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[Display omitted] • Biomass-derived hydrothermal char coated with metal nanoparticles were synthesized. • The composites exhibit both high microwave heating behavior and catalytic activity. • The catalysts achieved a rapid heating rate of 5.49 °C/s by microwave heating. • HCM-Co achieved a high liquid yield of 38.4 % at 500 °C. • The phenolic compounds reached a high relative content of 54.9%. In this study, three types of hydrothermal char-supported metal nanoparticle composites (HCM-Fe, HCM-Co, and HCM-Ni) were prepared using pinewood as the raw material via an ion hydrothermal pretreatment followed by microwave heating method, which were then served as both catalysts and microwave absorbers to enhance the rapid pyrolysis of pine wood particles for the selective preparation of phenols-rich bio-oil. The combined effects of hydrothermal carbonization and microwave heating enriched the pore structure of the composite surface, yielding ordered carbon structures such as carbon microspheres, carbon nanotubes, and graphite layers. Also, metal nanoparticles were generated and uniformly anchored on the hydrothermal char matrix by the graphite layers. The three types of hydrothermal carbon-based catalysts exhibit excellent microwave absorption performance, facilitating rapid heating of pine particles at a rate as fast as 5.49 °C/s. Among these catalysts, HCM-Co demonstrates the best catalytic performance, efficiently promoting the cleavage of the β -O-4 bond in lignin and achieving a liquid product yield of 38.4 % at 500 °C. The resulting bio-oil is characterized by its richness in phenolic compounds, accounting for 54.9 % of its composition, and partial mitigation of acidity. [ABSTRACT FROM AUTHOR]

The development of superior electrode materials using biomass as sustainable carbon sources is of great significance in promoting the practical application of supercapacitors. Herein, we prepared a N, O co-doped hierarchical porous carbon (GPC-0.9 N) with an ultra-high specific surface area of 2808.65 m2 g−1 and abundant microporous, mesoporous and macroporous structures through the straightforward pre-carbonization method using garlic peels combined with KHCO 3 /melamine activation. Additionally, the relatively high nitrogen (3.81%) and oxygen content (4.79%) can enhance the wettability of the carbon materials and introduce additional pseudocapacitance. As a result, the electrode material achieved a high specific capacitance of 396.25 F g−1 at 1 A g−1 and outstanding rate capability of 283.13 F g−1 at 25 A g−1 in 6 M KOH electrolyte in a three-electrode system. Meanwhile, the symmetrical supercapacitor based on the GPC-0.9 N electrode material showed a high energy density of 9.07 Wh kg−1 at the power density of 309.2 W kg−1. Furthermore, it exhibited excellent cycling stability, with 92.5% of the capacitance retained after 10000 cycles at 10 A g−1. This research provides insights for the rational design of a green, renewable and eco-friendly biomass-derived porous carbon that can be widely used as supercapacitor electrode materials in the future. • KHCO 3 and melamine were co-activated to synthesize N, O co-doped porous carbon. • A hierarchical porous carbon structure dominated by mesopores was obtained. • The N and O content reached 3.81% and 4.79% with a high specific surface area of 2808.65 m2 g−1. • The carbon electrode exhibits a high capacitance of 396.25 F g−1 at 1 A g−1. • The capacitance retention of the carbon electrode remained 92.5% after 10000 cycles at 10 A g−1. [ABSTRACT FROM AUTHOR]

