Potential Recycling Research Articles

Analysis of Waste Composition, Waste Generation and The Recycling Potential in The Natsepa Beach Tourism Area, Central Maluku Regency

Natsepa Beach is one of the famous tourist areas on Ambon Island. The presence of tourists in the area contributes to the production of both organic and inorganic waste which affects not only the aesthetics of the area but also the income of economic agents. The study aims to analyse waste composition, waste generation, and the recycling potency in Natsepa Beach. The study was conducted from July to August 2022 by applying a field observation method. The procedure of SNI 19-3964-1994, which regards urban waste collection methods to measure the composition and waste generation, was applied in this research. The results showed that the amount of organic waste, which is dominated by fruit peel waste (from rujak or fruit salads), is about 92.21%, whereas it is only about 7.79% of inorganic waste that comes from plastic waste. Total weight of waste that is generated by a person is around 0.12 kg/day or 0.46 liters/day in volume standard. Thus, it can be assumed that every visitor in Natsepa Beach produces 0.12 kg (0,11 kg of organic and 0,01 kg of inorganic waste). The potency to recycle organic waste into compost is 100% and eco enzyme is 78.52%. Furthermore, the potential plastic waste recycling is about 77.19%.

Assessing solid waste management practices in the Techiman municipality of Ghana and the potential of recycling for revenue mobilization and reduction of waste menace

There is increased municipal solid waste (MSW) generation in most municipalities across the globe. This study assessed the recycling potential and contribution of the informal sector to waste management in the Techiman municipality of Ghana. MSW was collected from 400 households for 10 continuous days and characterised. On average, 3.2 kg and 0.8 kg of MSW are generated per household and per person per day, respectively. The fractions of MSW were found to be 66.5% organics, 19.2% plastics, 3.3% paper, 3.2% metals, 1.6% leather and plastics, 0.9% glass, 0.6% textiles, 2.7% inert and 1.9% miscellaneous. Recycling potential for the Techiman municipality was found to be 29%, which means 29% of the respondents informally engage in recycling activities. The study also revealed that 33% of the respondents engage the services of the informal sector to dispose of their waste. Thirty-seven per cent (37%) of the respondents in the municipality dispose of their generated waste at various open designated sites, while 31% use public waste containers. The study further established that, incentives such as improved sanitation and financial rewards, free waste bins, among others, would greatly improve waste management. Also, formalisation and regulation of activities of the informal waste collectors can increase recycling and waste collection in the municipality.

SbB-g-GMA Copolymer as a Dual Functional Reactive Compatibilizer and Impact Modifier for Potential Recycling of PET and PS via Melt Blending Approach

SbB-g-GMA Copolymer as a Dual Functional Reactive Compatibilizer and Impact Modifier for Potential Recycling of PET and PS via Melt Blending Approach

Iodine Capture by Ag-Loaded Solid Sorbents Followed by Ag Recycling and Iodine Immobilization: An End-to-End Process

The article demonstrates the complete process of I2(g) capture using Ag-exchanged faujasite (AgX) and Ag-exchanged mordenite (AgZ) zeolite sorbents, the recovery of Ag for recyclability of iodine capture, and the immobilization of iodide (from the elution process) into an iodosodalite waste form, which is chemically and environmentally stable. The gaseous iodine, I2(g), was captured in the AgX via chemisorption by Ag and converted to AgI within the aluminosilicate zeolite frameworks. The elution reaction in Na2S resulted in the precipitation of Ag2S and dissolution of I– and Na+ into the aqueous solution, where powdered sorbent showed higher conversion efficiency than the granular form, which is attributed to Na2S-solution diffusion limitations in the granules. The Ag2S-containing aluminosilicate precipitates were filtered out of the solution, and the filtrate (aqueous solution) was used to synthesize iodosodalite to immobilize iodide. The iodine capture using the recovered Ag2S-containing sorbents shows equivalent iodine loadings to the AgX starting material of Qe = 0.355 g/g for powdered material and 0.255 g/g for granular material, demonstrating the potential recycling of Ag for iodine capture as Ag2S-based sorbents.

