Liquid-phase Products Research Articles

1T/2H-MoS2/CdS heterojunction for the co-production of lactic acid photoreforming to hydrogen and value-added chemicals

Solar-driven photoreforming of biomass to obtain green and clean energy H2 and high value-added chemicals is one of the most promising approach to tackle problems concerning energy crisis and environmental pollution. To achieve this goal, the design and synthesis of photocatalysts with efficient photocatalysis and selectivity is a top priority. We synthesized lamellar composition of floral MoS2-modified CdS composites to reform biomass-derived lactic acid efficiently and selectively to tartaric acid derivatives, pyruvic acid and H2. During photocatalysis, there is accumulation of photogenerated electrons on MoS2 as a reduction center for hydrogen-extraction reaction. The holes on CdS activate α-C-H and α-O-H in lactic acid to form the carbon-centered radical ⋅CCH3(OH)COOH and the oxygen-centered radical ⋅OCH(CH3)COOH. ⋅CCH3(OH)COOH was preferentially adopted for the coupling pathway to yield tartaric acid derivatives, and ⋅OCH(CH3)COOH was further dehydrogenated to form pyruvic acid. The liquid phase product of CdS was dominated by tartaric acid derivatives with a maximum selectivity of 75.0%. The liquid phase product of CdS/MoS2-7% was dominated by pyruvic acid with a maximum selectivity of 80.0%.

Effects of metal-loaded ZSM-5 catalysts on gas-phase products and PAHs formation characteristics during the co-pyrolysis of plastic with biomass

With the urbanization and population growth, the disposal of plastic waste has become a significant challenge, as the traditional methods often result in pollution and resource wastage. Pyrolysis technology offers a sustainable solution by converting the waste plastics into valuable gas or liquid fuels. The co-pyrolysis of plastics and biomass is an effective approach for synergistically managing these two types of solid waste. The polyethylene (PE) and salix psammophila (SP) was used to investigate the gas production characteristics and polycyclic aromatic hydrocarbons (PAHs) formation during the co-pyrolysis. Additionally, Cu/ZSM-5, Co/ZSM-5, and Ni/ZSM-5 catalysts were employed to investigate the effects of different metal-loaded catalysts on the co-pyrolysis process. The results indicate that, with the increase of the pyrolysis temperature, the yield of gas-phase products gradually increases, solid residue decreases, and liquid-phase products initially increase before declining, reaching their maximum at 500 °C. The synergistic effect promotes the formation of C2Hm (C2H2, C2H4, C2H6) and CH4, leading to the increase of the gas-phase product yields compared to the individual pyrolysis. The addition of catalysts further enhances the gas production: Cu/ZSM-5 boosts H2 yield, Co/ZSM-5 shows selectivity for CH4 and C2Hm, and Ni/ZSM-5 exhibits better selectivity for CO and H2. Under the various pyrolysis conditions, aromatic compounds and aliphatic hydrocarbons consistently dominate the liquid-phase products. With the increase of the pyrolysis temperature, the proportion of aliphatic hydrocarbons decreases, while the proportion of aromatic compounds increases. The addition of catalysts reduces the proportions of both aliphatic and aromatic compounds. PAHs generation is temperature-dependent, significantly increasing at 700 °C. At the low pyrolysis temperatures, the co-pyrolysis reduces PAHs yield, but at high temperatures, PAHs formation increases. The addition of catalysts decreases PAHs yield and toxicity equivalency. Cu/ZSM-5 promotes the cracking of two-ring PAHs, reducing two-ring PAHs yield. Co and Ni catalysts enhance the selective aromatization of small hydrocarbon molecules, forming low-ring PAHs and limiting PAHs aggregation. Overall, Ni/ZSM-5 demonstrates the best performance in enhancing gas production and reducing PAHs emissions, followed by Co/ZSM-5 and Cu/ZSM-5.

