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In the present study, the coked catalysts derived from catalytic reforming of the pyrolysis volatiles of polyethylene (PE), lignin (LG) and their mixture were developed as low-cost and environmentally-friendly carbon materials-containing composites to remove heavy metal ions from aqueous solution. The composites were thoroughly characterized by SEM, TEM, XRD, TGA and FT-IR and then their adsorption capability towards Pb(ii) was investigated. It is found that curved cone-shape carbon nanotubes (CNTs) with abundant structural defects and O-containing surface functional groups, such as C-O, CO and -OH, can be obtained from the catalytic reforming of the mixture of PE and LG. The CNT-containing catalyst composite presents a superior adsorption capability towards Pb(ii) when it is employed in Pb(ii) removal. Adsorption isotherm and adsorption kinetics studies show that the adsorption process can be well simulated by the Langmuir isotherm and pseudo-second-order model, demonstrating that the adsorption is subjected to a homogeneous and chemical process. The calculated maximum adsorption capacity is as high as 146.08 mg g-1, which is much higher than most of the adsorbents reported. Moreover, thermodynamic analysis reveals that the adsorption is spontaneous and endothermic. Accordingly, the used catalyst from the catalytic reforming can be developed as a low-cost and highly-efficient adsorbent.

Perovskites are good candidates as a catalyst support to enhance the catalytic performance of Ni catalysts in steam methane reforming for hydrogen production. To obtain a Ni/perovskite catalyst with a high activity and stability, different LaBO3 (B = Al, Fe, Mn), La0.7A0.3AlO3−δ (A = Ca, Ba, Ce, Zn, Sr, Mg) and La1−xMgxAlO3−δ perovskites were prepared and their role in supporting Ni catalysts was comprehensively investigated in the current work. Catalyst characterization methods, including XRD, H2-TPR, H2-TPD, XPS, TG and Raman spectroscopy, were also used to understand the underlying mechanisms. The results show that the doping of Ca, Ba, Ce and Zn in the A site of the perovskite lowers the catalytic activity, while the partial substitution of Mg and Sr could improve the activity of Ni/LaAlO3. More importantly, it is suggested that the Ni/La0.7Mg0.3AlO3−δ catalyst has an outstanding catalytic activity and resistance to carbon deposition, and there is some carbon deposited after a stability test lasting for 35 h. The excellent catalytic performance is determined to be due to the higher dispersion of active Ni, the greater the amount of surface oxygen, the stronger the interaction between the active metal and support due to the partial doping of Mg.

Thermo-chemical conversion of carbonaceous wastes such as tyres, plastics, biomass and crude glycerol is a promising technology compared to traditional waste treatment options (e.g. incineration and landfill). The process promotes the sustainable management of carbonaceous wastes and realizes the potential value of these wastes. Carbon nanotubes (CNTs) are one of the most extensively investigated and high-value materials due to their featured electrical, mechanical and physical properties. Producing CNTs from waste materials could solve the issues of waste management and simultaneously bring down the cost of CNT production. This review focuses on the four most abundant waste carbonaceous materials (waste tyres, plastics, biomass and crude glycerol) which have great potential to be alternative feedstocks for CNT production. The review considers the background of these four major types of waste to highlight the incentives in using thermo-chemical conversion to deal with these waste materials. Catalyst development for thermo-chemical conversion is discussed to summarize the most common catalysts and provide guidance for future novel catalyst improvement. Current research studies regarding CNT and hydrogen production from waste materials have been reviewed which show that the topic is highly attractive for researchers. The applications of CNTs have also been grouped based on different properties, aiming to guide the future research to explore the potential applications of CNTs synthesized from wastes. This review provides an overview of the recent developments in this research area and stimulates research to promote the deployment of the technology.

Carbon capture and sequestration technologies are essential to reduce CO2 emissions which are responsible for global warming. Carbon-based materials can play an important role in the reduction of CO2 emissions. These materials are normally produced from biomass through technologies such as pyrolysis and hydrothermal carbonization. The type of biomass feedstock and biomass conversion conditions can significantly affect the textual properties and surface chemistry of the carbon materials. Various modification methods such as material activation or N-doping can improve the properties of carbon materials to obtain better CO2 capture effects. This review summarizes recently reported research in the areas of using biomass-based materials for CO2 capture. The technologies of biomass conversion to carbon materials and modification of the carbon materials are critically analyzed. Meanwhile, the mechanisms of the CO2 capture process and research of different modification carbon materials for CO2 capture are also discussed. Finally, potential future research directions are suggested to promote carbon capture using biomass-based materials.

This study reports a set of new vapor liquid equilibrium (VLE) data for the binary mixture of 1,1,1,2-tetrafluoroethane (R134a) + propane (R290) at temperatures from 253.15 to 303.15 K, and the saturated vapor pressures of R290 and R134a at temperatures ranging from 253.15 to 323.15 K using a recirculation apparatus with view windows. The VLE data were correlated with the well-known NRTL-RK, Wilson-RK, and UNIQ-RK models. The results indicated that all the models showed good agreement with the experimental data. The average absolute relative deviations of pressure (AARDp) were between 0.01% and 0.02%, while the average absolute deviations of vapor phase mole fraction (AADy) were between 0.0035 and 0.0041. Positive azeotropic behavior could be observed for the R134a + R290 system, and the azeotropic point data at six temperatures from 253.15 to 303.15 K were presented.

Carbon quantum dots (CQDs), as a novel fluorescent carbon nanomaterial, have raised worldwide concern on account of their remarkable biocompatibility, water solubility, chemical stability, nontoxic...

