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Computational fluid dynamics (CFD) simulation of combustible solid waste (CSW) pyrolysis in a fluidized bed reactor with feeding rate of 5 kg/h was performed in this study. The multi-phase flow was simulated using the Euler-Euler method, and a multi-component and multi-step reaction method was adopted to describe the pyrolysis process of CSW. The user-defined functions (UDF) of heterogeneous reactions were programmed and coupled with the computational fluid dynamics (CFD) software. The simulation methods used were validated by comparing the simulated temperatures and product yields with the experimental results. Simulation results also indicated that the flow regime in the fluidized bed turned into stabilized fluidization gradually over pyrolysis time, and the mass flow rates of pyrolytic products at the outlet fluctuated within the range of ±10%. Pyrolysis temperature had the greatest effect on the product yield, while initial bed height had the most significant influence on product fluctuations. The CFD simulation results presented in this study provide valuable reference for the design and optimization of waste pyrolysis process. The average flow rates of pyrolysis products and their standard deviations over pyrolysis time. Unlabelled Image • The pyrolysis of combustible solid waste in a fluidized bed was simulated. • A multi-component model was used to present the raw material. • The multi-step pyrolysis model was adopted to describe the pyrolysis reactions. • The instantaneous flow regime and the mass flow rates of products were obtained. • The effects of parameters in the fluidized bed were also analyzed. [ABSTRACT FROM AUTHOR]

Based on the improved computational fluid dynamics and discrete element method (CFD-DEM), heat transfer and two-component flow of biomass and quartz sand have been studied from experiments and numerical simulation in this paper. During experiments, the particle temperature and moving images are respectively recorded by infrared thermal imager and high speed camera. With the increase of the velocity, the mixing index (MI) and the cooling rate of the particles are rising. Due to larger heat capacity and mass, the temperature of biomass drops slower than that of quartz sand. Fictitious element method is employed to solve the incompatibility of the traditional CFD-DEM where the cylindrical biomass are considered as an aggregation of numerous fictitious sphere particles arranged in certain sequence. By the comparison of data collected by infrared thermal imager and the simulated results, it can be concluded that experimental data is basically agreement with numerical simulation results. Directly affected by inflow air (25℃), the average temperature of particles in the bed height area (h >30 mm) is about 3 degrees lower than that of the other heights. When the superficial gas velocity is larger, the fluidization is good, and the gas temperature distribution is more uniform in the whole area. On the contrary, bubbles are not easy to produce and the fluidization is restricted at lower superficial gas velocity. Gas-solid heat transfer mainly exists under the bed height of 10 mm, and decreases rapidly on fluidized bed height. The mixing index (MI) is employed to quantitatively discuss the mixing effectiveness, which first rises accelerate, then rising speed decreases, finally tends to a upper limit. [ABSTRACT FROM AUTHOR]

• Mesoporous alkali metal oxide CeO 2 /γ-Al 2 O 3 was synthesized and used as catalyst. • Synthesized CeO 2 /γ-Al 2 O 3 and HZSM-5 were employed to form a dual catalytic stage. • Catalytic fast co-pyrolysis of bamboo sawdust and PE using a dual catalytic stage was conducted. • Catalyst to biomass ratio played a crucial role in the formation of hydrocarbon intermediates. • The additive effect of mono-aromatic hydrocarbons was favored with the increase of PE percentage. Fast co-pyrolysis of bamboo sawdust and waste plastic (linear low-density polyethylene, LLDPE) over a dual catalytic stage of synthesized CeO 2 /γ-Al 2 O 3 and HZSM-5 was conducted to enhance aromatic hydrocarbons production. Experimental results indicated that the catalyst to biomass (C/B) mass ratio played a determining role in the formation of hydrocarbon intermediates and a C/B mass ratio of 4 facilitated the production of aromatic hydrocarbons. Dual catalytic fast co-pyrolysis of bamboo sawdust and LLDPE using synthesized CeO 2 /γ-Al 2 O 3 and HZSM-5 increased the concentration of aromatic hydrocarbons and a CeO 2 /γ-Al 2 O 3 to HZSM-5 mass ratio of 1:3 maximized the target products. The content of aromatic hydrocarbons was increased at first and then decreased as the LLDPE percentage was elevated from 20% to 100% during the dual catalytic fast co-pyrolysis process, with the highest concentration obtained at 75% LLDPE percentage. In addition, the additive effect of monocyclic aromatic hydrocarbons was enhanced with the increasing of LLDPE percentage in the feedstock blends, and higher LLDPE proportion favored the production of xylenes, ethylbenzene, and alkylbenzenes as the additive effects were significantly promoted. [ABSTRACT FROM AUTHOR]

Abstract Phytoremediation is one of the most encouraging options for the elimination of heavy metals from contaminated soil. However, the treatment and exploitation of hazardous harvested hyperaccumulator biomass is a challenge recently. In this investigation, we propose a novel microwave-assisted chemical looping gasification (MACLG) process for the disposal of hyperaccumulator biomass, and syngas fuel production and trace element emissions from MACLG over hematite is evaluated. Experimental results show that the addition of hematite as oxygen carrier (OC) favors the production of H 2 and CO. The elevated operation temperature induces a decay in CO 2 yield and an increase in H 2 , CO and CH 4 yields. Meanwhile, a higher temperature causes an increased heavy metal percentage in syngas. On the other hand, the augmentation of steam flow and hematite content stimulates an uptrend for CO 2 and H 2 production and downtrend for CO generation. The percentage of each trace element in char after MACLG reduces with increasing steam flow, and its change in syngas presents the opposite trend. In addition, the proportions of trace elements in spent hematite and syngas tend to increase with an augmented hematite content whereas their portions in char reduce gradually. Moreover, our results suggest that activated carbon is capable of effective adsorption removal of heavy metals in syngas. Graphical abstract Unlabelled Image Highlights • Microwave-induced chemical looping gasification is developed. • Hyperaccumulator processing causes trace element emissions. • The use of hematite can improve syngas quality. • Heavy metal percentage in syngas rises with a higher temperature. [ABSTRACT FROM AUTHOR]

