This review on current US municipal solid waste-to-energy trends highlighted regional contrasts on technology adoption, unique challenges of each technology, commonly used decision support tools, and ...major operators. In US only 13% of MSW is used for energy recovery and 53% is landfilled. There are 86 WTE facilities that mostly use Mass-Burn and Refuse-Derived Fuel technologies and are concentrated in densely populated northeast (predominantly in New York) and the State of Florida. For the rest of the country most of the MSW ends up in landfills equipped with gas recovery, which is supplied to homes or used for electricity generation. However, there are many pilot and experimental systems based on advanced gasification and pyrolysis processes, which are viewed as potential technologies to respond to an issue of landfills nearing full capacity in various US states. These systems are viewed as “cleaner” (65% less toxic residue) than established mass burn technologies but not matured to commercialization due technical and cost hurdles. Operation and maintenance costs between $40-$100 per ton of MSW were reported for gasification systems. The heterogeneous nature of MSW, gas cleaning and air pollution controls are the main disadvantages. Key design and decision support tools used by the scientific community and major operators in US include: Techno-economic analysis, Life cycle sustainability assessment, and Reverse logistics modeling. A conclusion drawn from reviewed studies is that adoption of thermal WTE technologies in US could continue to increase, albeit slowly, in coastal and urban areas lacking suitable lands for new landfills.
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•Existing Mass-Burn Incinerators of the US face public opposition due air emissions.•Landfills with gas recovery remain dominant technology in Mid-West and West US.•US Energy companies are experimenting with Gasification and Pyrolysis of waste.•Plasma-arc gasification claim to reduce harmful pollutants but has challenges.•Techno-economic, Life cycle analysis & Reverse-Logistics modeling gauge challenges.
Lithium-ion batteries (LIBs) have attracted increasing attention for electrical energy storage applications in recent years due to their excellent electrochemical performance. The unprecedented ...growth trajectory in lithium-ion battery manufacturing perpetuated by the inception of electric vehicles (EV) results in a vast amount of spent LIBs reaching their end of life (EOL). From the perspective of resource circulation, procurement, and sustainability with an insight into the circular economy, an effective recycling system must be developed to recycle the spent LIBs. This paper provides a comprehensive overview of the current status of pyrometallurgical options for recycling spent LIBs. In particular, this study summarizes the thermal pretreatment methods used to recover the active cathode material and then discusses the developed extractive pyrometallurgical options for recycling spent LIBs. A summary is presented on some recent examples of laboratory and industrial-scale recycling processes to demonstrate the practical applications of pyrometallurgical options for recycling. Finally, the review sheds light on the battery recycling legislation, and challenges and future outlook for recycling LIBs are also discussed.
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•Current status on pyrometallurgical recycling of Li-ion batteries is presented.•The industrial pyrometallurgical recycling processes are reviewed.•The influence of legislation on recycling is summarized.•This review provides a rundown of limitations that will help to do further research.
Microplastics (MPs) derived from plastic wastes have attracted wide attention throughout the world due to the wide distribution, easy transition, and potential threats to organisms. This study ...proposes efficient Mg/Zn modified magnetic biochar adsorbents for microplastic removal. For polystyrene (PS) microspheres (1 µm, 100 mg/mL) in aqueous solution, the removal efficiencies of magnetic biochar (MBC), Mg modified magnetic biochar (Mg-MBC), and Zn modified magnetic biochar (Zn-MBC) were 94.81%, 98.75%, and 99.46%, respectively. It is supposed that the adsorption process was a result of electrostatic interaction and chemical bonding interaction between microplastics and biochar. The coexisting H2PO4- and organic matters in real water significantly affected the removal efficiency of Zn-MBC due to competitive adsorption effect. Microplastic degradation and adsorbent regeneration were accomplished by thermal treatment simultaneously. The degradation of adsorbed MPs was promoted by the catalytic active sites originated from Mg and Zn, releasing adsorption sites. Thermal regeneration maintained the adsorption capability. Even after five adsorption-pyrolysis cycles, MBC (95.02%), Mg-MBC (94.60%), and Zn-MBC (95.79%) showed high microplastic removal efficiency. Therefore, the low-cost, eco-friendly, and robust Mg/Zn-MBCs have promising potential for application in microplastic removal.