It is widely acknowledged that the increasing CO2 concentration has led to the rise of temperature in the earth. Thus, capturing CO2 to alleviate environmental catastrophic is becoming important and urgent. Among the CO2 sorbents reported, solid adsorbents are advantageous in CO2 adsorption, CO2/N2 selectivity, easy operation and good regeneration ability. Biochar-based sorbents are promising for CO2 capture because they are self-sufficient in energy requirements, wide availability, renewability, low cost, and high porous structure. In addition, N-containing functional groups are used to improve the capability of CO2 adsorption of biochar. This review aims to evaluate the preparation and performance of nitrogen-enriched biochar for CO2 capture. Throughout this review paper, the current N-containing precursors and biomass, as well as the technologies for the preparation of N-rich biochar are discussed. It is concluded that cheaper and more sustainable ways should be proceeded to produce N-rich biochar in the field of CO2 capture research.

Carbon nanotubes (CNTs) are promising nanofillers to enhance the mechanical performance of polymers. Through catalytic conversion, waste plastics can be converted into CNTs, which could be an alternative to commercial CNTs (cCNTs). Exploring a practical application of waste-plastic-derived CNTs will largely promote the technology development related to waste plastic management and CNT production. In this work, CNTs produced from plastics, named pCNTs, were applied as fillers to epoxy resin (EP), while commercial CNTs (cCNTs) were used as a reference. The carboxyl groups were effectively inserted on the CNT skeleton by a facile purification and modification. After ultrasonic dispersion, the modified pCNTs (M-pCNTs) were uniformly dispersed and loaded in the EP matrix. Better mechanical properties than EP were attained with a Young's modulus of 3776.9 MPa, a tensile strength of 37.3 MPa, a fracture strain of 6.32%, and a fracture strength of 111.7 MPa with 2 wt % M-pCNT loading. Thus, pCNTs enhanced the toughness of the EP composites and simultaneously retained the stiffness. It was suggested that CNT pull-out and bridging were predominant toughening mechanisms for pCNT/EP composites. Notably, the coated film developed between residual metal in M-pCNTs and EP built a strong interfacial interaction and reinforced the EP composites.

Ni-modified ZSM-5 catalysts are prepared by a one-pot hydrothermal synthesis method and applied to the steam reforming of naphthalene as a tar model compound. The effects of the reaction temperature, silica-alumina ratio (Si/Al) and metal content on the catalytic performance for reforming naphthalene are investigated. Characterization results indicate that the Ni-modified ZSM-5 catalysts maintain the original MFI structure of ZSM-5 and a portion of Ni is successfully introduced into the zeolite structure. When the reaction temperature is 800 °C, the conversion efficiency of naphthalene achieves 91.5% with a high yield (6.75%) of hydrogen. Zeolite catalysts with higher Si/Al ratios improve the conversion of naphthalene to syngas, demonstrating their better catalytic activity. An appropriate active metal content (2.4 wt%) contributes to the catalytic performance of the catalyst owing to the strong metal-support interaction, resulting in resistance to sintering and carbon deposition. The reaction mechanism involved in the catalytic reforming of naphthalene is proposed. The application of a novel one-pot hydrothermal synthesis method greatly promoted the catalytic activity of Ni@ZSM-5, which provided an appropriate and universal approach for the improvement and optimization of tar reforming catalysts.

The production of carbon nanotubes (CNTs) by catalytic pyrolysis of plastics is an environmentally friendly and promising method of waste treatment and energy/materials production. Three types of metal catalysts (Fe/cordierite, Ni/cordierite and Ni-Mg/cordierite) were utilized during the catalytic pyrolysis process of polypropylene in this work. Meanwhile, the influence of reaction pressure (0.5–1.25 MPa) on the synthesis of CNTs was investigated. Carbon formation, especially CNTs, through catalytic pyrolysis of plastics has been tested in a fixed bed reactor, and the materials have been analyzed by temperature program oxidation (TPO), scanning electron microscopy (SEM), high resolution transmission electron microscopy (TEM) and Raman spectroscopy. The highest yield around 93 wt.% filamentous carbon was obtained using the Ni-based catalyst. The strong metal-support interaction within the Ni-Mg-based catalyst suppressed CNTs growth and resulted in shorter and irregular cylindrical carbon tubes. The yield of more uniform and thick CNTs increased with the additional of appropriate reaction pressure, especially at 1.0 MPa (198 mg/gPP). However, an excessive reaction pressure weakened CNTs growth and produced shorter length and larger diameters (around 30–50 nm) CNTs. The fraction of CNTs decreased when the reaction pressure was higher than 0.5 MPa.

