Search

With the current decreasing fossil resources and increasing carbon dioxide emissions, researchers are increasingly concerned about the development and utilization of biomass resources. The development of bio-based waterborne polyurethanes (BWPU) provides a new direction for the utilization of biomass resources and the protection of the environment. BWPU has attracted much attention from academia and industry due to their good physical and chemical properties, no volatile organic compounds (VOCs) emissions, exploitation of renewable substances, and structural design-ability. BWPU typically includes the polymerization of bio-based monomers, such as animal and vegetable oils, the addition of bio-based nanofillers, such as cellulose, lignin, and chitosan, and antimicrobial modifications, such silver nanoparticles and carvacrol, which can effectively replace traditional petroleum-based resources. At present, there are few reviews on the synthesis and applications of BWPU. Therefore, this paper reviews the recent progress in the synthesis of BWPU, and focuses on its applications in coatings, adhesives and antimicrobials, which is expected to provide reference and summarize research priorities and issues. [Display omitted] • Summarize bio-based waterborne polyurethanes (BWPU) recently produced from bio-based raw materials. • Summarize the current applications of BWPU, including coatings, adhesives and antimicrobials. • Suggestions are provided for further future research by BWPU in other areas. [ABSTRACT FROM AUTHOR]

A plasma-assisted surface modification method was introduced to enhance the interfacial adhesion of rubber composites reinforced with ultra-high molecular weight polyethylene (UHMWPE) fibers. First various reactive monomers were grafted onto the fiber surface via a plasma-assisted radical polymerization reaction. Subsequently, the grafted fibers underwent RFL (resorcinol-formaldehyde-latex) dipping process to bolster their interfacial adhesion with rubber. Compared with the original UHMWPE fibers, the modified fiber-reinforced rubber composites showed an increase in H pull-out force by 105.3 %–165.7 N and peel strength by 145.2 % to 10.3 N/mm, reaching the level of general-purpose fabric-core conveyor belt (≥4.5 N/mm). After the modification, the dynamic fatigue life and aging stability of the fiber-reinforced rubber composites were significantly improved, thereby enhancing the service life and safety of the composites. The results show that this method greatly improves the chemical activity, hydrophilicity, and surface roughness of UHMWPE fibers with minimal damage, rendering it a promising choice for industrial applications. [Display omitted] • A new strategy for UHMWPE fiber modification applicable to rubber matrix was provided. • A rubber material that can be quickly vulcanized at low temperatures for use in textile core conveyor belts was prepared. • The H pull-out force between the modified UHMWPE fiber and rubber reached 165 N, which reached the application level. • The interfacial bonding mechanism and chemical reaction processes between modified fibers and rubber are elucidated. [ABSTRACT FROM AUTHOR]

Highlights • The traditional VOF model was modified by considering the interphase drag force. • The surface of the liquid film is a wavy structure. • The liquid film presents a comprehensive flow pattern of film, rivulet and droplet. • In the severe pyrolysis region, the change in the bulk temperature is insignificant. • The apparent heat transfer coefficient at different temperatures were discussed. Abstract Falling film pyrolysis can improve the quality of pyrolysis products of waste plastics. The pyrolysis process of molten plastics is a complex process and the interphase force has an important influence on the flow and heat transfer process of the liquid film. Based on OpenFOAM® and considered the interphase drag force, the flow behaviors and heat transfer characteristics of the liquid film during the falling film pyrolysis of molten plastics were numerically simulated by VOF (Volume of Fluid) method. The results show that the surface of the liquid film is a wavy structure and the liquid film presents a comprehensive flow pattern of film, rivulet and droplet. With the increase of pyrolysis temperature, the length of liquid film and the average apparent heat transfer coefficient decrease, and the average thickness increases slightly. With the increase of the liquid film inlet velocity, the liquid film thickness and the average apparent heat transfer coefficient increase. [ABSTRACT FROM AUTHOR]

Ni was introduced to FeWO 4 self-supporting electrode via a spontaneous redox reaction to break the symmetry of the FeO 6 octahedron, which facilitated the reconstitution and promoted the OER intrinsic activity of Fe sites in tungstate, leading to ultralow overpotentials at high current densities and superior stability of 500 h. [Display omitted] Electronic structure manipulation with regard to active site coordination is an effective strategy to improve the electrocatalytic oxygen evolution reaction (OER) activity. Herein, we present the structure–activity relationship between oxygen-atom-mediated electron rearrangement and active site coordination asymmetry. Ni2+ ions are introduced to FeWO 4 on Ni foam (NF) via self-substitution to break the symmetry of the FeO 6 octahedron and regulate d -electron structure of Fe sites. Structural regulation optimizes the adsorption energy of hydroxyl on the Fe sites and promotes the partial formation of hydroxyl oxide with high OER activity on the tungstate surface. Fe 0.53 Ni 0.47 WO 4 /NF with the asymmetric FeO 6 octahedron of Fe sites can achieve an ultralow overpotential of 170 mV at 10 mA cm−2 and 240 mV at 1000 mA cm−2 with robust stability for 500 h at high current density under alkaline conditions. This research develops novel electrocatalysts with impressive OER performance and provides new insights into the design of highly active catalytic systems. [ABSTRACT FROM AUTHOR]

