Journal of Material Cycles and Waste Management最新文献

Zinc was focused on as an element causing hardening retardation due to delayed hydration of Ordinary Portland Cement (OPC), and its hardening inhibitory effect and the mechanism of hardening enhancement by sodium aluminate were analyzed by X-ray diffraction and scanning electron microscopy/energy dispersive X-ray spectroscopy. The addition of zinc hydroxide retarded hardening at more than 0.3 mass%, as previously reported, and zinc produced calcium zincate hydrates (qatranaite) and inhibited the hydration of tricalcium silicate (C₃S), the main component of hydration of OPC. After the zinc had been fully consumed in qatranaite formation, C₃S started normal hydration. The addition of sodium aluminate caused earlier re-hydration of C₃S, which was inhibited by hydration, as the hydrates produced appeared to consume zincate anions. The rapid setting effect of sodium aluminate addition was also delayed by zinc hydroxide, but it was estimated that the addition of the same amount of zinc would ensure initial strength through early formation of hydrocalumite. In the longer term, strength was considered to be more enhanced by the onset of C₃S hydration.

Poultry litter (PL) disposal is a major concern for poultry farms around the world, it is estimated that millions of metric tons of this waste are generated globally and as consumption rates increase so does the associated waste; the usual means of disposal include soil fertilization and livestock feeding, however, these disposal strategies are linked with hazardous environmental consequences: eutrophication, ammonia (NH₃) emissions and leaching of heavy metals. New environmentally friendly processes have been developed in order to reduce the impact of poultry litter and provide new means of revalorization: proper management and selection, elemental recovery (P, K and N) and its use as biomass for energy generation. One of the most promising revalorization opportunities for this ash residue lies in the development of greener cementitious composites in the pursuit of net-zero energy projects by reducing the carbon footprint of the modified concrete by replacing cement or aggregates, given the typical chemical composition (> 40% CaO) of poultry litter ash (PLA). The present review deals with PLA potential to replace cement or fine aggregates in cementitious composites, how this substitution affects the transport properties of the resultant composite and the effects on strength development and future considerations to be further investigated.

Bottom ash needs a pre-treatment process to produce the finer particles until it is like cement material and has a good reactivity as pozzolanic material. This research investigates the effect of using bottom ash on the durability performance of concrete. The modified process was applied to bottom ash to produce finer particles that can improve the durability performances of concrete. The concrete used in this study is self-compacting concrete (SCC) due to its convenience. The bottom ash was pretreated by mechanical grinding before being used as supplementary cement materials (SCM), later called ground bottom ash, and applied from 10% to 50% as the partial replacement by the weight of cement. BA30 showed the highest compressive strength with an increasing percentage of 32% and had a similar value to BA0. The porosity of all mixtures was under 15%. The water absorption of all mixtures was under 10%. BA10, BA20, and BA30 reduced the permeability of the SCC, while BA50 increased the permeability of the SCC. BA30 had the lowest value of RCPT as 916.22 C. The results show that bottom ash positively affects the durability performance of SCC and can be used as an SCM to produce more sustainable cement-based construction materials.

In low- and middle-income countries, waste pickers organized in cooperatives and associations face legal, operational, and management challenges. This article proposes a method to assess the performance of waste picker organizations based on sustainability indicators, as well as suggesting relevant measures to improve the formal recycling and solid waste source-separated collection. The method was applied to evaluate ten organizations in a region comprising 12 municipalities in the state of Rio de Janeiro, Brazil. The sustainability indices indicated low performance of the organizations, highlighting the lack of investment resulting in low monthly income for waste pickers, low recovery rates of recyclable waste, and poor working, health and safety conditions. The size of the municipality and existence of a contract between the municipal governments and waste picker organizations were not decisive factors for achieving favorable performance. Additionally, in the study region, there is no evidence that favorable performance of an individual organization leads to higher rate of recyclable waste recovery. However, there is evidence suggesting that it leads to higher income for waste pickers. To improve performance, a set of measures that can support formation of waste picker organizations in Brazil and other countries was proposed and validated through participatory means.

The extensive use of plastics has led to the widespread presence of a new type of pollutant called “microplastics (MPs)” in aquatic environments. MPs have large specific surface areas and strong hydrophobicity. In particular, MPs provide a new ecological niche for microorganisms in aquatic environments, which attach to and subsequently form biofilms on microplastic (MP) surfaces. This paper reviews the factors affecting biofilm growth on MP surfaces and the effect of biofilms on the adsorption of other environmental pollutants onto MPs as well as difference analysis. Biofilm formation is influenced by many factors related to the environment, MPs (e.g., type, particle size, and additives), and properties of microorganisms; environmental factors play an especially important role. Crucially, biofilms change the density of MPs and hydrophobicity of the surface of MPs and can attach new functional groups, charged sites, and other additives to MP surfaces. Primarily owing to this, biofilms affect the adsorption of environmental pollutants such as heavy metals, POPs, and pathogenic microorganisms. Notably, such adsorption is affected by MP particle size and additives. In particular, biofilms have a considerable effect on the interactions between MPs and pollutants. Further, this article suggests directions for revealing the influence of biofilms on pollutant adsorption to MPs. This review provides a reference for studying the formation of biofilms on MPs surfaces in aquatic environments and the effect of biofilms on contaminant adsorption onto MPs.

