.2–2.8 %) were prepared with sand washing sludge and fly ash floating beads as the raw material and the pore-forming template, respectively. Also, the effects of particle size and content of fly ash floating beads on the structure and performance of the as-prepared ceramsite were investigated. The results indicated that the pore structure of the as-prepared ceramsite was directly dependent on size and content of the fly ash floating beads, suggesting that the performance of the as-prepared ceramsite can be customized by tuning size and content of the beads. Additionally, lightweight aggregate concrete prepared by using the as-prepared ceramsites exhibited improved 7-day and 28-day compressive strengths and reduced thermal conductivity compared with concrete prepared by using commercially available ceramsites. Overall, this study presents the preparation of ceramsite particles with both high strength and low density by using fly ash and sand washing sludge, both of which are abundant solid wastes in constructions, thus contributing to solid waste recycling in construction.

Assessment of Municipal Solid Waste of the Karwi

Abstract: Due to rapid increasing population, urbanization and industrialization waste generation rate also increases but, Municipal authorities are not able to collect all waste and they are not having advance technology for treating such waste it gives result in form of pollution. The paper aims to characterize the waste generated in municipality of Karwi, in the state of Uttar Pradesh, India. Municipal Solid waste(MSW) is a heterogeneous waste and composition of the waste varied from place to place. First of all, the entire study area was surveyed to obtain essential information regarding waste generation areas and collection points. On the basis of information, representative sample were selected in each point. Collected samples were thoroughly mixed and segregated into different categories and data represented in percentage. The characteristics of the municipal solid waste were determined in terms of the components, average mass (kg) and percentage .Characterization of municipal solid waste shows Karwi waste comprise maximum plastic (29.01%), Metal (0.025%), Wood(0.0215%), Cardboard(3.77%), Rubber(1.9%), Paper(5.1%), Rags(3.22%), Packaging Material (11.02%), Glass (8.42%), Compost (8.025%). Thus, on the basis of this study we may conclude that solid waste management and recycling is major issue of Varanasi district. We can reuse various types of waste depending upon the nature of waste. We can also make alternate use of that waste like energy production. Community participation in solid waste management may be a better option

A Business Management Model in the Circular Economy: Technological Solutions for Plastic Recycling

Objectives: this article develops a model for managing business processes in a circular economy using technologies for plastic recycling. Theoretical Framework: The theoretical idea and basis of the article consists in the development of project management methodology, process approach in the closed-loop economy, development of methods and economic tools aimed at effective resource management taking into account waste reduction and increased reuse of plastic fractions in Municipal Solid Waste (MSW). The application of digital technologies and solutions in the context of business process management in the field of plastics recycling will be substantiated, which will allow to identify new opportunities and reserves for optimising business processes in this field, increasing the efficiency of resource use, improving the environment and reducing costs. Method: the work uses a project approach, a process approach, digital modeling methods, and the “polluter pays” method. To implement the process approach, it is proposed to use the concept of Business Process Management (BPM). Competent business process management allows the company to react quickly to changing market conditions and customer orientation. Digital modelling in this paper means the representation of actions in the form of business processes in the organisation of solid waste management, the 'polluter pays' method means the economic assessment and accounting of environmental damage in waste management in the costs of business processes. Results and Discussion: The results of the study can be used to introduce the process approach to plastics recycling in individual regions and countries for the development of a green economy. According to the estimates of the authors, the optimisation and cost reduction of business processes, taking into account the environmental factor and the increase of the revenue part of the project from the reuse and inclusion in the economic turnover of plastic waste recycling products on the scale of the considered city (population of 1800 thousand people, area of 2856 ha, 18.14 tonnes of plastic waste accumulated per day) will reduce the costs of business process management by more than 200 thousand euros. Research Implications: the results of the study can be used to justify projects for the processing and recycling of solid municipal waste, including plastic waste, to introduce environmentally friendly production, to reduce the negative impact on the environment, to develop a process approach to the organisation of all activities for the collection of plastic waste in the city, district. In addition, the application of the proposed approach allows to obtain economic benefits for companies through the sale of secondary resources for the processing of plastic waste, as well as to reduce the negative impact on the environment. Originality/ Value: The originality of the research and its value lies in a new scientific formulation of the problem of reducing environmental pollution from plastic waste through the use of business processes in the field of plastic recycling and digital solutions, as well as the possibility of practical application of the results obtained in the field of green economy.

