查看更多>>摘要：The recycling and utilization of CO2 is gaining interest in the fight against global warming. Considering CO2 not as a waste or a pollutant but as an opportunity is a concept that could prove promising for producing clean fuels in the future, as well as for producing chemicals, plastics and building materials. The extent of the benefits of Carbon Capture and Utilization (CCU) is still uncertain due to its many interactions with the rest of the energy system, and several energy models are trying to explore this area. As the global climate issue becomes an urgent policy priority, the scientific community is helping decision-makers choose the optimal technologies to successfully meet climate targets and decarbonize society. This paper reviews energy models that represent CCU as a decarbonization solution in an effort to understand and identify knowledge and modeling gaps. The results first show that CO2 utilization is still poorly represented, and that when it is, it is rarely fully integrated. The conversion of CO2 into fuels or chemicals is by far the most modeled of all the options CCU encompasses, while other key technologies for the decarbonization of the industry sector are barely considered. We discuss current CCU modeling methods and provide recommendations for future modelers who want to implement this set of technologies in their models. Additionally, we discuss the socioeconomic drivers and barriers that could support or discourage the deployment of CCU in the future energy mix.
查看更多>>摘要：This study examines the efficacy of phenolic compounds derived from plant-based sources on hindering the progress of sulfur crystallization in the bulk of bitumen. This in turn helps retain bitumen's thermo-mechanical properties over time. A mechanism that causes gradual time-dependent changes in bitumen's thermo-mechanical properties is a progressive structuring of the amorphous sulfur to form dendritic structures giving rise to sulfur crystallization. Sulfur crystallization in bituminous composites is implicated in premature crack initiation under thermal and mechanical loads, reducing the service life of bituminous composites used in roads, airports, bridge decks, and roofs. Therefore, there is a need to control sulfur crystallization in bitumen bulk. This is even more urgent since due to the recent strict limit on the allowable sulfur content of marine fuels, refineries are shifting the sulfur from fuel to bitumen leading to production of high sulfur bitumen. Here, we hypothesize that phenolic compounds can hinder sulfur crystallization, which occurs over time and alters bitumen's thermo-mechanical properties. Our laboratory characterization showed that high-sulfur bitumen modified with bio-oil derived from wood pellet had the least property change during a period of 60 days observation. Our study of molecular level interactions showed that the predominant phenolic compounds in wood pellet oil have the capability to neutralize polysulfide radicals due to their excellent capability for hydrogen donation and electron delocalization within their phenoxyl radicals. Moreover, the radical scavenging of polysulfide by the produced phenoxyl radicals is energetically favorable. Therefore, the high efficacy of wood pellet can be attributed to its high concentration of phenolic compounds hindering the formation of sulfur dendritic structures and crystallization. Accordingly, the study outcomes show the feasibility of controlling the thermo-mechanical properties of highsulfur bitumen by hindering sulfur crystallization using phenolic compounds. A proper design and engineering of sulfur-extended bitumen informed by chemistry of bitumen's constituents contributes to resource conservation and sustainability in construction. For Table of Contents Only: Incorporation of phenol-rich bio-oils derived from wood-based biomass in the hindering sulfur self-assembly in sulfur-extended bitumen by neutralizing polysulfide radicals.
Bhambhani, Anuragvan der Hoek, Jan PeterKapelan, Zoran
11页
查看更多>>摘要：Resource recovery solutions are an essential part of a sustainable water sector. Sustainability of these solutions needs to be analysed to assess, compare and optimize them. Life Cycle Sustainability Assessment (LCSA) is the most commonly used framework for sustainability assessment. This review paper discusses three critical characteristics of water sector resource recovery solutions: (i) their potential to actively benefit natural processes through reciprocal services, (ii) their dependence upon natural resources and processes, and (iii) their goal to avoid transgression of environmental thresholds. We analyse these three characteristics in the context of the following features of LCSA: (i) it being a damage assessment-based framework, (ii) its treatment of economic and natural capital as substitutable and (iii) the absence of environmental thresholds and past emissions in its environmental assessment methodology. We use a real-life resource recovery case study from the Netherlands to evaluate and demonstrate the mentioned features of the existing LCSA framework. Our review indicates that, LCSA can be modified for application to resource recovery solutions if it includes reciprocity towards nature as an essential component, limits compensations between economic welfare and environmental damage, and incorporates environmental thresholds and past emissions.