Biomass-derived carbons with porous structures and abundant surface functional groups have been regarded as a competitive electrode material for supercapacitors due to their renewability and easily adjustable porosity. The low-cost and environmentally friendly synthesis method of O and P co-doped hierarchical porous carbon nanosheets from waste coconut shells using potassium bicarbonate (KHCO 3) and potassium dihydrogen phosphate (KH 2 PO 4) as both activators and co-doped agents have been investigated for high-performance supercapacitors. Under an appropriate KH 2 PO 4 dosage, the pore structure of PAC-0.9 contains micropores, mesopores and macropores, and its specific surface area is 892.06 m2 g−1. The specific capacitance of PAC-0.9 in three electrode system reached 371.63 F g−1 at a current density of 0.5 A g−1, and remained at 223.25 F g−1 even for a current density of 30 A g−1. The symmetrical supercapacitor assembled with PAC-0.9 as the electrode achieved an energy density of 9.15 Wh kg−1 at a power density of 500 W kg−1. At a current density of 5 A g−1, the specific capacitance of PAC-SSC can still retain 96.23 % after 10,000 charge-discharge cycles. [Display omitted] • Biomass-derived Carbon nanosheets electrode with O, P co-doped was prepared. • PAC-0.9 exhibits hierarchical porous structure with a high P content of 2.16 wt%. • PAC-0.9 exhibits high capacitance of 371.63 F g−1 at 0.5 A g−1. • PAC-SSC delivered an energy density of 9.15 Wh kg−1 at a power density of 500 W kg−1 • PAC-0.9 exhibit excellent capacity retention of 96.23 % after 10,000 cycles. [ABSTRACT FROM AUTHOR]

Based on the biological structure of biomass materials, the preparation of carbon materials with special pore structures and rich surface groups is an important route in the development of new carbon materials for electrodes. In this work, a nitrogen self-doped carbon with unique tubular channel structures was synthesized from garlic peels for the high-performance supercapacitor electrode application. The mild KHCO 3 was selected as the activator and therefore the biological structure of garlic peels is well preserved, showing a large number of long tubular channels with a diameter of around 50 nm. It was found that a nitrogen self-doped porous carbon material (SPC-4KC) with a nitrogen relative content of 1.77% and a large specific surface area of 1993.73 m2 g−1 was formed at 800 ℃ at a KHCO 3 /SPC mass ratio of 4:1. Using as the electrode material, the mass-specific capacitance of the SPC-4KC-based electrode reached 303.38 F g−1 at a current density of 1 A g−1 in the three-electrode system. In the two-electrode system, when the energy density is 7.42 W h kg−1, the power density is 314.33 W kg−1. Also, the material exhibits excellent cycle stability, with a capacitance retention of 94.87% after 5000 cycles at a current density of 10 A g−1. • Waste garlic peels were green synthesized into nitrogen self-doped porous carbon materials. • Nitrogen self-doped porous carbon materials have unique mesoporous tubular channels. • A mild, environmentally friendly activator, KHCO 3 , is employed and effective. • The obtained carbon electrode shows a high specific capacitance of 303.38 F g−1. • The material exhibits excellent cycle stability, with a capacitance retention of 94.87% after 5000 cycles at a current density of 10 A g−1. [ABSTRACT FROM AUTHOR]

In this paper, three-dimensional porous zeolite-based composite materials were synthesized from coal gasification fine slag (CGFS) via a feasible and simple NaOH activation and hydrothermal crystallization method. The composite materials were evaluated as catalysts for the catalytic reforming of biomass tar using toluene as a model compound. The results indicate that the structure and activity of the obtained zeolite-based catalysts are significantly influenced by the mass ratio of NaOH to CGFS. At NaOH to CGFS mass ratio of 0.5, a unique three-dimensional cage-like porous structure mainly composed of NaAlSiO 4 and ZSM-11 can be formed, and iron ions inherited from CGFS were reduced into metallic Fe on the surface of the material. Based on the developed pore structure and high surface activity, NaOH-GSP@0.5 showed excellent catalytic performance on toluene reforming, leading to the production of H 2 -rich fuel gas. The conversion rate of toluene was around 73% and remained excellent stability in 210 min continuous experiment at 800 °C, and the average yield for H 2 reached as high as 3900 μmol/min. The excellent catalytic performance of NaOH-GSP confirmed that it had great potential as a low-cost catalyst for biomass tar conversion and has broad application prospects in biomass gasification. [Display omitted] • Porous zeolite-based composites were synthesized from coal gasification fine slag. • ZSM-11 was formed at NaOH to CGFS mass ratio of 0.5. • NaOH-GSP@0.5 showed high catalytic activity in converting toluene into H 2 -rich gas. • The toluene conversion was around 73% and remained stable for 210 min. • The average yield for H 2 reached as high as 3900 μmol/min. [ABSTRACT FROM AUTHOR]