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•Mg/Zn-MBCs were prepared as adsorbents for microplastic removal.•The modification by Mg and Zn-MBC enhanced removal efficiency significantly.•Zn-MBC maintained stable adsorption performance in various conditions.•MBCs promoted MPs degradation by thermal treatment for adsorbents regeneration.•Recycled Zn-MBC showed the highest removal efficiency of reported adsorbents.
•Maximum specific capacitance of 68F g−1 at 5 mV s−1 was observed.•High porosity was achieved by controlled thermal annealing.•Outstanding electrosorption performance with a capacity of 36.9 mg g−1 ...was obtained.•High electrosorption capacity and low energy consumption were achieved using 6FDA-DMN-based CMS electrodes.
Capacitive deionization (CDI), apromisingprocessfor desalinatinglow-salinity water, is currently characterized by the prevalent use of activated carbon (AC) electrodes that exhibit somewhat suboptimal performance. One potential method for increasing the electrosorption capacity of an electrode involves boosting its porosity and conductivity by using conductive polymers or applying heat treatment to porous polymers. This study examines the performance of the capacitive deionization (CDI) process using a range of highly porous carbon molecular sieve (CMS) electrodes. These electrodes are derived from intrinsically microporous polyimide 4,4′-(hexa-fluoroisopropylidene) diphthalic-anhydride (6FDA)-3,3′ dimethyl-naphthidine (DMN) (6FDA-DMN) and prepared at temperatures of 600, 800, and 1000 °C. The electrodes that were produced exhibited a high Brunauer-Emmett-Teller (BET) surface area ranging from 574 to 729 m2g−1. Additionally, they displayed a symmetric cyclic voltammetry (CV) plot with a specific capacitance ranging from 17.75 to 67.91 Fg−1 at a scan rate of 5 mVs−1. The charge transfer resistance (Rct) values for the 6FDA-DMN-based CMS P1, P2, and P3 electrodes were measured to be 9.7 Ω, 1.2 Ω, and 0.9 Ω, respectively, in a 1 M NaCl solution. The CMS electrode, synthesized at a temperature of 800 °C (P2), exhibits exceptional electrosorption capabilities in a saline solution with a concentration of 600 mgL−1. It displays a remarkable capacity of 36.9 mgg−1 and a rate of 2 mgg−1min−1, surpassing the performance of activated carbons (ACs). This research establishes a pathway for optimizing the characteristics and performance of electrodes by thermal treatment. This research demonstrates for the first time the effect of thermal annealing on the CDI performance of CMS materials, which will aid in developing electrode materials for large-scale water desalination.
The richened reactive oxygen species (ROS) and their derived excessive inflammation at bone injured sites hinder osteogenesis of endosseous Ti‐based implants. Herein, anti‐oxidized polydopamine (PDA) ...is deposited on hydrothermal growth formed hydroxyapatite (HA) nanorods on Ti to form a core‐shell structural nanorod‐like array with HA as a core and PDA as an amorphous shell (PDA@HA), showing not only ROS scavenging ability but also near‐infrared (NIR) light derived photo‐thermal effects. PDA@HA suppresses inflammation based on its ROS scavenging ability to a certain extent, while periodic photo‐thermal treatment (PTT) at a mild temperature (41 ± 1 °C) further accelerates the transition of the macrophages (MΦs) adhered to PDA@HA from the pro‐inflammatory (M1) phenotype to the anti‐inflammatory (M2) phenotype in vitro and in vivo. Transcriptomic analysis reveals that the activation of the PI3K‐Akt1 signaling pathway is responsible for the periodic PTT induced acceleration of the M1‐to‐M2 transition of MΦs. Acting on mesenchymal stem cells (MSCs) with paracrine cytokines of M2 macrophages, PDA@HA with mild PTT greatly promote the osteogenetic functions of MSCs and thus osteogenesis. This work paves a way of employing mildly periodic PTT to induce a favorable immunomodulatory microenvironment for osteogenesis and provides insights into its underlying immunomodulation mechanism.