Interface Characterization of Consolidated PPGF Tapes on PPGF Mat Material.

Laminated composites with thermoset matrices are already well established in major engineering fields like automotive and aviation. The primary drawbacks of such thermoset-based composites are the high cycle times required during manufacturing and their limited potential for recycling. Providing an alternative to thermoset-based composites, thermoplastic matrix materials gained more and more momentum by addressing these previously mentioned drawbacks. The preferred manufacturing technique for these materials employs fiber-reinforced thermoplastic tapes consolidated and formed together with a compatible substrate. The most critical aspect for all these applications is the stress or load transfer between the thermoplastic tapes and the substrate. If the interface is too weak and fails prior to the substrate or tape, a high amount of theoretical mechanical performance is lost. The presented research investigates the influence of variations in manufacturing parameters, within the industrially relevant process window, on the interface strength of the final composite. The investigated composite material consists of PPGF UD tapes consolidated on a PPGF mat substrate. In particular, the influence of the consolidation parameters of pressure, temperature, and time are of special interest. The results of this work reveal a 400% increase in the measured mean strain energy release rate upon increasing the consolidation time from 60 s to 120 s at a consolidation temperature of 230 °C and a pressure of one bar. In contrast to this, an increase in the consolidation pressure, at constant temperature and time, leads to a minor improvement in the GC value of 20%. For testing and characterizing the corresponding interface properties, a mandrel peel testing setup was employed.

A Novel D-π-A Type Fluorescent Probe for Cu2+ Based on Styryl-Pyridinium Salts Conjugating Di-(2-picolyl)amine (DPA) Units.

A novel D-π-A type fluorescent probe L(NO3) for Cu (II) sensing was designed and fully characterized. The probe consists of a styryl-pyridine cation fluorescent group and a di-(2-picolyl)amine (DPA) receptor unit, which are linked by a phenyl group to form an electron donor-π-acceptor (D-π-A) conjugate system, especially the introduction of a nitrate counter anion for significantly enhanced water solubility of the probe. Fluorescence titration studies of the probe L(NO3) showed a higher selectivity for Cu2+ than other metal ions, and the emission spectrum was strongly quenched upon binding. The competitive binding assay and the low detection limit (0.932 µM) showed that the probe L(NO3) had strong anti-interference ability and excellent Cu2+ detection performance. The binding ratio of probe L(NO3) and Cu2+ was determined from Job's plot to be 1:1, which is consistent with the results obtained from X-ray crystal structures. Meanwhile, the probe showed instantaneous chemical reversibility when titrated with EDTA solution, indicating potential recycling properties of the probe. In addition, the design of inexpensive fluorescent test strips can perform the on-site and real-time detection Cu2+ with a color recognition application.

Selective Sulfation Roasting for Cobalt and Lithium Extraction from Industrial LCO-Rich Spent Black Mass

The extraction of cobalt from secondary resources has become crucial, as cobalt has been identified as a strategically important and critical raw material due to the high risks of supply chain disruptions. In this work, selective sulfation roasting was investigated as a potential recycling strategy to extract cobalt and lithium from an industrial lithium cobalt oxide (LCO)-rich black mass. Additionally, the effect of graphite on metal extraction was studied. In the first set of experiments, the sieved black mass fraction containing both cathode and anode materials was directly roasted in a predetermined composition of gas mixtures of SO2, O2, and Ar for 1 h at 850 °C. The gas composition was determined from Kellogg’s diagram to allow for the selective sulfation of Co and Li. In another set of experiments, the carbon present in the black mass was first removed by roasting the material in Ar for 2 h and then in an Ar and O2 gas mixture for five hours at 600 °C. Afterward, selective sulfation roasting was performed in mixtures of SO2, O2, and Ar gas similar to the previous set of experiments. For comparison, similar experiments were performed at 800 °C. The sulfation roasted black mass was leached in water to study the efficiency of Co extraction into the solution. Interestingly, the presence of carbon was found to be beneficial for Co extraction. The extraction efficiency for the first case (with carbon present in the raw material) was observed to be more than three times higher than in the second case (with carbon removed) for sulfation at 850 °C. The extraction efficiency and purity of the extracted Co were found to be better for higher temperature sulfation roasting conditions due to faster reaction kinetics. It was also found that almost all of the Li could be recovered while extracting Co. The maximum efficiency of the extraction was 99.51% Li and 61.21% Co for roasting under a gas flow of 10% SO2-10% O2-Ar at 850 °C for 60 min. These results suggest that Co and Li can be selectively extracted from the black mass by sulfation roasting pre-treatment followed by leaching in water. In holistic processing, the leach residue can then be further subjected to battery metal processing by state-of-the-art methods.

