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In this study, ex-situ catalytic pyrolysis of oxygen-containing polycarbonate (PC) was conducted to prepare carbon nanotubes (CNTs) and H 2 -rich syngas. This study examined the influence of the active metal components (Ni and Fe), catalyst pre-reduction, and pre-deoxygenation of pyrolysis volatiles on the catalytic performance and mechanism. Results show that the reductive constituents in pyrolysis volatiles make it difficult to reduce the Fe oxides, thus hindering the CNTs growth on Fe catalysts, compared to Ni catalysts. H 2 pre-reduction of Ni and Fe catalysts enhances the generation of CNTs and syngas. The pre-reduced Fe catalyst exhibits better carbon deposit performance, reaching 263 mg/g plastics . The pre-reduced Ni catalyst better facilitates the reforming reaction of CO 2 and H 2 O, resulting in higher syngas yields of 32.75 mmol/g plastics , with a volume proportion of 94.4 vol%. The addition of the deoxygenation catalyst Ni/HZSM-5 promotes the growth of CNTs with fewer defects and higher graphitization on Ni catalysts. The excess CO 2 and H 2 O generated by the introduction of Ni/HZSM-5 may oxidize the Fe 0 on pre-reduced Fe catalysts, inhibiting the growth of CNTs. The mechanism of the growth of CNTs and syngas from PC is also explored. The findings can provide theoretical guidance for the disposal of waste plastics., 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.)

Biomass wastes (BW) can be used to produce value-added products by multiple energy recovery technologies. However, the actual conversion results are unsatisfactory since heterogeneous feedstocks mixture with different characteristics are hard to optimally recovered in the same fine conversion process. This paper aimed to develop a new method to improve the energy conversion efficiencies, which focused on the rational matching of BW characteristics and demand for highly efficient energy recovery. Accordingly, this paper explored the correlation between BW representative characteristics and energy conversion efficiencies. The results showed that BW types with different characteristics had significant correlation with multiple utilization technologies (P value < 0.05). Existing BW sorting methods based on source/density showed limited promotion on downstream utilization since the large diversity of characteristics within groups. Furthermore, to assist efficient energy conversion of BW, a novel BW sorting mode, different from traditional manual and mechanical sorting methods, was established to achieve the matching between feedstocks and utilization technologies. The chemical properties, containing elemental composition and heating value, were selected as BW sorting criterion. According to new sorting categories, the fuel characteristics, reaction conditions and products performance in terms of its energy conversion process have more significant differences between groups than traditional sorting methods. The energy conversion efficiency can be improved by 10.71% than unsorted as least. The new BW sorting method towards efficient downstream energy recovery has feasibility in industrial applications. The future perspectives were also discussed. This work was helpful to improve the downstream energy utilization., 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. Published by Elsevier Ltd.)

With the rapid advancement of photopolymerization-based 3D printing technology, the volume of PCW has experienced a sharp increase. The potential environmental ramifications of PCW disposal demand careful consideration, especially given its current practice of being incineration alongside MSW. In this study, the TG-MS/FTIR system was carried out to probe the thermogravimetric characteristics and volatile byproducts during combustion. Various product compositions resulting from different mixing ratios of PCW incineration with MSW were investigated. It was observed that fluorene (C 13 H 10 ) and triphenylene (C 18 H 12 ) produced by PCW combustion 0.52 mg/g and 0.43 mg/g respectively, which are twice as abundant as those generated from normal plastic. When PCW incineration along with MSW, compounds such as naphthalene (C 10 H 8 ), cyclohexane (C 6 H 12 ), and heptane (C 7 H 16 ) were generated in concentrations of 1.25 mg/g, 1.05 mg/g, and 0.95 mg/g respectively, which are at least twice as much as with MSW incineration alone. The incineration of PCW with rubber and textiles resulted in the production of 2.34 mg/g to 3.76 mg/g more PAHs compared to PCW combustion alone. The incineration of PCW with paper resulted in the production of 3.12 mg/g to 5.15 mg/g more heptane, nonane, cyclohexane, pyrene, and anthracene than PCW combustion alone. Incineration of PCW with wood proved to be the cleanest method, with product contents primarily below 0.10 mg/g. When incinerated with food residues or normal plastic, most of the product content remained below 0.05 mg/g. Considering the environmental pollution resulting from PCW combustion, the disposal of PCW warrants careful consideration and management., 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.)

Highly active biochar has great application potential in heterogeneous catalysis and adsorptive processes. The complexity of carbonization process makes it difficult to construct target active sites. This work put forward a reactive descriptor based on pyrolysis parameters and intrinsic composition of biomass. Results show that the model showed better predictive performance for C-C/C=C (R 2  = 0.85), C=O (R 2  = 0.85) and defect (R 2  = 0.91) sites. The SHapley Additive exPlanation analysis shows that the pyrolysis parameters and the higher heating values are equally important for the active sites. The predictive performance and guiding role of the descriptor were validated by experiments. The descriptors proposed in this study integrated significant advantages of simplicity and easy accessibility, which would break the bottleneck of accurate construction of active sites and provide a theoretical basis for high-value resource utilization of biomass., 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.)

Cleanliness has been paramount for municipal solid waste incineration (MSWI) systems. In recent years, the rapid advancement of intelligent technologies has fostered unprecedented opportunities for enhancing the cleanliness of MSWI systems. This paper offers a review and analysis of cutting-edge intelligent technologies in MSWI, which include process monitoring, intelligent algorithms, combustion control, flue gas treatment, and particulate control. The objective is to summarize current applications of these techniques and to forecast future directions. Regarding process monitoring, intelligent image analysis has facilitated real-time tracking of combustion conditions. For intelligent algorithms, machine learning models have shown advantages in accurately forecasting key process parameters and pollutant concentrations. In terms of combustion control, intelligent systems have achieved consistent prediction and regulation of temperature, oxygen content, and other parameters. Intelligent monitoring and forecasting of carbon monoxide and dioxins for flue gas treatment have exhibited satisfactory performance. Concerning particulate control, multi-objective optimization facilitates the sustainable utilization of fly ash. Despite remarkable progress, challenges remain in improving process stability and monitoring instrumentation of intelligent MSWI technologies. By systematically summarizing current applications, this timely review offers valuable insights into the future upgrade of intelligent MSWI systems., 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.)

Biochar is a promising sorbent for Cd removal from water, while the disposal of the exhausted Cd-enriched biochar remains a challenge. In this study, pyrolysis was employed to treat the exhausted biochar under N 2 and CO 2 atmospheres at 600-900 °C, and the fate of Cd during pyrolysis and characteristics of high-valued products were determined. The results indicated that higher temperature and CO 2 atmosphere favored the volatilization of Cd. Based on the toxicity characteristic leaching procedure (TCLP) results, the pyrolysis treatment under both atmospheres enhanced the stability of Cd, and the leached Cd concentration of regenerated biochar obtained at high temperatures (>800 °C) was lower than 1 mg/L. Compared with the pristine biochar, the regenerated biochar demonstrated higher carbon content and pH, whereas the contents of oxygen and hydrogen declined, and exhibited promising sorption properties (35.79 mg/g). The atmosphere played an important role in modifying biochar properties and syngas composition. The N 2 atmosphere facilitated CH 4 production, whereas the CO 2 atmosphere increased the proportion of CO. These results implied that pyrolysis can be a valuable and environmental-friendly strategy for the treatment and reuse of exhausted biochar sorbent., 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. Published by Elsevier B.V.)

