Toxic Gas Emissions Research Articles

Trends of sustainable recycling technology for lithium‐ion batteries: Metal recovery from conventional metallurgical processes to innovative direct recycling

AbstractThe remarkable market growth of lithium‐ion batteries (LIBs) for various applications has been witnessed in the past two decades. However, as a retirement wave of more and more LIBs approaches, the disposed end‐of‐life batteries represent a growing hazard to ecosystem and human health. Recycling valuable metals from those spent LIBs still remain challenging because the current conventional metallurgical recycling processes involve the emission of toxic gas and waste chemicals as well as intensive energy consumption. These processes are not considered as green recycling approaches that contradict with the principles of carbon neutrality and circular economy embraced by the world. Hence, implementing green and sustainable recycling technologies of spent LIBs, especially for cathode materials, is an urgent need. This review provides a comprehensive understanding and critical evaluation of traditional pyrometallurgy, hydrometallurgy, and state‐of‐the‐art direct recycling for recovering valuable metal materials from the spent LIB cathode. The fundamentals, methods, efficiencies, and feasibility of the three recycling approaches are also assessed. In addition, the recent progress for green innovation of hydrometallurgical and direct recycling processes as well as the potential research tendency for spent LIBs are discussed.

Analysis and optimization of interior permanent magnet synchronous motor for electric vehicle applications using ANSYS Motor-CAD

The Permanent Magnet Synchronous Motor (PMSM) has the capability to high torque to current ratio, high power to weight ratio, high efficiency and stability. Due to the above positive points, PMSM is extensively employed in recent variable speed AC drives, particularly in electric vehicle applications. The electric vehicle is convenient for the city traffic without toxic gas emissions with low noise. PMSM became at the top of AC motor types due to the positive features written in the previous lines. However, it has two major drawbacks i.e. high cost and small speed range but it can be controlled and exceed to the small speed range with some control methods. A radial flux inner rotor PMSM architecture for electric vehicle application is presented in the project. The Interior Permanent Magnet Synchronous Motor (IPMSM) of the electric vehicle Leaf model, which was first produced by Nissan company in 2012, will be analyzed with ANSYS Motor-CAD and then the analysis results will be compared with the theoretical results and finally will be optimized in the project. The paper will provide insights about various change of parameters and their effects to the other parameters.

Investigation of novel expandable polystyrene/alumina aerogel composite thermal insulation material

Expandable polystyrene (EPS) foam is one of the most commonly used building thermal insulation materials due to its low thermal conductivity, apparent density as well and low cost. However, its high flammability and the release of a large number of toxic gases during combustion hinder its application. In this paper, using EPS foam and alumina aerogel (Al2O3) as insulation components, epoxy resin (EP) as a binder, and expandable graphite (EG) and ammonium polyphosphate (APP) as composite flame-retardant, a novel organic-inorganic composite thermal insulation material (EPS-AEA) was designed and fabricated. Experiment results showed that adding Al2O3 to EPS could further reduce the thermal conductivity of the obtained composite, and improve its mechanical properties. The addition of EG and APP composite flame-retardant could markedly enhance flame-retardant performance. With the addition of 4.17% Al2O3, and 50% EG/APP (1/1 mass ratio), the obtained EPS-AEA-1/1 composite showed superior fire resistance (reaching UL-94 V-0 rating and limiting oxygen index (LOI of 40.6%), high thermal insulation (thermal conductivity of 0.0487 W/(m·K)and applicable mechanical properties. In addition, EPS-AEA had excellent anti-hygroscopic properties (moisture ab-desorption rate within 0.5%) and fairly low toxic gas emissions during combustion, indicating its potential in practical application.

Battery thermal safety management with form-stable and flame-retardant phase change materials

Phase change materials (PCMs), characterized by zero energy consumption and high energy storage density capability, have a wide range of applications. However, the development of organic PCM is restricted by their low thermal conductivity, easy leakage and high combustibility. In this study, we produced a composite phase change materials (CPCM) with both high thermal conductivity and flame-retardant effect for application in battery thermal safety management. We demonstrated that addition of a porous network structure of EG as a shaping support to increase PA's thermal conductivity, and incorporation of environmentally safe and non-toxic silica-based flame retardant (SiO2 sol) improved the flame retardant properties. The optimum mass ratio of the CPCM was obtained by comprehensive analysis of the shape and thermal stability, energy storage performance and thermal conductivity. It was also verified by cone calorimetry that the CPCM outperformed pure PA in several aspects: heat release, smoke release rate and emission of toxic gases. The cooling and thermal runaway experiment of the battery module showed that the addition of CPCM had a positive effect on absorption of battery heat and extending the time between the thermal runaway spread of battery modules (21 s increasing to 396 s), providing valuable time for the safe evacuation of people in the event of a runaway fire.