Songwei Huan,1,* Tao Gui,1,* Qiutong Xu,1,* Songkuan Zhuang,2 Zhenyan Li,1 Yuling Shi,3 Jiebin Lin,3 Bin Gong,1 Guiqiang Miao,1 Manseng Tam,4 Huan-Tian Zhang,1 Zhengang Zha,1 Chunfei Wu3 1Institute of Orthopedic Diseases and Department of Bone and Joint Surgery, The First Affiliated Hospital, Jinan University, Guangzhou 510630, Guangdong, People’s Republic of China; 2School of Life Science, Xiamen University, Xiamen, Fujian 361005, People’s Republic of China; 3Department of Orthopedics, The Third Affiliated Hospital, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510405, People’s Republic of China; 4IAN WO Medical Center, Macao Special Administrative Region, People’s Republic of China*These authors contributed equally to this workCorrespondence: Zhengang Zha; Chunfei Wu Tel +86-20-38688617; Tel +86-13610075186Fax +86-20-38688000; Email tbri@jnu.edu.cn; wuchunfei666@163.comBackground: Chondrosarcoma is the second-most common type of bone tumor and has inherent resistance to conventional chemotherapy. Present study aimed to explore the therapeutic effect and specific mechanism(s) of combination BET family protein and HDAC inhibition in chondrosarcoma.Methods: Two chondrosarcoma cells were treated with BET family protein inhibitor (JQ1) and histone deacetylase inhibitors (HDACIs) (vorinostat/SAHA or panobinostat/PANO) separately or in combination; then, the cell viability was determined by Cell Counting Kit-8 (CCK-8) assay, and the combination index (CI) was calculated by the Chou method; cell proliferation was evaluated by 5-ethynyl-2′-deoxyuridine (EdU) incorporation and colony formation assay; cell apoptosis and reactive oxygen species (ROS) level were determined by flow cytometry; protein expressions of caspase-3, Bcl-XL, Bcl-2, γ-H2AX, and RAD51 were examined by Immunoblotting; DNA damage was determined by comet assay; RAD51 and γ-H2AX foci were observed by immunofluorescence.Results: Combined treatment with JQ1 and SAHA or PANO synergistically suppressed the growth and colony formation ability of the chondrosarcoma cells. Combined BET and HDAC inhibition also significantly elevated the ROS level, followed by the activation of cleaved-caspase-3, and the downregulation of Bcl-2 and Bcl-XL. Mechanistically, combination treatment with JQ1 and SAHA caused numerous DNA double-strand breaks (DSBs), as evidenced by the comet assay. The increase in γ-H2AX expression and foci formation also consistently indicated the accumulation of DNA damage upon cotreatment with JQ1 and SAHA. Furthermore, RAD51, a key protein of homologous recombination (HR) DNA repair, was found to be profoundly suppressed. In contrast, ectopic expression of RAD51 partially rescued SW 1353 cell apoptosis by inhibiting the expression of cleaved-caspase-3.Conclusion: Taken together, our results disclose that BET and HDAC inhibition synergistically inhibit cell growth and induce cell apoptosis through a mechanism that involves the suppression of RAD51-related HR DNA repair in chondrosarcoma cells.Keywords: chondrosarcoma, JQ1, HDAC, apoptosis, RAD51, DNA repair

Excessive atmospheric CO2 emission is regarded as one of the main factors causing global climate change. Thus, there is an urgent need to explore the possibility of CO2 capture and converting the captured CO2 to fuels or value-added products. Recently, an integrated carbon capture and utilization (ICCU) process performed in a single reactor under isothermal conditions draws intensive attentions due to the reduction of energy requirement for sorbent regeneration. However, from literature, normally a low loading of sorbent in dual functional materials (DFMs) was applied resulting in a very low CO2 capture capacity and consequent low CH4 yield in the ICCU process. Herein, we demonstrate the intermediate-temperature DFMs using inexpensive high-capacity MgO sorbent. The synthesized DFMs are a physical mixture of sorbent and Ru/CeO2 catalyst by the mass ratio of 2:1 allowing simultaneous regeneration of sorbent and conversion of CO2 in a single reactor at 300 °C. During the 1st cycle of ICCU process, 10Ru/CeO2-MgO exhibits the best ICCU performance with the highest CH4 yield of 7.07 mmol g−1 and CO2 conversion of 89 %. However, after 10 cycles of ICCU process, 5Ru/CeO2-MgO exhibits the highest CH4 yield (3.36 mmol g−1) and CO2 conversion (79 %), which are much higher than that of 2.5Ru/CeO2-MgO (1.13 mmol g−1 and 39 %) and 10Ru/CeO2-MgO (2.31 mmol g−1 and 69 %). It is mainly attributed to that more oxygen vacancies are remained in 5Ru/CeO2-MgO resulted from the metal-support interaction.

In order to realize a promissing disposal of solid wastes, especially for biomass and plastics, and the recovery of high value-added products, lignin (LG) and polyethylene (PE) were co-pyrolyzed with the addition of transition metals. Thermal behavior and kinetics of the mixtures affected by the type of transition metals (0.5 mmol/g Ni, Co, Fe and Mn), the concentration of Ni (0–1 mmol/g Ni), the ratio of LG to PE (4:1-1:4) and heating rate (10–40 °C/min) were investigated according to thermogravimetric analysis (TGA). It is found that the treatment of LG/PE with 0.5 mmol/g Ni, Co, Fe or Mn results in the decrease of the initial decomposition temperature of LG and PE in the mixture by 10–53 °C and 9–18 °C, respectively. According to the difference of weight loss (ΔW), the introduction of Fe and Mn has slight influences on the interaction between LG and PE while a negative effect of PE on the devolatilization of LG in LG/PE can be largely diminished with the involvement of Ni and Co. Kinetic analysis reveals that the pyrolysis of LG and PE can be well fitted by a single first order model reaction while two consecutive first order model reactions are needed to exactly describe the co-pyrolysis of LG/PE with or without transition metals. The E value of LG and PE in the mixture is reduced by 6.11–21.62 kJ/mol and 7.67–50.11 kJ/mol, respectively, when 0.5 mmol/g Ni, Co, Fe or Mn was involved. Moreover, the concentration of Ni, the ratio of LG to PE and the heating rate play important roles on the thermal behavior and kinetics of the co-pyrolysis of LG/PE.