Research on the dynamics and mechanism of thermal cracking of coal-based endothermic hydrocarbon fuels

Thermal cracking of endothermic hydrocarbon fuels (EHF) plays an important role in the endothermic process when the fuel temperature exceeds the supercritical temperature. To gain a deeper understanding of the thermal cracking behavior of EHF, this work discusses the thermal cracking law and reaction mechanism of coal-based EHF at different temperatures through static thermal cracking experiments, and establishes a total molecular reaction dynamics model containing 34 species and 24-step reactions based on product distribution. The results show that in the temperature range of 450℃ to 500℃, the gas phase yield of the fuel increases linearly from 8 % to 56 %, and the conversion rate reaches up to 96.1 %. The kinetic reaction of thermal cracking conforms to the primary kinetic equation, the cracking rate constant k is between 1.08×10−4∼7.92×10−4 s−1, the activation energy Ea=184.47±11.5 kJ∙mol−1, and the precursor factor lnA=21.61±3.0. Gas phase products include hydrogen, methane, ethane, ethylene, propane and butane. Liquid phase products include paraffins, alkyldecahydronaphthalenes and aromatic hydrocarbons. As the cracking depth increases, the degree of fuel branching first increases and then decreases, up to 0.33. Paraffins and alkyldecahydronaphthalenes are gradually converted into olefins, cyclic olefins, benzene, naphthalene, indene, fluorene and pyrene and other compounds. Based on the product distribution, the reaction mechanism of thermal cracking of coal-based EHF is speculated to include single-molecule β-cracking, bimolecular F-S-S, intramolecular H-transfer, cyclization and isomerization mechanisms.

Removal of dichloromethane from gas streams by droplet triggered gas discharge

The removal of dichloromethane (DCM) from gas streams by a novel gas discharge reactor triggered by solution droplets was experimentally investigated. The influences of operation parameters such as input energy, gas flow rate, oxygen concentration, droplet dropping frequency, and the solution composition of droplets on the effectiveness of reactor operation and DCM removal efficiency were examined. Experimental results showed that DCM in the gas stream can be effectively degraded, and the removal of DCM decreased with the increase of the initial DCM concentration in the gas stream. With the increase of droplet dropping frequency, the removal of DCM experiences a process from increase to decrease, and the optimal droplet dropping frequency is around 0.5–1 drop·s−1. It was also found that the oxygen concentration in the range of 5–10 % in the gas stream is better for DCM decomposition, and the use of alkaline solution as droplets can effectively improve the removal of DCM. The final gas phase products of DCM degradation were mainly CO2 and O3 with the presence of O2 in the gas stream, and the liquid phase products were chloride (Cl-) and hypochlorite (ClO-) ions.

Advances in Phosphogypsum Calcination and Decomposition Processes in Circulating Fluidized Beds.

Phosphogypsum (PG) is an industrial hazardous waste product discharged during wet-process phosphoric acid production. Once crystallized, the byproduct PG is filtered and separated from the liquid-phase product and sluiced to the disposal area near the production site for storage, seriously threatening the harmonious symbiosis between humans and nature. Therefore, devising effective solid waste management and cleaner production programs to contain and eliminate PG is of interest to researchers. In this study, the utilization status of PG is comprehensively reviewed, and a feasibility pathway for resourceful recovery of PG is proposed. The key challenges and countermeasures for the high-temperature calcination and decomposition of PG are analyzed and discussed. The visualization analysis based on bibliometrics reveals that the maximum recovery of abundant calcium (as CaO) and sulfur (as SO2) in PG and their utilization for the copreparation of calcium-based materials and sulfuric acid are the most suitable solutions for the large-scale application of PG. Five challenges that restrict the commercial promotion of PG calcination and decomposition processes are perfecting the calcium-sulfur conversion mechanism, establishing a process strengthening strategy, developing value-added technology routes, mastering unit scale-up regularity, and conducting sustainable performance assessment. Industrial applications are expected within 10-15 years.

Study on the changes and transformation characteristics of intermediate liquid products in hydrogen sulfide production from lignite degraded by sulfate-reducing bacteria.