[Display omitted] • Monolithic biochar-based catalysts decorated with graphitic carbon were synthesized. • The biological structure of pinewood was preserved with regular 20–40 μm channels. • High-density metal or alloy NPs were encapsulated on the wall of the channels. • The catalysts showed high activity and excellent stability in toluene reforming. Biomass materials forms special biological structures in their growth process, and these structures can be well retained via thermochemical conversion, which have great potential to be used as a porous support for the preparation of high-performance catalysts. In this paper, the monolithic biochar-based catalysts with unique long and through micro channels decorated with graphitic carbon covered metal nanoparticles were synthesized through hydrothermal combined carbonization and evaluated in toluene cracking and steam reforming to evaluate their potential in biomass tar decomposition. The as-prepared catalysts inherited the pore structure of the biomass material, showing neatly arranged channels with a diameter of around 20–40 μm, which can act as flow-through microreactors for the toluene reforming. Co, Ni and Co-Ni alloy nanoparticles were formed on the surface of the channels and anchored by graphitic carbon layers, providing abundant and stable active sites for the catalytic reaction. The Ni-Co alloy nanoparticles achieved the synergistic effect of Co and Ni, and the corresponding catalysts (PC@CoNi/GC) exhibited higher performance and better stability than the catalysts with pure Co and Ni nanoparticles. By using PC@CoNi/GC as the catalyst, the toluene conversion reached 95.51% for the toluene cracking and 100% for the toluene steam reforming at 700 °C, and maintained excellent stability during long-term continuous operation of 2 h and 9 h, respectively. H 2 and CO were the main products with a small amount of CO 2 and CH 4. Carbon nanotubes were uniformly grown during the toluene reforming process, which may strengthen the adsorption and disturbance of reactants, thus ensuring the stability and activity of PC@CoNi/GC. [ABSTRACT FROM AUTHOR]

Plastics originate from the synthesis of chemical products, and the regeneration of chemical products from waste plastics through catalytic pyrolysis helps to reduce the dependence on fossil resources and improve the treatment of waste, which is an important aspect of current sustainable social development. In this study, metasequoia was used as a biomass precursor and three porous char-supported nanocatalysts (Fe-MEC, Ni-MEC, and Co-MEC) were synthesized via a simple and feasible microwave heating method, which were then used as catalysts for the preparation of high-quality liquid oil from polystyrene powder via an ex-situ catalytic pyrolysis method. The results indicate that Fe-MEC, Ni-MEC, and Co-MEC possessed good pore structures due to the microwave-heating and catalytic effect of these metals, and metal nanoparticles are generated and uniformly anchored on the matrix of the char support. Using these catalysts, the yield of liquid product from polystyrene pyrolysis decreased slightly, while the gas yield increased slightly. Fe-MEC catalysis reached the highest liquid yield of 91% among the three catalysts. The catalysts can improve the yield of a series of high-value liquid products such as toluene, ethylbenzene, and α-methyl styrene. The catalysts also exhibited excellent cycle stability, and carbon nanotubes were formed which are less prone to deactivation. [Display omitted] • Biomass char-supported nanocatalysts were prepared via microwave heating method. • The catalysts exhibit porous structure with well-dispersed metal NPs on the matrix. • Fe-MEC catalysis reached a high liquid yield of 91.15% from polystyrene pyrolysis. • The yields of high-value oil products are significantly improved. • The catalysts exhibit excellent stability with carbon nanotubes generated the surface. [ABSTRACT FROM AUTHOR]