In order to minimize coke formation during microwave-assisted catalytic fast pyrolysis (MACFP) of poultry litter for bio-oil production, hierarchical ZSM-5/MCM-41 catalyst samples are synthesized and employed in this work, and the effect of NaOH concentration used during catalyst preparation on MACFP of poultry litter is investigated. The catalyst characterization results demonstrate that MCM-41 mesoporous structure is formed in hierarchical ZSM-5/MCM-41 catalyst as the outer shell layer coupled with ZSM-5 as the inside core. For product distribution, when the NaOH concentration increases from 1.5 to 3.0 mol/L, the coke yield decreases, the oil fraction yield first decreases and then increases, and the yields of water and gas first increase and then decrease. For chemical compositions in oil fraction, the relative contents of aliphatic hydrocarbons, aromatic hydrocarbons and oxygen-containing aromatic compounds first increase and then decrease, whereas the relative content of oxygen-containing aliphatic compounds first decrease and then increase. [ABSTRACT FROM AUTHOR]

Catalytic fast co-pyrolysis (co-CFP) of bamboo residual (BR) and waste lubricating oil (WLO) over dual catalytic beds of MgO and HZSM-5 were carried out in an analytical PY-GC/MS. The effects of pyrolysis temperature, catalyst types, HZSM-5/MgO mass ratio and WLO percentage on products distribution and selectivities of aromatics were investigated. Experimental results revealed that 600 °C promoted the total peak area of volatile matters and accelerated the yields of furans and phenols. Compared to HZSM-5, MgO exhibited pronounced deacidification via ketonization and aldol condensation reactions as the minimum yield of acids (2.116%) and the maximum yield of ketones (28.805%) could be obtained. Furthermore, given the selectivity of phenols, MgO not only spurred the increase of overall phenols yield, but also facilitated the selectivity of light phenols like phenol and 4-methyl-phenol. With respect to the co-CFP of BR and WLO, a HZSM-5/MgO mass ratio of 3:2 largely accelerated the yield of aromatics via Diels-Alder reaction. Simultaneously, the WLO percentage played a vital role in the yield of hydrocarbons (i.e. aromatics + olefins & alkanes), and the maximum yield (70.305%) could be attained at the percentage of 60% as a function of significant activation of hydrocarbon pool. [ABSTRACT FROM AUTHOR]

In order to minimize coke yield and improve hydrocarbon production during microwave-assisted catalytic fast pyrolysis of spent edible mushroom substrate, ZSM-5 zeolite catalyst is modified with pre-coking treatment, chemical vapor deposition of SiO 2 , and ethylene diamine tetraacetie acid (EDTA) chemical modification method, respectively (labeled PC-ZSM-5, SiO 2 -ZSM-5 and EDTA-ZSM-5). Experimental results show that all the modification methods result in a loss of external acid sites of ZSM-5. Among the three modified catalysts, the maximum oil fraction yield and the minimum coke yield are obtained with SiO 2 -ZSM-5. The relative content of hydrocarbons in oil fraction increases in the following order: SiO 2 -ZSM-5 > EDTA-ZSM-5 > PC-ZSM-5 > original ZSM-5. Moreover, SiO 2 -ZSM-5 shows the highest relative contents of toluene and xylene, whereas original ZSM-5 produces the lowest ones. Besides, the selectivity of benzene in aromatics follows the order of original ZSM-5 > EDTA-ZSM-5 > PC-ZSM-5 > SiO 2 -ZSM-5, while the selectivity of toluene + xylene presents the opposite trend. [ABSTRACT FROM AUTHOR]

Raw montmorillonite (MMT) was modified by intercalation-exfoliation method to improve the capture capacity of heavy metals (Pb, Zn, Cr and Cd) during coal combustion. Scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) Spectroscopy and Brunner-Emmett-Teller (BET) indicated that intercalation agents cetyltrimethylammonium bromide (CTAB) and sodium dodecyl benzene sulfonate (SDBS) could be successfully inserted into the interlayer of MMT during the intercalation step, additionally exfoliation process could peel off the MMT into fine flakes. The co-combustion of coal and MMTs was conducted in a tube furnace from 900 to 1300 °C. Results indicated that with the increase of temperature, the retention ratio of Pb, Zn and Cd gradually decreased, especially higher than 1200 °C with a great capture capacity reduction, whereas for Cr, it rose first and then decreased. The capture performance of modified MMT on Pb, Zn and Cr was obviously improved. However, for Cd, adverse effect was observed, of which the capacity was even worse than that of raw MMT in some cases. According to the mechanism analysis, the intercalation-exfoliation modification of MMT primarily enhances the chemisorption of heavy metals by exposing more active sites, which facilitates the fixation of heavy metals in the form of aluminosilicates. [ABSTRACT FROM AUTHOR]