Heterogeneity of pyrolytic parameters in municipal solid waste (MSW) significantly hinders its waste-to-energy efficiency. So far, hardly any light has been shed on current pyrolytic heterogeneity conditions or feasible pyrolytic homogeneity enhancement approaches of MSW. Accordingly, pyrolytic properties (E a and logA) of 130 MSW samples in 6 categories were collected from literature. A kinetic parameters clustering-based sorting strategy for MSW was proposed. A so-called C index was established to compare their sorting performance for E a and logA against two traditional sorting strategies (substance categorization and density clustering). Results showed that the proposed sorting strategies outperformed the traditional ones in pyrolytic homogeneity enhancement, where the optimal C&#95;E a and C&#95;logA reached 1578.30 kJ/mol and 93.11 -log min. Among investigated clustering methods, k-means clustering outperformed hierarchical clustering, which could be attributed to its adaptability to the sample structure. Future perspectives involving data set expansion, model framework development, and downstream technologies matching were also discussed. The index C established in this study can be used to evaluate other clustering models., 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.)

Excavated waste is a byproduct of microbial decomposition and fermentation following landfill disposal. The effective management and utilization of excavated waste offer broad prospects for environmental and resource protection, as well as economic growth. While current research predominantly focuses on plastics in landfills, the physico-chemical properties of excavated waste over extended landfilling time remain unclear. This study aimed to address this gap by excavating waste from a landfill in Tianjin, China, with a maximum landfilling time of 18 years. The findings revealed that, compared to municipal solid waste (MSW), the excavated waste exhibited increased calorific value, ash content, and fixed carbon content after screening the landfill-mined-soil-like-fine fraction. The average calorific value of the excavated waste could reach 57.8 MJ/kg. Additionally, the oxygen content in the excavated combustible waste exceeded that of MSW, increasing from 25.59 % to 34.22 %. This phenomenon is potentially linked to the oxidation of attached soil impurities and waste. The study identified polyethylene (PE), polypropylene (PP), expanded polystyrene (EPS), polyethylene terephthalate (PET), and wood as the primary combustible components. Notably, the excavated waste exhibited a significant decrease in surface gloss, adopting a rough texture with apparent holes, potentially attributed to the acidification and corrosion of organic matter during fermentation. Nevertheless, the breaking of molecular bonds could also contribute to waste fragmentation. Furthermore, an increase in landfilling time resulted in a more pronounced decrease in mechanical properties. For instance, the failure load of PE decreased from 15.61 N to 6.46 N, and PET reduced from 884.83 N to 186.56 N. The chemical composition of excavated waste has changed, with -OH and CO observed in PE with an 18-year landfilling time. In conclusion, these results provide a theoretical foundation for the recycling of excavated waste and contribute to the advancement of waste management and recycling technologies., 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. Published by Elsevier B.V.)

The interaction of fuel with NOx chemistry is important for the construction of the reaction mechanism and engine application. In this work, the reaction pathways of n C 5 H 12 + NO 2 were studied by high-level electronic structure calculations (DLPNO-CCSD(T)-F12/cc-pVTZ-F12//B2PLYPD3/cc-pVTZ). The rate constants were calculated by using the multistructural canonical transition-state theory with the Eckart tunneling method (TST/MS-T/ET). The studied condition is in a wide temperature range of 298-2400 K. The influence of MS-T anharmonicity and tunneling effect will be clarified for these site-specific H-abstraction pathways. The result reflects the large deviation introduced by the treatment of MS-T anharmonicity, especially at a high temperature. For the same type of reactions, the rate constants of H-abstraction both occurring at the secondary carbon are not almost identical. The branching ratios show that abstraction from the secondary site forming cis -HONO (R2c) contributes 36-78% to n C 5 H 12 consumption in the temperature range of 298-2400 K. The current results show that the multistructural torsional anharmonicity has a crucial influence on the accurate estimation of branching ratios.

Tar problem seriously hinders the development of biomass gasification. The tar formation of biomass is greatly influenced by cellulose. In this work, PY-GC/MS was employed for providing a precise insight into the formation of primary and secondary products, and a tar contribution index was introduced to evaluate the potential of tar formation from different origins. Combined with statistical analysis and corroboration by DFT analysis, key intermediates for tar formation are recognized, and corresponding influence is confirmed. A new framework from cellulose to tar was built. The secondary reaction acts a more important role for tar formation. The aromatic precursors and high-activity small-molecular gases are two key compounds responding to tar formation, and the existence of high-activity small-molecular gases could significantly reduce the energy barrier during tar formation. For furans, the energy barrier can be reduced from 100.2 kcal/mol to 74.2 kcal/mol in the presence of ethylene., 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.)

Emerging contaminants can be removed effectively in heterogeneous Fenton-like systems. Currently, catalyst activity and contaminant removal mechanisms have been studied extensively in Fenton-like systems. However, a systematic summary was lacking. This review summarized: 1) The effects of various heterogeneous catalysts on emerging contaminants degradation by activating H 2 O 2 ; 2) The role of active sites in different catalysts during the activation of H 2 O 2 and their contribution to the generation of active species; 3) The modulation of degradation pathways of emerging contaminants. This paper will help scholars to advance the controlled construction of active sites in heterogeneous Fenton-like systems. Suitable heterogeneous Fenton catalysts can be selected in practical water treatment processes., 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.)

Rapid pyrolysis is a promising technique to convert biomass into fuel oil, where NO X emission remains a substantial environmental risk. NH 3 and HCN are top precursors for NO X emission. In order to clarify their migration path and provide appropriate strategies for their controlling, six up-to-date machine learning (ML) models were established to predict the NH 3 and HCN yield during rapid pyrolysis of 26 biomass feedstocks. Cross-validation and grid search methods were used to determine the optimal hyperparameters for these ML models. The support vector regression (SVR) model achieved optimal accuracy among them. The optimal root means square error (%), mean absolute error (%), and R 2 of test set for NH 3 /HCN yield were 1.2901/1.1531, 1.0501/0.84712, and 0.98253/0.96152, respectively. In addition, based on the results of Pearson correlation analysis, the input variables with a weak linear correlation with the target product were eliminated, which was found capable of improving the prediction accuracy of almost all ML models except SVR. While after input variables elimination, the SVR model still showed the optimal NH 3 and HCN yield prediction accuracy. It reflects SVR's great significance and potential for predicting the yield of NO X precursors during rapid biomass 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 B.V. All rights reserved.)

Dissolved organic matters (DOM) are widely present in different water sources, causing significant effects on water treatment processes. Herein, the molecular transformation behavior of DOM during peroxymonosulfate (PMS) activation by biochar for organic degradation in a secondary effluent were comprehensively analyzed. Evolution of DOM was identified and inhibition mechanisms to organic degradation were elucidated. DOM underwent oxidative decarbonization (e.g., -C 2 H 2 O, -C 2 H 6 , -CH 2 and -CO 2 ), dehydrogenation (-2H) and dehydration reactions by · OH and SO 4 ·- . N and S containing compounds witnessed deheteroatomisation (e.g., -NH, -NO 2 +H, -SO 2 , -SO 3 , -SH 2 ), hydration (+H 2 O) and N/S oxidation reactions. Among DOM, CHO-, CHON-, CHOS-, CHOP- and CHONP-containing molecules showed moderate inhibition while condensed aromatic compounds and aminosugars exhibited strong and moderate inhibition effects on contaminant degradation. The fundamental information could provide references for the rational regulation of ROS composition and DOM conversion process in a PMS system. This in turn offered theoretical guidance to minimize the interference of DOM conversion intermediates on PMS activation and degradation of target 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 © 2023 Elsevier Ltd. All rights reserved.)