The changes and transformation laws of intermediate liquid-phase products during the anaerobic degradation of lignite by sulfate-reducing bacteria in the formation of hydrogen sulfide play an important role in supplementing and improving the existing theories on the genesis of hydrogen sulfide gas in coal mines. In this paper, H2S gas and key intermediate liquid-phase products produced during the anaerobic degradation of lignite by sulfate-reducing bacteria were detected and analyzed by gas chromatography and gas chromatography-mass spectrometry. The results showed that the process of hydrogen sulfide production from lignite degradation by sulfate-reducing bacteria can be roughly divided into four stages: slow production phase, rapid growth phase, steady production phase, and slight decline phase. In this reaction system, the SO42- concentration showed a decreasing trend, the pH value showed an increasing trend, and the ORP value decreased and then slightly increased with time. Ten volatile component types were detected during the experiment: straight-chain alkanes, branched-chain alkanes, alcohols, aldehydes, ketones, olefins, amines, lipids, acids and phenols. The key components in the intermediate liquid phase products were straight chain alkanes, straight chain alkanes, acids, alcohols, phenols and amines. PAHs, alkanes, and phenols are closely related to H2S production, while amides stimulate nitrogen production. The process is divided into three stages: hydrolysis stage, H2S gas production stage, and decay stage. Liquid-phase intermediates play an important role in the formation process of coal mine BSR hydrogen sulfide and the mechanism of coal mine H2S genesis.

Mechanistic analysis of hydrogen-rich Co-gasification of pine wood and polypropylene-based waste masks using Fe/Dol catalyst

Disposable masks, predominantly made of polypropylene melt-blown fabric, present a significant environmental challenge due to their large volume and resistance to natural degradation. This study explores the co-gasification of forestry waste, specifically pine wood, and waste masks to enhance biomass gasification efficiency while enabling the high-value utilization of waste materials. The Fe/Dol catalyst, prepared by loading transition metal Fe onto calcined dolomite using the impregnation method, was tested in a two-stage fixed-bed gasification system. Steam was employed as the gasifying agent. The study systematically examines the effects of steam flow rate, gasification reforming temperature, the mixing ratio of pine wood to masks, and Fe loading on the catalyst's performance in gas-phase and liquid-phase product formation.Characterization analyses revealed that Fe oxides facilitate the cleavage of aromatic rings in aromatic compounds, leading to the formation of two-carbon chain segments and promoting the production of ethylene and propylene from aliphatic hydrocarbons. Additionally, the catalyst enhanced tar cracking, generating free radicals and ring bonds. Experimental results indicate that at a steam flow rate of 3 mg/min, a gasification temperature of 850 °C, a pine wood to mask mixing ratio of 1:2, and an Fe loading of 8 %, the hydrogen (H2) volume fraction reached 52.48 %, with a gas yield of 1.67 m³/kg and a hydrogen production rate of 78.25 g/kg.

Study of the co-pyrolysis behavior and bio-oil characterization of walnut shell and polyethylene by thermogravimetric analyzer and bubbling fluidized bed

In the present work, co-pyrolysis experiments of walnut shell (WS), polyethylene (PE) and their blends were performed in the thermogravimetric analyzer and lab-scale bubbling fluidized bed reactor, to clarify co-pyrolysis behaviors, synergy interactions and pyrolysis oil properties. Besides, the HZSM-5 zeolite was used as the catalyst and its catalytic characteristics were studied. Results indicated that as PE mass ratio rose from 0 to 100 %, the initial temperature monotonically increased from 265.4 to 417.3 °C, while its terminal temperature progressively decreased from 668.3 to 527.5 °C, suggesting that the addition of PE was able to accelerate the pyrolysis of samples. The co-pyrolysis of blends was distinguished into three stages, with a negative interaction observed in the first stage and positive interactions found in second and third stages. Besides, in the bubbling fluidized bed experiments, the liquid phase product yield first elevated and then reduced with rising temperature, and a high temperature promoted the degradation of oxygen-containing compounds and enhanced aromatics generation. The synergistic interaction in the co-pyrolysis of WS and PE declined the liquid phase product yield while elevating the gas phase product yield. On the other hand, blending with PE facilitated the generation of alkanes and olefins, while inhibiting the contents of oxygen-containing components and aromatics, and simultaneously, the heavy oil fraction was increased. Finally, the carbon deposited on the surface of catalysts was amorphous carbons, and could be removed by oxidation process, whereas its catalytic properties progressively declined with rising cycle number, leading to a downtrend of aromatics and olefins and an opposite trend for oxygen-containing components.