[Display omitted] • The type of dopant atom changed the physiochemical characters of catalysts discriminately. • Surface chemical properties of catalysts determined their catalytic and anti-poisoning performances. • The support doped catalysts showed the better low temperature SO 2 resistance. • The formation of ammonium bisulfate species is inhibited on Sb/Si doping V 2 O 5 /TiO 2 catalysts surfaces. • The electronic transfer caused by formed surface sulfate species improved SCR activity of V 2 O 5 /Sb-TiO 2. The Sb/Si doped TiO 2 prepared by sol–gel method were used as supports of V 2 O 5 /TiO 2 SCR catalysts in order to improve SCR activity and SO 2 resistance. The type of dopant atoms changed catalyst physiochemical properties discriminatively. Surface chemical properties of catalysts played more important role in their catalytic performance. Simultaneous enhanced surface acidity and redox capacity leaded to the better SCR activity for V 2 O 5 /Sb-TiO 2 compared with other catalysts. The low temperature SO 2 resistance was improved for the support doped catalysts. The special electronic charge migration brought by surface sulfate species for V 2 O 5 /Sb-TiO 2 even elevated its SCR activity during SO 2 resistance test, which was due to the formation of new acid sites and enhancement of redox performance. Even though NO x conversion for V 2 O 5 /Si-TiO 2 decreased, the relative stable efficiency was kept at low temperatures with SO 2. The results proved hetero atom doping in TiO 2 by sol–gel method was a useful method to improve low temperature SO 2 resistance of catalysts. By contrast, Sb is a better choice for the development of support doped V 2 O 5 /TiO 2 SCR catalyst used in a wide temperature range. [ABSTRACT FROM AUTHOR]

Different activated carbon materials are prepared from a series of solid wastes (sawdust, acrylic fabric, tire powder and rice husk) by combination of the KOH activation method and steam activation method. The influences of several parameters such as pH, contact time, adsorbent dosage and temperature on adsorption performance of Pb 2 + with those different carbon adsorbents are investigated. The results demonstrate that C rice husk performance well in the adsorption process. In the following, the C rice husk is used to explain the adsorption mechanism of Pb 2 + by SEM-EDS, FT-IR and XPS. The results illustrate that the surface oxygen-containing functional groups such as carboxyl, lactone group, phenolic hydroxyl and other alkaline metal ions like Na + and K + have significant effect on the adsorption process. A reasonable mechanism of Pb 2 + adsorption is proposed that the ion exchange play key roles in the adsorption process. In addition, the effects of Cu 2 + , Zn 2 + on the Pb 2 + adsorption capacity with the four carbon adsorbents are also studied and the results demonstrate that other heavy metals play positive effects on the adsorption of Pb 2 + . [ABSTRACT FROM AUTHOR]

[Display omitted] • Adsorption and diffusion of Hg0 in UiO-66 was investigated by molecular simulations combined with experiments. • A good agreement was obtained between experimental data and molecular simulations. • The dynamical and structural properties of Hg0 in UiO-66 were used to interpret the adsorption mechanism. Adsorption of elemental mercury (Hg0) in flue gas using the porous materials is a promising technology. We conducted the molecular simulations and experiments of the adsorption and diffusion of Hg0 in UiO-66 at 393 K. The calculated adsorption isotherms using GCMC simulation are in good agreement with the experimental data. The flexible force field for UiO-66 is reasonable for the study of the thermodynamic and dynamic properties of Hg0 in this structure. The free energy and density distribution of Hg0 were performed, and showed that Hg0 was preferentially located in the tetrahedral cages in UiO-66. The dynamic properties of the Hg0 in the flexible UiO-66 were studied by molecular dynamics. The diffusion mechanism can be explained by the inter-cage hopping events. A lower decay of the VACFs for Hg0 in the flexible UiO-66 was observed at the higher loading. Further analysis of the radial distribution functions, Hg0 molecules are found with higher probability near the O1 atoms of the tetrahedral cage in the framework. Based on structural and dynamics properties, we achieve a fundamental insight into adsorption mechanism. We anticipate these results could provide insights into the adsorption and diffusion of Hg0 for the development of new porous materials. [ABSTRACT FROM AUTHOR]

• Catalytic conversion of bisphenol A polycarbonate over HZSM-5 was conducted. • A 5-fold increase of aromatic hydrocarbons was attained in HZSM-5 (38) catalyzed run. • A reaction temperature of 700 °C led to a maximum content of aromatic hydrocarbons. • Co-pyrolysis of polycarbonate with PS produced more monocyclic aromatic hydrocarbons. • The additive effect of monocyclic aromatic hydrocarbons was maximized at 70 % PC percentage. Thermochemical conversion of plastic wastes is a promising approach to produce alternative energy-based fuels. Herein, we conducted catalytic fast co-pyrolysis of polycarbonate (PC) and polystyrene (PS) to generate aromatic hydrocarbons using HZSM-5 (Zeolite Socony Mobil-5, hydrogen, Aluminosilicate) as a catalyst. The results indicated that employing HZSM-5 in the catalytic conversion of PC facilitated the synthesis of aromatic hydrocarbons in comparison to the non-catalytic run. A competitive reaction between aromatic hydrocarbons and aromatic oxygenates was observed within the studied temperature region, and catalytic degradation temperature of 700 °C maximized the competing reaction towards the formation of targeted aromatic hydrocarbons at the expense of phenolic products. Catalyst type also played a vital role in the catalytic decomposition of PC wastes, and HZSM-5 with different Si/Al molar ratios produced more aromatic hydrocarbons than HY (Zeolite Y, hydrogen, Faujasite). Regarding the effect of Si/Al molar ration in HZSM-5 on the distribution of monocyclic aromatic hydrocarbons (MAHs), a Si/Al molar ratio of 38 maximized benzene formation with an advanced factor of 5.1. Catalytic fast co-pyrolysis of PC with hydrogen-rich plastic wastes including polypropylene (PP), polyethylene (PE), and polystyrene (PS) favored the production of MAHs, and PS was the most effective hydrogen donor with a ∼2.5-fold increase. The additive effect of MAHs increased at first and then decreased when the PC percentage was elevated from 30 % to 90 %, achieving the maximum value of 32.4 % at 70 % PC. [ABSTRACT FROM AUTHOR]