Management System for Safety, Health and Environmental Risks at Jasa Contratistas S.A.C.

The investigation focused on establishing a comprehensive regulatory framework for Safety, Health and Environment at JASA Contratistas S.A.C., based on Peruvian legislation, including Law No. 29783 and Supreme Decree No. 023-2021-MINAM. The methodology covered the initial characterization, the definition of environmental policy objectives and the evaluation of occupational risks through IPERC matrices. 122 regulatory items were identified, with 56% meeting the criteria of the Occupational Health and Safety Management System (SGSST). In the environmental field, a 3.38% reduction in deforestation was evident, a 7% increase in solid waste recycling and a 5% improvement in environmental management. After the implementation of the SGSST, occupational risks decreased from 25% to 10.71%, while in the environmental aspect, deforestation reached 2.10%, solid waste treatment increased to 17.5%, and the pro-environmental attitude of employees improved by 20.8%. This system not only improved risk control and reduced accidents, but also increased productivity, ensured regulatory compliance, strengthened competitiveness and encouraged improved environmental behavior among staff.

Preparation of aragonite-rich whisker materials from magnesium slag and salt lake bischofite and its effects on cement properties

This study develops an innovative wet carbonation process utilizing Magnesium Slag(MS), Salt Lake Bischofite (SLB), and CO2 to prepare carbonized materials mainly composed of aragonite and active silica gel, all raw materials were solid wastes. Subsequently, it was employed as Supplementary Cementitious Materials (SCMs) additive in cement, with the goal of efficiently capturing carbon dioxide and transforming aragonite whiskers into high-value products. Investigated the parameters influencing the formation of aragonite, including temperature and the concentration of the SLB solution, while exploring the nucleation and growth mechanisms of aragonite. The findings reveal that under 80 °C, the suspension of MS with 0.83 % SLB solution swiftly produces needle-like aragonite whiskers with single crystal lengths ranging from 10-20 μm and diameters of 0.3–0.5 μm. With the increase in SLB concentration, the aspect ratio of aragonite whiskers decreases. Additionally, highly polymerized amorphous silica gel was also detected. Therefore, Carbonated Aragonite-type Magnesium Slag (CAMS) (34.0901 m2/g) exhibits a significantly larger specific surface area compared to MS (0.9877 m2/g), representing an enhancement factor of 34.5 times, which concurrently bolsters its capability to adsorb reactive ions. During the carbonation process, 1 g of MS can sequester and solidify 0.403 g of CO2. Furthermore, incorporating CAMS as SCMs into cement mixtures notably enhances both the compressive and flexural strengths of cement mortar. These findings offer a sustainable approach to the recycling of solid waste, CO2 sequestration, and the improvement of cement-based material properties.

Legal aspects of solid waste recycling and disposal in Kazakhstan: international standards and national regulation in the context of a circular economy

The Republic of Kazakhstan, possessing significant natural resources and a rapidly developing economy, is faced with growing volumes of municipal solid waste (MSW), which requires effective measures for their processing and disposal. The main purpose of this study is to analyze the legal aspects of solid waste management in Kazakhstan, assess the compliance of national legislation with international standards and explore the potential for integrating the principles of a circular economy. The study covers the current state of the legal regulation of solid household waste in Kazakhstan and identifies key problems. The use of methods of political and legal analysis, comparative legal approach and system analysis helps to assess how modern initiatives can contribute to improving solid waste management and maintaining environmental balance. The conclusions of the study indicate the need to improve the legislative framework of Kazakhstan for the management of solid household waste. The introduction of a new Ecological Code based on the European principles of waste management hierarchy and extended producer responsibility is an important step forward. However, further progress requires the adoption of the Law “On Waste”, which would specify the implementation of the principles of the circular economy. The importance of creating conditions for small and medium-sized businesses in the field of waste recycling and increasing environmental awareness of the population through informing and involving public organizations and the media is also emphasized.