[Display omitted] • Biochar-based catalysts were prepared for microwave-induced biomass pyrolysis. • Biochar combines good porous structure and excellent microwave absorption performance. • PCM-FeNi significantly improved gas fuels yield to 574.84 mL/g. • PCM-FeCo promoted the selective production of mono-phenols in bio-oil up to 74% Biochar-based catalysts have great potential for microwave-induced biomass pyrolysis due to the combination of their excellent microwave absorption performance, good porous structure, and high catalytic activity. In this work, the potential of biochar-based catalysts for microwave-induced catalytic biomass pyrolysis to produce gaseous fuel and upgrade bio-oil was explored and the role of the structural characteristics and Fe-series modification was revealed. The results indicated that the catalytic performance of pure biochar was influenced by their microstructures, and the KOH-activated biochar with abundant microporous structures could effectively promote the gas yields from biomass pyrolysis under microwave heating conditions. With the loading of Fe0 crystal nanoparticles on biochar, the catalytic activity of biochar was greatly enhanced, resulting in an increase in combustible gas (CO, H 2 and CH 4) yield by 50 % compared to pure biochar, reaching 502.09 mL/g at 650 °C, as well as significant simplification of the bio-oil. Furthermore, the Fe-series alloy crystals exhibit superior catalytic activity over Fe0, further improving gas yields and promoting bio-oil upgrading. The biochar loading of Fe 0.64 Ni 0.36 nanoparticles resulted in a combustible gas yield as high as 574.84 mL/g, and the production of hydrocarbons was greatly enhanced, with a high relative content of 33.9 % in bio-oil. Biochar-based CoFe nanoparticles promoted selective production of H 2 , with a yield as high as 230.84 mL/g, and the content of mono-phenols in the bio-oil was improved to 74.0 % with the composition of a high phenol relative content of 17.508 %, a trans-isoeugenol relative content of 17.260 %, and a guaiacol relative content of 12.780 %. [ABSTRACT FROM AUTHOR]

In this study, char-supported metal composites (0.2Ni-RHC, 0.2Fe-RHC and 0.2Co-RHC) were prepared via impregnation and subsequent microwave heating method, which were used as both microwave absorbers and catalysts for in-situ microwave-induced pyrolysis of pine sawdust, aiming to obtain high-quality fuel gas based on the interaction of microwave radiation and metal active sites in catalysts. The results showed that well-dispersed nanoparticles were generated in the three catalysts, which were firmly anchored on the matrix of the char support by several layers of graphitic carbon. The catalysts exhibited excellent microwave absorbing properties, a rapid heating rate was achieved which realized the temperature rise from room temperature to 800 °C within 110 s 0.2Fe-RHC exhibited the best catalytic performance among these three catalysts, with a high gas yield of 73.4% and low solid and bio-oil yield of only 4.1% and 13.6%, respectively. The yield of H 2 and CO increased from 137.7 to 190.6 mL/g and from 241.2 mL/g to 393.9 mL/g compared with that of pure RHC. The microwave heating behavior and the catalytic activity of char-supported Fe catalyst were also influenced by the loading amount of Fe. [Display omitted] • Biochar-supported metal composites were prepared as catalysts and microwave absorbers. • Porous biochar support with well dispersed metal nanoparticles were obtained. • The catalysts can be heated to 800 °C within 1.5 s by microwave heating. • The gas yield reached 73.4% with H 2 and CO yield of 190.6 and 393.9 mL/g for 0.2Fe-RHC. • Excessive Fe loading reduced the catalytic activity of biochar-supported Fe catalysts. [ABSTRACT FROM AUTHOR]

The conversion of bio-waste rich in heteroatoms into useful porous carbons with good chemical properties is a feasible approach contributing to electrode materials for supercapacitors. In this work, rapeseed meal rich in crude protein is used as the precursor to synthesize N,S self-codoped porous carbons. The carbon sample obtained via pre-carbonization followed by KOH activation (RM@HTC) exhibits a developed micro-mesoporous interconnected carbon structure with a large specific surface area of up to 3283.2 m−2 g−1. The N and S atoms are well retained with a N content of 1.49% for RM@HTC. In a three-electrode system, the RM@HTC-based electrode reaches a high specific capacitance of 303.4 F g−1 at a current density of 1 A g−1, and the specific capacitance is retained at 210.0 F g−1 at 10 A g−1. In a two-electrode system, the energy density reaches 9.0 W h kg−1 at a power density of 625.0 W kg−1. RM@HTC also exhibits excellent cycle stability with a capacity retention rate of 92.9% after 10 000 charge–discharge cycles at 10 A g−1. [ABSTRACT FROM AUTHOR]