查看更多>>摘要：The dual need to remove CO2 from our emissions and treat alkaline industrial residues such as ash materials motivate the design of innovative pathways to simultaneously capture and convert CO2 into mineralized carbonates. Direct carbon mineralization is one approach that addresses the need to simultaneously treat alkaline industrial residues and mineralize CO2 emissions. Low CO2 solubility in water and slow kinetics at ambient temperature have challenged the direct carbon mineralization of alkaline industrial residues. To address these challenges, the use of CO2 capture solvents that enhance CO2 solubility and facilitate accelerated carbon mineralization of fly ash at temperatures below 90 C is investigated. Calcium carbonate formation results in the inherent regeneration of the solvent. The carbon mineralization extents of non-calcium carbonate content in fly ash were 50% and 51% and in waste ash were 58% and 62% in 2.5 M sodium glycinate and 30 wt% MEA solutions, respectively. The experiments were performed at 50 C for 3 h with CO2 partial pressure of 1 atm in a continuously stirred slurry environment with 15 wt.% solid. Furthermore, nanoscale CaCO3 is successfully synthesized from dissolved calcium using CO2-loaded sodium glycinate and surfactants such as CTAB (Cetyl Trimethyl Ammonium Bromide). Surfactants such as CTAB bind to the calcium carbonate surface and regulate the growth of calcium carbonate particles. These innovative approaches demonstrate the feasibility of directly storing CO2 in fly ash and waste ash as calcium carbonate and producing nanoscale calcium carbonate using regenerable CO2 capture solvents.
查看更多>>摘要：The recycling for reproduced carbon fibers (rCFs) attracts more interests in the industrial community of green manufacturing and the academic field of function-enhanced composites. To sufficiently exert the potentials and extend the application life cycle of rCFs, here we propose a technology of electric field induced manipulation to achieve the operational stages of recovery and reutilization for short-chopped carbon fibers (SCCFs) under the same configuration. Considering the electric property of SCCFs and expected functional objectives, the multimaterial receiving anode comprised of polar dielectric layer and metal plate was originally designed. Performance characteristics of steady-state and step-rising electrical excitations were investigated for respective operational stages, and dynamic behaviors on the recycling state of SCCFs were observed by experiments. Accordingly, the working principle of this novel approach was preliminarily discussed. The results show that a large scale of SCCFs would experience the state manipulations of dispersion and collection based on electrostatic induction, and directed transport driven by dielectric polarization. This study suggests a pollution-free and lowcost method with high-efficiency to recycle rCFs, and further has broad application prospects in the preparation of resin-based function-enhanced composites and disposing conductive tiny objects.
查看更多>>摘要：Photovoltaic (PV) power generation systems are expected to play an indispensable role in the future power supply towards the carbon-neutrality target in China. However, without appropriate practices and systems being set up for recycling, recovering, and reusing, tremendous waste materials would occupy land space and pollute environment, posing threats to human health. Effective management of End-of-Life (EoL) PV modules serves a critical part for sustainable development of solar PV power. Here, we developed a complex network model considering incomplete and imperfect information to simulate its scheme and policies for PV module recycling. Three types of recycling modes and three policy scenarios were simulated and analyzed, and sensitivity analyses of risk levels, PV manufacturing and recycling costs are conducted for the robustness test. Based on the current status of recycling technology, the policy of mandatory recycling will impose additional costs and negatively impact the PV system adoption, while the subsidy policies can partially offset such negative impacts. Subsidies targeted at either recycled capacity of PV modules or electricity generated from PV power during its life time show similar effects. In addition, the subsidy policies also bring benefits in enhancing the robustness of the whole PV market. The fluctuation caused by unsystematic risks including project relocation, uncertainties in land contracts, PV module replacement, etc., will also be smoothed.
查看更多>>摘要：Life cycle analysis (LCA) is a powerful method for assessing the net environmental impacts of a product, as well as improving the design or use of the product to minimize these impacts. Lithium-ion batteries are widely used in small-scale portable electronics including cellular phones and tablets, most often without the benefit of thermal regulation to improve performance or extend the battery cycle life. This work explores the potential benefits of active cooling on lithium-ion battery life cycle environmental impacts (resource extraction, manufacturing and use phases) using a streamlined LCA approach that couples first principles electrochemical modeling and dynamical systems modeling with traditional battery life cycle assessment methodology. Six impact categories-global warming potential, energy use, PM2.5, PM10, nitrogen oxides, and sulfur oxides-are evaluated for lithium cobalt oxide-graphite (LCO-C) batteries in a cellular phone design with and without active cooling. Active cooling of LCO-C batteries provides substantial benefits when coupled with cell designs employing thicker electrodes. The results indicate that active cooling using a simple fan design and 55.4 mu m cathode thickness can reduce environmental impacts by 5% to > 30% depending on battery discharge rate and ambient temperature. With 75 mu m cathode thickness and 3C discharge rate, nearly 45% reduction in environmental impacts is pre-dicted with active cooling across all impact categories. Life cycle environmental impacts are reduced as active cooling helps maintain a high battery cycle life even with high fractions of active components in the battery.