A new multifunctional flame-retardant coating for cotton fabric to enhance smoke suppression, and UV shielding properties

Turmeric powder (TP) is used in the textile industry as a colouring agent, but its impact on the flammability properties of textiles wasn’t investigated. In this work, new coatings containing TP and TP with melamine polyphosphate (MPP) were utilized to enhance the thermal stability, flame retardancy, colour strength (K/S), and UV-protection factor (UPF) of cotton fabric (CF). Flammability tests indicated that TP alone failed to prevent flame spread in the fabric, and it increased the emission of toxic gases, especially CO and CO2. In contrast, the MPP/TP coating was able to put an end to the spread of a flame in CF, and the samples achieved self-extinction. The value of the limiting oxygen index (LOI) of CF was 18.2%, and it enhanced in MPP/TP containing samples to be 37.8%. K/S and UPF values showed that MPP/TP coatings improved the K/S and UPF values of CF to 2.9 and 290, respectively. Additionally, they lowered the toxic gases produced during CF combustion and the maximum specific optical density (Dsmax) of CF. The new coatings improved the char residue production in treated samples at 750 °C compared to CF, according to the thermogravimetric analysis (TGA) data. Untreated and treated samples' mechanical and physical characteristics were measured and compared. Analysis of smoke toxic gases and inspection of char remained following the smoke density test revealed that MPP/TP coating enhanced the flame retardancy of CF in both the condensed and gas phases.

Surface engineering and functionalization of MoS2-based nanoarchitecture for constructing epoxy composites with excellent fire resistance and mechanical properties

To overcome the shortcomings of epoxy resins (EP) such as high flammability and emission of toxic gases, a MoS2-based nanoarchitecture (CeZrOx-MoS2@PDA) was designed and prepared through surface engineering and functionalization method. At 2 wt% incorporation, the nanoarchitectures were homogeneously dispersed in EP matrix, showing good conditions for the formation of strong labyrinth barrier effect. Concurrently, EP/CeZrOx-MoS2@PDA offered enhanced thermal stability with higher char residues and lower maximum weight loss rate (MLR) value. Furthermore, the peak heat release rate (PHRR), total heat release (THR) and smoke factor (SF) of EP/CeZrOx-MoS2@PDA were reduced by 35.5%, 29.1% and 54.5%, respectively, while the CO release rate and CO2 release rate were dropped significantly, which was associated with the strong labyrinth effect, good char-forming effect and beneficial free radical quenching effect of CeZrOx-MoS2@PDA nanoarchitecture. Moreover, the ternary nanoarchitecture also resulted in a 56.8% increase in the storage modulus of EP composites. Therefore, the CeZrOx-MoS2@PDA developed in this work contributed to the generation of high performance EP with excellent fire resistance and mechanical properties, providing a promising strategy for the design of superior EP composites.

Evaluating Fire Performance: An Experimental Comparison of Dovetail Massive Wooden Board Elements and Cross-Laminated Timber

The use of adhesives and metal connectors is vital in engineered wood product (EWP) composition. However, the utilization of adhesives poses sustainability and recyclability challenges due to the emission of toxic gases. Similarly, metal fasteners negatively impact the disposal, reusability, and recyclability of EWPs. An alternative solution that exclusively employs pure wood, known as dovetail massive wooden board elements (DMWBEs), eliminates the need for adhesives and metal fasteners. This paper presents an experimental comparative assessment of the fire/charring performance of DMWBEs and cross-laminated timber (CLT). Model-scale test specimens measuring 200 mm in thickness, 950 mm in width, and 950 mm in length were vertically tested according to EN 1363-1. The charring behavior of DMWBEs closely resembled that of solid timber, with only a slight increase in the charring rate. Charring primarily occurred in the third lamella layer out of five, with no observable flames or hot gases on the unexposed side. The dovetail detail effectively prevented char fall-off with the tested lamella thickness. CLT specimens exhibited a notable rise in the charring rate due to the fall-off of the first lamellae layer.