• Recycling benzene and ethylbenzene was explored by CFP of plastics over zeolites. • Polystyrene wastes favored the formation of targeted aromatic hydrocarbons. • USY zeolites was proved to be effective in the production of ethylbenzene. • A Si/Al mole ratio of 5.3 in USY maximized the concentration of targets. • Catalyst to PS ratio was optimized at 1.5 to produce benzene and ethylbenzene. Recovering waste plastics by catalytic fast pyrolysis to selectively generate aromatic hydrocarbons is a promising approach to dispose of solid wastes. In the present work, catalytic conversion of polystyrene over ultra-stable Y zeolites (USY) was conducted to directionally produce benzene and ethylbenzene. Experimental results indicated that catalyst type considerably affected the distribution of aromatic hydrocarbons, and USY with high surface area (734 m2/g), large pore size (5.6 nm), and an abundant amount of strong acid sites (1.21 mmol/g) exhibited the most effective shape selectivity for ethylbenzene and benzene generation as the yield enhanced rate reached 401.8% and 61.1%, respectively. Plastic type also played a vital role in the formation of desirable aromatic hydrocarbons, and polystyrene was more beneficial to the production of ethylbenzene as a 54-fold increase was obtained compared to polycarbonate in the catalytic degradation process. Concerning reaction conditions to maximize the formation of benzene and ethylbenzene in the catalytic decomposition of polystyrene, the catalyst/feedstock mass ratio, Si/Al mole ratio in USY, and catalytic conversion temperature could be optimized at 1.5, 5.3, and 650 °C, respectively. [ABSTRACT FROM AUTHOR]

• Catalytic conversion of rubber wastes over zeolites was conducted to produce aromatics. • A pyrolysis temperature of 750 °C was effective to the formation of aromatics. • USY zeolites shows robust catalytic performance for the production of targeted aromatics. • HY was more favorable to the generation of alkylbenzenes in the catalytic conversion of rubber wastes. • USY zeolites with SiO 2 /Al 2 O 3 mole ratio of 5.3 increased the content of aromatics to the most extent. Catalytic conversion of rubber wastes to produce an alternative fuel resource is a promising approach to dispose of solid wastes and address environmental issues. In this study, catalytic fast pyrolysis (CFP) of rubber wastes over acidic zeolites was conducted, and the effect of SiO 2 /Al 2 O 3 mole ratio of USY zeolites on the formation of aromatic hydrocarbons was explored. Experimental results indicated that alkenes and aromatic hydrocarbons were the main pyrolytic products obtained from fast pyrolysis of rubber wastes, and the pyrolysis temperature played a vital role in the formation of aromatics with the highest concentration achieved at 750 °C. Moreover, catalyst types also affected the catalytic degradation of rubber wastes since limonene was completely decomposed in the presence of zeolites. Compared to SAPO-34, zeolites with higher external surface area, stronger Brønsted acid sites, and larger pore size, including USY, HY, and Hβ, were more effective in the production of aromatic hydrocarbons with the highest content obtained from USY catalyzed run. Given the observed effect of SiO 2 /Al 2 O 3 mole ratio of USY zeolites on the formation of aromatic hydrocarbons during the CFP of rubber wastes, USY with low SiO 2 /Al 2 O 3 ratio of 5.3 was more beneficial to the generation of aromatic hydrocarbons, while that with higher SiO 2 /Al 2 O 3 mole ratio (11.5) facilitated the formation of alkenes. Simultaneously, the product distribution of aromatic hydrocarbons obtained from CFP of rubber wastes over USY zeolites was dominated by xylenes, alkylbenzenes, and toluene, and USY with SiO 2 /Al 2 O 3 mole ratio of 5.3 was more active in the production of toluene and xylenes. [ABSTRACT FROM AUTHOR]

The chemical looping co-gasification of nitrogen-containing algal biomass and coal could effectively realize the high-value utilization of gasification products, but the mechanism of conversion of nitrogen-containing pollutants is not clear. In this work, the effects of the different ratios of microalgae on the co-gasification process were first explored, and the results showed that the 40 % coal + 60 % microalgae blending had the best synergistic effect, with a comprehensive synergistic index (CSI) of 1.35 as the maximum value. The effects of temperature, the ratio of OCs to feed (O/C) and steam flow rate on the evolution of nitrogen-containing species in the co-gasification products were explored based on the optimal mixing ratio, and the results showed that elevating the reaction temperature promotes the generation of nitrogen oxide precursors, and an appropriate amount of steam could inhibit the generation of NOx. The nitrogen in coke mainly came from the Maillard reaction between carbonyl (-CO) compounds and amino (-NH 2 ) compounds and its main forms are pyridine nitrogen (N-5) and pyrrole nitrogen (N-6). Based on the nitrogen accumulation forms in the products of each phase, the mechanism of nitrogen transport and conversion in the chemical looping co-gasification of coal and microalgae (CM-CLCG) process was proposed. This study provides a reference for the synergistic utilization of coal and biomass and the control process of nitrogen-containing pollutants., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2025 Elsevier B.V. All rights reserved.)