Insight into co-pyrolysis of waste polypropylene and engine oil for liquid hydrocarbons and interaction mechanism by kinetic analysis and DFT simulation

Plastic pyrolysis is an efficient and cost-effective way of processing plastic waste, producing oil, gas, and coke. Oil production from waste plastics is a promising technology, and co-pyrolysis of multicomponent materials can help to promote reactions and optimize the products. Therefore, this study examines the co-pyrolysis reaction of another hazardous waste, engine oil, with waste plastics. The co-pyrolysis performance of plastic is first evaluated and the TG-DTG curve is dynamically analyzed. Then the synergistic behavior of polypropylene and engine oil co-pyrolysis is revealed through a combination of experiments, kinetic analysis, and DFT calculations. For physical interactions, waste engine oil can improve heat and mass transfer performance during pyrolysis, significantly increase the heating rate of the reactants. Furthermore, the yield of liquid-phase products is increased. For chemical interactions, the optimal pyrolysis path was studied according to activation energies and the interaction mechanism was elucidated. Moreover, the optimal pyrolysis paths of the engine oil and PP were identical, with the resulting pyrolysis products having minimal difference in carbon chains. However, the detailed reaction paths need to be further explored owing to the complexity of the process. And the detailed composition of the pyrolysis products requires further comprehensive analysis.

Cu-Fe bimetallic MOFs with long lifetime separated-state charge for enhancing selectivity for CO2 photoreduction to CH4

Improving the CO2 to CH4 conversion efficiency of Cu metal-organic frameworks (Cu-MOFs) catalysts is important for promoting carbon capture and utilization. In this work, a series of novel Cu-Fe bimetallic MOFs photocatalysts (Cu-BTB-Fe with 0.5 wt%, 1.0 wt%, 2.0 wt%, and 4.0 wt% of Fe; H3BTB = 1,3,5-tris(4-carboxyphenyl) benzene) were synthesized by a bimetallic site (Cu and Fe) design strategy in order to improve the electron-hole separation efficiency and CO2 adsorption activation. Findings indicated that the as-synthesized Cu-BTB-2 wt% Fe catalyst exhibited excellent catalytic performance for the conversion of CO2 to CH4 and CO under simulated sunlight irradiation, providing a yield of 32.20 μmol∙g−1∙h−1 and a selectivity of 69.24 % for CO2 to CH4 conversion as well as a yield of 14.29 μmol∙g−1∙h−1 for CO2 to CO conversion without liquid phase products. This is because the Cu-Fe bimetallic sites can continuously supply photoinduced electrons with long separated-state decay lifetime to efficiently activate CO2. Specifically, the Cu-BTB-Fe catalysts provided a high proportion of effective photoinduced electrons with long decay lifetime for the CO* hydrogenation process through a unique electron transfer mechanism, while the strong affinity between CO2 and [Cu2(COO)4]-Fe active units enabled high CO2 adsorption activation and rapid CO2 reduction. The present approach, hopefully, would help to establish feasible pathway for the development of novel highly selective Cu-based MOFs photocatalysts for CO2 photocatalytic reduction yielding CH4.