In order to broaden the temperature range of NO oxidation reaction in flue gas and maintain high oxidation efficiency, various loading amounts of MnOx-CoOx/TiO2 mesoporous catalysts were tested in the catalytic oxidation of NO. It was found that 15%MnOx-CoOx(2 : 1)/TiO2 demonstrated the best adsorption performance to oxygen species and contained more oxygen vacancies, as well as the best surface oxygen mobility, thus exhibiting excellent NO catalytic oxidation activity. O3 (O3/NO < 1) combined with 15%MnOx-CoOx(2 : 1)/TiO2 improved the oxidation efficiency of NO at 50-400 °C, especially below 250 °C. When the temperatures were less than 250 °C, the oxidation efficiencies of NO by O3 over 15%MnOx-CoOx(2 : 1)/TiO2 were 5-13% higher than the calculated theoretical efficiencies. This indicated that there was a synergistic effect between O3 and 15%MnOx-CoOx(2 : 1)/TiO2 below 250 °C. Based on the results of in situ DRIFTS studies, it was deduced that monodentate nitrates were the main intermediates that produced a synergistic effect due to the introduction of O3. In addition, O3 accelerated the transformation between nitrate species, decreased the decomposition temperature of nitrate species, and inhibited the accumulation of nitrate ions, thus improving the oxidation efficiency of NO.

CaO is a promising material as an alternative CO2 capture material which can be used at high temperature. However, CaO sinters to form large particles under long-term high temperature conditions, resulting in a rapid decrease of its surface area and the capacity of CO2 capture. Incorporating CaO into inert materials is a promising strategy to enhance the performance of CO2 capture. This work investigated a novel composite material called mesocellular siliceous foam (MCF)-supported CaO to enhance the stability and capacity of CaO-based materials for CO2 capture. The crystal structure, surface morphology and porosity property of the developed composite materials were investigated. Thermogravimetric measurements were carried out to study the cyclic CO2 capture performance of the MCF-supported CaO composites. The results showed that a part of CaO reacted with the silica wall, and the formation of Ca2SiO4 within the MCF framework limited the presence of CaO in the mesopores, thus inhibited the sintering of CaO. The sample of MCF-3CaO exhibited a better performance of CO2 capture and long-term stability, compared with the materials prepared with lower CaO loading. This work contributes to the development of high temperature CO2 capture adsorbents, which can be applied for decarbonizing major industrials e.g. power plant.

An integrated carbon capture and utilization (ICCU) process present an ideal solution to address anthropogenic carbon dioxide (CO 2) emissions from fossil fuel-driven electricity production, allowing for capturing and subsequent utilization of CO 2 instead of current release into the atmosphere. Effective dual-functional materials (DFMs), through the combination of CO 2 sorbents and catalysts, can not only capture CO 2 but also convert it into higher-value chemicals, such as CH 4 or CO, under isothermal conditions within a single reactor are highly desirable for ICCU processes. In this study, we investigate the mechanism of ICCU over 10 %NiCaO by the time-resolved operando XAS/DRIFTS/MS and the influence of a reduction pretreatment on the process and the products formed. During the 1st stage of the ICCU process (carbon capture), CaO adsorbs CO 2 resulting in bicarbonate, carbonate, and formate species formation. At the same time, the Ni catalytic active species are oxidized by CO 2, leading to the formation of NiO and CO. However, pre-treating the same DFM under hydrogen, during heating to operating temperature, resulted in a switch to CH 4 production, suggesting the presence of high levels of surface adsorbed H 2. During the 2nd stage of ICCU (CO 2 conversion), the NiO generated during capture is reduced by H 2 to metallic Ni, which facilitates the reduction of bicarbonates, carbonates, and formats, via H 2 dissociation, to produce and liberate gaseous CO. Thus, both adsorption and catalytic sites are regenerated for the subsequent ICCU cycle.

CO2is one of the most important greenhouse gases leading to severe environmental issues. The increase of CO2emissions from the consumption of fossil fuels has received much research attention. One promising solution to reduce the impact of CO2is to integrate CO2capture and utilization (ICCU), which shows many advantages compared to traditional separate CO2capture and utilization (CCU) processes. The ICCU process shortens the path of CO2utilization such as CO2transportation and storage, and further negates the need for purification of products owing to the high conversion of CO2. As an emerging integrated process, the improvement of ICCU performance is crucial for future applications. This review analyses and discusses the influence of the key process parameters of ICCU such as temperature, the presence of O2or H2O in CO2, GHSVetc., to provide guidance for future investigation. The development and application of dual functional materials (DFMs) in ICCU are investigated and the roles and influence of interaction between adsorbents and catalysts are discussed. CaO showed superiority as an adsorbent to combine with CO2utilization catalysts owing to its low cost and high CO2capture capacity. The DFM system has opportunities to retard the deactivation of CaO owing to the presence of catalysts and the formed interaction. Nevertheless, there are several considerations from the industrial application perspective such as the reduction of overall cost and the possible post-processing requirements.

Carbon nanomaterials, such as carbon nanoonions (CNOs), possess promising applications in various fields. There are urgent demands to synthesize carbon nanomaterials from a green and renewable carbon source. In this study, solid CNOs with relatively uniform size distribution (with diameters of about 30-50 nm), abundant structure defects and oxygen-containing surface functional groups (such as -OH and -COOH) are developed from co-pyrolysis of lignin (LG) and polyethylene (PE) in the presence of Ni-based catalysts. The type of catalyst, the concentration of catalyst and catalytic co-pyrolysis temperature play important roles in the morphologies and properties of CNOs as confirmed by TEM and SEM. Furthermore, the produced CNOs can act as a low-cost and highly-efficient adsorbent to remove Cu(ii) from aqueous solution according to a homogeneous monolayer, chemical action-dominated, endothermic and spontaneous process. The theoretical maximum adsorption capacity of CNOs calculated from the Langmuir model is 100.00 mg g