Mg 2+ impregnation, intercalation-exfoliation, and thermal activation methods were employed to create various types of modified vermiculite (MV), with their combination creating linked-modified vermiculite (LMV). Copyrolysis of MV with municipal sludge (MS)/aged refuse (AF) in a fluidized bed improved heavy metal (HM) stability compared to copyrolysis of original vermiculite, with LMV demonstrating superior performance compared to other types of MV. The HM retention rate, potential ecological risk assessment, and form distribution analysis supported the efficacy of the approach. Doping of MS with AF was not beneficial to reducing the hazards posed by HMs. New calculation models for HM hazard assessment were developed that integrated HM concentration and form. Without additives or when only original vermiculite was added, increased pyrolysis temperature facilitated the reduction of hazards posed by HMs, indicating that HM form greatly influenced the effectiveness of the pyrolysis reaction. The characteristics of the reaction with multiple coexisting HMs and vermiculite at different pyrolysis temperatures were investigated via simulations, and the effect of interactions between HMs was explored. HMs mainly exhibited repulsive interactions, and adsorption became more unfavorable with increasing pyrolysis temperature as the repulsive force increased. The Cr, Cu, and Zn atoms in compounds formed covalent bonds with the O atoms of LMV, in contrast to the ionic bonds formed by the Pb and Cd atoms in some compounds, which may explain the differences in their reactivities with LMV., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Pyrolysis is effective in reducing the volume of solid waste and sludge, and produces less pollutants than incineration and landfill, but the process still suffers from heavy metal pollution. Four types of intercalated-exfoliated modified vermiculite (UIV, DIV, TIV and 3IV) were prepared using urea, dimethylsulfoxide, tributyl phosphate and 3-aminopropyltriethoxysilane as intercalators for the control of Cd, Cr, Cu, Pb and Zn in municipal sewage sludge (MSL), paper mill sludge (PML), municipal domestic waste (MWA) and aged refuse (AFE). The larger the interlayer spacing of the vermiculite, the more favorable the retention of heavy metals. 3IV was the most effective additive, with an average retention of more than 75 % of all heavy metals at 450 ℃ for the four raw materials. Cr, Cu, Pb and Zn were all at low potential ecological risk (Pr), while Cd was moderate or considerable Pr, and the addition of 3IV reduced the Pr. Distribution of intercalators between vermiculite interlayers was haphazard, and interlayer spacing results were close to those of the experiment (except for tributyl phosphate). The reactive electrons mainly flowed from the Highest Occupied Molecular Orbital (HOMO) of vermiculite flakes to the Lower Unoccupied Molecular Orbital (LUMO) of heavy metal chlorides. In contrast, the reactive electrons mostly flowed from the HOMO of heavy metal oxides to the LUMO of vermiculite flakes. Heavy metal oxides were more readily adsorbed on vermiculite flakes than heavy metal chlorides, and the adsorption capacity of Cr and Zn was stronger than that of Cd, Pb and Cu., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Increasing amounts of solid waste and sludge have created many environmental management problems. Pyrolysis can effectively reduce the volume of solid waste and sludge, but there is still the problem of heavy metal contamination, which limits the application of pyrolysis in environmental management. The intercalated-exfoliated modified vermiculite (IEMV) by intercalators of sodium dodecylbenzene sulfonate, hexadecyltrimethylammonium bromide and octadecyltrimethylammonium bromide were used to control the release of Cd, Cr, Cu, Zn and Pb during pyrolysis process of sludge or solid waste. The retention of heavy metals in sludge was generally better than that in solid waste. The IEMV by octadecyltrimethylammonium bromide as the intercalator calcined 800 °C (STAB-800) was the best additive for heavy metal retention, and the retention of Cr, Cu and Zn was significantly better than that of Pb and Cd. Cr, Cu, Zn and Pb were at low risk, while Cd had considerable risk under certain circumstances. New models were proposed to comprehensively evaluate the results of the risk and forms of heavy metals, and the increasing temperature was beneficial in reducing the hazards of heavy metals by the addition of STAB-800. The reaction mechanism of heavy metals with vermiculite was revealed by simulation of reaction sites, Fukui Function and Frontier Molecular Orbital. Thermal activation-intercalated-exfoliated modified vermiculite (T-IEMV) is more reactive and had more active sites for heavy metals. Mg atoms and outermost O atoms are the main atoms for T-IEMV to react with heavy metals. The Cr, Cu and Zn have better adsorption capacity by T-IEMV than Pb and Cd. This study provides a new insight into managing solid waste and sludge and controlling heavy metal environmental pollution., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Na + /K + /Mg 2+ /Ca 2+ expansion-modified vermiculite and calcination expansion (700 °C, 800 °C and 900 °C)-modified vermiculite (700-Mg-V, 800-Mg-V and 900-Mg-V) were prepared as additives to control the emission of five heavy metals (Zn, Cr, Cu, Pb, and Cd) during the pyrolysis of municipal sewage sludge, paper mill sludge, municipal domestic waste, and aged refuse. Mg 2+ -Modified vermiculite obtained via thermally activated calcination at 800 °C retained 65% of heavy metals from all raw materials at 450 °C. Zn, Cr, and Cu retained nearly 90%. Although modified vermiculite could reduce the ecological risk, Cd had an ecological risk level higher than Zn, Cr, Cu, and Pb. The fine textural properties, laminated morphology, and expansion capacity of modified vermiculite were positively correlated with its retention of heavy metals. Heavy metals interacted with the (002) surface of vermiculite, and the reactions were mainly concentrated near the 17-O and surrounding atoms. The heavy-metal monomers were less capable of binding to the (002) surface of vermiculite than the oxides and chlorides of heavy metals. The effect of heavy-metal oxides and chlorides binding to the (002) surface of vermiculite was related to heavy metals., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