(Invited) Plasma Reforming of Liquid Hydrocarbons

Engineering systems that more sustainably use our natural resources is central to both reducing the risks associated with CO2 emissions and making the long-term transition to a more circular, sustainable, and electrified economy. In particular, developing electrically driven technologies to leverage the energy density of liquids to produce clean fuels, e.g., H2, without making CO2, could be game changing. Here, we investigate the potential of directly exciting plasmas in liquid hydrocarbons to create multi-phase reaction environments, i.e., environments where plasma (ionized gas), H2, gaseous and liquid hydrocarbons, and solid carbon are all present simultaneously, to produce H2, unsaturated C2s, and carbon. The ultimate target is direct transformation of liquid hydrocarbons to gaseous H2 and solid, easy-to-separate carbon using electricity that can be provided from any source and/or points of use.This talk will focus on our recent experiments to strike and sustain low and high frequency plasma discharges in liquid hydrocarbon jets to simultaneously generate gaseous H2, C2s, and solid carbon at high rates. Preliminary experiments show that (i) input energy is not wasted in simply vaporizing the liquid - so the system’s specific energy input preferentially drives hydrocarbon cracking; (ii) discharge drive frequency and plasma space time have a big effect on the H2 specific energy requirement (SER) and H2 generation rate, respectively; (iii) feedstock chemistry affects the H2 and C2 products observed; (iv) carbon particulates rapidly form in the liquid hydrocarbon, but they can be separated easily; and (v) the SER for H2 production is 25-30 kWhr/kg, roughly two times less than water electrolysis in practice (60 kWhr/kg). Hydrocarbon conversion, reaction rates, and characterization of the plasma (OES, high speed imaging), gas (MS), liquid (GC/MS), and solid phase (SEM, Raman) products as a function of plasma operating conditions (high and low AC drive frequency; liquid-plasma contact time) and hydrocarbon source will be discussed.

The mechanism on liquefaction of waste tire by ethanolysis

Thermo-chemical treatment methods are pivotal for effectively managing waste tire rubber (WTR) while promoting energy efficiency and emission reduction. This study investigates the liquefaction of WTR within a thermal ethanol environment, exploring temperature ranges (200–300 °C) and residence times (0–80 min) to discern the role of ethanol in tire degradation. Additionally, the study includes liquefaction experiments with cyclohexane as a solvent to contrast the effect of ethanol, and comparison between ethanol and water to elucidate solvent impact. Results indicate that at 300 °C for 40 min, oil yields peak at 53.05 % for a WTR/ethanol mass ratio of 1:8 and at 51.64 % for a ratio of 1:6, notably surpassing hydrolysis outcomes. By contracting with the results from the liquefaction with cyclohexane as solvent, the involvement of ethanol can facilitate liquid phase products, primarily alkenes and oxygen-containing compounds, attributed to aromatization inhibition. Heavy oils and heteroatomic compounds are characterized through Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS), detecting hydrocarbons and heteroatom compounds like NxOy, Ox, Sx, NxOySz, NxSy, and Nx. Notably, sulfur, a significant pollutant, predominantly manifests as sulfide in chars. These findings offer valuable insights into advancing waste tire recycling technologies.

Effect of polyethylene terephthalate plastics on nitrogen, sulphur and chlorine contaminants via sludge pyrolysis and Pb/Cu adsorption properties of biochar

ABSTRACT Pyrolysis is an effective process for disposing of municipal sewage sludge (SS). Plastics can affect the SS pyrolysis behaviour and pyrolysis products due to their low ash and high hydrocarbon ratio. The secondary pollutants from the pyrolysis process may also be affected. Therefore, polyethylene terephthalate (PET), a typical plastic, was chosen to investigate the release characteristics of pollutants containing nitrogen, sulphur, and chlorine via SS pyrolysis, and the changes of biochar to adsorb two typical heavy metals, Pb and Cu. The pyrolysis of PET plastics facilitates the migration of N toward solid and liquid-phase products, S and Cl to the gas-phase products via pyrolysis. Oxygenated compounds of pyrolytic volatiles decreased from 38.18% to 28.43%, concurrently promoting the formation of phenolic compounds. The co-pyrolysis improved the quality of biochar and the ability to adsorb Pb and Cu. This systematic study can provide some support for the further improvement of SS pyrolysis technology, and will also be beneficial for subsequent applications.

Effect of the Nature, the Content and the Preparation Method of Zeolite‐Polymer Mixtures on the Pyrolysis of Linear Low‐Density Polyethylene

The effect of the preparation method of the mixture catalyst/polymer on the linear low‐density polyethylene (LLDPE) pyrolysis is studied by comparing the results obtained when the polymer and the catalyst (Hβ or HZSM‐5) are extruded or simply mixed in powder form. By improving the polymer/catalyst contact through extrusion, the polymer degradation took place at lower temperature. The effect of extrusion is more pronounced with Hβ compared to HZSM‐5 owing to the highest external surface of Hβ. While the yields of gas/liquid/coke do not differ with the preparation method when HZSM‐5 is used as catalyst, more significant amount of liquid phase and high production of paraffins are observed when Hβ/LLDPE mixture is extruded, according to random scission pathway reactions. The subsequent reactions are limited by the size of the pore, which impede hydrogenation reactions, producing high molecular weight molecules. Regardless of zeolite type, the micropores of the zeolite are more affected by deactivation by coke when extrusion method is used, this effect being much more important for HZSM‐5. This result is a consequence of a polymer pre‐degradation during the extrusion process in which the first cracks of the polymer at low temperature and the first pore blockages can be generated.