Early hydration and mechanical performance of composited cementitious system prepared from high temperature calcined molybdenum tailings

To improve the recycling of solid waste and achieve the secondary utilization of waste resources, this study investigates the preparation of molybdenum tailings composited binders by high temperature calcination using molybdenum tailings, limestone, bauxite, and iron concentrate powder. Besides, to explore the mechanical properties of the new molybdenum tailings composited binders, a molybdenum tailings composited mortar was prepared. The mechanical properties, micro performance and hydration mechanism of the new molybdenum tailings composited binders were studied. Finally, the carbon dioxide emission of green molybdenum tailings composited binders/molybdenum tailings composited mortar was evaluated by the life cycle assessment method. The results show that the compressive strength of molybdenum tailings composited binders gradually increases with the increase of calcination temperature. When the calcination temperature is 1350 °C, the compressive strength and flexural strength at 28 days are 44.17 MPa and 7.56 MPa, respectively, which are 3.65 % and 4.63 % higher than control group made by P·O 42.5 cement. The early strength of molybdenum tailings composited binders increases slowly, and the later strength increases rapidly. In addition, there is more C2S in the matrix, resulting in a slow hydration heat rate and low cumulative hydration heat. Compared with other groups, the hydration kinetic parameters and hydration rate of molybdenum tailings composited binders under 1350 °C were the lowest. The main hydration prodcuts of molybdenum tailings composited binders are C-S-H, calcium hydroxide, and Aft gels. Compared with P·O 42.5 cement paste and mortar, the carbon dioxide emission of molybdenum tailings composited binders/molybdenum tailings composited mortar is reduced by 42.82 % and 29.08 %, respectively, which can indicate that the new binders can produce less carbon dioxide. Overall, this study can provide new ways for the development of the new binder mixed with plenty of molybdenum tailings, and offer a novel way for recycling the molybdenum tailings, and also present some valuable experimental results for the application of molybdenum tailings in infrastructures.

Foreign waste ban and green development of Chinese manufacturing industry: Comprehensive evidence based on provincial data

Since the reform and opening up, imported solid wastes have pushed China's economic growth while also bringing about serious environmental problems. In this context, China has introduced a ban on “foreign waste” for imported solid waste. Based on the provincial panel data from 2010 to 2020, this paper calculates the Green Total Factor Productivity (GTFP) of the manufacturing industry to measure the level of green development of the manufacturing sector, and evaluates the comprehensive impact of the “foreign waste” ban on the green development of the manufacturing industry by using the continuous Difference-in-Differences method. The study finds that the foreign waste ban greatly promotes the greening of China's manufacturing sector, mechanism analysis shows that foreign waste ban stimulates innovation by innovation effects and increases production cost by cost effects, and the policy effect has heterogeneity as it is more prominent in coastal areas, areas with a lower proportion or a higher level of green development. This result suggests that the promotion of domestic solid waste recycling should be accompanied by further guidance on efficient factor mobility, with different measures based on regional heterogeneity.

3D printed concrete incorporating waste rubber: Anisotropic properties and environmental impact analysis

The recycling and reuse of solid wastes mark the construction industry's development towards sustainable and green technologies. 3D printing technology using recycled solid materials is in great demand for intelligent and low-carbon construction. This paper incorporates crumb rubber (0–1 mm) into the printing ink and analyses the fresh and hardened properties. The results showed that the flowability was positively correlated with rubber ratio but negatively with fiber content. R40F15 (40% rubber and 1.5% fiber) obtained the optimal flowability for 3D printing, which remained above 15 mm for 30min. The compressive strength peaked when incorporating 1.5% fiber, while the flexural strength reached the bottom. X direction generated the highest compressive strength in the whole anisotropic tests, followed by the Y and Z directions. The highest strengths of 1.5% and 2.0% fiber content were 69.45 MPa and 64.5 MPa, incorporating 20% rubber. Thus, surfaces anticipated to bear higher loads in compression should be aligned with the X-axis or, at a minimum, avoid alignment with the Z-axis for optimal structural performance. Y direction obtained the highest flexural strength in all anisotropic tests when incorporating 1.5% fiber. Results from digital image correlation test supported that fiber tended to agglomerate in the Y direction. Besides, the environmental analysis was conducted in this paper to quantitively calculate the impacts of all raw materials to the environment.