Energy transition under mineral constraints and recycling: A low-carbon supply peak

What are the implications of primary mineral constraints for the energy transition? Low-carbon energy production uses green capital, which requires primary minerals. We build on the seminal framework for the transition from a dirty to a clean energy in Golosov et al. (2014) to incorporate the role played by primary minerals and their potential recycling. We characterize the optimal paths of the energy transition under various mineral constraint scenarios. Mineral constraints limit the development of green energy in the long run: Low-carbon energy production eventually reaches a plateau. We run our simulations using copper as the limiting mineral and we allow for its full recycling. Even in the limiting case of a 100% recycling rate, after five to six decades green energy production is 50% lower than in the scenario with unlimited primary copper, and after 30 decades, GDP is 3–8% lower. In extension scenarios, we confirm that a longer life duration of green capital delays copper extraction and the green energy peak, whereas reduced recycling caps moves the peak in green energy production forward.

Direct Recycling of WC-Co Grinding Chip.

Grinding is a finishing process for high precision, high surface quality parts, and hard materials, including tool fabrication and sharpening. The recycling of grinding scraps, which often contain rare and costly materials such as tungsten carbide (WC-Co), has been established for decades. However, there is a growing need for more energy-efficient and environmentally friendly recycling processes. Currently, grinding sludges, which are a mixture of abrasives, lubricants, and hard metal chips, are only treated through chemical recycling. Direct recycling ("reuse" of chips as raw material) is the most effective but not yet viable process due to the presence of contaminants. This paper presents an oil-free dry grinding process that produces high-quality chips (i.e., oil-free and with few contaminants, smaller than 60 mesh particle size) that can be directly recycled, as opposed to the oil-based wet grinding that generates sludges, which require indirect recycling. The proposed alternative recycling method is validated experimentally using WC-Co chips from a leading hard metals' processing specialized company. The contaminant level (oxygen 0.8 wt.%, others < 0.4 wt.%), granulometry (chip D50 = 10.4 µm with grain size < 3 µm) and morphology of the recycled chips' powder is comparable to commercial powders proving the research and industrial potential of direct recycling. The comparison of sintered products using recycled and commercial powder provided equivalent characteristics for hardness (HRA of 90.7, HV30 of 1430), porosity grade (A02-04) and grain size (<3 µm).

Fresh and Mechanical Properties of High-Performance Self-Compacting Concrete Containing Ground Granulated Blast Furnace Slag and Polypropylene Fibres

The purpose of this study was to evaluate the appropriateness of polypropylene fibres (PP) to decrease the brittleness of high-performance self-compacting concrete (HPSCC). The influence of PP fibre content on the fresh and mechanical assets of PP-fibre-reinforced HPSCC was investigated. PP fibres were applied with 0, 0.025, 0.05, 0.075, 0.125, 0.25% contents to the HPC blends with high cement replacement by ground granulated blast furnace slag (GGBS). The impact of PP fibre fraction on fresh properties of HPSCC, counting passing capability as well as filling parameters is discussed. In addition, the mechanical properties, i.e., compressive, splitting tensile, and flexural strengths, were evaluated after 7 and 28 days of specimens’ maturation in water. The higher content of PP fibres gradually reduced the HPSCC workability and improved the mechanical properties. The high performance of fresh and hardened ecological HPSCCs containing 46% GGBS instead of cement with 0.025–0.25% PP fibre content proves the great potential of using these composites in various applications in the construction industry. The advantages of the potential recycling of GGBS include, among others, the reduced use of cement in a durable material, reduced amount of waste in landfill and lower emission levels of greenhouse gases.