Pyrolysis has been examined as an attractive alternative to incineration for municipal solid waste (MSW) disposal that allows energy and resource recovery; however, it has seldom been applied independently with the output of pyrolysis products as end products. This review addresses the state-of-the-art of MSW pyrolysis in regards to its technologies and reactors, products and environmental impacts. In this review, first, the influence of important operating parameters such as final temperature, heating rate (HR) and residence time in the reaction zone on the pyrolysis behaviours and products is reviewed; then the pyrolysis technologies and reactors adopted in literatures and scale-up plants are evaluated. Third, the yields and main properties of the pyrolytic products from individual MSW components, refuse-derived fuel (RDF) made from MSW, and MSW are summarised. In the fourth section, in addition to emissions from pyrolysis processes, such as HCl, SO 2 and NH 3 , contaminants in the products, including PCDD/F and heavy metals, are also reviewed, and available measures for improving the environmental impacts of pyrolysis are surveyed. It can be concluded that the single pyrolysis process is an effective waste-to-energy convertor but is not a guaranteed clean solution for MSW disposal. Based on this information, the prospects of applying pyrolysis technologies to dealing with MSW are evaluated and suggested. [ABSTRACT FROM AUTHOR]

Pyrolysis has been examined as an attractive alternative to incineration for municipal solid waste (MSW) disposal that allows energy and resource recovery; however, it has seldom been applied independently with the output of pyrolysis products as end products. This review addresses the state-of-the-art of MSW pyrolysis in regards to its technologies and reactors, products and environmental impacts. In this review, first, the influence of important operating parameters such as final temperature, heating rate (HR) and residence time in the reaction zone on the pyrolysis behaviours and products is reviewed; then the pyrolysis technologies and reactors adopted in literatures and scale-up plants are evaluated. Third, the yields and main properties of the pyrolytic products from individual MSW components, refuse-derived fuel (RDF) made from MSW, and MSW are summarised. In the fourth section, in addition to emissions from pyrolysis processes, such as HCl, SO 2 and NH 3 , contaminants in the products, including PCDD/F and heavy metals, are also reviewed, and available measures for improving the environmental impacts of pyrolysis are surveyed. It can be concluded that the single pyrolysis process is an effective waste-to-energy convertor but is not a guaranteed clean solution for MSW disposal. Based on this information, the prospects of applying pyrolysis technologies to dealing with MSW are evaluated and suggested. [ABSTRACT FROM AUTHOR]

To solve the poor interface between aramid fiber and rubber, this paper studies a method of constructing nanostructures on the fiber surface. First, functional groups such as hydroxyl and amino groups were introduced onto aramid fiber through the Michael addition of tannic acid and polyethyleneimine. Then, the modified aramid fiber was impregnated in the aramid nanofiber/carbon nanotube aqueous dispersion to prepare a surface-coated fiber. The fibers and surface nanostructures were characterized by scanning electron microscopy, transmission electron microscope, Raman spectroscopy, X-ray photoelectron spectroscopy, thermalgravimetric analysis, and H pull-out tests in detail. The results show that the H pull-out force of the coated fiber is increased by 126.4% compared with the original aramid fiber, which is due to the good mechanical interlocking at the interface of the composites. In addition, carbon nanotubes could form a conductive path through mutual entanglement and overlap on the surface of aramid fiber, which also gives the function of real-time monitoring of deformation of the composites. [Display omitted] [ABSTRACT FROM AUTHOR]

According to the bionic strategy inspired by a "metal ions-induced poisoning behavior of biomolecules", a newly found glycine-based water-soluble polyacetylenes are elaborately designed and synthesized to simulate the transition on secondary structure in the presence of Cu2+ ions in aqueous solution. The "random coil to helical" conformation transition provided that the selective detection of new polyacetylene-type probe towards Cu2+ exhibited an outstanding time-efficiency and reliability with the corresponding detection limitation around 0.128 mg/L. [Display omitted] • Water-soluble substituted polyacetylene-type probe (P-Gly-NH 2) for Cu2+ detection was elaborately developed via a bionic strategy. • Cu2+selective detection was realized by the "random coil to helical" conformation transition of P-Gly-NH 2. • A specific and sensitive Cu2+ detection was swiftly achieved on the basis of UV–vis characterization. The interaction between heavy metal ions (e.g. Cu2+, Pb2+, Cr6+) and bioactive biomolecules can severely cause the "poisoning behavior" due to the secondary structure transition. While in a bioinspiration strategy, functional polymers with the ability of selectively responding to metal ions can be used as effective probe candidate for metal ion detection. Herein, a series of functional substituted polyacetylenes with glycine pendants (P-Gly-NH 2) are deliberately designed and synthesized as a fresh member of polymeric probe arsenal for selective ions recognition. According to chemical and structural characterization including FT-IR, NMR, GPC, UV–vis and so on, the synthesized P-Gly-NH 2 polymers with glycine amide pendants possess random coil conformation on the conjugated main chains. Benefit from remarkable water-soluble ability and secondary structure, P-Gly-NH 2 can simulate the biomolecules and apply for heavy metal ions detection in aqueous solution. Because of the complexing interaction with Cu2+, the particular "random coil to helical" conformation transition of P-Gly-NH 2 backbone can be observed by UV–vis characterization in ion recognition experiments. Moreover, the relevant results of ions interfering and titration experiments also confirm that this selective detection towards Cu2+ exhibits an outstanding time-efficiency and reliability with the corresponding detection limitation around 0.128 mg/L. As revealed in UV–vis, Raman, FT-IR and XPS spectra characterization, this conformation transition of P-Gly-NH 2 is owing to the complexing interaction between Cu2+ and nitrogen atoms in polymer side groups, resulting in an ordered cis -cisoidal helical structures in polymer backbones. In a word, this study not only paves a new way for design and synthesis of water-soluble amino acid-based substituted polyacetylenes, but also implements the functional polymeric probes for selective and sensitive detection of heave ions through a bioinspiration strategy. [ABSTRACT FROM AUTHOR]