Adsorption ability of sugar scum as industrial waste for crystal violet elimination: Experimental and advanced statistical physics modeling

Recycling solid industrial waste into useful resources is the most critical aspect of managing waste. Herein, for detoxifying poisonous crystal violet dye (CV) in aqueous media, sugar scum (SS) as an underutilized industrial discard has been tested as a promising adsorbent.The SS was thoroughly analyzed beforehand and after the adsorption process through various characterization techniques. Several operational factors, including pH, biosorbent dosage, dye concentration, and temperature, were optimized, reaching 24 mg.g-1 at (pH 10, 2 g.L−1 of SS, 10 mg.L−1 of CV and 25 °C). The bioadsorbent's performance was assessed through a range of studies involving kinetic, equilibrium (using both conventional and statistical physics models), and thermodynamic investigations.Based on the results, the equilibrium curves best fit the Freundlich model, indicating that multilayer adsorption occurs on a heterogeneous active sites surface. The statistical physics models provided detailed physiochemical insights, the double-layer with two energies model was most accurately describing the data, with a high saturation capability of 371 mg.g−1. Most interactions occur at a single adsorption site (70 %), with the remaining 30 % at two sites, involving both parallel and non-parallel orientations. The mesoporous structure of the SS surface provides an optimum size for CV adsorption. Pore filling, Van der Waals forces, hydrogen bonding, π-π and electrostatic interactions are proposed as the possible mechanisms in the CV-SS system. Thermodynamic measurements indicate that CV adsorption is spontaneous (ΔG° < 0) and exothermic ΔH° (− 41.390 kJ mol−1).The SS recyclability was assessed, exhibiting encouraging sustainability with a slight fall in effectiveness (∼7 %) after 5 sequential usages. Altogether, this study makes a substantial contribution to the promotion of ecological water treatment strategies, which highlights the utility of using SS as an environmental alternative to water contaminant remediation.

Affordable and sustainable clean energy generation potentials from municipal dumpsites: case study of Oke saje dumpsite, Abeokuta, Ogun State, Nigeria

The operating method of final waste disposal in Oke saje area of Abeokuta is direct open dumping and burning. This study was conducted at a major dumpsite in Abeokuta, to investigate the existing waste management systems, characterize solid wastes generated, and estimate for the sustainable energy generation potentials. Exploratory study design was adopted for a period of six (6) months, May to November, 2023. Seven (7) randomly selected plots of 1sq.m were located on Oke saje dumpsite, from where solid wastes were collected from top to the depth of 300 mm. Waste components were weighed to obtain the weight-based characterizations. Sorting into major waste components was in accordance with College and University Recycling Council (CURC) grouping system with modifications to accommodate peculiar waste stream generated in Oke saje dumpsite. Waste samples were taken to laboratory to carry our necessary physical, chemical and proximate analyses. Estimated total solid waste generation in Oke- saje, dumpsite was 3,718,832.03 kg (3718.83 tonnes). Estimated energy content of solid wastes was 46370.47MJ. This implies that there is possibility of electricity generation up to 12.881MWh from daily steam production. An integrated solid waste management concept adoptable to Oke- saje, dumpsite, has zero waste concept of about 46 % waste material recyclable (from composting, bio-fuel production and recyclables), with electricity generating potential of 5.923 KWh and 56 % energy recovery (from electricity generation, incineration-derived ash and residual ash for landfilling or soil enhancement), of about 6.956 KWh. Considering the high material recyclability, reusability and energy recovery potentials from solid wastes generated from Oke saje dumpsite, it was recommended that the Ogun State Waste Management Authority adopts affordable, sustainable and integrated waste management options of waste minimization and sorting from the source, reuse, recycling, and incineration of solid waste generated from the large communities within the state.

Effect of sintering behavior and phase evolution on glass-ceramics entirely derived from ferrochrome slag and fluorite tailings

The recycling of solid waste is widely regarded as the one of the most crucial issues of sustainability. This is particularly evident in the industrial sector, where the production of slags is huge and their handling presents a significant challenge. In this study, solid wastes from the industrial sector, namely ferrochrome slag (Fs) and fluorite tailings (Ft), were employed for the preparation of glass-ceramics by the sintering method. Three glasses were prepared by using the melt-quenching method, with a weight ratio of 60∼70 % Fs and 40∼30 % Ft (designated S30, S35, and S40, where the higher number indicates a greater Fs content). The sintering and crystallization behaviors of these glasses were characterized by hot-stage microscopy (HSM) and differential thermal analysis (DTA). It was observed that S40 glass exhibited a weak sintering capacity in comparison to that of S30 and S35 glass, which can be attributed to the robust crystallization propensity of S40 glass. The coarser glass frits were subjected to sintering experiments at varying temperatures, which demonstrates that the predominant crystalline phase is augite and that Cr2O3 remains present in all sintered samples. Besides, a transition of the Cr2O3 crystal into uvarovite was observed in S40 glass sintered at 1050 °C. The sintering time controlling experiment demonstrated that both wollastonite and the Ca-rich flow formed during sintering are vital for the formation of uvarovite. The formation of uvarovite can enhance the hardness of GCs. All GCs samples sintered at 1050 °C and 1120 °C exhibit comparable mechanical performance.