Rapid scio-economic expansion in Bhopal city, with population growth from 14.35 lakhs in 2001 to 26 lakhs in 2023— roughly twice as much—during this time. If we compare with solid waste generation (SWG) in present and expected increase in years 2001, 2023, and 2035, it is 500 t/d, 800 t/d, and 2735 t/d, respectively, which shows almost three times higher from present generation. This led to the problem of solid waste management due to limited availability resources. This paper gives correlation between development aspects based on life index such as physical quality of life Index and SWG. The present study quantifies the SWG of Bhopal city using the socio-economic data such as per capita income, gross domestic product, physical quality of life index, population, and SWG of Bhopal city that forecast the future status. Abovementioned socio-economical parameters were used for forecast model and for this, multiple linear regression analysis was used for study. Based on the study and after correlation with SWG, it is found that population is in highest correlation than gross domestic production at current price, per capita income at current price, and physical quality of life index, respectively. The high value of R² is 0.99638 in the models which is near 1. This will help the urban municipal solid waste management bodies to effectively manage solid waste in a sustainable manner.

The growing importance of repurposing waste ash from biomass power plants as a fertilizer material is evident. This study systematically investigates the feasibility of employing manure ash obtained from a biomass power plant for applications in fertilizer production. In this study, initially, waste poultry manure ash (PMA) was attempted to be modified by HCl, H₂SO₄, and HNO₃ to enhance the solubility of plant nutrients in its composition. SEM and XRD were used for the molecular and chemical characterization of the ash samples. The ash samples modified with acid were comparatively tested with triple superphosphate fertilizer (TSP) to determine their effects on the growth and nutrition of lettuce plants. The long-term use of ash and ash-derived fertilizer materials and whether they create a negative impact on soils have been determined through a simulation study. The most effective modification on the water solubility of nutrient elements, especially P, in PMA samples is achieved through modification with H₂SO₄. Similarly, in the plant experiment, PMA + H₂SO₄ treatment is superior to TSP. In the simulation study, it has been observed that the direct application of PMA in the long term further increases the pH in calcareous and high-pH soils, and the PMA + H₂SO₄ application is the most suitable for maintaining soil pH stability. It is well understood that effective recycling of PMA can provide an economical and alternative source of phosphorus. Additionally, PMA serves as a significant fertilizer due to the presence of other essential plant nutrients in its composition.

Plastic is valued for its flexibility to be utilized in different applications, yet it poses a significant threat to our environment because of mismanaged plastic waste. India’s compound annual growth of plastic consumption has been around 7% for a decade. Despite this significant growth, there has not been a comprehensive study of Indian plastic flows since 2000. This work presents a 20-year update, detailing plastic production, consumption by all plastic types and sectors, and the overall material flow for 2018–19 to fill the gap in the data on post-consumer plastic flows. The analysis reveals a total plastic production of 19.3 Mt, 22% of which is Polyethylene as the most wildly used plastic. The total mass of plastic in products distributed in various applications is 23.9 Mt. Key sectors for plastic consumption are Packaging (30%), Textiles (17%), and Buildings and Construction (16%). Plastic waste generation is 15.5 Mt, primarily from packaging and textiles. Only 13% of this plastic gets recycled, 46% is mismanaged, and the rest incinerated or dumped. The study’s unique nationwide, mass-balanced, transparent approach offers a rigorous reference point for decision-makers. Yet, the lack of reliable data is the main barrier to design, implement, and monitor of policy interventions.

Retired lithium nickel cobalt manganese oxide-type lithium-ion power batteries (NCMs) pose considerable challenges for recycling due to high contamination levels and low efficiency in the recovery process. Despite these complexities, NCMs contain significant amounts of precious metals, making them a substantial untapped resource with immense recycling potential. This study optimizes heat treatment conditions for NCMs focusing on cathode materials and the current collector. The optimal parameters of 280 °C, 2 h, and 60 s were identified through systematic discharge, disassembly, crushing, and sorting processes. Precious metal recovery rates exceeded 90%. Thermogravimetric-thermal differential analysis at 400 °C revealed the complete removal of bonding agents between the electrode materials. A comprehensive cost analysis was conducted using a mathematical model for retired power batteries revenue, scrutinizing the consumption costs and benefits of pyrometallurgical, hydrometallurgical, and physical recovery processes for NCMs. The input–output efficiencies were 6.56%, 28%, and 23%, respectively. This study supports the viability of physical recycling for a future mechanical–chemical combination approach to reduce production costs and environmental impacts. The proposed method holds economic, environmental, and industrial development value and provides a guide for sustainable recycling practices in the lithium-ion battery industry.

It is crucial for rural residents to consciously separate their domestic waste to improve their living environment and build beautiful villages. Exploring the decisive factors of household waste separation in rural China can offer more precise guidance for waste segregation, thereby contributing to the establishment of a more efficient and sustainable waste management system. Using the 2022 China rural revitalization comprehensive survey data (CRRS), this paper combined the least absolute shrinkage and selection operator (LASSO) algorithm with the Logit model to identify the determinants of waste separation in rural China from multiple aspects. It was found that families with better internet conditions, more equipment, and online training are more willing to participate in waste separation. Families who are more satisfied with the various tasks of the village committee are more willing to separate waste. Additionally, greater concern about food safety, and active learning of health knowledge are more inclined to engage in waste separation. Thus, this paper proposes improving internet conditions, enhancing satisfaction with village cadre work and promoting health awareness education.