Abstract: A study was undertaken to determine whether the performance of dry methane reforming could be affected by catalyst particle clusters in circulating fluidized bed reformers. Flow behavior and chemical reactions through a quiescent catalyst cluster were predicted. The distributions of gas temperature and concentrations of gas species were obtained using a simple two-dimensional model with Rh/Al2O3 catalyst particles. Numerical results show that the reforming reaction rate on catalyst particles in the cluster is much smaller than the rate on isolated catalyst particle in the stream. The molar ratio of H2/CO is increased due to catalyst particle clustering. The effects of gas temperature, inlet gas velocity and reactor pressure on reforming reactions are also investigated. [Copyright &y& Elsevier]

[Display omitted] • MSW pyro-gasification process with HTFG as heating source and gasifying agent. • Roles of CO 2 , H 2 O, and mixture of CO 2 /H 2 O/O 2 in HTFG were investigated. • Energy share in the gas products was approximately 75% for model flue gas supply. • The residue tar can be used to produce HTFG. • The interaction between the char gasification and volatile reforming was explored. With the implementation of municipal solid wastes (MSW) source segregation collection policy, the combustible waste components are suitable for pyrolysis treatment to recover value-added energy such as gas or oil. In this research, the volatile compounds from MSW pyrolysis were reformed by the char obtained from the same process and the high-temperature flue gas (HTFG) of 1200 °C was supplying as heating resource and gasifying agent in a tailor-made experimental set-up. The final yields and properties of the syngas, char, and oil after reforming were investigated. Experimental studies showed that the composition of HTFG had a significant influence on the products. As the HTFG being CO 2 and its flowrate increased from 0 to 4 L/min/(kg MSW), the energy share in the gas first increased from 8.29 to 15.1 MJ/(kg MSW) with a higher heat value (HHV) of 19.9 MJ/Nm3, then it decreased slightly with a further increase in the flowrate. However, as the HTFG was H 2 O or the model flue gas (consisting of CO 2 , H 2 O, O 2 and N 2), the higher flowrate always increased the energy share and cold gasification efficiency (CGE) in the gas products. Both CO 2 and H 2 O participated the volatiles' reforming reactions and enhanced char gasification; while the volatiles' reforming inhibited char gasification. When the flowrate of the model flue gas increased from 0 to 12.04 L/min/(kg MSW), the oil and char yields decreased and the CGE increased to more than 75%, which was much higher than that from direct air gasification of MSW; moreover, the gas products had much higher HHVs. This research provides a guidance for producing high-quality syngas from the MSW. [ABSTRACT FROM AUTHOR]

• A deacidification model was build considering the evaporation process of droplets. • The removal of SO 2 is inhibited by HCl during wet deacidification. • The content and distribution of deacidifier in the droplet were predicted. Deacidification is an indispensable process when cleaning the sludge incineration flue gas. To ensure the flue gas meets the emission standard, guarantee the long-term stable operation of the purification system, and provide theoretical basis for the combined operation of different deacidification methods in the future, a numerical simulation model based on the Euler-Lagrangian method is established to study the wet flue gas deacidification process by using the computational partical fluid dynamic software—Barracuda. The mass transfer process between gas phase and droplets is considered by using the two-film theory, and the effects of evaporation from droplets and vapor condensation in the flue gas during wet deacidification are considered. The model is verified by comparison with experiments, and the calculation results considering the evaporation and condensation process are closer to the experimental results. Besides, the competition mechanism of HCl and SO 2 during the deacidification process and the influence of different operation parameters on the deacidification efficiency are analyzed; the detailed distribution of different substances in the deacidification tower are obtained. The removal efficiency increases when stoichiometric ratio (SR), droplet velocity, and spray angle increased; the removal efficiency decreases when droplet size increased. The results have important guiding significance for the optimization and design of flue gas deacidification tower. [ABSTRACT FROM AUTHOR]

• A MSW pyrolysis database is established with 332 valid data points. • An artificial neural network model containing 10 hidden layers proposed. • Satisfactory coefficients of determination obtained for predicting pyrolysis products. • SHAP analysis revealed that ash content and temperature are most important inputs of the model. Pyrolysis is a promising method for recovering resources and energy products from municipal solid waste (MSW). Predicting MSW pyrolysis products is crucial for establishing an efficient pyrolysis system for resource recovery. In this study, a database was established based on MySQL to record relevant information on MSW pyrolysis, which includes the MSW ultimate analysis results, proximate analysis results, parameters of pyrolysis operation and yields of pyrolysis products, etc. Based on the database and with help of a deep artificial neural network (ANN) which contains 10 hidden layers, a prediction model was successfully established to predict the yield of char, liquid and gas products from MSW pyrolysis. The results showed that the coefficients of determination for predicting the yields of char, liquid and gas from the MSW pyrolysis are 0.841, 0.84, and 0.85, respectively; these values demonstrate an accuracy comparable to that achieved for product prediction from single biomass, indicating a successful model performance. The results also show that ash content and temperature are the most important input factors influencing the outputs, namely, yields of char, liquid and gas. The results of this study can help to achieve a more efficient design of the pyrolysis system and improve the recovery of the desired pyrolysis products. [ABSTRACT FROM AUTHOR]