It is of great significance to reduce the secondary risk of heavy metals during the pyrolysis of paper sludge. This study used kaolin and alumina-silica-based xerogels to control heavy metals released during sludge pyrolysis. Pyrolyzing a mixture of sludge and 7% kaolin at 400 °C achieved high retention rates for Cu (95.85%), Zn (95.97%), Pb (97.15%), Cd (84.23%), and Cr (84.05%) when the pyrolysis tail gas was treated with 9 g of xerogel. The addition of kaolin facilitated the transformation of Cu, Zn, Pb, and Cr from the unstable fraction to the stable fraction in pyrolysis biochar, reducing their leachability. The xerogels also played a crucial role in adsorbing and stabilizing the heavy metals. The results of thermodynamic equilibrium calculations showed that Pb(g), PbS(g), PbCl 2 (g), PbCl(g), Zn(g), ZnCl 2 (g), and Cd(g) were the main gaseous products of Zn, Pb, and Cd during paper sludge pyrolysis. The Pb atoms in PbCl 2 and PbS, and the Zn atoms in ZnCl 2 bond with the oxygen atoms on the kaolin surface by covalent bonds, while the Cl atoms in PbCl and the Pb atoms of elemental lead form ionic bonds with H and O atoms on the kaolinite surface, respectively. These experimental and simulation results offer new ideas for controlling heavy metals during sludge pyrolysis., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Experiment and mechanism studies on the enrichment of Pb, Cd, Zn, As, and Cr by modified kaolin were investigated during MSW (municipal solid waste) pyrolysis at 450 ~ 650 °C. The results showed that γAlOK(micro- and nano-γAl 2 O 3 by hydrothermal method modified kaolin) was relatively selective for the solid phase enrichment of Cr and As, while CaHPK (CaHPO 4 impregnated modified kaolinite) was more advantageous for the adsorption of Pb and Zn, which might be related to the thermal stability of γAl 2 O 3 and the thermal conversion of CaHPO 4 . Compared with the original kaolin, the adsorption and retention capacity of γAlOK for As was improved by 20 ~ 30%. Moreover, the retention rate of modified kaolin for Cd decreased from 66.75 to 30.30% at 450 ~ 650 ℃, and the effect of temperature on the volatilization of Cd was always greater than the active components on the surface of modified kaolin. In the fluidized bed experiment, the physical mixing of different modified kaolin achieves complementary advantages on the retention capacity of heavy metals. In addition, the ∆E between Ca 2 P 2 O 7 and PbCl 2 is smaller than that of γAl 2 O 3 at 500 ~ 650 °C, i.e., their electron transfer induction is stronger, and therefore more favorable for electron transfer and stable chemical bond formation., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The deactivation of catalyst is a significant reason for its limited application during the catalytic fast pyrolysis (CFP) process. To reduce the coke formation, binary compound impregnation (BCI) and chemical liquid deposition (CLD) were used to modify HZSM-5 catalysts. At the same time, the self-designed microwave reactor separated the pyrolysis of bamboo and catalytic upgrading of primary vapor, which made the catalytic effect more thorough. Experimental results indicated that CLD used TiO 2 deposition to cover external acid sites, while BCI by phosphorus-nickel could cover and partly destroy superficial acid sites through two different ways. Within the scope of the loaded amount studied, the yield of aromatic hydrocarbons in the oil phase increased at first and then decreased, while the coke formation reduced continuously. BTX (benzene, toluene and xylene), the most valuable product in bio-oil, drastically increased by 39.1% and 22.6% respectively over the CLD and BCI modified catalysts. Considering the catalytic performance as well as cost, CLD over HZSM-5 has more advantages in the CFP process to upgrade bio-oil., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020. Published by Elsevier B.V.)

Catalytic fast co-pyrolysis of waste greenhouse plastic films and rice husk over a hierarchical HZSM-5/MCM-41 catalyst was performed in an analytical Py-GC/MS. We evaluated the effect of pyrolysis temperature and the ratio of rice husk to waste greenhouse plastic films on the total peak area of condensable organic products and CO 2 . In order to evaluate synergy possibilities among the two feedstocks, we performed non-catalytic pyrolysis and catalytic fast pyrolysis of rice husk and waste greenhouse plastic films separately. In addition, we report results for the catalytic fast co-pyrolysis of the mixture rice husk and waste greenhouse plastic films. The maximum relative content of hydrocarbons from catalytic fast co-pyrolysis of rice husk and waste greenhouse plastic films is obtained at 600 °C. When the mass ratio of rice husk to waste greenhouse plastic films is 1:1.5, the relative content of hydrocarbons reaches a maximum (71.1%). The hierarchical micro-mesoporous composite molecular sieve used in this work has outstanding catalytic activity and increases the relative content of hydrocarbons., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