A core‐shell structural nanorod‐like array with hydroxyapatite as the core and polydopamine as the shell suppress the inflammation based on its reactive oxygen species scavenging ability, and the periodic photo‐thermal treatment at 41 ± 1 °C further accelerates the transition of the macrophages on the array towards the anti‐inflammatory M2 phenotype through activation of the PI3k‐Akt1 signaling pathway to facilitate osteogenesis.
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•Oyster shells (OS) and sewage sludge ash (SSA) co-incinerated produced P fertilizer.•Oxy-steam atmosphere and 7.5 % OS led to the highest P bioavailability (46.8 mg·g−1).•Oxy-steam ...atmosphere elevated P bioavailability and metal ecotoxicity of ash.•Oxy-steam atmosphere and 15% OS maximized Pbio and minimized metal contents of SSA.•Excessive OS addition increased leachable chromium form.
The study was aimed at the reutilization of oyster shells (OS) as a calcium-based additive to turn sewage sludge ash into phosphate fertilizer, employing the oxygen-enriched combustion technology. This process transformed all non-apatite inorganic phosphorus into apatite phosphorus with the incorporation of a 7.5% Ca-based additive. OS demonstrated comparable effectiveness to CaO in catalyzing this transformation in the oxygen-steam atmosphere. The amount of OS added and the atmosphere type significantly influenced the P bioavailability of sewage sludge ash. The oxygen-steam atmosphere, with its increased water vapor concentration, facilitated the decomposition of CaCO3 and initiated reactions with calcium phosphate to form hydroxyapatite, thus substantially enhancing P bioavailability. The oxygen-steam atmosphere increased not only metal volatilization but also the ecological toxicity of residual metals, particularly Pb, mainly in the form of F2. Excessive OS addition appeared to elevate the toxicity of Cr. Therefore, additional strategies for metal removal or passivation are needed to improve the safety of sewage sludge ash with high metal content.
Thermal modification of wood causes chemical changes that significantly affect the physical, mechanical and biological properties of wood; thus, it is essential to investigate these changes for ...better utilization of products. Fourier transform infrared spectroscopy and size exclusion chromatography were used for evaluation of chemical changes at thermal treatment of oak wood. Thermal modification was applied according to Thermowood process at the temperatures of 160, 180 and 210 °C, respectively. The results showed that hemicelluloses are less thermally stable than cellulose. Chains of polysaccharides split to shorter ones leading to a decrease of the degree of polymerization and an increase of polydispersity. At the highest temperature of the treatment (210 °C), also crosslinking reactions take place. At lower temperatures degradation reactions of lignin predominate, higher temperatures cause mainly condensation reactions and a molecular weight increase. Chemical changes in main components of thermally modified wood mainly affect its mechanical properties, which should be considered into account especially when designing various timber constructions.
The current environmental pollution and global warming may cause a serious ecological crisis. The conversion of renewable resources, especially from biomass could be a promising option to alleviate ...this crisis. Traditionally, carbon produced from petrochemicals and coal are typically using large amount of energy and produce substantial quantities of pollutants. There is a need to develop alternative and effective methods to synthesize carbon from renewable resources with high performance and minimal environmental impact. Biochar is a rich carbon material derived from plant-based biomass. Biochar is one of the most ideal materials in various applications by considering it is low thermal conductivity, high porosity, high surface area, renewability, high stability, high carbon content and bulk density. In this regard, biochar has been widely recognized as the suitable candidate for sustainable carbon material. Thus, in this review, recent progresses towards the applications of biochar-based materials in various applications, such as wastewater treatment, soil amendments, catalyst or catalyst precursors and energy storage, are summarized and discussed. The various sources of biomass, synthesis techniques, and the effects of various factors involved in the carbonization process to generate different physicochemical properties biochar from the biomass is elaborated. Also, this review is highlighting the characteristics of the biochar and the carbonization mechanisms of different synthesis technologies. This review shows the great potential of different applications of biochar, which is expected to simulate new development to promote the use of biochar materials to achieve a sustainable environment and circular bio-economy.