Восстановление плодородия малопродуктивных дерново-подзолистых почв, вновь вводимых в сельскохозяйственный оборот

The purpose of research is to develop agro-reclamation measures to restore the fertility of low-productive sod-podzolic sandy loam soils for the conditions of the southern part of the Non-Chernozem Zone of Russia. Objectives: to conduct a comparative assessment of the impact of granular fertilizer based on turkey droppings and a liquid-phase biological product (LPBP) on increasing soil fertility, phenological characteristics of plants, crop yields and their quality. Six variants of the field experiment were developed: control variant (without fertilizers); granular fertilizer based on turkey droppings at a dose of 15 t/ha; granular fertilizer based on turkey manure at a dose of 15 t/ha together with pre-sowing seed treatment with 1 % LPBP; pre-sowing seed treatment with 1 % LPBP; granular fertilizer based on turkey droppings at a dose of 30 t/ha. The application of organic ameliorant and pre-sowing treatment of seeds with a biological pre¬paration help to improve the agrochemical parameters of the soil, and, as a result, a higher yield of perennial grasses. The best option is option G30, where the yield was 48.3 t/ha of green mass of grass in total for 2 cuttings, which is 33.8 % more than the control option. In the G15 and G15 LPBP options, the harvest was practically not inferior and exceeded the control option by 30.5 and 24.4 %, respectively, soil fertility indicators improved: soil acidity decreased to 4.8–5.0 (pHsol) and 5.4–5.6 (pHwod), an increase in organic matter by 33.9 %, the content of mobile phosphorus and mobile potassium, and the concentration of total nitrogen increased significantly.

Phenolics production via the catalytic pyrolysis of organosolv lignin over praseodymium doped lanthanum nickelate

To fully utilize the aromatic ring structure of lignin and realize high value addition, organosolv lignin (OL) extracted from papermaking waste liquid was subjected to catalytic pyrolysis for the production of phenolic compounds. Using self-made carbon nanospheres as a template, cellular La0.8Pr0.2NiO3 perovskite was prepared by the sol-gel method and used as catalyst in the pyrolysis of OL at 600 °C for 3 h. The yield of liquid-phase product was 21.34 %, and the selectivity of phenolic compounds reached 70.20 %, constituting increases by 43.41 % and 25.87 % compared with the yield and selectivity of the catalyst-free process, respectively. After four cycles of regeneration, La0.8Pr0.2NiO3 perovskite still demonstrated good structural and catalytic stability. This work provides a theoretical basis for the development of green and sustainable chemical products.

Radiolytic degradation of 1,2,4-trichlorobenzene (TCB) in some organic solvents by gamma rays: The kinetic properties of complete dechlorination of TCB and its pathway

This study investigates the degradation of TCB in methanol, ethanol, hexane, and benzene solutions using gamma radiolysis. Kinetic properties of TCB dechlorination and its pathway are examined, with TCB selected as a representative chlorinated organic compound. Chromatograms of irradiated samples and mass spectra of liquid-phase products are presented. The change in concentration of TCB, dichlorobenzenes (DCB), chlorobenzene (MCB), and benzene with absorbed doses are observed. The radiation-chemical yield (G values) of TCB in the solvents are calculated as 1.83, 2.56, 1.93, and 1.84 100eV−1 in methanol, ethanol, hexane, and benzene solutions, respectively. 100 % degradation of TCB by gamma irradiation is found to be efficient in polar solvents but leads to a wide variety of byproducts in low polar solvents, particularly the formation of polychlorinated biphenyls in TCB + benzene solutions, making benzene an incompatible medium. The main dechlorination pathway of TCB involves the formation of 1,4-DCB, MCB, and benzene.Environmental Implication.The gamma irradiation of chlorinated organic compounds, focusing on TCB as a model compound, was investigated due to its status as a hazardous material for the environment and living organisms. TCB is a byproduct of the dechlorination of certain chlorinated pesticides listed under the Stockholm Convention's Persistent Organic Pollutants (POPs) list, which prohibits their production and use. Gamma irradiation was found to be an effective method for the degradation of chlorinated compounds, achieving 100 % degradation during irradiation. The study underscores the potential of gamma irradiation as a viable approach for the treatment of chlorinated compounds, particularly in addressing environmental and health concerns associated with TCB and related compounds.