This work presents studies on the co-combustion of anthracite coal and wood pellets in fluidized bed. Prior to the fluidized bed combustion, thermogravimetric analysis are performed to investigate the thermodynamic behavior of coal and wood pellets. The results show that the thermal decomposition of blends is divided into four stages. The co-firing of coal and wood pellets can promote the combustion reaction and reduce the emission of gaseous pollutants, such as SO 2 and NO. It is important to choose the proportion of wood pellets during co-combustion due to the low combustion efficiency caused by large pellets with poor fluidization. Wood pellets can inhibit the volatilization of trace elements, especially for Cr, Ni and V. In addition, the slagging ratio of wood pellets ash is reduced by co-firing with coal. The research on combustion of coal and wood pellets is of great significance in engineering., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

The high concentration of oxygenated compounds in pyrolytic products prohibits the conversion of hemicellulose to important biofuels and chemicals via fast pyrolysis. Herein a dual-catalyst bed of CaO and HZSM-5 was developed to convert acids in the pyrolytic products of xylan to valuable hydrocarbons. Meanwhile, LLDPE was co-pyrolyzed with xylan to supplement hydrogen during the catalysis of HZSM-5. The results showed that CaO could effectively transform acids into ketones. A minimum yield of acids (2.74%) and a maximum yield of ketones (42.93%) were obtained at a catalyst to feedstock ratio of 2:1. The dual-catalyst bed dramatically increased the yield of aromatics. Moreover, hydrogen-rich fragments derived from LLDPE promoted the Diels-Alder reactions of furans and participated in the hydrocarbon pool reactions of non-furanic compounds. As a result, a higher yield of hydrocarbons was achieved. This study provides a fundamental for recovering energy and chemicals from pyrolysis of hemicellulose., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Co-combustion of sedum plumbizincicola and sewage sludge was performed in a tubular furnace. The influence of experimental conditions on the partitioning of Zn, Cd, and Pb was investigated. The results showed that 30% sewage sludge was proposed as the optimal ratio for the co-combustion as a compromise between low calorific value and high amount of heavy metal remained in the bottom ash. High temperature increased the volatilization degree of heavy metals, among which the performance of Cd and Pb was obvious than Zn. Rising oxygen concentration was beneficial to the formation of heavy metal compounds, and the effect of oxygen on Zn was the most pronounced. Thermodynamic equilibrium calculation was carried out to forecast heavy metal compounds. The results demonstrated that Zn, Cd, and Pb mainly generated ZnAl 2 O 4 , CdSiO 3 and PbSiO 3 in solid phase, which are partly confirmed by X-ray diffraction (XRD). The promising results offered a great possibility of heavy metal immobilization, indicating the combustion of Sedum plumbizincicola with sewage sludge is an effective way for waste disposal., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Niobium oxide as the promoter was doped in the V/WTi catalyst for the selective catalytic reduction (SCR) of NO. The results showed that the addition of Nb 2 O 5 could improve the SCR activity at low temperatures and the 6wt.% additive was an appropriate dosage. The enhanced reaction activity of adsorbed ammonia species and the improved dispersion of vanadium oxide might be the reasons for the elevation of SCR activity at low temperatures. The resistances to SO 2 of 3V6Nb/WTi catalyst at different temperatures were investigated. FTIR spectrum and TG-FTIR result indicated that the deposition of ammonium sulfate species was the main deactivation reason at low temperatures, which still exhibited the reactivity with NO above 200°C on the catalyst surface. There was a synergistic effect among NH 3 , H 2 O and SO 2 that NH 3 and H 2 O both accelerated the catalyst deactivation in the presence of SO 2 at 175°C. The thermal treatment at 400°C could regenerate the deactivated catalyst and get SCR activity recovered. The particle and monolith catalysts both kept stable NO x conversion at 225°C with high concentration of H 2 O and SO 2 during the long time tests., (Copyright © 2017. Published by Elsevier B.V.)

This work presents studies on the combustion of Composite Biomass Pellets (CBP S ) in fluidized bed using bauxite particles as the bed material. Prior to the combustion experiment, cold-flow characterization and thermogravimetric analysis are performed to investigate the effect of air velocity and combustion mechanism of CBP S . The cold-state test shows that CBPs and bauxite particles fluidize well in the fluidized bed. However, because of the presence of large CBPs, optimization of the fluidization velocity is rather challenging. CBPs can gather at the bottom of the fluidized bed at lower gas velocities. On the contrary, when the velocity is too high, they accumulate in the upper section of the fluidized bed. The suitable fluidization velocity for the system in this study was found to be between 1.5-2.0m/s. At the same time, it is found that the critical fluidization velocity and the pressure fluctuation of the two-component system increase with the increase of CBPs mass concentration. The thermogravimetric experiment verifies that the combustion of CBPs is a first-order reaction, and it is divided into three stages: (i) dehydration, (ii) release and combustion of the volatile and (iii) the coke combustion. The combustion of CBPs is mainly based on the stage of volatile combustion, and its activation energy is greater than that of char combustion. During the combustion test, CBP S are burned at a 10kg/h feed rate, while the excess air is varied from 25% to 100%. Temperatures of the bed and flue gas concentrations (O 2 , CO, SO 2 and NO) are recorded. CBPs can be burnt stably, and the temperature of dense phase is maintained at 765-780°C. With the increase of the air velocity, the main combustion region has a tendency to move up. While the combustion is stable, O 2 and CO 2 concentrations are maintained at about 7%, and 12%, respectively. The concentration of SO 2 in the flue gas after the initial stage of combustion is nearly zero. Furthermore, NO concentration is found to be closely related to O 2 : the NO reaches its peak value after initial stage and later decreases with the continued depletion of O 2 . Towards the end of combustion, NO increases with the increase of O 2 ., (Copyright © 2017 Elsevier B.V. All rights reserved.)