Hydrochemistry, Sources and Management of Fracturing Flowback Fluid in Tight Sandstone Gasfield in Sulige Gasfield (China)

Hydraulic fracturing technologies have been frequently utilized in the oil and gas industry as exploration and development efforts have progressed, resulting in a significant increase in the extraction of natural gas and petroleum from low-permeability reservoirs. However, hydraulic fracturing requires a large amount of freshwater, and the process results in the production of large volumes of flowback water along with natural gas. In this study, three tight sandstone gas wells were fractured in the Sulige gasfield (China), and a total of 103 flowback fluid samples were collected. The hydrochemical characteristics, water quality and sources of hydrochemical components in the flowback fluid were discussed. The results show that the flowback fluid is characterized by high salinity (Total dissolved solids (TDS) up to 38,268mg/L, Cl- up to 24,000mg/L), high concentrations of metal ions (e.g., Fe, Sr2+, Ba2+) and high chemical oxygen demand (COD). The flowback fluid is a complex mixture of fracturing fluid and formation water, and its composition is impacted by water-rock interactions that occur during hydraulic fracturing. The major contaminants include COD, Fe, Ba2+, Cl-, Mn and pH, which constitute a high risk of environmental pollution. Meanwhile, chemical elements such as K, Ba and Sr are unusually enriched in the flowback fluid, which has an excellent potential for recycle of chemical elements. The Sulige gasfield's flowback fluid recovery methods and treatment scenarios were discussed, taking into consideration the pollution and resource characteristics of the flowback fluid. Options for dealing with the flowback fluid include deep well reinjection, reuse for making up fracturing fluid, recycling of chemical elements and diverse reuse of flowback water. This research offers guidance for managing the fracturing flowback fluid in unconventional oil and gas fields.

Recycling potential of MWCNTs/HDPE nanocomposite filament: 3D printing and mechanical characterization

Recycling potential of MWCNTs/HDPE nanocomposite filament: 3D printing and mechanical characterization

Sustainable Production of Emerging Diesel Additive from Butene by Palladium-Catalyzed Alkoxycarbonylation

Pentanoic esters are a new class of biofuels (additives) and are typically produced from biomass-derived levulinic acid/esters via hydrogenation-cyclization/ring-opening/hydrogenation three-step transformations. Here, a one-step and atom-economic alkoxycarbonylation route is developed to produce pentanoic esters from widely available 1-butene. Based on the screening of 21 monophosphine and 26 diphosphine ligands, a Pd/diphosphine ligand (bis(2-diphenylphosphinophenyl) ether, DPEphos) system gives 91% yield of linear and branched ethyl pentanoate (78/22 ratio) with a turnover number (TON) up to 26100 and demonstrates outstanding recycle potential. The apparent activation energy (Ea) of 1-butene alkoxycarbonylation in the presence of this catalytic system was estimated to be 89.4 kJ/mol via kinetic measurements. More importantly, homogeneously blending 10 vol % of the resultant esters in pure diesel can improve the low-temperature fluidity and pumpability of diesel and decrease the emission of exhaust pollutants of diesel without affecting the power performance of diesel engines. Compared with pure diesel, the CO, NOx, HC, and soot emission of blend diesel at 2500 rpm are reduced by 28%, 9%, 6%, and 42%, respectively. This work provides a promising route to produce high-performance fuel additive and simultaneously broadens the comprehensive utilization of C4 olefin.