Biomass hydrothermal carbonization solution-assisted synthesis of intercalation-expanded core–shell structured molybdenum disulfide for efficient adsorption of Cr (VI) in electroplating wastewater treatment

Cr (VI) is a common heavy metal pollutant in electroplating wastewater. This study introduces the liquid-phase product from the hydrothermal reaction of coffee grounds (CGHCL) into the synthesis process of molybdenum disulfide, assisting in the fabrication of an intercalated, expanded core–shell structured molybdenum disulfide adsorbent (C-MoS2), designed for the adsorption and reduction of Cr (VI) from electroplating wastewater. The addition of CGHCL significantly enhances the adsorption performance of MoS2. Furthermore, C-MoS2 exhibits exceedingly high removal efficiency and excellent regenerative capability for Cr (VI)-containing electroplating wastewater. The core–shell structure effectively minimizes molybdenum leaching to the greatest extent, while the oleophobic interface is unaffected by oily substances in water, and the expanded interlayer structure ensures the long-term stability of C-MoS2 in air (90 days). This study provides a viable pathway for the resource utilization of biomass and the application of molybdenum disulfide-based materials in wastewater treatment.

Effect of lignin modification on the selectivity of pyrolysis products from softwood kraft lignin

The synthesis of phenol via pyrolysis of lignin can be envisaged as a prospective approach for the high-value utilization of lignin, Herein, we describe an in-depth investigation of the selective modification of lignin to effectively adjust the distribution of lignin pyrolysis products. We found that hydroxypropyl modification of lignin can facilitate the elimination of methoxy from the lignin macromolecule and improve the selectivity of phenol products. In addition, increasing the carbon number of the lignin side chains causes polymerization of pyrolysis products, which is unfavorable for the synthesis of fine chemicals via lignin pyrolysis. Conversely, an increase in lignin side-chain hydroxyl content can lead to more liquid-phase products from lignin pyrolysis, and the selectivity of phenol and its congeners will also increase. As a result, the yield of liquid products obtained via pyrolysis of lignin modified via selective oxyalkylation can reach 52 %, and the relative content of phenol and its homologs can reach 45.2 %.

The main structural-phase states of interaction between model corium of a nuclear reactor and a sacrificial material based on Al2O3 and a lead layer

This article presents the results of post-experimental studies of the interaction of model light water reactor corium with a candidate sacrificial material (SM) based on Al2O3 (corundum) and a lead layer. The purpose of the experiments was to study the features of the interaction of the sacrificial material with corium in the conditions of simulating a severe accident with core meltdown. An active interaction of corium with the sacrificial material was established as a result of the research. This is confirmed by the fact that part of the sacrificial material entered into physical and chemical interaction with the components of corium with the formation of liquid-phase reaction products and, as a result, creating different conditions for the crystallization of corium. The study of the phase composition showed that the microstructure of solidified corium in various areas after interaction with the sacrificial material is represented by a phase of the (U,Zr, …)O2±x type with different types of crystal lattice. At the same time, the phase analysis showed a close correspondence of the composition of the solid solutions to the initial ratio of uranium and zirconium in the model corium charge. This allows us to conclude that liquid zirconium interacted with aluminum oxide during the experiment. Thus, it was concluded that the proposed sacrificial material is promising based on the results obtained and the identified features of the interaction of aluminum oxide with the lead layer and the corium of a nuclear reactor.