Due to the wide applications of polyurethane (PU), production is constantly increasing, accounting for 8% of produced plastics. PU has been regarded as the 6th most used polymer in the world. Improper disposal of waste PU will result in serious environmental consequences. The pyrolysis of polymers is one of the most commonly used disposal methods, but PU pyrolysis easily produces toxic and harmful nitrogen-containing substances due to its high nitrogen content. This paper reviews the decomposition pathways, kinetic characteristics, and migration of N-element by product distribution during PU pyrolysis. PU ester bonds break to produce isocyanates and alcohols or decarboxylate to produce primary amines, which are then further decomposed to MDI, MAI, and MDA. The nitrogenous products, including NH3, HCN, and benzene derivatives, are released by the breakage of C-C and C-N bonds. The N-element migration mechanism is concluded. Meanwhile, this paper reviews the removal of gaseous pollution from PU pyrolysis and discusses the removal mechanism in depth. Among the catalysts for pollutant removal, CaO has the most superior catalytic performance and can convert fuel-N to N2 by adsorption and dehydrogenation reactions. At the end of the review, new challenges for the utilization and high-quality recycling of PU are presented., 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.)

Potassium (K) is one of the essential macronutrients for plant growth, while most agricultural soils are suffering from K deficiency worldwide. Therefore, it is a promising strategy to prepare K-enriched biochar from biomass waste. In this study, various K-enriched biochars were prepared from Canna indica at 300-700 °C by pyrolysis, co-pyrolysis with bentonite, and pelletizing-co-pyrolysis. The chemical speciation and release behaviors of K were investigated. The derived biochars showed high yields, pH values, and mineral contents, which were affected by the pyrolysis temperatures and techniques. The derived biochars contained a significant amount of K (161.3-235.7 mg/g), which was much higher than the biochars derived from agricultural residues and wood. Water-soluble K was the dominant K species in biochars with a proportion of 92.7-96.0%, and co-pyrolysis and pelletizing promoted the transformation of K to the exchangeable K and K silicates. In comparison with the C. indica derived biochars (83.3-98.0%), the bentonite-modified biochar showed a lower cumulative release proportion of K (72.5% and 72.6%) in a 28-day release test, meeting the Chinese National Standard for slow-release fertilizers. In addition, the pseudo-first order, pseudo-second order, and Elovich models well described the K release data of the powdery biochars, and the pseudo-second order model was the best fit for the biochar pellets. The modeling results indicated that the K release rate decreased after the addition of bentonite and pelletizing. These results indicated that the biochars derived from C. indica could be used as potential slow-release K fertilizers for agricultural application., 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.)

Pyrolysis of oily sludge (OS) is a feasible technology to match the principle of reduction and recycling; however, it is difficult to confirm the feasible environmental destination and meet the corresponding requirements. Therefore, an integrated strategy of biochar-assisted catalytic pyrolysis (BCP) of OS and residue utilization for soil reclamation is investigated in this study. During the catalytic pyrolysis process, biochar as a catalyst intensifies the removal of recalcitrant petroleum hydrocarbons at the expense of liquid product yield. Concurrently, biochar as an adsorbent can inhibit the release of micromolecular gaseous pollutants (e.g. HCN, H 2 S, and HCl) and stabilize heavy metals. Due to the assistance of biochar, pyrolysis reactions of OS are more likely to occur and require a lower temperature to achieve the same situation. During the soil reclamation process, the obtained residue as a soil amendment can not only provide a carbon source and mineral nutrients but can also improve the abundance and diversity of microbial communities. Thus, it facilitates the plant germination and the secondary removal of petroleum hydrocarbons. The integrated strategy of BCP of OS and residue utilization for soil reclamation is a promising management strategy, which is expected to realize the coordinated and benign disposal of more than one waste.

Recently, Fenton-like systems have been widely explored and applied for the removal of organic matter from wastewater. Two-dimensional (2D) MXene-based materials exhibit excellent adsorption and catalysis capacity for organic pollutants removal, which has been reported widely. However, there is no summary on the application of MXene-based materials in Fenton-like systems for organic matter removal. In this review, four types of MXene-based materials were introduced, including 2D MXene, MXene/Metal complex, MXene/Metal oxide complex, and MXene/3D carbon material complex. In addition, the Fenton-like system usually consists of adsorption and degradation processes. The oxidation process might contain hydrogen peroxide (H 2 O 2 ) or persulfate (PS) oxidants. This review summarizes the performance and mechanisms of organic pollutants adsorption and oxidants activation by MXene-based materials systematically. Finally, the existing problems and future research directions of MXene-based materials are proposed in Fenton-like wastewater treatment systems., 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 © 2022 Elsevier B.V. All rights reserved.)

Semipermeable membrane-covered composting is one of the most commonly used composting technologies in northeast China, but its humification process is not yet well understood. This study employed a semipermeable membrane-covered composting system to detect the organic matter humification and bacterial community evolution patterns over the course of agricultural waste composting. Variations in physicochemical properties, humus composition, and bacterial communities were studied. The results suggested that membrane covering improved humic acid (HA) content and degree of polymerization (DP) by 9.28% and 21.57%, respectively. Bacterial analysis indicated that membrane covering reduced bacterial richness and increased bacterial diversity. Membrane covering mainly affected the bacterial community structure during thermophilic period of composting. RDA analysis revealed that membrane covering may affect the bacterial community by altering the physicochemical properties such as moisture content. Correlation analysis showed that membrane covering activated the dominant genera Saccharomonospora and Planktosalinus to participate in the formation of HS and HA in composting, thus promoting HS formation and its structural complexity. Membrane covering significantly reduced microbial metabolism during the cooling phase of composting., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Agricultural application contributes major consumption of antibiotics worldwide. As veterinary antibiotics are poorly metabolized by animals, most of them end up in agricultural waste, which is increasingly subject to thermal treatment, such as torrefaction, pyrolysis, etc. However, there is a lack of research on their thermal decomposition mechanisms and products elucidation. Therefore, this study investigated the thermal decomposition of four major veterinary antibiotics groups (β-lactams, tetracyclines, fluoroquinolones, sulfonamides) with emphasis on their thermal stability, structural transformation and antibacterial activity. Results show that thermal treatment can remove the parent antibiotics with their antibacterial activity except for gatifloxacin (GAT). Although the parent form of GAT was fully removed at 200 °C, its products showed significant antibacterial activity against E. coli. We present novel evidence that the PhO-CH 3 chemical bond on GAT preferentially brake to generate methyl radical, which underwent a substitution reaction at the para position of phenol. This reaction also occurred during the thermal decomposition of antibiotic analogues, balofloxacin and moxifloxacin, whose thermolysis products also showed significant antibacterial activity. Furthermore, these thermolysis products may present potentially cardiotoxic and pose higher risks to human health than their parent forms, based on the comparison with a group of drugs withdrawn from the market., 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 © 2022 Elsevier Ltd. All rights reserved.)