Toward Viable Industrial Solid Residual Waste Recycling: A Review of Its Innovative Applications and Future Perspectives

Industrial solid residual waste (ISRW) generated during and/or due to the making of energy, heat, and raw materials poses a major threat to a sustainable future due to its large production quantities and complex characteristics. Especially improper disposal of ISRW (e.g., coal ashes, municipal waste residue, and biomass ashes) not only threatens human health but can also cause environmental hazards such as water, soil, and air pollution, upsetting the global balance. Given the environmental impacts as well as increasingly stringent disposal regulations, lack of landfills, and economic constraints, more sustainable and naturally friendly management strategies are being adopted for ISRW. While numerous studies in the literature have considered various characteristics of ISRW, a complete appraisal of the entire practice, from making to disposal, is still lacking. This paper presents an overview of the making, features, and traditional and innovative managing tactics of ISRW within the context of a general legal framework. This paper provides a scientific review of the various production types, global production quantities, and characteristics of ISRW. Additionally, the orthodox management strategies of ISRWs are scrutinized from a sociological and ecological standpoint, and diverse techniques for more viable and secure management are elucidated. This review culminates in an examination of the global impact and advantages of ISRW management policies based on legislation and regulations. Consequently, this paper seeks to elucidate the extant practices and a few recent advancements pertaining to ISRWs. Additionally, it underscores the ecological, sociological, and economic issues engendered by ISRWs and proposes innovative applications and production technologies.

Efficient and emission-reduced recovery of high-purity copper from waste enameled copper wires

The escalating demand for refined copper intensifies research into the recycling of copper-based solid waste, exemplified by recovery of copper from waste enameled copper wires (WECWs). Despite its potential, the pyrolysis process for WECWs is hindered by embrittlement, diminishing both recycling yield and quality. Our study pioneers the elucidation of the embrittlement mechanism during WECWs pyrolysis through atom probe tomography and first-principles calculations, revealing that hydrogen, a byproduct of paint film pyrolysis, accumulates at copper grain boundaries, inducing embrittlement by reducing adhesion energy. We introduce two innovative strategies to mitigate hydrogen-induced embrittlement: vacuum pyrolysis and enhanced N2 flow. These approaches significantly reduced hydrogen content from 11.1 % to about 5 % and increased elongation from 2.65 % to 15 %. Moreover, pyrolysis efficiencies of 92.79 % and 91.4 % were achieved, respectively, at temperatures 50 °C lower than conventional methods. Our findings provide crucial theoretical insights into embrittlement and offer effective recovery strategies for copper from solid waste.

A dual-driven fusion model of evaluating the performance and carbon emissions for recycled waste pavement

Solid waste recycling is an essential approach for the sustainable transition of transportation infrastructure development. In this study, a holistic model for recycled waste pavement was developed, achieving a breakthrough in eco-efficiency-based pavement material design. Using this model, we can not only individually assess the technical feasibility of the pavement material and its carbon emissions, but also realize the unified dimensional quantification of multidimensional parameters based on decision-making expectations using a metrics fusion system, thus achieving high-level sustainability decisions for pavement schemes. The proposed model was validated by evaluating the comprehensive properties of steel slag pavements to determine a suitable and durable pavement solution. This study provides a decarbonization strategy for the transportation sector considering waste-recycled pavement design, which may promote the development of more resilient transportation infrastructure and significantly contribute to achieving carbon neutrality and mitigating climate change.•A model for solid waste pavement was established based on synthesized assessing feasibility and carbon emissions.•The field performance and climate system impacts of pavements with solid waste materials were assessed.•It was demonstrated that recycling steel slag for pavement construction can reduce carbon emissions by >50 %.•Our results contribute to achieving sustainable transportation infrastructure systems to mitigate climate issues.•Our methodology can be used not only for road construction but also in the civil engineering field.