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•Discussed the biomass feedstock for biochar materials.•The relationship between factors, production technologies and the physicochemical properties of biochar.•The synthesis and preparation methods of biochar materials affect their applications.•The challenges covered to develop economically feasible biochar production technologies.
Graphene is an advanced carbon energy material due to its excellent properties. Reduction of graphene oxide (GO) is the most promising mass production route of graphene/reduced graphene oxide (rGO). ...To maintain graphene’s properties and avoid restacking of rGO sheets in bulk, the preparation of 3-dimensional porous graphene sponge via 2-dimensional rGO sheets is considered as a good strategy. This article presents a facile route to synthesize graphene sponge by thermal treating GO powder at low temperature of 250 °C under N2 atmosphere. The sponge possesses macroporous structure (5–200 nm in size) with BET specific surface area of 404 m2 g–1 and high conductivity. The photocatalytic H2 production activity of the rGO sponge with a sensitizer Eosin Y (EY) and cocatalyst Pt was investigated. The rGO sponge shows highly efficient dye-sensitized photocatalytic H2 evolution compared to that obtained via a chemical reduction method. The maximum apparent quantum yield (AQY) reaches up to 75.0% at 420 nm. The possible mechanisms are discussed. The synthesis method can be expanded to prepare other graphene-based materials.
•Salmonella was detected in 8.2% (71/870) raw cocoa bean samples.•Except for one sample, Salmonella contamination level ranged from 0.3 to 46 MPN/g.•A min. 5 log reduction at the CCP step in cocoa ...processing is considered adequate.
Salmonella in raw cocoa beans (n = 870) from main sourcing areas over nine months was analyzed. It was detected in 71 (ca. 8.2%) samples, with a contamination level of 0.3–46 MPN/g except for one sample (4.1 × 104 CFU/g). Using prevalence and concentration data as input, the impact of thermal treatment in cocoa processing on the risk estimate of acquiring salmonellosis by a random Belgian chocolate consumer was calculated by a quantitative microbiological risk assessment (QMRA) approach. A modular process risk model from raw cocoa beans to cocoa liquor up to a hypothetical final product (70–90% dark chocolate tablet) was set up to understand changes in Salmonella concentrations following the production process. Different thermal treatments during bean or nib steam, nib roasting, or liquor sterilization (achieving a 0–6 log reduction of Salmonella) were simulated. Based on the generic FAO/WHO Salmonella dose–response model and the chocolate consumption data in Belgium, salmonellosis risk per serving and cases per year at population level were estimated. When a 5 log reduction of Salmonella was achieved, the estimated mean risk per serving was 3.35 × 10−8 (95% CI: 3.27 × 10−10–1.59 × 10−7), and estimated salmonellosis cases per year (11.7 million population) was 88 (95% CI: <1–418). The estimated mean risk per serving was 3.35 × 10−9 (95% CI: 3.27 × 10−11–1.59 × 10−8), and the estimated salmonellosis cases per year was 9 (95% CI: <1–42), for a 6 log reduction. The current QMRA model solely considered Salmonella reduction in a single-step thermal treatment in the cocoa process. Inactivation obtained during other process steps (e.g. grinding) might occur but was not considered. As the purpose was to use QMRA as a tool to evaluate the log reduction in the cocoa processing, no postcontamination from the processing environment and ingredients was included. A minimum of 5 log reduction of Salmonella in the single-step thermal treatment of cocoa process was considered to be adequate.
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