In this paper, rapeseed meal is selected as the biomass raw material, KOH is used as the active agent, and N–P co-doped biomass carbon-based materials are prepared by co-activation synthesis of dopant and activator. The obtained N–P co-doped biomass carbon-based material (RM@NP) exhibits a large surface area of 3765.7 m2 g with a hierarchical structure of meso- and micropores. RM@NP is effectively doped with nitrogen and phosphorus elements, resulting in relative mass fractions of nitrogen and phosphorus of 2.32 % and 0.17 %, respectively. To assess their potential as electrode materials for supercapacitors, the electrochemical performance of the carbon materials is investigated. In a three-electrode system, the specific capacitance of the RM@NP reaches 460.0 F g−1 at 1 A g−1 in 6 M KOH, and also the specific capacitance is 344.3 F g−1 at 10 A g−1, with the corresponding retention rate of the capacitance is calculated of 75.0 %. When the specific energy is 10.1 W h kg−1, the RM@NP specific power reaches 625.0 W kg−1 in a two-electrode system. After 10,000 cycles, a retention rate of the capacitance of 83.9 % is achieved. [Display omitted] • N–P co-doped porous carbon is prepared from rapeseed hectoliter as precursor. • As a high-performance supercapacitor electrode material. • Achieved a high specific surface area of 3765.7 and great mesopore structure. • The specific capacitance reached 460.0 F g−1 at 1 A g−1 in three-electrode system. • The carbon-based electrode reached 6.4 W h kg−1 at a power density of 3125.0 W kg−1. [ABSTRACT FROM AUTHOR]

Coal gasification fine slag (CGFS) is an important byproduct in the coal gasification process with a huge annual output in China and its efficient and green conversion is one of the key issues in the development of coal chemical technology. In this study, using CGFS as the raw material, a facile method was designed for the preparation of multifunctional porous carbon-silicon composites through one-step alkali fusion based on its carbon, silicon and metal elements composition. It was found that the reaction proceeded more adequately using KOH as the activator and the obtained material (T-K1) was mainly composed of micropores and mesopores. A great number of prismatic nepheline crystals were formed and embedded in the honeycomb porous carbon. The specific surface area of T-K1 reached 424.33 m2/g with a variety of active functional groups on the surface. The porous composite exhibited great potential as a multifunctional adsorbent and catalyst. Using T-K1 as an adsorbent, its equilibrium adsorption capacity on methylene blue (MB) reached 208.44 mg/g at 298 K. The adsorption process was consistent with the situation described by the pseudo-second-order kinetic and the Langmuir model, and the adsorption mechanism mainly originated from cation exchange, van der Waals forces, π-π interaction, hydrogen bond and electrostatic attraction. In addition, T-K1 can act as both a catalyst and a microwave absorber in the microwave pyrolysis of biomass. Taking pine sawdust as an example, H 2 and CO in the gas product were enriched with high yields of 126.4 and 178.9 ml/g at 550 °C respectively, and the relative content of the phenolic in bio-oil increased to 53.6%. It is believed that this process can provide a useful alternative for the high-value-added transformation of solid waste containing carbon and silicon. [Display omitted] • Porous carbon-silicon composites were synthesized from coal gasification fine slag. • T-K1 was prepared by facile one-step alkali fusion using KOH as an activator. • T-K1 was multifunctional and combined great adsorption and catalytic properties. • The equilibrium adsorption capacity of T-K1 for methylene blue reached 208.44 mg/g. • The content of the phenols was 53.6% and H 2 and CO were enriched during catalysis. [ABSTRACT FROM AUTHOR]

The Russia-Ukraine conflict and the COVID-19 pandemic have made fossil energy more urgent, and the catalytic pyrolysis of biomass is conducive to energy transformation to achieve global sustainable development. In this paper, the influence mechanisms of different metal ions on biomass pyrolysis under conventional heating and microwave heating conditions were studied. Through thermogravimetric analysis, it was found that the existence of metal ions could change the pyrolysis behaviors of biomass, leading to different degrees of changes in the main pyrolysis temperature and range. Compared with conventional heating conditions, metal ion-loaded biomass samples exhibited higher heating rates under microwave heating conditions due to the possible hotspot phenomenon, resulting in increased gas yields and decreased bio-oil yields. Among them, the trivalent iron ion exhibited excellent catalytic properties for gas generation, with a high gas yield of 57.9% and a bio-oil yield of 12.1%. The components in bio-oil were greatly simplified by microwave irradiation, the number of the bio-oil compounds from the pyrolysis of Fe-loading pine sawdust was reduced to 77, and the GC-MS area of light compounds with carbon number less than 10 was increased to 84.4%. Phenol and furan in bio-oil are also catalytically converted into aromatic hydrocarbons, which are ideal chemical raw materials. [Display omitted] • Fe (Ⅲ) promoted the secondary weight loss of biomass at about 666 °C. • Metal ions shorten the microwave heating time of biomass to less than 3 min. • Gas and syngas yields of the Fe–P samples reached 57.9% and 559.6 mL/g respectively. • A composite of biomass porous carbon and metal was obtained. • The number of compounds in bio-oil was reduced to 49, 77 and 71 by metal ions. [ABSTRACT FROM AUTHOR]