The nature of Zn species and their roles in catalytic cracking of high-density polyethylene (HDPE) thermal decomposing vapor over Zn-promoted HZSM-5 (Zn/Z5) for aromatics were investigated. The Zn/Z5 zeolites were prepared using ion exchange and impregnation methods followed by H 2 reduction. Results indicated that hydrogen reduction of the Zn/Z5 significantly improved the aromatic yield. [ZnOH]+ and bridged Zn2+ species were critical species promoting BTX formation, with the former demonstrating higher activity. Besides, the synergistic effect between the Zn species and Brønsted acid sites on HZSM-5 boosts the aromatic yield. Incorporation of Zn was also found to promote long-chain scission. Among all the Zn/Z5, hydrogen reduced 2 wt% Zn/Z5 (SAR=25) is most effective in producing BTX, with a maximum yield of BTX (48%) and BTX selectivity (93%); hydrogen reduced 2 wt% Zn/Z5 (SAR=50) produced the highest yield of total aromatics (53%). [Display omitted] • First investigation on nature and roles of Zn species on HDPE aromatization. • [ZnOH]+ was found to have the greatest contribution in promoting aromatization. • Incoporation of Zn also promoted the cracking of long-chain intermediate. • H 2 treatment is vital to improving BTX yield by optimizing Zn species distribution. • A maximum of 53% aromatic yield and a 93% BTX selectivity were obtained. [ABSTRACT FROM AUTHOR]

Highlights • Mechanical properties of waste papers are closely correlated with devolatilization. • Start of devolatilization caused a sudden decrease in relative storage modulus ( E ′ r). • Kinetics of storage modulus change is investigated referring to activation energy. • E ′ r can be predicted with mass loss ratio and CO 2 emission. Abstract This article details a correlation study on early devolatilization behaviors (drying & volatile emission at 25–240 °C) and the change in mechanical properties (expressed by viscoelasticity) of four types of waste papers. The early stage of devolatilization was investigated using the TG-FTIR and mechanical properties using the dynamic mechanical analysis (DMA) method. The results show that the elastic and viscous mechanical properties showed obvious correlations with free and bound water evaporation and volatile emission. The storage modulus (E ′) and loss modulus (E ″) of the papers decreased as temperature increased and at the two important temperatures, namely 100 °C, the start of bound water evaporation, and 150 °C, the start of devolatilization in TG & DTG curves, E ′ showed extrema. Especially the relative storage modulus ( E ′ r) exhibited a sudden decrease at around 150 °C, where the activation energy of thermochemical conversion jumps from low values to high values, indicating the start of devolatilization. CO 2 is the major compound of the volatiles and it is well correlated with E ′ r in exponential function model and can be used as an index for predicting the E ′ r of the waste papers in their early devolatilization stage; while during the drying stage, mass loss ratio can be used to predict E ′ r of the waste papers. [ABSTRACT FROM AUTHOR]

The low quality municipal solid wastes (MSW) derived char has a potential to be used as a methanation catalyst to achieve low-cost methanation of the syngas derived from MSW, and its performance with varying reaction parameters should be explored for better application. In this study, a MSW char supported Ni-based catalyst (Ni-MSWC) was prepared by impregnation; the influences of CO 2 and CH 4 impurities in the raw syngas on methanation and the feasibility of conducting methanation in a low-pressure condition were investigated, then the catalyst's response to the changing parameters was identified. The results showed that the presence of low concentration CO 2 in the H 2 -rich syngas is favorable to the gasification of the char carrier and activates Ni-MSWC catalyst. However, it also promotes F–T synthesis reaction and leads to a decrease in the methane yield (Y CH4). The decrease in reaction pressure causes a decrease in Y CH4 and results in coke formation; but inhibits F–T synthesis reaction and increases methane selectivity (S CH4). A higher reaction pressure increases system complexity and accelerates char carrier consumption. Moreover, presence of methane by 2.8% (vol.) promotes the methanation of CO 2 through the methane dry reforming reaction, but it inevitably causes coke formation and affects the catalyst's stability. Based on Y CH4 and Ni-MSWC's responses, CO:CO 2 ≥ 3:2 and reaction pressure of 1 MPa (gauge pressure) are recommended, which help to inhibit the side reactions and maintain a high Y CH4 (>95%). [Display omitted] • Methanation performance of the syngas explored using the Ni-MSWC catalyst. • The ratio of CO/CO 2 in the syngas recommended to be not less than 3/2. • Lower CO 2 concentration in the syngas helps to activate the MSWC carrier. • 80% or more CH 4 yield from CO x obtained at atmospheric pressure. • The feeding CH 4 promotes the CO 2 conversion but causes carbon deposition. [ABSTRACT FROM AUTHOR]