Biomass as a renewable energy source

Conventional energy sources such as fossil fuels, oil, coal and natural gas methane are non-renewable energy sources that were once considered primary energy sources and are depleted due to intensive use which has led to the escalation of the global energy crisis. In addition, the use of fossil fuels has a significant disadvantage in terms of the emission of toxic and harmful gases into the atmosphere that pollute the environment. An alternative to the use of fossil fuels is to obtain energy by processing biomass obtained in the process of photosynthesis and used as a raw material for bioenergy production. Biomass refers to non-fossilized biological material obtained from living or until recently living organisms and biodegradable organic or carbon-based material originating from plants, animals, plant materials and microorganisms. Bioenergy can be defined as a source of energy obtained from organic matter or biomass that is explicitly used for energy purposes. Bioenergy is the largest renewable energy source in the world, which still has a large share in the supply of renewable energy sources and accounts for 70% of the total supply of renewable energy sources. Today, bioenergy is the only form of energy that meets the criteria of a closed system, in terms of the creation of carbon dioxide and solid material products of combustion. Most of the carbon released in the form of carbon dioxide is absorbed by the next generation of plants through photosynthesis or through minerals from the soil. Therefore, biomass is becoming one of the key energy resources in the fight against global warming and depletion of fossil fuel reserves. It should be noted that the primary advantage of biomass as an energy source is not in its significant potential, but in renewability. Renewability is the essential advantage that biomass has over conventional, fossil fuels that are nonrenewable and therefore cannot be the basis for long-term planning of sustainable growth that implies rational use of energy. Biomass is not a source of energy in transition, as it is often presented, but a resource that is becoming increasingly important as a modern energy source. Therefore, this chapter provides a detailed overview of biomass as the world’s largest source of renewable energy, including definitions of biomass, a history of biomass use, and current bioenergy production from biomass. Data on theclassification/categorization of biomass and the main methods for the production of bioenergy from biomass, as well as the advantages and disadvantages of using biomass for bioenergy production, are presented. Emphasis is placed on the impact of biomass on the environment and biodiversity, as well as the most significant current challenges in the use of biomass for bioenergy production, including moisture content and density of biomass, its complexity and diversity, selection of optimal pre-treatment methods and biomass processing conditions and lack of biomass data, as well as challenges to the economic sustainability of bioenergy production from biomass and other environmental, economic and social challenges.

Insight into the Mechanism of Selective Catalytic Reduction of NO by CO over a Bimetallic IrRu/ZSM-5 Catalyst in the Absence/Presence of O2 by Isotopic C13O Tracing Methods.

The development of efficient catalysts for the selective catalytic reduction of NO by CO (CO-SCR) in the presence of O2 is highly desirable for controlling the emission of toxic gases from tailpipes. Here, a bimetallic IrRu/ZSM-5 catalyst was prepared for the selective catalytic reduction of NO by CO in the presence of O2 (5%) for the low-temperature treatment of exhaust gas. IrRu/ZSM-5 afforded 90% NOx conversion in the range of 225-250 °C and maintained 90% NOx conversion after 12 h of reaction. Ru addition inhibited agglomeration of the Ir particles during the reduction process and provided more active sites for NO adsorption. Isotopic C13O tracing and in situ diffuse reflectance infrared Fourier-transform spectroscopy experiments were used to elucidate the CO-SCR mechanism in the absence or presence of O2. NCO could easily form on the surface of catalysts in the absence of O2, whereas NCO formation has been inhibited owing to the quick consumption of CO in the presence of O2. Moreover, some byproducts such as N2O and NO2 are generated in the presence of O2. Finally, a possible mechanism for CO-SCR under different conditions was proposed based on in situ experiments and physicochemical analyses.