Biochar (e.g. pyrochar and hydrochar) is considered a promising adsorbent for Cd removal from aqueous solution. Considering the vastly different physicochemical properties between pyrochar and hydrochar, the Cd 2+ sorption capacity and mechanisms of pyrochars and hydrochars should be comparatively determined to guide the production and application of biochar. In this study, the hydrochars and pyrochars were prepared from Napier grass by hydrothermal carbonization (200 and 240 °C) and pyrolysis (300 and 500 °C), respectively, and the physicochemical properties and Cd 2+ sorption performances of biochars were systematically determined. The pyrochars had higher pH and ash content as well as better stability, while the hydrochars showed more oxygen-containing functional groups (OFGs) and greater energy density. The pseudo second order kinetic model best fitted the Cd 2+ sorption kinetics data of biochars, and the isotherm data of pyrochar and hydrochar were well described by Langmuir and Freundlich models, respectively. In comparison with hydrochar, the pyrochar exhibited better Cd 2+ sorption capacity (up to 71.47 mg/g). With increasing production temperature, the Cd 2+ sorption capacity of pyrochar elevated, while the reduction was found for hydrochar. The mineral interaction, complexation with surface OFGs, and coordination with π electron were considered the main mechanisms of Cd 2+ removal by biochars. The minerals interaction and the complexation with OFGs was the dominant mechanism of Cd 2+ removal by pyrochars and hydrochars, respectively. Therefore, the preparation technique and temperature have significant impacts on the sorption capacity and mechanisms of biochar, and pyrochar has better potential for Cd 2+ removal than the congenetic hydrochar., 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 © 2022 Elsevier Ltd. All rights reserved.)

A biomass gasification ash disposal method, recirculating it to gasification process, was proposed in this work. The recirculation reusability was analyzed via reusing corn straw (CS) gasification ash for six recirculation in a gasifier. Metals, especially K, got enriched in ash during ash recirculation. Under the 1st ash recirculation, CO content, H 2 content and lower heating value of gas products increased from 16.02 to 19.97 vol%, from 11.30 to 15.72 vol%, from 5.38 to 6.47 MJ/Nm 3 , respectively. Moreover, it also exhibited an ability in tar decomposition, resulting in a tar reduction (4.63 g/Nm 3 for raw CS gasification and 3.62 g/Nm 3 for 1st ash recirculation). These positive effects gradually increased during the first four ash recirculation. The positive effects highly depended on the accumulation of metals (K, Na, Ca, Mg, and Fe) in ash. The positive effect did not increase as the fifth and sixth ash recirculation were conducted, resulting from the constant metals content in ash. Grey relational analysis showed that the total content of these metals was the most significant influencing parameter, followed by K content, water-soluble K content, Ca content, respectively. Moreover, pollutant SO 2 could be captured by CaO during ash recirculation. This reaction competed with simultaneous CaO carbonation reaction, while it was inferior to the latter. Thus, only the first and second ash recirculation exhibited satisfactory ability in SO 2 capture. In summary, ash recirculation in gasification process was feasible for upgrading gasification performance and its effect was persistent., 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 © 2022 Elsevier Ltd. All rights reserved.)

Sorption is considered a cost-effective technique for cadmium (Cd) removal from water, while the exhausted Cd-enriched sorbent should be properly disposed of. In this study, pyrolysis of exhausted hydrochar sorbent was conducted at 300-900 °C, and the behavior of Cd and the physicochemical properties and environmental applications of the regenerated biochar were investigated. The vaporization of adsorbed Cd in hydrochar was greatly enhanced by elevating pyrolysis temperature, and almost no Cd was observed in the regenerated biochars obtained at 700-900 °C. In comparison with the raw hydrochar, the regenerated biochars showed higher pH, ash content, and carbon content, while the contents of hydrogen and oxygen decreased. According to the toxicity characteristic leaching procedure result, the toxicity and mobility of Cd in hydrochar were greatly reduced after pyrolysis. Notably, the regenerated biochar showed much higher Cd sorption capacity (26.05-30.24 mg/g) than the raw hydrochar (6.70 mg/g). Surface complexation with oxygen-containing functional groups was the dominant Cd sorption mechanism for hydrochar, and precipitation between Cd 2+ and carbonates dominated the Cd removal by the regenerated biochars. These results illuminated that pyrolysis can be an effective technique for the harmless disposal of exhausted hydrochar sorbent and the regeneration of valuable biochar., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Two kinds of C 8 isomers, di-n-butyl ether (DNBE) and 1-octanol, as potential oxygen-containing alternative fuels, show important value in the trade-off between efficiency and emission. In the present work, the effects of DNBE/1-octanol with different proportions (0, 10%, and 20%) blended into diesel on the combustion characteristics, fuel economy, and emission characteristics in a six-cylinder heavy-duty diesel engine were studied at low, medium, and high loads. 1-Octanol with a 20% blending ratio showed different combustion characteristics in the cylinder compared with the other fuels. The economic analysis showed that the brake specific fuel consumption of DNBE-diesel blend fuels was higher than that of 1-octanol-diesel blend fuels, while brake thermal efficiency was the opposite tendency. The emissions of nitrogen oxides (NOx), hydrocarbons (HC), and carbon monoxide (CO) were affected by the types of blend fuels, blending ratios, and loads. In comparison with 1-octanol-diesel blend fuels, the addition of DNBE in diesel promoted the emission of nitrogen oxides, but inhibited the emissions of soot, HC, and CO. DNBE- and 1-octanol-diesel blend fuels increased the weighted brake specific fuel consumption but decreased the weighted brake thermal efficiency compared with diesel in the World Harmonized Stationary Cycle test cycle of Euro VI regulation. The weighted NOx, HC, soot, and CO emissions of blend fuels depended on the types of blend fuels and blend ratios. The weighted NOx, HC, and soot emissions were reduced by blending 1-octanol into diesel, while the weighted CO emission was increased. The weighted CO and soot emissions of diesel blended with DNBE were reduced than that of diesel., 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 © 2022 Elsevier Ltd. All rights reserved.)

Ketohydroperoxides (KHPs) are oxygenates with carbonyl and hydroperoxy functional groups, and they are generated under combustion and atmospheric conditions. Their fate is crucial for secondary organic aerosol formation in the troposphere and for the ignition processes of biofuels in advanced combustion engines. We investigated the thermodynamics and kinetics of nine hydrogen abstraction reactions from four ether KHPs by OH. We find that the rate constants are strongly affected by entropic effects whose estimation requires a consideration of higher-energy conformers of the transition state. A density functional was selected for these reactions by comparison to coupled cluster calculations, and it was used for calculations by multistructural canonical transition-state theory with multidimensional tunneling over the temperature range of 200-2000 K. We find that the effect of multistructural torsional anharmonicity is very large and quite different for the various ether KHP reactions. A leading cause of the structural dependence is the dominance of entropic factors due to the lack of hydrogen bonding in some of the higher-energy conformers of the transition states. Four of the reactions involve abstraction from the α-carbon (the carbon vicinal to the hydroperoxide group); they exhibit nonmonotonic temperature dependence with complex fuel-specific dependence. The rate constants for abstraction from a non-α-carbon of a given KHP can be faster than the ones for abstraction from an α-carbon; in two cases, this is due to entropy, and in one case, the non-α-carbon abstraction has a lower energy barrier. Tunneling and recrossing effects are also found to be important.

Today, domestic cats are important human companion animals for their appearance and favorable personalities. During the history of their domestication, the morphological and genetic portraits of domestic cats changed significantly from their wild ancestors, and the gut microbial communities of different breeds of cats also apparently differ. In the current study, the gut microbiota of Ragdoll cats and Felinae cats were analyzed and compared. Our data indicated that the diversity and richness of the gut microbiota in the Felinae cats were much higher than in the Ragdoll cats. The taxonomic analyses revealed that the most predominant phyla of the feline gut microbiota were Firmicutes, Bacteroidota, Fusobacteriota, Proteobacteria, Actinobacteriota, Campilobacterota, and others, while the most predominant genera were Anaerococcus , Fusobacterium , Bacteroides , Escherichia-Shigella , Finegoldia , Porphyromonas , Collinsella , Lactobacillus , Ruminococcus&#95;gnavus&#95;group , Prevotella , and others. Different microbial communities between the Ragdoll group and the Felinae group were observed, and the compared results demonstrated that the relative abundances of beneficial microbes (such as Lactobacillus , Enterococcus , Streptococcus , Blautia , Roseburia , and so on) in the Ragdoll group were much higher than in the Felinae group. The co-occurrence network revealed that the number of nodes and links in the Felinae group was significantly higher than the Ragdoll group, which meant that the network of the Felinae group was larger and more complex than that of the Ragdoll group. PICRUSt function analyses indicated that the differences in microbial genes might influence the energy metabolism and immune functions of the host. In all, our data demonstrated that the richness and diversity of beneficial microbes in the Ragdoll group were much higher than the Felinae group. Therefore, it is possible to isolate and identify more candidate probiotics in the gut microbiota of growing Ragdoll cats.