The selective catalytic reduction (SCR) activities of the MoO 3 doped V/WTi catalysts prepared by the incipient wetness impregnation method at low temperature were investigated. The results showed that the addition of MoO 3 could enhance the NO x conversion at low temperature and the best SCR activity was obtained when the dosage of MoO 3 reached 5wt.%. The NH 3 -TPD and DRIFTS experiments indicated that the addition of MoO 3 changed the type and number of acid sites on the surface of catalysts and reaction activities of acid sites were altered at the same time. The redox capacity and amount of active oxygen species got improved for V3Mo5/WTi catalyst, which could be confirmed by the H 2 -TPR and transient response experiments. Water vapor inhibited the NO x conversion at low temperature. Deposition of ammonium sulfate or bisulfate might be main reason for the loss of catalytic activity in the presence of SO 2 at low temperature. Choosing the suitable NH 3 /NO ratio and elevation of reaction temperature both could weaken the influence of SO 2 on the SCR activity of the V3Mo5/WTi catalyst. Thermal treatment of the deactivated catalyst at 350°C could get the low temperature activity recovered. The decrease of GHSV improved the deNO x efficiency at low temperature and we speculated that the rational technological process and operation parameters could contribute to the application of this kind of catalysts in real industrial environment., (Copyright © 2016. Published by Elsevier B.V.)

Catalytic fast co-pyrolysis (co-CFP) offers a concise and effective process to achieve an upgraded bio-oil production. In this paper, co-CFP experiments of waste cooking oil (WCO) and tea residual (TR) with HZSM-5 zeolites were carried out. The influences of pyrolysis reaction temperature and H/C ratio on pyrolytic products distribution and selectivities of aromatics were performed. Furthermore, the prevailing synergetic effect of target products during co-CFP process was investigated. Experimental results indicated that H/C ratio played a pivotal role in carbon yields of aromatics and olefins, and with H/C ratio increasing, the synergetic coefficient tended to increase, thus led to a dramatic growth of aromatics and olefins yields. Besides, the pyrolysis temperature made a significant contribution to carbon yields, and the yields of aromatics and olefins increased at first and then decreased at the researched temperature region. Note that 600°C was an optimum temperature as the maximum yields of aromatics and olefins could be achieved. Concerning the transportation fuel dependence and security on fossil fuels, co-CFP of WCO and TR provides a novel way to improve the quality and quantity of pyrolysis bio-oil, and thus contributes bioenergy accepted as a cost-competitive and promising alternative energy., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Objective: To develop a high-accuracy, better-safety and low-cost cervical pedicle locator system for guiding cervical pedicle screw placement., Methods: Cervical pedicle screw locator system was made of stainless steel. Ten cervical specimens from voluntary donation were divided into two groups according to compatibility design: control group in which 60 screws were planted into C(2-7) by free hand; and experimental group in which 60 screws were planted into C(2-7) under the guidance of three-dimensional locator system. The condition of screw insertion was observed and the accuracy was evaluated by the integrity of pedicle walls., Results: In the control group, 32 screws (53.33%) were placed inside the pedicles and 28 (46.67%) were outside; 9 screws (15.00%) led to nerve root injury, 5 screws (8.33%) caused vertebral artery injury and no spinal cord injury occurred; and the qualification ratio of screw insertion was 76.67% (excellent 32, fair 14, poor 14). While in the experimental group, 54 screws (90.00%) were placed inside the pedicles and 6 (10.00%) were outside; 1 screw (1.67%) caused vertebral artery injury and no nerve root injury and spinal cord injury occurred; and the qualification ratio of screw insertion was 98.33% (excellent 54, fair 5, poor 1). There was significant difference between the two groups (P < 0.05)., Conclusion: Cervical pedicle screw locator system has the advantages of easy manipulation, high accuracy of screw placement and low cost. With further study, it can be applied to the clinical.

Objective: To summarize the effect of self-setting CPC on the repair of bone defect after tumor resection in children., Methods: From December 1998 to December 2006, 32 patients with benign bone tumor were treated, and the bone defect was repaired by CPC. Among them, there were 21 males and 11 females, aged 4-14 years old (9.8 on average). The course of disease was 3-18 months. There were 12 cases of non-ossifying fibroma, 8 of bone cyst, 7 of osteoid osteoma and 5 of fibrous dysplasia. The bone defect was located in femur in 15 cases, in tibia in 8 cases, in humerus in 6 cases and in other positions in 3 cases. The range of bone defect was 2.0 cm x 1.5 cm x 1.0 cm - 10.0 cm x 5.0 cm x 4.0 cm. CPC spongiosa granules of 3-23 g were filled in 26 cases, including 3 children with pathologic fracture and internal fixation with plate, and injectable CPC of 5-20 mL was filled in 6 bone cyst cases., Results: Thirty-two patients obtained healing by first insertion. All the patients were followed up for 12-48 months (23.5 months on average). No allergic reaction, toxicity, rash or high fever was found after operation. There was no pain or pruritus at the incisions. The X-ray films showed that the implanted CPC began to fuse with the host bone 4-9 months (7 month on average) after operation. The internal fixation was removed within 6-12 months of operation. And CPC spongiosa granules were absolutely absorbed within 8-36 months of operation. However, injectable CPC could be found 4 years after operation. The children's limbs could do normal exercises. Finally, bone matrix grew well and no recurrence was found., Conclusion: CPC in repairing bone defect after benign bone tumor in children is a safe, economical, convenient and non-toxic method.