In the present study, the coked catalysts derived from catalytic reforming of the pyrolysis volatiles of polyethylene (PE), lignin (LG) and their mixture were developed as low-cost and environmentally-friendly carbon materials-containing composites to remove heavy metal ions from aqueous solution. The composites were thoroughly characterized by SEM, TEM, XRD, TGA and FT-IR and then their adsorption capability towards Pb(ii) was investigated. It is found that curved cone-shape carbon nanotubes (CNTs) with abundant structural defects and O-containing surface functional groups, such as C-O, C[double bond, length as m-dash]O and -OH, can be obtained from the catalytic reforming of the mixture of PE and LG. The CNT-containing catalyst composite presents a superior adsorption capability towards Pb(ii) when it is employed in Pb(ii) removal. Adsorption isotherm and adsorption kinetics studies show that the adsorption process can be well simulated by the Langmuir isotherm and pseudo-second-order model, demonstrating that the adsorption is subjected to a homogeneous and chemical process. The calculated maximum adsorption capacity is as high as 146.08 mg g

CO2 capture and utilization has been considered as an up-and-coming short- to mid-term approach to mitigate the excessive CO2 emission. Comparing to the conventional separate capture, transportation and conversion arrangement, the integrated CO2 capture and utilization (ICCU) could largely simplify the complex process and reduce the energy consumption. However, the poor stability of high-temperature CO2 sorption/desorption severely limit the potential of ICCU. Therefore, it is indispensable to develop a new sorbent/catalyst system ensuring the high-efficiency and long-term operation of the ICCU. In this paper, we propose and demonstrate the feasibility and performance of using K2CO3-doped Li4SiO4 as an efficient CO2 sorbent for ICCU operating at a relatively low temperature by dry reforming of methane. Results show that the ratio of H2/CO produced is stabilized at 1 ± 0.05 in the pre-breakthrough stage, and the duration extends to be 1.6 times of the original value in the cyclic operations, displaying an excellent performance in reaction matching and process stability.

In this study, a novel nanoscale iron oxide (FeOx) modified carbon nanotubes composite (FeOx@CNTs) was synthesized through a combined ball milling–hydrothermal two-step method and tested for aqueous Sb(III) removal efficiency and mechanisms. FeOx nanoparticles was successfully loaded on the surface of CNTs through functional groups such as hydroxyl (–OH), C–H, and C–O to enhance the removal efficiency of Sb(III) through adsorption and surface complexation. At a dosage of 0.02 g, a FeCl3·6H2O-to-CNTs mass ratio of 3:1, and an initial solution pH of 6.3, the amount of Sb(III) removed by the prepared FeOx@CNTs reached 172 mg/g, which was 42.9 times higher than that of the pristine CNTs (4.01 mg/g). Chemical adsorption and oxidation were the main removal mechanisms. At the equilibrium Sb(III) concentration of 6.08 mg/L, 6.56% of initial Sb(III) was adsorbed onto the surface of FeOx@CNTs, and 81.3% of initial Sb(III) was oxidized to Sb(V) with lower toxicity. The pseudo-second-order kinetic model could better describe the adsorption of Sb(III) onto the FeOx@CNTs composite, indicating that adsorption was mainly controlled by chemical sorption. In the adsorption isotherm equation, the Redlich–Peterson model provided a better fit of Sb(III) adsorption onto the FeOx@CNTs composite than the Langmuir and Freundlich models, which further indicated that the adsorption process was a hybrid removal process dominated by chemical sorption. The presence of CO32− slightly promoted the removal of Sb(III) from aqueous solution. The synthesized composite was magnetic and could be easily separated from the solution by an external magnetic field at the end of the sorption experiment. Based on these findings, the FeOx@CNTs nanocomposite is expected to provide an environmentally-friendly adsorbent with a strong sorption capacity for remediating Sb(III) in water environments.

Reverse water–gas shift reaction using renewable H2 is a promising route for CO2 upgrade, however, it is restricted by the equilibrium. The chemical looping reverse water–gas shift reaction using oxygen carriers (i.e. Fe) has proven a more effective CO2 utilization process to produce CO. However, CO2 with high purity is needed to obtain concentrated CO. Herein, we propose a calcium chemical dual looping using one-pot sol–gel synthesized Ca-Fe dual functional materials (DFMs). The CO2 in the exhaust gas (∼10% CO2) can be captured and transformed into carbonates and then in-situ converted into CO through continuous chemical looping in H2 atmosphere. This process avoids CO2 enrichment, storage and transportation and simultaneously realizes efficient CO2 conversion. The Ca-Fe DFMs possessed significantly improved catalytic efficiency (enhanced real-time CO generation rate) compared to CaO. It is found that Ni1Fe9-CaO could optimally achieve 11.3 mmol gDFM−1 CO yield, 82.5% CO2 conversion and 99.9% CO selectivity at 650 °C. Notably, Ni1Fe9-CaO displayed high CO2 conversion (>80%) and CO selectivity (>99.9%) during the cycle tests and possessed enhanced stability in relation to CO yield after 10 cycles (20.9% and 35.5% decrease for Ni1Fe9-CaO and CaO, respectively). Herein, Ca2Fe2O5 plays two roles: acting as an oxygen carrier for in-situ chemical looping to produce CO and a thermally stable physical barrier to retard the sintering of CaO. It is noted that Fe-related species could be reduced into the metallic state at the end of hydrogenation, resulting in CO formation in the following CO2 capture process.