Flame resistant of birch plywood according to Main Ingredients of Fire retardant paint

This study aims to comparative analyze the flame resistant of birch plywood according to using fire retardant paints. As interest in eco-friendly environmental issues has recently increased, wood, an eco-friendly material, is being used when people choose materials for interior design and furniture. Since wood is easily combustible and susceptible to fire, it should be mainly treated with a flame-retardant material to make up for the vulnerability. Bromine-based and chlorine-based materials, a type of halogen-based system with good flame resistant, were used for flame retardant treatment but those substances can cause toxic and harmful gas emissions when a fire occurs. That’s why these have been still regulated by rules. Although research to solve such problems has been actively conducted to develop phosphorus compound-based materials, nitrogen compound-based materials, and boron compound-based materials as fire retardant paints by applying different numbers and amount of fire retardant paint depending on each type and characteristic of it, attempts to comparative analyze the performance of each fire retardant paint have been still insufficient. Therefore, in order to analyze how the effect of the flame resistant varies whenever the main components and theoretical application amount of each fire retardant paint are applied differently, this study intends to measure the char length and area of birch plywood according to standard of the Nation Fire Agency in Republic of Korea. In this experiment, we used three types of fire retardant paints, each containing ammonium polyphosphate, emulsion resin, and phosphorus-based mixture as main components. Each fire retardant paint was applied to the birch plywood in 150g/m2, 180g/m2, 180g/m2 based on the theoretical application amount. As a control, a non-flame-retardant treated specimen was added. Based on the experiment, the following conclusions were obtained. First, the after flame time and after glow time satisfied the flame resistant standard of the Nation Fire Agency of Republic Korea regardless of the fire retardant paint for each manufacturer. Second, the flame resistant according to the fire retardant paint of each manufacturer was tested. As a result, when ammonium polyphosphate-based fire retardant paint was treated on birch plywood, the value of char length and char area was the smallest, and the effect of flame resistant was clearly shown to be excellent. Third, one fact was confirmed based on the results of previous studies and this study. When two types of fire retardant paint containing a phosphorus-based mixture were treated on a birch plywood, the flame resistant was different according to the technology development of each manufacturer. Through this study, the effect of the flame resistant was different depending on the fire retardant paint of each manufacturer. In order to secure fire safety of indoor furniture using wood construction and wood in the future, it is necessary to select fire retardant paints with high flame resistant depending on the materials of each type. Also, it is judged that it is necessary to compare and analyze the flame resistant of each manufacturer's fire retardant paint for various tree species. Not only that, The results of this study are expected to be used as basic data for selecting fire retardant paints with high flame resistant for each tree species and used as basic data for the production of semi-non-combustible wood suitable for flame resistant standard of the Nation Fire Agency of Republic Korea in the future.

The effect of dietary Yucca schidigera extract supplementation on productive performance, egg quality, and gut health in laying hens with Clostridium perfringens and coccidia challenge

Yucca schidigera extract (YSE) is a green feed additive that is known to reduce toxic gas emissions and promote intestinal health in animal production. This study investigated the potential of dietary YSE supplementation to mitigate the negative effect of Clostridium perfringens and coccidia infection on productive performance and gut health in laying hens. A total of 48 Lohmann gray laying hens (35 wk of age) were randomly allotted to 1 of 2 groups (n=24) fed with either a basal diet or a YSE-supplemented diet for 45 d. From d 36 to 45, half of the hens in each group were orally administrated with Clostridium perfringens type A and coccidia. This challenge impaired productive performance and egg quality (P < 0.05), destroyed jejunal morphology and functions (P < 0.05), induced jejunal epithelial cell apoptosis (P < 0.05), and downregulated the antioxidant capacity and Nrf2 pathway expression of jejunal mucosa (P < 0.05) in laying hens. Supplementing YSE in the laying hen diet, to some extents, improved productive performance and egg quality (P < 0.05), and alleviated the effect of challenge on morphology, functions, cell apoptosis, and antioxidant capacity in the jejunum (P < 0.05). Overall, the results suggested that dietary YSE supplementation might mitigate the negative effects of Clostridium perfringens and coccidia infection on gut health, and thereby improve the productive performance and egg quality of laying hens, possibly through enhancing the antioxidant capacity of the jejunum.