The emerging photopolymerization-based 3D printing industry has led to a growing concern for the disposal of photocured waste (PCW), which is inevitably generated during the life cycle of photopolymerization-based 3D printing. In order to shed light on suitable thermochemical treatment and utilization approaches of PCW, this work comprehensively investigated the properties and kinetics during PCW pyrolysis via TG-FTIR/GC-MS analysis. The results demonstrated that the main decomposition of PCW sample happened in the range 320-550 °C with a total weight loss of 93.34 wt%. According to the result of four kinetic models, the activation energy of PCW sample was approximately 228.58-245.05 kJ/mol. Finally, the FTIR and GC-MS results manifested that the main components of volatiles released at different heating rates were the same. The volatiles mainly include (S)-(+)-2-hydroxy-2-phenylprop, benzaldehyde, benzophenone (photo-initiator), benzoic acid, benzoylformic acid etc., which have a multitude of potential applications. However, these volatiles produced by PCW pyrolysis have a certain toxicity and potential hazard. This study demonstrates insightful fundamentals for thermochemical disposal of PCW, which appears to be potentially valuable with the rapid development of the photopolymerization-based 3D printing industry., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

The directional regulation of oxidation capacity in the carbon-based peroxymonosulfate (PMS) activation system is a promising strategy for wastewater purification. In this work, a novel iron cobalt and nitrogen co-doped carbonized wood sponge (FeCoNCWS) was developed. A superb catalytic performance for sulfamethoxazole (SMX) degradation (∼100.0%) was obtained within 30 min in FeCoNCWS800/PMS system at 60 °C. Besides, the reactive oxygen species (ROS) contribution was verified at different reaction temperatures. Specifically, the primary roles of sulfate and hydroxyl radicals (SO 4 - and OH) in SMX removal weakened, while the secondary role of singlet oxygen ( 1 O 2 ) in SMX degradation was enhanced with the rise of reaction temperature in FeCoNCWS800/PMS system. Interestingly, defects, graphitic N and carbonyl (CO) groups were vital active sites for PMS activation to produce 1 O 2 , which was facilitated at higher reaction temperature. Besides, the metal sites were identified as PMS activators for SO 4 - and OH generation, which was promoted under lower reaction temperature. The findings revealed a novel internal temperature-dependent PMS activation mechanism, which can help to regulate the oxidation capacity of PMS activation system rationally for pollutant degradation., 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 © 2022 Elsevier Inc. All rights reserved.)

The combustion mechanism of biogas mixture is unclear, which leads to the lack of basis for the control of operating parameters. Combustion characteristics and reaction path of typical low calorific value biogas with variation of preheating temperature and air equivalence ratio ( Φ ) are discussed in this paper. Preheating can not only improve the flame propagation speed and flame temperature, but also increase the proportion of NO in the product at the end of combustion flame. To some extent, improving combustion efficiency and NOx control are contradictory operating parameters. The amount of NO increases with the increase in flame distance. The maximum value of NO appears when Φ is 1.1. NO formation rate is improved by preheating the biogas. The paths of N 2 → N 2 O →NO, N 2 → NNH →NO, and N 2 →NO are all enhanced. When the equivalence ratio changes from 1.0 to 0.8, NO formation rates decrease., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Zuo, Qi, Ma, Sun, Luo, Ren, Zhang, Guo, Cheng and Li.)

Plastic wastes have posed serious threats to the environment, including decrease of soil nutrient effectiveness and agricultural production as well as emerge of ecological instability. Fuel conversion from plastic waste is regarded as a promising strategy for its disposal and energy utilization. Plastic wastes can be converted into target fuels by adjusting cracking of chemical bonds. Currently, numerous technologies regarding fuel conversion from plastic wastes have been reported, including conventional pyrolysis, novel heat treatment and advanced oxidation. However, systematic summary and comparative analysis of different technologies are still scarcely reported. In this review, fuel conversion from plastic wastes was summarized comprehensively, highlighting novel heat treatment and advanced oxidation technologies reported in recent years. Furthermore, the superiority and drawbacks of each technology were analyzed, and future prospects of technology application were proposed. With lower reaction temperature and higher-value fuel, novel heat treatment of plastics is more popular than traditional one. Advanced oxidation can be controlled to convert plastics into fuels under room temperature and pressure, guiding the new normal in energy utilization of plastic wastes. This review aims to provide inspiration for energy utilization of solid waste, addressing the issues of white pollution and energy shortage., (Copyright © 2021 Elsevier B.V. All rights reserved.)

The harmless treatment of heavy metal-enriched hyperaccumulator biomass is the main barrier to the industrialization of phytoremediation. Hydrothermal conversion of Sedum alfredii using different solvents (i.e ·H 2 O and HCl) at 210-300 ℃ was performed to investigate the behaviors of Cd and Zn, and the characteristics and potential application of the derived hydrochars were determined. Low temperature and HCl addition favored the removal of Cd/Zn from the solid phase. The highest removal efficiencies of Cd (95.0%) and Zn (89.3%) were achieved at 210 ℃ with the presence of HCl. The yield, pH, ash content, element concentration, functional groups, and crystalline minerals of the derived hydrochar were influenced by the reaction temperature and addition of HCl. The leaching risk of Cd and Zn was significantly reduced by hydrothermal conversion. The addition of HCl facilitated the immobilization of Zn, while it enhanced the mobility of Cd. Moreover, the hydrochar derived at 210 ℃ showed increased sorption capacity towards Cu, and the addition of HCl greatly improved the energy density of hydrochar. These results suggest that HCl-mediated hydrothermal conversion could be a promising technique to achieve the separation of Cd and Zn from hyperaccumulator biomass as well as the production of value-added hydrochar., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Renewable wood sponge with lamellar structure, compressibility and three-dimensional porous frameworks exhibits excellent functionalization application potential in various fields. Herein, cobalt and nitrogen (Co/N) co-doped carbonized wood sponge (CoNCWS800) was prepared successfully for peroxymonosulfate (PMS) activation to degrade sulfamethoxazole (SMX). The CoNCWS800 material exhibited admirable catalytic activity in PMS activation to oxidize SMX molecules (99.7% within 60 min). Electron paramagnetic resonance (EPR) analysis, quenching tests and electrochemical experiments confirmed the existence of both radical (SO 4 ·- ,·OH and O 2 ·- ) and non-radical ( 1 O 2 and direct charge transfer) pathways during the SMX degradation process. Co species were verified as major contributors for the generation of multiple radicals via activating PMS. Surface defective structure and ketonic CO groups performed the positive linear correlation with reaction kinetic constants, revealing the critical role of the two active sites in PMS activation via non-radical process. This study provides a unique insight in PMS activation mechanism via both radical and non-radical pathways of wood sponge-based functional materials., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Peroxymonosulfate (PMS)-based advanced oxidation processes (PMS-AOPs) as an efficient strategy for organic degradation are highly dependent on catalyst design and structured active sites. However, the identification of the active sites and their relationship with reaction mechanisms for organic degradation are not fully understood for a composite catalyst due to the complex structure. Herein, we developed a family of Co encapsulated in N-doped carbons (Co-PCN) with tailored types and contents of active sites via manipulated pyrolysis for PMS activation and ciprofloxacin (CIP) degradation, focusing on the correlation of active sites to generated reactive species and degradation routes of organics. The structure-function relationships between the different active sites in Co-PCN catalysts and reactive oxygen species (ROS), as well as bond breaking position of CIP, were revealed through regression analysis and density functional theory calculation. Co-N x , O-C═O, C═O, graphitic N, and defects in Co-PCN stimulate the generation of 1 O 2 for oxidizing the C-C bond in the piperazine ring of CIP into C═O. The substitution of F by OH and hydroxylation of the piperazine ring might be induced by SO 4 •- and • OH, whose formation was affected by C-O, Co(0), Co-N x , graphitic N, and defects. The findings provided new insights into reaction mechanisms in PMS-AOP systems and rational design of catalysts for ROS-oriented degradation of pollutants.