Lignocellulosic paper waste constitutes a major waste stream globally, which should be valorised for chemical production. However, paper properties (e.g., feedstock composition, cellulosic crystallinity, and thermal stability/degradability) vary with raw materials and pulping processes. This study investigated levulinic acid (LA), hydroxymethylfurfural (HMF), and furfural production by H

A novel and eco-friendly C–Ni/Al2O3 composite was prepared through Ni/Al2O3 coking during the catalytic reforming of volatiles from co-pyrolysis of lignin and polyethylene. The influence of Ni loading (0–20%) in the Ni/Al2O3 catalyst and catalytic reforming temperature (500–800 °C) on the characteristics of the C–Ni/Al2O3 composite was investigated, involving the analysis of SEM, XRD, TPO and FTIR. Fibrous carbon on the C–Ni/Al2O3 composite was produced by the catalyst Ni(10%)/Al2O3 at reforming temperatures of 600 and 700 °C, which was oxidized at around 500 °C according to the TPO analysis. The maximum deposition of carbon in the C–Ni(10%)/Al2O3 composite was about 10.86%, achieved at a catalytic reforming temperature of 700 °C. Abundant oxygen-containing functional groups were observed on the C–Ni/Al2O3 composite through the FTIR analysis, leading to the outstanding adsorption performance for pollutant removal from aqueous systems. The optimal C–Ni/Al2O3 composite was selected to investigate the effect of process conditions on the adsorption performance for Pb(II), Cr(VI), rhodamine B (RhB) and methyl orange (MO). The adsorption isotherms for the four mentioned pollutants were well fitted by the Langmuir model and the maximum adsorption amount for Pb(II), Cr(VI), RhB and MO was estimated to be 223.52, 54.90, 290.76 and 95.71 mg g−1, respectively. The results indicated that the as-prepared C–Ni/Al2O3 composite had potential for the removal of heavy metal ions and hazardous organic compounds from aqueous systems.

Excessive anthropogenic CO2 emission in the atmosphere is considered as one of the main contributions to the serious climate changes. However, with the growth of global economics, more fossil fuels will be consumed to feed the global activity, especially in developing countries. Thus, CO2 needs to be captured for storage or converted to fuels or value-added chemicals. Herein, we propose and demonstrate a one-pot method synthesized dual functional materials (DFMs), which contain a sorbent coupled with a catalyst component, allowing the sorbent regeneration and CO2 conversion to CO are performed simultaneously in a single reactor. This process requires no additional thermal energy for the regeneration of sorbents. In addition, CeO2 is incorporated into the DFMs to largely enhance the stability of the materials for the process, and the influence of different Ce loadings on the performance of integrated CO2 capture and conversion is studied. It is found that the DFMs with a Ca/Ni/Ce molar ratio of 1:0.1:0.033 displays almost 100% CO selectivity and 51.8% CO2 conversion in the reverse water-gas shift (RWGS) reaction and a remarkable cyclic stability after 20 cycles of integrated CO2 capture and conversion. Therefore, the incorporation of Ce into DFMs has two profits, for one thing, the oxygen vacancies generated by CeO2 directly reduces the dissociated CO2 regenerated from the DFMs, demonstrating the high CO yield; for another, the well-dispersed CeO2, which could act as a physical barrier, effectively prevents the growth and agglomeration of CaO crystallite and NiO species.

As a multi-beneficial amendment, biochar is reasonable and reliable to be employed as an amendment to implement soil remediation. An overview on the manufacture, applications for contaminated soil restoration and revegetation, as well as recommended aspects for future work has been accomplished. One of the objectives of this work presented herein was to determine the effect of feedstock and preparation conditions such as pyrolysis temperature, retention time, gas flow rate, additives on the biochar characteristics and application potentials. Besides, relevant modification or activation technologies have been discussed for the improvement of the biochar functions. The application of biochar could adjust the soil structure (surface area, pore size and distribution etc.), improve the soil physicochemical properties (pH, cation exchange capacity, water retention capacity etc.) and enhance the uptake of soil nutrients for plant growth; In addition, it also can be used to adsorb various contaminants (heavy metals, organic matters), modify the habit and function of microorganism and mitigate climate problem by changing the bioavailability of elements (C, N, K etc.) in soil. These results also provided the possibility to expend the application of biochar to modify the degraded soils in the saline-alkali soil and industrial regions, further increase the usable area of cultivated land. The future research directions could be suggested as long-term field trials, the evaluation of environmental risk and the optimization of biochar production. Moreover, the relevant mechanisms should be adequately considered for maximizing the all-around efficiency of biochar amendments.

Biomass pyrolysis is a promising thermal chemical processing technology to produce renewable and sustainable energy materials. However, the interaction between biomass components (cellulose, hemicellulose and lignin) during pyrolysis process needed further investigation. In this work, an in-situ Reflectance Infrared Fourier Transform Spectroscopy (in-situ DRIFTS) reactor was introduced to investigate the interactions assisted with Thermogravimetric Analysis (TGA). The experiments demonstrate that there exist complicated interactions between the main components of biomass during pyrolysis. The results from TGA/DTG indicate that the interactions between cellulose and xylan introduce higher pyrolysis temperature, while the interactions between cellulose and lignin, xylan and lignin, resulte less weight loss. The increase of compression pressure for the mixture of main components changes the weight loss of the mixture. The results from in-situ DRIFTS show that the decomposition and aromatization of xylan are promoted when the cellulose is added. Cellulose will also hinder the accumulation of the benzene rings of the lignin. The in-situ DRIFTS experiment results also suggest that the contact pressure between the components conduct more residue solid, mainly because the dehydration reaction of the mixture samples was inhibited and the charring process was promoted, especially the reaction between cellulose and lignin.