In situ nanofibrillation of polypropylene/polyethylene/poly(ethylene terephthalate) ternary system: A strategy of upgrade recycling

Upgrade recycling of multicomponent polymer blends remains a great challenge due to the inherent immiscibility of most polymer combinations. Herein, we report a new and efficient strategy potential for upgrade recycling of polypropylene/polyethylene/poly(ethylene terephthalate) (PP/PE/PET) ternary system, through in situ nanofibrillation of PET with the aid of extrusion-hot stretching and further annealing stretching. PET fibrils with high aspect ratios are achieved in the ternary blends by extrusion-hot stretching, and adding compatibilizer and further annealing stretching reduce the average diameter of PET fibrils down to as low as 240 nm. The PET nanofibrils suppress the relaxation of orientated structure during the hot stretching progress, which increases the orientation factor of PP from 0.08 to 0.30. During further annealing stretching, the PP molecular chains are highly oriented under the extensional flow field and PE grows epitaxially on the oriented PP substrate regardless of the presence of PET nanofibrils, promoting the interfacial adhesion between PP and PE. The high orientation of PP and PE, the epitaxial crystalline structure and PET nanofibrils impart remarkably enhanced tensile strength (up to 481.2 MPa), elasticity modulus (up to 4.85 GPa) and elongation at break (up to 1004.9%) to the PP/PE/PET ternary blends. This work could provide significant guidance for the high-performance processing and upcycling of waste PP, PE and PET materials.

Revisiting the oldest manure of India, Kunapajala: Assessment of its animal waste recycling potential as a source of plant biostimulant

India's oldest documented manure, most commonly referred to as Kunapajala, has a long history of over 1,000 years in crop cultivation. Kunapajala is primarily an in-situ decomposition technology of animal waste and can potentially provide an eco-friendly pipeline for recycling bio-waste into essential plant nutrients. This traditional animal manure, in addition, also contains dairy excreta (e.g., feces and urine), dairy products (e.g., milk and ghee), natural resources (e.g., honey), broken seeds or grains, and their non-edible by-product waste. Here, we aimed to assess the waste recycling and plant biostimulant potential of Kunapajala prepared from livestock (e.g., Black Bengal goats) or fish (e.g., Bombay duck) post-processed wastes over different decomposition periods, e.g., (0, 30, 60, and 90-days). In this study, an in-situ quantification of livestock- (lKPJ) and fish-based Kunapajala (fKPJ) reveals a dynamic landscape of essential plant primary nutrients, e.g., (0.70 &amp;gt; NH4-N &amp;lt; 3.40 g•L−1), (100.00 &amp;gt; P2O5 &amp;lt; 620.00 mg•L−1), and (175.00 &amp;gt; K2O &amp;lt; 340.00 mg•L−1), including other physico-chemical attributes of Kunapajala. Using correlation statistics, we find that the plant-available nutrient content of Kunapajala depicts a significant (p &amp;lt; 0.0001) transformation over decomposition along with microbial dynamics, abundance, and diversities, delineating a microbial interface to animal waste decomposition and plant growth promotion. Importantly, this study also reports the indole 3-acetic acid (IAA) content (40.00 &amp;gt; IAA &amp;lt; 135.00 mg•L−1) in Kunapajala. Furthermore, the bacterial screening based on plant growth-promoting traits and their functional analyses elucidate the mechanism of the plant biostimulant potential of Kunapajala. This assay finally reports two best-performing plant growth-promoting bacteria (e.g., Pseudomonas chlororaphis and Bacillus subtilis) by the 16S ribotyping method. In support, in-planta experiments have demonstrated, in detail, the bio-stimulative effects of Kunapajala, including these two bacterial isolates alone or in combination, on seed germination, root-shoot length, and other important agronomic, physio-biochemical traits in rice. Together, our findings establish that Kunapajala can be recommended as a source of plant biostimulant to improve crop quality traits in rice. Overall, this work highlights Kunapajala, for the first time, as a promising low-cost microbial technology that can serve a dual function of animal waste recycling and plant nutrient recovery to promote sustainable intensification in agroecosystems.