Low-cost and concentrated industrial wastes have been recognized as a sustainable resource for preparation of new functional materials. Here, a new method was designed for the synthesis of porous composites containing high-purity Na–P1 zeolite and porous carbon from waste coal gasification fine slag (CGFS), which was treated first by acid leaching to controllably remove metal impurities and adjust Si/Al ratio, followed by NaOH fusion and hydrothermal treatment. By leaching with 1.0 mol/L HCl solution, the Si/Al ratio of the raw CGFS increased to 5.7, and the obtained CZ-1.0 consisted of high-purity Na–P1 zeolite with a typical cone-shaped flower cluster shape. The residue carbon in CGFS can be further activated to form porous carbon and graphite carbon layers interposed in the zeolite structure. The specific surface area and pore volume of CZ-1.0 reached 153.91 m2/g and 0.18 cm3/g, respectively. CZ-1.0 exhibited remarkable adsorption performance for methylene blue (MB) with the adsorption capacity reaching 137.5 mg/g for 100 mg/L MB solution. The adsorption process is mainly controlled by the chemisorption mechanism, and the adsorption of MB by CZ-1.0 may include ion exchange, hydrogen bond interaction, π-π bond interaction and van der Waals force. NaCl solution was successfully used as the desorption agent to regenerate the composite material, and the removal rate remained above 92% after five cycles. This work provides an effective strategy to synthesize a practically applicable adsorbent from the waste coal gasification fine slag for the purification of MB wastewater. • Na–P1zeolite/porous carbon composites were prepared from coal gasification fine slag. • The structure of the composites can be precisely controlled by acid leaching. • The specific surface area and pore volume reached 153.91 m2/g and 0.18 cm3/g. • The adsorption capacity reached 137.5 mg/g for 100 mg/L methylene blue solution. • The removal rate retained above 92% after five regeneration cycles by NaCl solution. [ABSTRACT FROM AUTHOR]

The recycling of the solid wastes produced in the industrial process and converting them into functional materials with unique structures are of great significance for the sustainable development of human society. In this study, a facile and scalable synthesis method was designed for the preparation of mesoporous composite materials from waste coal gasification fine slag using K 2 CO 3 as a mild chemical additive to chemically recombine SiO 2 and Al 2 O 3. At a fine slag to K 2 CO 3 mass ratio of 1:1, a mesoporous composite material (OMB-KB) mainly composed of faujasite-Na and amicite was obtained, which possessed a uniformly porous and loose structure with a specific surface area of 40.26 m2/g and the pore size range of 2–50 nm. Metals inherited from the raw slag and various chemical groups existed on the surface of OMB-KB, making the materials have unique surface chemical properties. OMB-KB exhibited ultra-high adsorption performance on malachite green (MG), and the adsorption capacity reached 7218.31 mg/g when 0.01 g of OMB-KB and 300 ml of MG solution with a concentration of 300 mg/L were used for the adsorption at 298K. The increase of pH was beneficial to the adsorption of cationic MG, and the removal efficiency reached an excellent state at pH ≥ 6. The good fitting of the pseudo-second-order kinetic model and the Freundlich isotherm model suggested that the adsorption process was dominated by chemisorption. The thermodynamic analysis showed that the adsorption of OMB-KB to MG was endothermic, entropy-increasing and entropy-controlled. The adsorption of MG by the material was realized through the exchange interactions between cations, as well as the electrostatic attraction and van der Waals forces between –OH groups and MG. Meanwhile, the oxygen-containing groups and π-electrons in the carbon layer could also adsorb MG molecules by electrostatic attraction. [Display omitted] • A mesoporous composite was synthesized from coal gasification fine slag. • A facile and scalable synthesis method was designed using K 2 CO 3 as a mild additive. • OMB-KB mainly consisted of faujasite-Na and amicite with nearly 100% of mesopores. • OMB-KB exhibited a large adsorption capacity of 7218.31 mg/g on malachite green. • The adsorption process was dominated by chemisorption and was endothermic. [ABSTRACT FROM AUTHOR]