Driving EU sustainability: Promoting the circular economy through municipal waste efficiency

The need to balance ecosystems and ensure the well-being of all people underlines the urgency of closing product life cycles. In recent years, the circular economy (CE) has emerged as one of the most relevant factors in achieving the Sustainable Development Goals. This paper presents a systematic literature review (SLR) of waste management efficiency at the European level. Furthermore, it presents a standard data envelopment analysis (DEA) of 27 European countries over the period 2017–2021, focused on municipal waste. Three models (i.e., economic, technical, sustainable) are proposed to optimise the rates of municipal waste recycling and circular material use.The SLR, based on an initial set of 216 articles that was subsequently refined through double screening to 31, highlights the strategic role of the waste management, recycling and municipal solid waste triangle. The results of the DEA indicate stronger synergy between technical and sustainability dimensions than between economic and sustainability components. Moreover, they highlight fragmented performance in Europe, with distinct clusters of countries emerging as top performers in each of the three models, and the Netherlands, Slovenia, France, Italy, Germany and Sweden demonstrating superior performance for both CE outcomes and sustainable performance. Overall, the results emphasise the strategic role played by technology in facilitating an efficient circular model of municipal waste management to minimise landfilling and other environmentally detrimental practices, thereby stimulating the development of sustainable communities for optimised waste management, in line with broader sustainability objectives.

Revitalizing municipal solid waste recycling: Review of current U.S. policies and potential directions for the circular economy

Municipal Solid Waste (MSW) recycling is a pivotal pillar in waste reduction and sustainable resource management. However, the United States (U.S.) is behind its schedule for the national recycling rate goal of 50% by 2030, which California is almost achieving. To this end, we review and compare the national and California recycling policies. Our analysis reveals that while there have been some positive changes toward sustainable waste management practices, significant gaps remain, particularly in the lack of a comprehensive national recycling law. The current federal allocation of funds has also been inadequate for achieving the national goal. Therefore, we identify policy options to grow toward a national policy and funding for recycling infrastructure and education. Using California as a model, we provide federal law options to balance recyclable supply and demand. These options are paired with future U.S. MSW policy and research directions.

Sustainable pyrolytic carbon negative electrodes for sodium-ion batteries

Considering both sustainability and potential applications in various industrial sectors, pyrolytic carbon from the recycling of organic solid wastes can play a significant part in the unfolding energy revolution. Further innovations in circular-economy waste loops can facilitate higher economic benefits and lower environmental impacts, where a number of opportunities for improving pyrolytic carbon by choices of precursors, easy regulation of pyrolysis conditions and potential post-treatments. Here we propose a method to synthesize sustainable high-quality nanotube-like pyrolytic carbon using waste pyrolysis gas from the decomposition of waste epoxy resin as precursor, and conduct the exploration of its properties for possible use as a negative electrode material in sodium-ion batteries. The obtained pyrolytic carbon shows better cycling and rate performance than benchmark commercial hard carbon, retaining ∼105 mA h g−1 after 2000 cycles at 100 mA g−1 and exhibiting ∼57 mA h g−1 at 1 A g−1. Since the slope-dominated nature of pyrolytic carbon leads to high performance dependence on defects and pore structure, we therefore also investigate the preferred design of pore structure via pore-forming by post-treatment. It is found that reversible adsorption/desorption on defect sites and optimal pore structure are highly needed for pyrolytic carbon toward practical applications. This work highlights the potential of waste pyrolysis gas itself as a valuable feedstock for the production of value-added carbon materials.

Energy-saving and benign hydrogen production by coal gasification fine slag-assisted Water electrolysis

ABSTRACT Integrating anodic coal gasification fine slag oxidation with cathodic hydrogen evolution reaction presents an environmentally friendly and energy-efficient solution for solid waste recycling and hydrogen production. This innovative approach exhibits higher activity and stability than conventional water electrolysis, while also preventing anode degradation due to its benign reaction conditions. The kinetic investigations have revealed that slag oxidation occurs more rapidly than water oxidation. Specifically, slag undergoes direct and indirect oxidation within the potential regions below and above those of water oxidation, respectively. This study has the potential to shed light on the mechanisms underlying slag electrolysis and offer valuable insights for the simultaneous recycling of solid waste and hydrogen production.