Valorization of hazardous plastic wastes into value-added resources by catalytic pyrolysis-gasification: A review of techno-economic analysis

Plastic waste pollution has grown exponentially since the 1950s. This situation was exacerbated when the volume of personal protective equipment (PPE)-based plastic waste surged after the COVID-19 pandemic. Plastic waste management such as landfills and incineration have adverse effects on the environment and human health due to the leaching of hazardous chemicals and the emission of toxic gases. Modern solutions such as biodegradable plastics and green brick technology are expensive and not well developed to valorize the current accumulation of plastic waste. This has led to the emergence of thermal degradation processes, which is faster and more realistic to solve the PPE-based plastic waste buildup. Pyrolysis and gasification systems to valorize plastic waste into hydrocarbons and fuels are discussed and compared with examples respectively. Scoping review approach is employed to conduct this study. To further increase the value of the final product of plastic waste management, the integrated pyrolysis system to upcycle plastic waste to carbon nanomaterials (CNMs) and the factors affecting the production of non-condensable gases are critically reviewed. The importance of feedstock composition, catalyst type, pyrolysis operating condition (including gas condition and temperature profiles) based on various studies is discussed. The potential and limitation of an integrated pyrolysis system are assessed from kinetic analysis, economic analysis and life-cycle assessment. This review is expected to contribute to the industrial-scale development of sustainable upcycling of plastic waste and enhance the production of desirable gas components for CNM synthesis for environmental sustainability.

Harnessing the Capabilities of Microorganisms for the Valorisation of Coal Fly Ash Waste through Biometallurgy

Coal fly ash (CFA) is a highly versatile raw material that has the potential to yield multiple value-added products, including cenospheres, zeolites, carbon nanotubes, and fertiliser substrates. Despite its versatility, a majority of these components are often overlooked, and CFA is primarily used for construction. Conventional processing methods of CFA are known to pose significant environmental challenges, including the leaching of hazardous materials, emission of toxic gases, and the high energy consumption needed to extract the value-added components. Herein, we explore the potential of biometallurgical approaches as an eco-friendly alternative to conventional processing methods for the comprehensive utilisation of CFA. Our focus is on the application of different microorganisms to CFA, the domestication of microorganisms, preprocessing of CFA to facilitate effective biometallurgical processes, the use of bioreactors, and synthesis of nano silica particles. We also propose a novel method for extracting the value-added components from CFA using a preprocessing technique (i.e., washing cycle), combined with multiple interactions with biometallurgical processes. Adopting this approach, we not only enhance environmental stewardship but also improve the circular economic aspects of multi-component utilisation, while providing valuable insights for the development of sustainable techniques for utilising CFA.

Optimal Design and Performance Analysis of a Digitally Controlled Biogas Power Generation System Suitable for DC Microgrid

Renewable energy sources are gradually becoming an alternative to fossil fuel-based power sources. It helps in overcoming the energy crisis and minimizing the emission of toxic gases as well as ensuring a step towards achieving a carbon–neutral environment. For the uninterrupted supply of power in the area of the weak distribution of electricity, clean energy sources are proven to be a feasible solution for electrification. This work aims to design a unique concept of a biogas-fuelled power-generating system and analysis performance that can enhance renewable-based power generation. The optimization of the bio-power generation system has been carried out through the HOMER software. The power plant’s performance with a digital control system has been investigated in MATLAB at fully loaded conditions. The efficacy of the system has been validated experimentally on a hardware setup resulting in an increase in power generation efficiency of about 14%. A comparative experimental study has been presented to exhibit the benefit of the designed system over the conventional bio-power generation system like the minimization of power losses and reduced no of associated equipment as required in the conventional system. Besides that, the estimated cost of the design of the power plant and its payback period has also been investigated for a limited period of years. It has been revealed that the proposed design of the Biogas power plant and its performance is substantially efficient and can be recommended for utilization in a microgrid or any small-scale power generating system.