The recycling of the solid wastes produced in the industrial process and converting them into functional materials with unique structures are of great significance for the sustainable development of human society. In this study, a facile and scalable synthesis method was designed for the preparation of mesoporous composite materials from waste coal gasification fine slag using K 2 CO 3 as a mild chemical additive to chemically recombine SiO 2 and Al 2 O 3. At a fine slag to K 2 CO 3 mass ratio of 1:1, a mesoporous composite material (OMB-KB) mainly composed of faujasite-Na and amicite was obtained, which possessed a uniformly porous and loose structure with a specific surface area of 40.26 m2/g and the pore size range of 2–50 nm. Metals inherited from the raw slag and various chemical groups existed on the surface of OMB-KB, making the materials have unique surface chemical properties. OMB-KB exhibited ultra-high adsorption performance on malachite green (MG), and the adsorption capacity reached 7218.31 mg/g when 0.01 g of OMB-KB and 300 ml of MG solution with a concentration of 300 mg/L were used for the adsorption at 298K. The increase of pH was beneficial to the adsorption of cationic MG, and the removal efficiency reached an excellent state at pH ≥ 6. The good fitting of the pseudo-second-order kinetic model and the Freundlich isotherm model suggested that the adsorption process was dominated by chemisorption. The thermodynamic analysis showed that the adsorption of OMB-KB to MG was endothermic, entropy-increasing and entropy-controlled. The adsorption of MG by the material was realized through the exchange interactions between cations, as well as the electrostatic attraction and van der Waals forces between –OH groups and MG. Meanwhile, the oxygen-containing groups and π-electrons in the carbon layer could also adsorb MG molecules by electrostatic attraction. [Display omitted] • A mesoporous composite was synthesized from coal gasification fine slag. • A facile and scalable synthesis method was designed using K 2 CO 3 as a mild additive. • OMB-KB mainly consisted of faujasite-Na and amicite with nearly 100% of mesopores. • OMB-KB exhibited a large adsorption capacity of 7218.31 mg/g on malachite green. • The adsorption process was dominated by chemisorption and was endothermic. [ABSTRACT FROM AUTHOR]

• Coal gangue rich in metals was used to prepare char-supported catalysts. • Coal gangue char can reduce the activation energy required for pine pyrolysis. • The yield of gas increased with the increase of the coal gangue char mass ratio. • The liquid product yields decreased by 19.01% at PS and CG mass ratio of 1:2. Developing low-cost and high-performance catalysts is an important part of the development of biomass pyrolysis technologies. In this study, the coal gangue rich in metals was used to directly prepare a char-supported catalyst, and metals in coal gangue were hoped to act as catalytic sites for in-situ biomass catalytic pyrolysis and secondary tar cracking. The influence of coal gangue char on pine pyrolysis behavior and kinetics was investigated in the thermogravimetric analyzer and a fixed bed reactor. The thermogravimetric analysis showed that the addition of coal gangue char caused the movement of the initial weight loss temperature and the maximum weight loss peak of the samples to the high-temperature region. With the increase of the coal gangue char mass ratio, lower apparent activation energies of the samples were achieved in the conversion range of 0.2–0.8. Through fixed-bed isothermal pyrolysis experiments, it was found that the yield of gas increased with the increase of the coal gangue char mass ratio, while the tar yield decreased quickly. The yield of H 2 and CO was significantly improved by the coal gangue char, further confirming the catalytic performance of coal gangue char on the cracking of tar molecules. [ABSTRACT FROM AUTHOR]