In this research morphological techniques were used to characterize dechlorination process of PVC when it is in the mixed waste plastics and the two important factors influencing this process, namely, the proportion of PVC in the mixed plastics and heating rate adopted in the pyrolysis process were investigated. During the pyrolysis process for the mixed plastics containing PVC, the morphologic characteristics describing PVC dechlorination behaviors were obtained with help of a high-speed infrared camera and image processing tools. At the same time emission of hydrogen chloride (HCl) was detected to find out the start and termination of HCl release. The PVC contents in the mixed plastics varied from 0% to 12% in mass and the heating rate for PVC was changed from 10 to 60 °C/min. The morphologic parameters including “bubble ratio” (BR) and “pixel area” (PA) were found to have obvious features matching with PVC dechlorination process therefore can be used to characterize dechlorination of PVC alone and in the mixed plastics. It has been also found that shape of HCl emission curve is independent of PVC proportions in the mixed plastics, but shifts to right side with elevated heating rate; and all of which can be quantitatively reflected in morphologic parameters vs. temperature curves. [ABSTRACT FROM AUTHOR]

The reaction mechanism and the interfacial modulus gradient of the interfacial transition layer between the environmentally friendly dipping system (PAL) and the rubber have not been fully studied. In order to better understand the chemical structures and nano-mechanical properties of the interface between the dip layer and the rubber, we used advanced atomic force microscope (AFM) and nanoscale Fourier transform infrared spectroscopy (nano-FTIR) to perform detailed analysis in this article. The characterization of interfacial nano-mechanical properties and chemical structures is very significant for the illustration of interfacial adhesion mechanism. AFM can effectively characterize the detailed interfacial modulus gradient and the thickness of interface, while nano-FTIR can comprehensively measure the interfacial chemical structures and the distribution of chemical bonds. The results suggest that the thickness of the interface between the PAL dip layer and the rubber matrix is 175 nm, and the crosslinking density of the interfacial layer is high, which explains that the failure location of fiber/rubber composites after pull-out tests occurs on the side of the rubber matrix. Similarly, the microstructure of resorcinol-formaldehyde-latex (RFL) system was also characterized, and the preparation of RFL usually requires carcinogenic and toxic substances such as formaldehyde and resorcinol. [Display omitted] • The reaction mechanism and interfacial modulus gradient of the PAL and the rubber have been fully studied. • Nano-FTIR can measure the interfacial chemical structures and the distribution of chemical bonds. • The thickness of the interfacial transition layer between the PAL and the rubber is about 175 nm. [ABSTRACT FROM AUTHOR]

Pyrolysis, a promising method for extracting energy and value-added chemicals from municipal solid waste (MSW), encounters challenges associated with generation of inferior quality oil and low-quality char byproducts. In this context, this study proposed catalytic reforming of pyrolysis volatiles derived from MSW, using MSW char (MSWC) and modified MSWC-based catalysts to produce high-quality oil containing monocyclic aromatic hydrocarbons (MAH), alkanes and alkenes, and H 2 -rich gas products. Three groups of modified MSWC-based catalysts are prepared through the activation of MSWC with Na 2 CO 3 , Zn(NO 3) 2 ⋅6 H 2 O and ZnCl 2 for the reforming process. Experimental findings reveal that impregnating MSW with ZnCl 2 , specifically the ZnCl 2 /C-1:1 char from one-step pyrolysis, exhibits the most favorable catalytic performance, with a 47% selectivity of MAH in oil product, yielding > 25 wt% oil at 450 °C and a calorific value of 26.24 MJ/kg. Simultaneously, 44 wt% of MSW is converted into gas products with a 49 v/v% H 2 concentration for ZnCl 2 /C-1:2 catalyst. The Na 2 CO 3 -activated MSWC catalyst corresponds to the highest oil yields and achieves an alkane selectivity of 45.95 area% in the oil product, while Zn(NO 3) 2 -activated MSWC catalyst corresponds to the highest oxygen compounds in the oil product, thus with the lowest calorific value of 19.4 MJ/kg. These results highlight that varying catalyst modifications to MSW char can effectively improve the production of distinct oil compounds, with Zn[OH]+ species and higher Lewis-acid content in the catalyst exerting a positive influence on aromatic hydrocarbon production; and Na 2 CO 3 facilitating alkane production. This study thus provides valuable insights for upgrading oil product quality and increasing H 2 concentration in gas products, particularly at lower pyrolysis and reforming temperatures. • The effective catalysts for producing hydrocarbon oil contain Lewis-acid. • The ZnCl 2 /C-1:1 catalyst obtained the highest monocyclic aromatic hydrocarbons selectivity of 47%. • Three groups of char-based catalysts all improved H 2 concentration in the gas. • The ZnCl2/C-1:2 catalyst corresponds to H 2 content of 49% in gas product. [ABSTRACT FROM AUTHOR]