Hydrogen sorption and storage in a solid matrix can greatly improve its safety and efficiency when compared to the compressed gas or liquid hydrogen storage system, and kinetics mechanisms are of interest towards the development of such materials. In this study, the composites of Mg-Ni-Cu doped with singe-walled carbon nanotubes (Mg-Ni-Cu/CNTs) were synthetized. The activation performance, isothermal hydrogen sorption and desorption were systematically tested, and the experimental data were analyzed using the shrinking core model. The results show that three cycles of hydrogen sorption and desorption may be enough to fully activate Mg-Ni-Cu/CNTs and the stability can be kept for 150 cycles. A 10.1 wt% of Cu and 50.3 wt% of Ni in Mg-Ni-Cu/CNTs facilitates the hydrogen sorption and a reversible hydrogen capacity of ∼3.35 wt% can be achieved at 310 °C and 3.0 atm, and hydrogen capacity and kinetics shows significant decline during contact with 1.0 vol% CO impurity. Considering desorption at 600 °C, the kinetic profiles are about linear and desorption is completed within minutes. The gas-solid reaction processes for hydrogen sorption undergo three different rate-limiting stages, and hydrogen desorption can only be divided into two stages of surface chemical reaction and product layer diffusion.

Porous materials with photochromic units are currently under investigation as light allows for environmentally friendly and highly energy-efficient control for gas separation and storage, chemical sensing, and drug delivery. In the application of photo-switching materials to CO2 capture, researchers have tried to endow a diversity of porous materials such as metal-organic frameworks and porous organic polymers with photo-responsive units. This review highlights photochromic units and methods used for different types of photo-responsive adsorbents of CO2 and some examples of adsorbents with photo-switching properties. These sorbents are also promising for application to direct air capture of CO2. In particular, the cost of adsorbent regeneration could be reduced by using sorbents with light-induced regeneration. The key purpose of this review is to motivate more research into photo-switching sorbents for CO2 capture with the control of capture or release by simply switching the light on and off.

Carbon dioxide (CO2) capture using CaO-based adsorbents has recently attracted intense attention from both academic and industrial sectors in the last decade due to the high theoretical capacity of CO2 capture, low cost, and potential use in large scale. However, the successful development of CaO-based adsorbents is limited by significant sintering of adsorbent particles over a number of cycles of CaO carbonation/calcination. In this work, a systematic understanding of fundamental aspects of the cyclic carbonation/calcination of CaO-based materials is reviewed. A number of efforts have been discussed to improve the sintering-resistant properties of CaO-based adsorbents, such as decreasing the particle size and increasing the surface area, dispersing CaO on inert support, as well as surface modification. In particular, severe process conditions such as carrying out material calcination under pure CO2 atmosphere were considered for the development of CaO-based materials. In addition, important process parameters for CaO-based carbon capture such as CO2 partial pressure, carbonation temperature, carbonation time and the presence of contaminants have been reviewed, as well as the reactivation of spent sorbents. Synthetic CaO-based adsorbents have better performance than natural adsorbents due to the improved porosity and the presence of nanosized particles. The promising capacity and stability of CO2 capture can be obtained when the synthetic adsorbents have high surface area and mesopores and/or CaO particles are stabilized using inert materials such as Ca12Al14O33. With an increase of steam concentration in the process, the decay of CO2 capture capacity was mitigated due to the formation of a stable pore structure. The calcium looping technology has been demonstrated in pilot scale combining with catalytic reforming or gasification process. However, the reduction of sorbent costs and the optimization of process conditions (e.g. carbonation and calcination time) still need to be tested in larger scale to reduce the overall costs and enhance the overall energy efficiency. Material attrition is a key challenge in large-scale demonstration of calcium looping process. Novel technology could be developed to avoid the transportation of solid sorbents. For example, by integrating with CO2 conversion to methane, the capture of CO2 and the regeneration of bifunctional sorbents can be carried out at the same temperature in a fixed bed reactor. This can be fulfilled by introducing hydrogen to the stage of sorbent regeneration. However, much more fundamental understanding is required in this area, such as the exploration of synergies between sorbent regeneration and catalytic conversion of CO2.

Biomass gasification is one of the most promising technologies to convert renewable biomass feedstock to useful energy and chemicals for decarbonizing the current industrial activities. However, complex tar compounds are formed in the produced syngas. The presence of tar in syngas is undesirable due to a series problems caused, such as the decrease of overall efficiency and the clogging and contamination of downstream equipment. Until now, catalytic steam reforming has been widely studied for the efficient removal of tar. Previous review articles have focused on the catalytic reforming of tar by categorizing various catalysts as basic catalysts, nickel-based catalysts, non-nickel based catalysts, alkali metal catalysts, zeolite catalysts, and carbon-supported catalysts, etc. Ni-based steam-reforming catalysts have attracted much attention due to their high activity for tar reduction, low-cost and easy regeneration. However, the deactivation caused by the coke deposition and metal sintering remains the greatest challenge for the deployment of the technology. Therefore, modified Ni-based catalysts are now most frequently used for catalytic reforming of tar. At present, few review articles reported the modification of Ni-based catalysts for catalytic reforming of tar compounds. Based on this, the preparation, modification and development methods of Ni-based catalysts for catalytic reforming of tar are reviewed in this paper, aiming at promoting the catalytic performance of conventional Ni-based catalysts, in terms of high catalytic activity, long-term stability and better selectivity towards low molecular weight compounds.

The distance between catalytic sites (Ni) and sorbents (CaO) on the performance of integrated CO2 capture and utilization (ICCU) process is crucial important because the sorbents demonstrate a dramatic volume increase during carbonation reaction (1st stage of ICCU) and sequentially cover the catalytic sites and retard the CO2 conversion (2nd stage of ICCU). Herein, we synthesized various Ni/CaO-based dual functional materials (DFMs) with different distances between active sites and sorbents to provide different volume spaces for the growth of CaCO3 during the carbonation reaction. It is found that both 1%NiCaO and 10%NiCaO synthesized by a one-pot method exhibited a low CO2 conversion (38% and 45%, respectively) and CH4 selectivity (58% and 69%, respectively) as the distance between catalytic sites and sorbents was so close that the Ni active sites were covered by the formed CaCO3 during carbonation reaction. With the increase of the distance by physical mixing method, the CO2 conversion and CH4 selectivity of 1%Ni/CeO2-CaO-phy were largely increased to 62% and 84%, respectively at 550 °C and atmospheric pressure when captured CO2 from 15% CO2/N2. This is attributed to the fact that the Ni active sites were still well dispersed on the surface of CeO2 nanorods instead of being covered by the newly formed CaCO3.