Due to rapid deactivation of catalysts, the effective conversion of biomass with oxygen-rich and hydrogen-deficient characteristics to transportation fuels and high-valued chemicals via catalytic pyrolysis remains a challenge for commercialization. Hydrogen-rich plastic is used as feedstock co-fed with biomass to improve the catalytic pyrolysis process. The present work aims to investigate the co-pyrolysis process of cellulose and polyethylene (PE) over MgO by TG combined with photoionization time-of-flight mass spectrometry (PI-TOF-MS), which features on-line detection of catalytic pyrolysis products in real time. The MgO catalyst could improve the pyrolysis of cellulose and enhance the CC bond breaking of PE, respectively. During catalytic co-pyrolysis, the yields from olefins and furan as well as its derivatives can be enhanced obviously. Further, the formation of additional aromatics can be observed due to the Diels-Alder reaction. This work shows TG coupled to PI-TOF-MS is a powerful setup to study and optimize catalytic co-pyrolysis process., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

HCHO is the most concerned indoor air pollutant that photocatalytic degradation is a feasible approach. To achieve efficient and complete degradation of HCHO under visible light irradiation, heteroatoms are usually doped in TiO 2 . But using natural materials as a dopant instead of expensive and toxic chemicals to fertilize TiO 2 remains challenging. This paper proposes a sustainable and green approach to synthesize an efficient N, Ca co-doped TiO 2 photocatalyst (TIMP) by using the insoluble matrix proteins (IMPs) extracted from abalone shell. TIMP-0.8 achieves near completely degradation HCHO within 45 min under visible light at ambient temperature and exhibits superior stability after 7 cycles. TIMP-0.8 has monodispersity with smaller diameter, high porosity, abundant defects and high adsorption affinity for surface hydroxyls compared with pure TiO 2 . With the assistance of IMPs, the rate-determining step of HCHO degradation changes from -COOH oxidation to spontaneous decomposition of HCO 3 - , significantly facilitating the elimination and mineralization of HCHO. Overall, IMPs from abalone shell are natural surfactant, bio-templet, and dopant for TiO 2 modification, contributing to desirable visible-light photocatalytic performance for HCHO degradation. This paper provides new insight for high-value utilization of waste shell and photocatalytic indoor purification., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Limited availability of fossil energy and serious environmental pollution have caused the emergence of bio-oil, which can serve as an alternative and promising green energy source. However, bio-oil generated from the rapid pyrolysis of biomass cannot be utilized immediately owing to its corrosivity, instability, and low heating value. Herein, the electrocatalytic hydrogenation (ECH) process towards bio-oil upgrading is reviewed. Specifically, the ECH integrates the advantages of mild operating conditions, no petrochemically derived hydrogen and good controllability. The influence of different factors on the conversion of bio-oil components and product selectivity in the ECH process are presented comprehensively. In addition, various reaction mechanisms are discussed in the designed ECH systems. Finally, some challenges need to be further overcome for real bio-oil reduction in the ECH process: exploration of efficient multifunctional electrocatalysts for specific bio-oil components and determination of the dominant steps in the complicated reaction path network., (© 2020 Wiley-VCH GmbH.)

Wastewater treatment by duckweed is a naturally sustainable technology. However, its development is limited due to the lack of a follow-up treatment of duckweed. The duckweed was proposed for the treatment of rural domestic wastewater and agricultural wastewater, and it was further processed to produce bio-oil via hydrothermal liquefaction at various temperatures (250 °C-370 °C) and residence times (15-60 min). The highest bio-oil yield of 35.6 wt% was obtained at 370 °C, 45 min. The higher heating value of bio-oil was 40.85 MJ/kg, and the H/C ratio (1.72-1.98) was similar to that of petroleum (1.84). The gas chromatography-mass spectrometry analysis results revealed that the bio-oil mainly consisted of N-heterocycles, cyclic ketones, esters, amides, long-chain hydrocarbons, phenols, and aromatic intermediates. Valuable compounds (3-pyridinol, 2-pyrrolidinone, and its analogues) of high concentration were identified in the water-soluble organic matter. Compared with other materials, this study produced higher-quality bio-oil and water-soluble organic matter., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

This paper proposes a sustainable and facile approach for the synthesis of photocatalysts in which shell waste is used as support material. The synthesized photocatalysts exhibited a significant performance in the mineralization of organic substances under solar irradiation or artificial lighting. Calcined abalone shell with a TiO 2 loading of 23.4% led to a significant improvement in optical absorption: the degradation efficiencies of methylene blue (MB) after 140 min under UV light, vis light, UV-vis light, and natural sunlight were 93%, 96%, 100%, and 100%, respectively. Notably, the byproducts obtained after the degradation by commercial P25 TiO 2 disappeared with the utilization of shell waste as support material. The Na, Sr, S present in the calcined abalone shell were doped into the substitutional sites of TiO 2 and were indispensable to achieve the desired band-gap narrowing and photocatalytic performance; moreover, the Ti and Zn oxides in the calcined abalone shell acted as semiconductors and improved the charge separation efficiency of TiO 2 . Above all, this paper describes a green synthesis based on the use of waste seashell. This material acts as an excellent photocatalyst support for environmental pollution treatments, leading to the 'control of waste by waste' and opening up new possibilities for shell waste reutilization and sustainable chemistry., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Considering the advantages (e.g. agglomeration mitigation) and disadvantages (e.g. inorganic species catalysis removal) of biomass demineralization, it is valuable to investigate its effects on gasification performance, thus assessing its necessity prior to performing gasification. To accomplish this, corn straw (CS) was demineralized to different degrees with H 2 O and HCl, respectively. H 2 O and HCl demineralization behaved different abilities to inorganic species removal. Cellulose and hemicelluloses content decreased, while lignin content increased, especially with HCl demineralization. The experiments were investigated by using a bench-scale downdraft fixed-bed gasifier at 600-800 °C and were further analyzed via thermogravimetric coupled with Fourier transform infrared spectrometry. Demineralization demonstrated a positive effect on gasification at lower temperatures (600-700 °C) for a dominant effect of lignin content and an insignificant effect of inorganic species removal. However, the catalysis of inorganic species increased as the temperature increased, resulting in the highest H 2 (11.30 vol%) and CO (16.02 vol%) production of raw CS compared to demineralized CS at 800 °C. Inorganic species had a dual positive effect on CO generation, promoting both CO 2 and char generation leading to a higher CO yield following Boundouard reaction, and increasing the formation of active intermediates thus producing more CO. These effects enhanced when the gasification temperature increased. Additionally, inorganic species catalyzed the aromatic rings rearrangement to generate more H 2 O, thus driving the endothermic Primary water-gas to produce H 2 . This was also positively correlated with gasification temperature. Therefore, raw CS demonstrated higher H 2 and CO production than demineralized CS at a higher gasification temperature. Moreover, the promotion effect of inorganic species on thermal devolatilization of methoxyl groups and Methanation reaction led to the higher CH 4 production of raw CS. This research clarifies the effects of biomass demineralization on its gasification and suggests the potential application., 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 Elsevier B.V. All rights reserved.)