CONCENTRATED SOLAR THERMAL TECHNOLOGY FOR POWER GENERATION AND ITS CASE STUDIES

The dependence on conventional energy sources since the Industrial revolution has increased extensively, affecting our environment. Over-exploitation of natural resources has led to the increased global average temperature rise of approximately 2°C per year and the emission of toxic gases and byproducts that can cause health complications. Further, it can cause acid deposition due to the reaction between Nitrogen oxides and Sulphur dioxide mixing with water, Oxygen, and other chemicals in the air which affects architecture, crops, marine, and wildlife. Hence, there is an urgent need to transition from conventional sources like fossil fuels to renewable energy. Solar energy is of two types: Solar Photovoltaic (PV) where Photovoltaic cells (panels of semiconductor cells) are used to collect both direct and scattered rays and convert them into electricity and Solar Thermal Energy where the sun’s heat is captured. So our area of research involves CST technology and a detailed analysis and case study of India One Solar Thermal Power Plant located in Abu Road, Rajasthan, and PS10 located in Seville, Spain, and check its economic feasibility. There are benefits and drawbacks to CST technology. Even though India One and PS10 are noteworthy accomplishments in the field of renewable energy, there are still several issues with the technology that need to be resolved in order to make it a more viable and affordable choice.

Extensive Gaseous Emissions Reduction of Firewood-Fueled Low Power Fireplaces by a Gas Sensor Based Advanced Combustion Airflow Control System and Catalytic Post-Oxidation

In view of the tremendous emissions of toxic gases and particulate matter (PM) by low-power firewood-fueled fireplaces, there is an urgent need for effective measures to lower emissions to keep this renewable and economical source for private home heating available in the future. For this purpose, an advanced combustion air control system was developed and tested on a commercial fireplace (HKD7, Bunner GmbH, Eggenfelden, Germany), complemented with a commercial oxidation catalyst (EmTechEngineering GmbH, Leipzig, Germany) placed in the post-combustion zone. Combustion air stream control of the wood-log charge combustion was realized by five different control algorithms to describe all situations of combustion properly. These control algorithms are based on the signals of commercial sensors representing catalyst temperature (thermocouple), residual oxygen concentration (LSU 4.9, Bosch GmbH, Gerlingen, Germany) and CO/HC-content in the exhaust (LH-sensor, Lamtec Mess- und Regeltechnik für Feuerungen GmbH &amp; Co. KG, Walldorf (Germany)). The actual flows of the combustion air streams, as calculated for the primary and secondary combustion zone, are adjusted by motor-driven shutters and commercial air mass flow sensors (HFM7, Bosch GmbH, Gerlingen, Germany) in separate feedback control loops. For the first time, the residual CO/HC-content (CO, methane, formaldehyde, etc.) in the flue gas is in-situ monitored with a long-term stable AuPt/YSZ/Pt mixed potential high-temperature gas sensor, which allows continuous estimation of the flue gas quality with an accuracy of about ±10%. This parameter is not only an essential input for advanced combustion air stream control but also provides monitoring of the actual combustion quality and logging of this value over a whole heating period. By many firing experiments in the laboratory and by field tests over four months, it could be demonstrated that with this long-term stable and advanced automated firing system, depression of the gaseous emissions by about 90% related to manually operated fireplaces without catalyst could be achieved. In addition, preliminary investigations at a firing appliance complemented by an electrostatic precipitator yielded PM emission depression between 70% and 90%, depending on the firewood load.

Recovery of carbon from rice straw for production of high-value products by Chlorella sorokiniana TH01 through mixotrophic cultivation

Rice straw is an abundant agricultural by-product in Viet Nam. Rice straw mainly contains carbohydrate (e.g., hemicellulose and cellulose), an abundant carbon source for biological production of high-value products, which is being used for animal feeding, burning or disposal in most suburban and rural areas of Viet Nam. The treatment of rice straw by burning and/or disposal has caused environmental pollution due to emission of greenhouse gases (e.g., CO2, CH4), toxic gases (CO, SOx, NOx) and dust. It is critical to apply technological measures replacing the traditional method to sustainably treat the huge volume of rice straw. In this study, rice straw carbohydrate was transformed to sugar-rich hydrolysate via a different chemical and enzymatic treatment methods for cultivation of Chlorella sorokiniana TH01 to produce lutein, lipid and protein. Data showed that the combined treatment of NaOH/H2SO4/Enzyme resulted in the maximal glucose and xylose hydrolysis efficiency of 96.32% and 93.43%, respectively. C. sorokiniana TH01 displayed the best growth in the hydrolysate with initial sugar concentration of 15 g/L diluted in BG-11 medium, achieving the maximal biomass concentration of 6.5 g/L (biomass yield of 0.44 g DCW/g substrate). Lutein, lipid, carbohydrate and protein contents were determined as 7.2, 350, 220 and 260 mg/g biomass, respectively. The sugar utilization efficiency by C. sorokiniana TH01 was determined as 94.67%. C. sorokiniana TH01 exhibited a promising capability in recovery of carbon from rice straw for production of high-value multiple commercial products, keeping rice straw in a circular economy and finally reaching a carbon-neutral process.

