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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.)

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.)

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_E a and C_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.)

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.)

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.)

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.)

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.)

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.)

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.)