Thermomechanical Analyses of Alkali-Treated Coconut Husk-Bagasse Fiber-Calcium Carbonate Hybrid Composites

Natural fiber-reinforced composites can contribute to reducing carbon footprint goals due to their ability to reduce overall product weight, bio-diverse feedstocks, and recyclability potential. In this work, natural fiber-based composites containing the reinforcement of coconut husk and bagasse fiber with calcium carbonate (CaCO3) ingredients were prepared and analyzed. The composites were analyzed for mechanical, thermomechanical, and morphological properties. The reinforcements were chemically functionalized using 5% w/v NaOH to enhance their interactions with the epoxy resins. The chemical functionalization created perforation on the fiber surface, improving the interlocking of fibres with the resin material and strengthening the mechanical performance of the composite. The composites developed using modified reinforcement treatment resulted in increased tensile strength (64.8%) and flexural strength (70%). The reinforcement treatment influenced the hydrophilicity, and the water absorption of treated composites was reduced more than five times compared to the unmodified composites. Scanning electron microscopy revealed morphological changes due to fiber modification, the underlaying mechanism of fiber contraction, and enhanced fiber matrix interface interlocking and adhesion strengthening. Thermal analysis confirmed that alkali treatment improves the crystallinity of the fiber and thereto the degradation temperature of treated fiber composites (both bagasse and coconut husk), which is 375.27 °C, the highest amongst the developed hybrid composites.

Environmental assessment of silicon kerf recycling and its benefits for applications in solar cells and Li-ion batteries

Silicon and its usage in photovoltaics and advanced Li-ion traction batteries is a key material for the decarbonisation of the energy and mobility sector. To achieve sustainable silicon-based products, an efficient raw material processing is required. However, the production of silicon and its purification is energy- and resource intensive. Further, during the production of photovoltaic cells, about 40% of the silicon used is lost as sawdust, the so-called silicon kerf, which is often not recycled to a high quality. Compared to primary production, silicon recycling requires less electrical energy and no fossil reductants. However, an environmental assessment of the GHG reduction potential of silicon kerf recycling in comparison to primary production of silicon is limited in literature.In this paper, we will provide a comprehensive environmental assessment of silicon kerf recycling located in Sichuan and Xinjiang in China and Germany, since China is the biggest producer of silicon worldwide. For the assessment of the recycling, a detailed process-specific material and energy flow balance based on industry and literature data is used. The results are evaluated with relation to the primary production of metallurgical silicon and a sensitivity analysis of used electricity mix and transport distance is performed. Results show that recycled metallurgical silicon from silicon kerf creates up to 77% lower GHG emissions compared to conventional primary silicon. Further, environmental hotspots are identified and discussed. Based on the findings, recommendations for target-oriented process engineering are given to further reduce the material-related GHG impacts of silicon based products. Finally, the impact of the results is reflected on the market potential of innovative products like photovoltaics and Li-ion batteries.

Prediction of scrap volume and recyclable resource potential of distributed photovoltaic power generation equipment in the Beijing-Tianjin-Hebei region

Prediction of scrap volume and recyclable resource potential of distributed photovoltaic power generation equipment in the Beijing-Tianjin-Hebei region

Catalytic routes towards polystyrene recycling.

Polystyrene (PS) is one of the most popular plastics due to its versatility, which renders it useful for a large variety of applications, including laboratory equipment, insulation and food packaging. However, its recycling is still a challenge, as both mechanical and chemical (thermal) recycling strategies are often cost-prohibitive in comparison to current disposal methods. Therefore, catalytic depolymerization of PS represents the best alternative to overcome these economical drawbacks, since the presence of a catalyst can improve product selectivity for chemical recycling and upcycling of PS. This minireview focuses on the catalytic processes for the production of styrene and other valuable aromatics from PS waste, and it aims to lay the ground for PS recyclability and long-term sustainable PS production.

Potential mediated electrochemical recycling and sensing of cadmium ions in wastewater over ZnO/SA-g-PPy biocomposite

Potentiometric sensing and electrochemical recycling of cadmium ions have been demonstrated over bio-nanocomposite film of zinc oxide, sodium alginate, and polypyrrole using a laboratory-designed electrochemical setup.