The lack of standardized products is a key hindrance to the widespread commercialization of municipal solid wastes (MSW) pyrolysis technology. In this paper, a cost-effective roadmap employing pyro-gasification and methanation processes is developed, with CH 4 -rich gas as the target product. In this roadmap, a two-stage catalytic conversion of "MSW → syngas → CH 4 -rich gas" was realized using MSW char, a by-product of the pyrolysis process as the catalyst/catalyst carrier. The results showed that, in the pyro-gasification stage, a syngas yield of 1.3 L/g MSW could be obtained at 800 °C and a steam-to-MSW mass ratio of 0.4, with a H 2 fraction reaching 56.6 vol%. The effective conversion of MSW to syngas was attributed to the superior catalytic activity of the MSW char. By comparing the catalytic activity and structural characteristics of the chars produced from various waste components, it could be determined that the high catalytic activity of the char required both active minerals derived from contaminated plastics and residue, and an appropriate proportion of carbon matrix from the biomass components in MSW. The gasified MSW char (G-MSWC), co-produced with the syngas, served as a carrier for the subsequent methanation catalyst. Due to the activation effect of steam during the syngas production stage, the pore structure of G-MSWC was improved and its defect density also increased. Consequently, G-MSWC demonstrated enhanced Ni–C interaction, facilitating the methanation activity. The final product from the methanation stage achieved a CH 4 concentration of 52.9 vol%, and a CH 4 yield of 11.25 mol/kg MSW. The above findings demonstrate the feasibility of the complete roadmap from MSW to CH 4 and provide valuable guidance for decentralized MSW management based on pyrolysis technology. [Display omitted] • A novel complete roadmap was developed to convert MSW into methane-rich gaseous fuel. • Wastes pyrolysis char as a catalyst for both syngas production and subsequent methanation. • Mixed MSW pyrolysis produced a more active char catalyst compared to any independent component. • Fuel gas with methane of up to 53 vol% was obtained from dry MSW at atmospheric pressure. [ABSTRACT FROM AUTHOR]

[Display omitted] • First study on pretreatment of Ga promoted zeolite on HDPE and PP aromatization. • H 2 -O 2 treatment maximized aromatic to 65% yield, with 90% BTEX selectivity. • BTEX yield of HDPE decreased with increasing pore size. • Ga promoted Hβ displayed 82% selectivity of ethylene and propene in gas. The effects of pretreatment and structure of zeolite on aromatization of high-density polyethylene (HDPE) and polypropylene (PP) over different Ga-promoted zeolites (HZSM-5, hierarchical HZSM-5, HY, Hβ, and USY) were investigated. Hydrogen reduction of Ga-promoted HZSM-5 resulted in a higher yield of alkenes during HDPE pyrolysis but did not lead to increased production of total aromatic hydrocarbons. The reduction and subsequent oxidation of Ga/Z5 led to the formation of GaO+ species with high dehydrogenation activity. This resulted in a remarkable 65% yield of aromatics, with a BTEX (benzene, toluene ethylbenzene and xylene) overall yield of 60% and a selectivity of 90% of the liquid product. Increasing the Ga loading decreased the BTEX yield due to pore blockage and a decrease in the amount of Brønsted acid sites. The BTEX yield over Ga-promoted zeolites was found to be strongly related to the pore size of the zeolite, whereas its yield over the parent zeolite was not strongly dependent on the pore size. Diffusion of the cracking intermediates was found to have a more significant impact on the aromatization of PP than HDPE. The highest BTEX yield for HDPE was achieved with Ga-promoted HZSM-5, while Ga-promoted hierarchical HZSM-5 exhibited the highest BTEX yield for PP. Furthermore, Ga(1)/Hβ-Redox demonstrated remarkable selectivity (90%) towards ethylene and propylene in the gas phase, surpassing other zeolites (37%-68%). [ABSTRACT FROM AUTHOR]

• Self-supplied steam reforming was investigated in a continuous system. • Designed continuous system permitted to produce high quality syngas continuously. • Sewage sludge char activated the steam to promote the yield of syngas. • Energy recovery efficiency analysis gave a suitable value for moisture content. A technology of sewage sludge (SS) pyrolysis coupled with self-supplied steam reforming of the volatile is developed to utilize the latent heat of the steam vapor released in the SS drying & pyrolysis process. An integrated reactor consisting of a vertical free-falling pyrolysis section and a horizontal screw-moved reforming section is designed for this purpose. The performance of the reactor shows that by changing the moving speed of the char in the reforming section, high quality syngas with an H 2 /CO ratio of 4.37 and a percentage of H 2 + CO up to 66.58 vol% can be obtained at approximately 570–600 °C for the dry SS. There is an optimum moving speed of the screw for producing the highest volume of the syngas. A higher moving speed of the screw also results in a higher concentration of the aromatic compounds in the final pyrolysis oil. When the initial moisture content of SS increases from 0 to 65.50%, the H 2 /CO ratio and H 2 /CO 2 ratio in the syngas increase from 4.37 to 30.87 and from 2.1 to 2.6 correspondingly, and the final oil yield decreases from 24.03 wt% to 14.16 wt%. Moreover, the total energy recovery efficiency decreases from 88.85% to 61.92%, while the energy portion of syngas shows a peak of 44.18% of the total energy input when the initial moisture content is 41.26%. The integrated reactor also provides a good opportunity for adding a catalyst such as dolomite to make the process more effective. The technology developed in this paper provides an approach to deal with SS with a relatively high moisture content. [ABSTRACT FROM AUTHOR]