查看更多>>摘要：The rapid development of advanced technologies has increased the demand for critical elements, such as Mn, Co, and Ni. A systematic study was conducted to develop a process for producing high-purity Mn, Co, and Ni products from an acid mine drainage (AMD). As major contaminants, Fe and Al in the solution were sequentially precipitated and eliminated by elevating the pH to around 4.00 and 6.50, respectively. After that, a pre-concentrated slurry containing 3,794 mg/L Mn, 59 mg/L Co, 127 mg/L Ni, and 300 mg/L Zn was obtained by collecting the precipitates formed in the pH range of 6.50 to 10.00. The pH of the pre-concentrated slurry was decreased to around 5.00 by adding HCl to re-dissolve Co, Ni, and Zn for further purification. At this pH, greater than 50% of Mn remained undissolved, and filtration of the undissolved material resulted in a product with around 30 wt.% Mn. Sodium sulfide was added into the re-dissolved solution to selectively precipitate Co, Ni, and Zn while remaining Mn in the solution. Almost 100% of Co, Ni, and Zn but only around 15% of Mn were precipitated using a sulfur to metal molar ratio of 1 at pH 4.00. The sulfide precipitate was calcined at 200 degrees C for 2 h and then completely dissolved in 1.2 M HCl. The critical elements existing in the dissolved solution were efficiently separated using a two-stage solvent extraction process. Ultimately, Co and Ni products with almost 94% and 100% purity were obtained by sulfide and alkaline precipitation, respectively.
查看更多>>摘要：Urban mining is regarded as an important strategy to replace primary raw materials in the building sector. This study presents a bottom-up dynamic building stock model to explore the potential of urban mining to reduce primary material consumption and greenhouse gas (GHG) emissions in the residential building sector of the Netherlands. The model builds upon geo-referenced individual buildings, making it possible to analyze the spatiotemporal pattern of material supply from demolition and material demand for construction and renovation. The main results can be summarized as three points. (1) Urban mining cannot meet future material demand due to the new construction caused by population increase and its limited ability to supply the required kinds and amounts of materials. Therefore, large amounts of primary materials still have to be consumed in the future. (2) The generation of demolition wastes and the requirement for materials will be mainly concentrated in the big cities (e.g. Amsterdam, Rotterdam, and The Hague). (3) The GHG emission reduction potential of urban mining is very small and is not as large as the transition to a greener electricity mix. Recycling together with a greener electricity mix would reduce annual GHG emissions by about 40% in 2050 compared to 2020. This study provides a tool to link future material inflows and outflows in space and time. It further helps to assess the performance of strategies aimed at closing the material loops and reducing GHG emissions in the building sector.
查看更多>>摘要：While aquaculture is critical to global food and nutrition security, the fast development of aquaculture pro-duction systems has recently increased concerns about resource overexploitation and associated environmental impacts. Understanding how sustainable is current global aquaculture practice is important given its potential impacts on key sustainable development goals (SDGs). Here, for the first time, we developed a food-energy-water-carbon (FEWC) composite sustainability index (0-100) to assess the sustainability of global aquaculture across countries. Results indicate that the overall sustainability of global aquaculture is low (average score = 26) with none achieving a high sustainability score (75-100) and almost all practicing aquaculture in a relatively low sustainable way (0-50). Considering the sub-sustainability at a sector level, 80% of countries had at least two sectors among FEWC falling into the low sustainable zone (score less than 25). Regarding the environmental impacts, global aquaculture production accounted for approximately 1765.2 x 10(3) TJ energy use, 122.6 km(3) water consumption, and 261.3 million tonnes of greenhouse gas emissions in 2018. China led all countries by contributing to more than half of global aquaculture water consumption and greenhouse gas emissions, followed by India and Indonesia. This study highlights the significance of cross-sectoral management and policymaking to achieve global aquaculture sustainability.
NSTL
Elsevier