China is an agricultural country, approximately producing more than 1000 million tons of crop straw in 2018. The utilization of straw as energy can replace fossil fuels, protect environment and guarantee energy security. Biomass fuel has been regarded as renewable energy with the characteristics of carbon-neutral, and low emissions of nitrogen oxides and sulfur dioxide. Biomass molded fuel (BMF), a major type of biomass fuel, has attracted particular attention. Currently, the BMF industry in China develops slowly. To achieve the rapid and healthy development of the industry, in this paper, a three-part standard system as fuel side, production and combustion equipment side and pollutant emission side is proposed to regulate the BMF market. Simultaneously, a policy system consisting of legislation, development plans and incentive measures also is introduced to maintain policy consistency and continuity., Competing Interests: Declaration of competing interest We declare that we have no financial and personal relationships with other people or organizations that can inappropriately influence our work, there is no professional or other personal interest of any nature or kind in any product, service and/or company that could be construed as influencing the position presented in, or the review of, the manuscript entitled., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Co-pyrolysis is a promising approach to recover energy from sewage sludge (SS) and municipal solid waste (MSW). Hg emission during this process has serious environmental risks. To reduce the environmental impact, orthogonal experiments on the blending ratio, heating rate, pyrolysis temperature, and residence time were conducted during SS and MSW co-pyrolysis. Variance analysis was used to determine the influence and synergetic effects of these factors. Multivariate nonlinear, neural network, random forest, and support vector machine models were used to simulate the Hg distribution based on four parameters, which were later optimized to optimize the Hg fixing ratio in pyrolysis char. The Hg was mainly distributed in the pyrolysis gas and char. The variance analysis results indicate that the blending ratio is the key factor influencing Hg distribution, and there is little synergetic effect among the four factors. Further experiments showed that a blending ratio of 87.5 SS wt% could enhance Hg fixation in char. The neural network model shows the best simulation performance with a mean relative error of 8.92%. The optimal parameters are a heating rate of 7 °C/min, pyrolysis temperature of 300 °C, and residence time of 10 min, resulting in a Hg fixing ratio of 25.68 wt% in pyrolysis char. The simulated Hg fixation characteristics correlate with the experimental results. This study provides insights into Hg distribution under various conditions during co-pyrolysis of SS and MSW. It is hoped that this work can contribute to the control of Hg during the waste treatment and utilization process., 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 Elsevier Ltd. All rights reserved.)

Low-lipid content algae have demonstrated potential in the bio-crude production because of their high yield and robust ability to adapt to hostile cultivation environment in mass cultivation. Hydrothermal liquefaction (HTL) technology is an effective method to convert wet algae to bio-crudes directly. In this study, the HTL processes of two low-lipid content algae, Nannochloropsis sp. and Sargassum sp., were investigated under various reaction temperatures (260-320 °C). Results showed that the bio-crudes yield of Nannochloropsis sp. (39.05 wt% to 54.11 wt%) was significantly higher than that of Sargassum sp. (3.11 wt% to 9.49 wt%). The higher heating value of Nannochloropsis sp. (35.92 MJ/kg to 37.88 MJ/kg) were also slightly higher than that of Sargassum sp., (33.63 MJ/kg to 35.23 MJ/kg). GC-MS analyses showed that Nannochloropsis sp. bio-crude mainly contained amides and N-heterocyclic compounds while Sargassum sp. bio-crude mainly contained N-heterocyclic compounds and ketones. Alcohols were the major aqueous phase compounds for both algae. For Nannochloropsis sp., glycerin accounted for the largest proportion in alcohols, while dianhydromannitol and 1,5-anhydro-d-mannitol were the major alcohols component for Sargassum sp. Based on the compositions of the HTL products and the feedstock, a reaction pathway network of the HTL process of low-lipid algae was proposed in this study. Amino acids related interactions like acylation and Maillard reaction were prominent in HTL process of these two algae, which effectively converted protein and carbohydrate compounds into bio-crudes., Competing Interests: Declaration of competing interest All the authors of this article confirm that no author has any conflict of interest to disclose. All authors have approved the version submitted for publication. The work in this article is original and has not been published previously. The article is not under consideration by any other journal., (Copyright © 2019. Published by Elsevier B.V.)

Heterogeneity is a most serious obstacle for treatment and utilization of biomass and waste (BW). This paper proposed a fast characterization method based on infrared spectroscopy and machine learning models, thus to roughly predict the elemental composition and heating value of BW. The fast characterization results could be used to sort different BW components by their suitable downstream utilization techniques. The infrared spectra based hybrid model contained a feature compression section to extract core information from raw infrared spectra, a classification section to distinguish inorganic dilution, and a regression section to generate the elemental composition and heating value results. By parameters optimization, the accuracy of this hybrid model reached 95.54%, 85.53%, 92.40%, and 92.49% for C content, H content, O content, and low heating value prediction, respectively. The robustness analysis was conducted by completely rearranging the training and test sets, and it further validated the hypothesis that the infrared spectra contains enough qualifying and quantifying information to characterize these properties of BW. Compared with previous literature, the C-H, C-O, and O-H correlations in BW were also well kept in the predicted results. This work is hoped to enhance upstream sorting system design for treatment and utilization of BW., Competing Interests: Declaration of interests 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 © 2019 Elsevier B.V. All rights reserved.)

This study investigated catalytic reforming, which is a thermochemical process, as a pioneering method to treat biogas slurry (wastewater from biogas plants) and generate hydrogen. Experimental validation for treating biogas slurries from digested cattle manure, fish intestine, and wheat straw was performed on Ni/α-Al 2 O 3 catalyst. The results showed that the total organic carbon, total nitrogen, and PO 4 3- ion contents in biogas slurry could be reduced by 98.69, 98.01, and 99.32%, respectively. The highest hydrogen yield was obtained in the treatment of biogas slurry from digested cattle manure at 750 °C, in which the hydrogen yield and hydrogen concentration were 13.85 L hydrogen / L BS and 79.77 vol %, respectively. Changes in the crystalline phase and structure of the catalyst were observed during catalytic reforming of biogas slurry. Active metal oxidization and carbon deposition were likely to be important factors affecting catalytic stability. The mass flow evaluation verified the hydrogen generation potential by the catalytic reforming of biogas slurry, which was close to the methane generation capability of the upstream biogas plant. However, additional effort is required to address the high energy consumption of this method. These findings provide fundamental knowledge about the potential of applying thermochemical techniques to treat and utilize high total organic carbon-containing wastewaters.