• Volatiles/hot char interaction exploited for upgrading MSW pyrolysis products. • Impacts of temperature, C/V ratio and GHSV on products investigated. • Gas yield increased at higher interaction temperature and C/V ratio. • Syngas with H 2 /CO molar ratio of 2:1 obtained at 600 °C and C/V = 1.5. • Oil yield reduced and light aromatics (1–3 rings) constitute >60% of the oil. The gas and oil product derived from municipal solid waste (MSW) pyrolysis was upgraded by utilizing the interaction between the volatile compounds and the char and the mechanism involved is explored. The influences of operation parameters, including interaction temperature, char/volatiles mass ratio (C/V) and gas hourly space velocity (GHSV) of the volatiles on the distribution and property of the upgraded products were investigated. The results showed that the higher interaction temperature, higher C/V and lower GHSV favored the conversion of condensable volatiles into gas products, thus increasing the gas yield in the outlet stream. The highest gas yield (44.14 wt%) was obtained at 700 °C with the natural C/V ratio (0.8) and GHSV, which was twice of the gas yield in the volatiles. The chemical energy portion of gas increased to 8065 kJ/kg MSW from 3209 kJ/kg MSW at this condition. Syngas with H 2 /CO molar ratio of around 2 can be obtained at 700 °C with C/V ratio of 0.8 or at 600 °C with higher C/V ratios (C/V = 1.5–2.2). Oxygenates and acidity of the reformed oil products decreased; but monoaromatics and light polyaromatics concentration increased greatly. Heavy polycyclic aromatic hydrocarbons (PAHs) in the liquid products were degraded after volatiles/hot char interaction. Suitable conditions can be varied and recommended for obtaining different desired high-quality products based on this process. [ABSTRACT FROM AUTHOR]

Highlights • Interaction between De-NO and De-SO 2 in a PCDP reactor is investigated. • De-NO and De-SO 2 compete each other in a PCDP reactor with the former prevailing. • The interaction involves inter-reactions and competing reactions for active radicals. • The mechanism describing the interaction is proposed and verified. Abstract The interaction between De-NO and De-SO 2 from flue gas in a pulsed corona discharge plasma (PCDP) reactor was studied experimentally. A mechanism and kinetic scheme of De-NO and De-SO 2 inside the PCDP reactor has been proposed and verified by comparison of the simulated and experimental results. The dominant radicals and elementary reactions are confirmed through sensitivity analysis. It has been found that there is significant interaction between the De-NO and De-SO 2 processes in a PCDP reactor, and that the De-NO reactions prevail over the De-SO 2 ones. The interaction consists of competitive reactions between NO and SO 2 involving oxidative radicals, as well as interaction reactions between NO, SO 2 and their derivatives. Through sensitivity analysis it has been found that the most effective elemental reaction to De-NO is NO + HO 2 <=> OH + NO 2 and that the most helpful radical is HO 2. The most effective reaction for De-SO 2 is SO 2 + O <=> SO 3 and the most helpful radical is atomic O. The study reveals the interaction mechanism between De-NO and De-SO 2 in PCDP and provides a theoretical basis to improve the performance of simultaneous NO and SO 2 abatement in a PCDP reactor. [ABSTRACT FROM AUTHOR]

• Oroxylin A alleviates uterine fibrosis in mice with intrauterine adhesion. • The increased pyroptosis of macrophages is observed in intrauterine adhesion mice. • SIRT3 is targeted by Oroxylin A in inhibition of macrophage pyroptosis. • Oroxylin A inhibits macrophage pyroptosis via SIRT3-SOD2-ROS pathway. Intrauterine adhesion (IUA) is manifested by endometrial fibrosis and inflammation, which seriously affects female reproductive health. Macrophages are mainly inflammatory cells and have been reported to participate in the fibrosis of IUA. Oroxylin A (OA), a kind of flavonoid compounds, was showed to possess the inhibitory effects on inflammation and fibrosis. However, the role of OA in IUA remains unclear. In the present study, we found that OA effectively alleviated the level of inflammation and uterine fibrosis in IUA mice. OA also decreased the macrophage pyroptosis which increased in uteri of IUA mice. Pyroptosis is a programmed cell death accompanied by an inflammatory response. Moreover, OA repressed the mediators of pyroptosis including the expression of NOD-like receptor family pyrin domain containing 3 (NLRP3), caspase-1 and Gasdermin D (GSDMD) and the release of IL-1β, IL-18 and cleaved-caspase-1 in J774A.1 cells induced by LPS/ATP in vitro. Mechanistically, the alleviation of OA on uterine fibrosis is achieved by inhibiting macrophage pyroptosis via SIRT3-SOD2-ROS pathway. Our data indicate that OA may serve as an effective agent for the treatment of the endometrial fibrosis with IUA. [ABSTRACT FROM AUTHOR]