Recycling Spent Lithium-Ion Batteries Using Waste Benzene-Containing Plastics: Synergetic Thermal Reduction and Benzene Decomposition.

Spent lithium-ion batteries (LIBs) and benzene-containing polymers (BCPs) are two major pollutants that cause serious environmental burdens. Herein, spent LIBs and BCPs are copyrolyzed in a sealed reactor to generate Li2CO3, metals, and/or metal oxides without emitting toxic benzene-based gases. The use of a closed reactor allows the sufficient reduction reaction between the BCP-derived polycyclic aromatic hydrocarbon (PAH) gases and lithium transition metal oxides, achieving the Li recovery efficiencies of 98.3, 99.9, and 97.5% for LiCoO2, LiMn2O4, and LiNi0.6Co0.2Mn0.2O2, respectively. More importantly, the thermal decomposition of PAHs (e.g., phenol and benzene) is further catalyzed by the in situ generated Co, Ni, and MnO2 particles, which forms metal/carbon composites and thus prevent the emissions of toxic gases. Overall, the copyrolysis in a closed system paves a green way to synergistically recycle spent LIBs and handle waste BCPs.

Excellent hydrocarbon tolerance of CeO2-WO3-SnO2 oxide catalyst for the NH3-SCR of NO

The tolerance of NH3-SCR catalysts towards hydrocarbon compounds (HCs) is very important for their practical application on diesel vehicles. In this study, the HC resistance of CeWSnOx, V2O5-WO3/TiO2 and Cu-SSZ-13 catalysts was systematically investigated using propene, toluene and n-pentane as model HCs. Experimental results suggested that the fresh and hydrothermally aged CeWSnOx showed much better HC tolerance than the Cu-SSZ-13 and V2O5-WO3/TiO2. This property mainly originated from the strong HC oxidation capacity of the CeWSnOx due to Sn introduction, which significantly inhibited side reactions, including the HC ammoxidation and the carbon deposition reactions. In contrast, an undesired HC ammoxidation reaction occurred at medium temperatures over the Cu-SSZ-13 and at medium-high temperatures over V2O5-WO3/TiO2, especially in the presence of propene, accompanied by the emission of toxic HCN gas. The high HC tolerance of CeWSnOx gives it promise for application on heavy-duty diesel after-treatment systems in the future, especially those with the SCR-on-DPF or cc-SCR configuration.

Recent advances in biogas production using various bio-waste’s and its potential application: An overview

With continuous increase in the global population, the energy consumption has increased tremendously which has primarily increased our dependence on fossil fuels, in tum causing great environmental problems. Depleting fossil fuels reserves and increased emission of toxic gases in our atmosphere is a big environmental hazard. Also in India, each year billions of dollars are spent for the import of these conventional fuels which further devaluates the currency there by causing a big setback to national economy.Biogas is an environment friendly fuel which has the capabilities to be used as fuel in future vehicles thereby, reducing the import of conventional fuels. The current biogas generation technologies available gives less yield in more days, with high percentage of impurities. The presence of incombustible gases such as CO2, H2S and water vapour reduces its calorific value and makes it difficult to transport and compress. Biogas with more than 90% methane can be obtained using processes like adsorption, absorption, cryogenic and membrane separation. Carbon emission between base CNG and purified biogas is the same.This review provides summary of biowaste materials like cattle dung, spoiled food, chicken manure, vegetable waste and rice husk. It has been seen that a substrate of Cow-Dung mixed with other biowastes like rice husk or vegetable peelings can satisfactorily achieve a yield hike of 44% under mesophilic(30–40 °C) condition with the pH of 4–7. Presence of certain catalyst like NaOH also positively affects the biogas generation. Biogas digesters fed with a substrate profile of 25% cow-dung and 75% food-waste give 80% higher yield within 10 days of loading with minimal impurities. Results of using this biogas mixed with CNG in engines is also elaborated.