Heavy metal stabilization by chemical chelating agent and solidification by cement are technologies currently used to reduce the leaching of heavy metals in municipal solid waste incineration (MSWI) fly ash. This paper studied the physico-chemical properties of the fly ash, heavy metals content in the fly ash, and the leaching concentration of the heavy metals from fly ash. The effect of four chelating agents namely dithiocarbamate (1#), dithiocarbamic acid dipotassium salt (2#), amino dithiocarbamate chelating resin (3#) and thiourea (4#) on the stabilization and leaching of heavy metals were investigated. Different addition ratios (1%, 2% and 3% w/w) of the chelating agents, various curing time (7, 14, 28 days), and different amounts of the cement (10%, 15% and 20% w/w) were used in order to find the agent with the optimum stabilization and leaching of heavy metals as well as find the effect of combining the agent and cement. The results showed that the dithiocarbamate (1#) chelating agent had the best stabilizing performance due to the three-dimensional structure after their reaction. The addition of cement to the fly ash led to the immobilization of heavy metals due to the C-S-H gel formation. The technology of cement solidification and chelating agent stabilization was optimal from the point of economic cost and the complexity aspect., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

The thermal decomposition of furfural is investigated in a flow tube reactor at 30 Torr by synchrotron vacuum ultraviolet photoionization mass spectrometry (SVUV-PIMS) at temperatures from 1023 to 1273 K. Over 20 kinds of pyrolysis products, including short-lived radicals, stable oxygen-containing compounds, and hydrocarbons, are identified from the scanning photoionization efficiency (PIE) spectra. Vinylketene (CH 2 ═CH-CH═C═O), which has been shown to be an important primary product, is also directly observed. The possible steps of hydrogen atom addition and hydrogen atom abstraction in the thermal decomposition of furfural are studied by theoretical calculations at the CBS-QB3 level. In addition to unimolecular decomposition, hydrogen atom addition followed by ring opening can lead to the production of vinylketene.

Incineration is well used to treat municipal solid wastes (MSW) but is difficult to treat sewage sludge (SS) because it requires a large amount of heat to remove high content of moisture in SS. Over 50 billion tons of SS are discharged annually in China, and the need for a better waste treatment strategy is urgent. This paper is to introduce a waste disposal technology referring to the integrated treatment of MSW and SS. Four scenarios were analyzed including Mono-incineration of MSW (Case 1) and SS (Case 2), co-incineration of SS and MSW by traditional (Case 3) and integrated ways (Case 4), in terms of environment, energy and economic impact by means of LCA, CED and TEA method. From the environmental perspective, the top four mid-point categories involving the largest effect on four cases are N-C (non-carcinogens), OLD (Ozone layer depletion), TET (Terrestrial eco-toxicity), and GWP (Global warming potential). Case 4 has the most positive effect on climate change and resources (-1.44 kg CO 2  eq and -18 MJ, respectively) according to end-point categories. From the view of energy, Case 4 shows the best performance of energy efficiency, and significantly saves the non-renewable energy (0.21 t coal per ton feedstock compared with Case 3). From the economic part, Case 4 is preferentially potential with the best profit, cutting down 79.08% of cost in coal than that in Case 3. These results provide understandings of developing an effective approach for co-treating MSW and SS in the near future., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Based on the statistics data, this paper estimated the quantity of biomass resource, and then the distribution of emissions from its combu3stion and gasification was analyzed in Tibet in 2015. The main conclusions are as follows: (1) biomass energy is rich in Tibet and its geographical distribution and quantity mainly depends on the relationship between ecological zones and the climate conditions. Crop straw is mainly distributed in Xigazê, Lasha, Qamdo and Shannan with the total quantity of 3.29×10 6 t/year; while animal dung is mainly distributed in Nagqu, Qamdo and Xigazê with the total quantity of 1.69×10 7 t/year. For the acquirable quantity of crop straw and animal dung is 7.27×10 6 t/year, mainly distributed in Nagqu, Qamdo and Xigazê. (2) The energy production potential of crop straw and animal dung in Tibet for combustion (thermal efficiency: 22.5%), HLG (system efficiency: 28.75% based on our investigation) and VLG (system efficiency: 38.75%) is 2.56×10 10 J/year, 3.28×10 10 J/year and 4.42×10 10 J/year, respectively. (3) Compared to the household combustion, the reduction of SO 2 is 72% with HLG and 97% with VLG, and the NOx reduction is 79% with HLG, 96% with VLG and 72% with gasification-combustion case., (Copyright © 2018 Elsevier B.V. All rights reserved.)

The catalytic cracking upgrading reactions over HZSM-5 of different model compounds of bio-oil have been studied with a self-designed fluid catalytic cracking (FCC) equipment. Typical bio-oil model compounds, such as acetic acid, guaiacol, n-heptane, acetol and ethyl acetate, were chosen to study the products distribution, reaction pathway and deactivation of catalysts. The results showed: C 6 -C 8 aromatic hydrocarbons, C 2 -C 4 olefins, C 1 -C 5 alkanes, CO and CO 2 were the main products, and the selectivity of olefins was: ethylene>propylene>butylene. Catalyst characterization methods, such as FI-IR, TG-TPO and Raman, were used to study the deactivation mechanism of catalysts. According to the catalyst characterization results, a catalyst deactivation mechanism was proposed as follows: Firstly, the precursor which consisted of a large number of long chain saturated aliphatic hydrocarbons and a small amount CC of aromatics formed on the catalyst surface. Then the active sites of catalysts had been covered, the coke type changed from thermal coke to catalytic coke and gradually blocked the channels of the molecular sieve, which accelerated the deactivation of catalyst., (Copyright © 2018 Elsevier B.V. All rights reserved.)

The thermogravimetric (TG) experiments of cattle manure were carried out from room temperature to 900°C at five different heating rates (10, 20, 30, 40 and 50°C/min) and the kinetics of the main decomposition process were analyzed with different methods. TG curves indicate that the major decomposition process of cattle manure could be roughly divided into three stages. The average activation energy of each stage calculated by Coats-Redfern method are 68.95, 2.63 and 55.32kJ/mol respectively. The kinetic parameters given by Distributed Activation Energy Model method, Flynn-Wall-Ozawa method and Vyazovkin method are all show that the activation energies keep stable (at around 122.4, 126 and 123.8kJ/mol respectively) under 60% conversion degree and then changed dramatically (ranging from 129.9 to 454.9kJ/mol). Power law (P3) was determined as an appropriate reaction mechanism using master-plots method. The kinetic parameters calculated by Vyazovkin method can give the best agreement with the experimental results., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Digestate is a byproduct from biomass anaerobic digestion process. Gasification of dried digestate to produce gasesous product might be a promising route. In this work, air gasification of digestate with high ash content was performed in a downdraft fixed bed gasifier at temperature varying from 600°C to 800°C and air equivalence ratio (ER) ranging from 0.25 to 0.30. The ash melting properties were firstly detected by the Intelligent Ash Melting Point Test, and the by-products (biochar and ash) were analyzed. The results showed that no ash slagging was observed and therefore it is feasible to operate digestate gasification under 800°C and ER ranging from 0.25 to 0.30. High temperature favored gas production, 800°C is proposed for digestate gasification in the present study. ER with a medium value improved gas quality and cold gas efficiency (CGE), and the optimal LHV of 4.78MJ/Nm 3 and CGE of 67.01% were obtained with ER of 0.28. High ER favored the increase of gas yield and decrease of tar concentration, and the optimal gas yield of 2.15 Nm 3 /kg and tar concentration of 1.61g/Nm 3 were achieved with ER of 0.30. Improved molar ratio of H 2 /CO varying from 1.03 to 1.08 was obtained at 800°C, indicating gaseous product has the potential for chemical synthesis processes (12 /CO<2). The byproducts biochar and ash could be applied on land as fertilizer., (Copyright © 2017 Elsevier Ltd. All rights reserved.)