The effective disposal of municipal solid wastes (MSW) and its incineration-derived fly ash (IFA), which contains large amounts of heavy metals (HMs) and chlorine (Cl), is an urgent task. In this study, IFA was used to reform MSW pyrolysis volatiles within 500–800 °C. The changes of reformed pyrolysis products, the migration characteristics of HMs and Cl between IFA and pyrolysis products were investigated. The results indicated that the O- and Cl-containing compounds in pyrolysis oil tended to decrease, light hydrocarbons and its calorific value increased accordingly after reforming; more CH 4 and H 2 gases were produced concurrently. The increase in reforming temperature enhanced these trends. The IFA absorbed Cl from volatiles during reforming, which reduced HCl in the gas product. The toxicity equivalent (TEQ) of PCDD/Fs in IFA decreased dramatically from 0.47 μg/kg to 0.0055 μg/kg after reforming at 500 °C, and it decreased with increasing reforming temperature. Some of the HMs' concentrations in the used IFAs increased, but their leaching capacity all decreased significantly at 800 °C except for Cr. The used IFA at 800 °C (IFA-800) corresponded to the lowest HMs leaching concentrations and could meet the landfill requirements; while the used IFA at 500 °C (IFA-500) corresponded to the maximum carbon deposition of 14.63 wt%, providing the energy source for its melting. Therefore 800 °C was recommended for harmless disposal of IFA, and 500 °C was better for a further melting of IFA., The contamination of pyrolysis liquid caused by inorganic Cl-containing compounds at 500 and 800 °C with much lower levels than the original. This study showed the hazardous properties of IFA can be dampened after interacting with MSW pyrolysis volatiles within the tested temperature range, and provided a good chance for the simultaneous disposal of IFA and recovery of high-quality MSW pyrolysis products. [Display omitted] • IFA used to reform MSW pyrolysis volatiles and being stabilized simultaneously. • The reforming caused 5.20–14.65 wt% of carbon deposition on the used IFAs. • Cl transferred from volatiles to IFA after reforming, but PCDD/Fs in IFA decreased. • The HMs leaching capability of IFA-800 reduced dramatically except for Cr. • 800 °C recommended for IFA stabilization and 500 °C recommended for IFA melting. [ABSTRACT FROM AUTHOR]

[Display omitted] • Promotion effect of the char combustion on its ash melting investigated. • The carbon contained in the MSWC resulted in an earlier melting of the ash in it. • Kinetic parameters of the char combustion and the ash melting were obtained. • Simulation models for combustion and melting established and validated. • O 2 content in the combustion air is more important than carbon content in MSWC. The municipal solid wastes pyrolysis char (MSWC) is a mixture of carbon and ash. Its direct melting contributes to the harmless and most weight-reducing disposal of the municipal solid wastes (MSW). To investigate the impact of the MSWC's combustion on its ash melting, in this research direct MSWC melting was investigated, the apparent activation energies and pre-exponential factors of the char combustion and ash melting reactions were obtained experimentally; reaction models of the MSWC's combustion and its ash melting were established for MSWC in a crucible and for a single particle to investigate the important factors affecting the ash melting. Thermodynamic analysis results showed that the presence of carbon can reduce the ash melting temperature by approximately 40 °C. The apparent activation energies of combustion and ash melting were 148.06 kJ/mol and 878.79 kJ/mol, respectively; but the MSWC combustion rate was much faster than that of ash melting. The combustion heat promoted its ash melting in a crucible inside furnace. The simulation results for a single MSWC particle showed that both the combustion and ash melting processes can be promoted by increasing the surrounding temperature and O 2 concentration in combustion air; while the higher carbon content in the MSWC only slightly improved ash melting when supplying air for combustion. Moreover, a reduction in the MSWC's particle size can make the carbon combustion faster but does not contribute to higher ash melting ratio due to the increase in specific heat dissipation; and particle radius larger than 1.5 mm would result in incomplete combustion of MSWC. These findings can provide guidance for the application of the MSW pyrolysis and char melting technology. [ABSTRACT FROM AUTHOR]

Behavior of ignition and combustion of coal particle cluster under a quiescent condition was numerically simulated by solving balance equations of mass and enthalpy with combustion kinetic models of volatiles and char. Two-flame structure, one flame penetrating into the cluster and the other moving out of the cluster, was predicted during the combustion of coal particle cluster. Effects of radiative heat transfer, group number, ambient temperature, coal particle size, and oxygen concentration on ignition and combustion of coal particle clusters were also analyzed. Simulations indicated that the gas volume fraction of coal particle cluster increases with time after devolatilization. Gas velocity passing through the cluster surface varied significantly at volatile liberation. The ignition time delay was reduced with the increase of ambient temperature. The cluster devolatilization rate and char burning rate increased while the ignition time delay decreased with the increase of ambient oxygen concentration. [Copyright &y& Elsevier]

Chars from wastes/biomass pyrolysis are widely used as catalysts. But their catalytic mechanism is not clear enough. To explore the role of inorganics in char-based catalysts, in this research, chars from municipal solid wastes (MSW) and wheat straw (WS) were compared for their catalytic performances and structure changes in reforming volatiles from MSW and WS pyrolysis. Results showed that MSW char (ash: 43 wt%) was more active than WS char (ash: 16 wt%) in reforming both volatiles within 500–700 °C, which facilitated higher syngas yield. 74% of the metals existed as non-evaporable acid-soluble inorganics in MSW char, which favored the transformation of microcrystalline carbon into amorphous carbon by carbon gasification yet increased aromaticity of its carbon matrix; while 27% of metals in WS char were organically bound alkali and alkaline-earth metals (AAEMs), and aromaticity of its carbon lattice increased from 0.39 to 0.67 with increase in reforming temperature. Additionally, WS char was characterized with larger aromatic ring size after reforming temperatures. Rich acid-soluble inorganics in MSW char were found to be favorable to its high activity; while migration of AAEMs caused the lower activity of WS char. These findings will help to improve catalytic activity of char-based catalysts. [Display omitted] • Role of inorganics in different speciation in char-based catalysts explored. • MSW char with more inorganics showed better catalytic performance than porous WS char. • Acid-soluble inorganics hinder microcrystallization and enrich functional groups on the surface. • Migration of organically bound and water-soluble AAEMs led to larger aromatic ring size. [ABSTRACT FROM AUTHOR]