[EN]The activity and stability of a 10 wt%NiO/CaO catalyst were tested in the sorption enhanced ethanol steam reforming (SEESR) in a fluidized bed reactor. The effect of temperature in the 600-750 degrees C range was analyzed and the performance of the catalyst at 700 degrees C was assessed by conducting cycles of SEESR reaction and CO2 desorption. At zero time on stream, an increase in temperature enhanced ethanol steam reforming reactions, and therefore H-2 production increased from a yield of 20.3 wt% at 600 degrees C to 22 wt% at 750 degrees C. However, high temperatures hindered the catalyst sorption performance, i.e., CO2 capture declined from 7.9 to 2.1 mmol(CO2) g(cat)(-1). In order to evaluate the catalyst performance throughout the cycles and relate it with its features, both fresh and deactivated catalysts were characterized in detail by N-2 adsorption-desorption, X-ray fluorescence (XRF), X-ray diffraction (XRD), temperature programmed reduction (TPR) and oxidation (TPO) and transmission electron microscopy (TEM). Subsequent to 12 cycles, the catalyst CO2 capture performance was slightly lower than that of the fresh one (approximately 7%) and hardly changed in the next cycles. Furthermore, the use of the same temperature for SEESR reaction and CO2 desorption led to the highest adsorption capacity of the catalyst over multiple cycles. This work was carried out with financial support from the Spain's Ministries of Science, Innovation and Universities (RTI2018-098283-J-I00 (MCIU/AEI/FEDER, UE) and (RTI2018-101678-BI00 MCIU/AEI/FEDER, UE) and Science and Innovation (PID2019-107357RB-I00 (MCI/AEI/FEDER, UE) , the Basque Government (IT1218-19 and KK-2020/00107) . This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 823745. Maria Cortazar also thanks the Basque Government for her research training grant.

In order to cope with the global energy crisis and environmental pollution problems, there are urgent needs for clean energy such as biomass-derived hydrogen. CaO is effective to promote hydrogen production from biomass gasification due to its high capacity of in-situ CO2 capture. In this work, a two-stage fixed bed reactor was used to produce hydrogen by catalytic conversion of biomass with and without in-situ CO2 capture. In addition, three Ni loadings (5 wt%, 10 wt%, and 20 wt%) supported by Al2O3 and sol-gel CaO have been prepared and tested. The BET analysis shows the surface area of the catalysts increases first and then decreases with the increase of Ni loading. Results from high-resolution transmission electron microscopy (HRTEM) images reveals that NiO particles are well distributed over the porous CaO. The X-ray diffraction (XRD) analysis indicates the NiO nanocrystalline size is increased with increasing Ni loading on Ni/Al2O3, and the most homogeneous dispersion was shown by 10 wt% Ni/CaO. Around 666 mgCO2/gCaO of CO2 adsorption capacity and 850 min stability were obtained using the sol-gel CaO sorbent. Compared to the reference Ni/Al2O3 catalysts, the resistance of carbon deposition on the Ni/CaO results in a lower coke deposition, which is attributed to the basicity of the catalysts. In addition, the increase of loading promotes the decomposition of biomass-derived oxygenated compounds. Much more hydrogen is obtained using the Ni/CaO catalysts compared with Ni/Al2O3 due to in-situ CO2 capture. However, the sintering and particle agglomeration using the 20 wt% Ni-catalyst might be responsible for the reduction of hydrogen production. The highest H2 concentration of 19.32 vol% at 424 °C was obtained when the 10 wt% Ni/CaO catalyst was used.

Digestate from Anaerobic Digestion (AD) is a very common waste produced by European biogas plants and its current method of reuse is as a fertilizer or as soil amendment. This in turn however gives rise to some other environmental concerns which include greenhouse gas emissions and volatilization of ammonia causing ammonia pollution. Biochar is an environmentally friendly and low-cost product for CO2 capture and sequestration. Thus, we have provided one simple method to convert AD digestate into biochar-based sorbents of CO2. In addition, the nitrogen-functionalised porous carbon has been reported to be effective in improving the uptake of CO2. However, most of them were prepared using multiple steps. In this work, N-doped biochar was prepared by a one-step method of modifying AD digestate by urea. The results show that the addition of N can increase CO2 uptake significantly. Thus, the adsorbent modified by urea with a ratio of 1:1 results in the highest CO2 uptake capacity (1.22 mmol g−1), indicating digestate's potential application for carbon capture and storage.

Biomass gasification is considered as a promising renewable energy technology to address climate change caused by greenhouse gas emissions and produce portable and clean energy products. However, biomass must be combusted in the traditional gasification to maintain the process, while excessive gasification temperature will lead to ash sintering, resulting in the shutdown of the equipment. Autothermal biomass gasification is directly maintained by carbonation reaction, which can maximize the production of combustible gas and reuse carbon dioxide in the flue gas. Lab-scale results indicated that similar H2 yield can be obtained via Auto-CaL-Gas technology at lower operating temperatures. Moreover, H2 concentration increased by 23.29% at 650 °C with CaO than at 750 °C without CaO, and 14.11% at 550 °C with CaO than at 650 °C without CaO, respectively, thus saving energy consumption and improving total energy efficiency in the biomass gasification process.