Understanding the influence of metaplast (fragments of coal macromolecular network in char) on polycondensation during coal pyrolysis is beneficial for studying the mechanism of coal conversion and realizing the regulation of coal pyrolysis products. The solvent extraction and swelling treatment of rapid pyrolysis char was carried out to reduce the content of metaplast. The metaplast extracted with tetrahydrofuran (THF) solvent contained abundant aromatic compounds with a low degree of polycondensation, and its orientation distribution in char was disordered. After solvent extraction and swelling, the reactivity of the residues was enhanced, making more residues convert into liquid and gas products during the re-pyrolysis. Solvent extraction and swelling only increased the specific surface area of the char from 4 m(2)/g to 5 m(2)/g and 7 m(2)/g, respectively, and at P/P-0 < 0.05, the N-2 adsorption isotherms of 500HLL, R500HLL, and S500HLL essentially overlap, indicating that metaplast cannot directly influence pyrolysis by occupying pores. In re-pyrolysis, the relative growth rates of 4 & times; 4 and larger aromatic sheets in the extraction and swelling residues were decreased from 66.35% (char without solvent treatment) to 52.21% (char after extraction treatment) and 36.4% (char after swelling treatment), respectively. It indicates that metaplast can promote the polycondensation. After solvent treatment, the orientational concentration of aromatic cores in the char increased during re-pyrolysis, whereas that in the untreated char did not. It indicates that the metaplast was more likely to being trapped by the char's skeletal framework through cross-linking reactions or pore adsorption and was further polycondensed with the volatiles to form amorphous aromatic cores within the char matrix.

Alcohol feeding had been recognized as an effective strategy for boosting methane production during anaerobic digestion of waste activated sludge (WAS). However, the mechanisms were curtly attributed to the promotion of direct interspecies electron transfer (DIET). Anaerobic digestion of WAS with a series of concentrations of glycerol were conducted. When eliminated methane production from glycerol, the remaining methane production was still 15-32 % higher than that without glycerol. However, the differences in the efficiency of volatile solid removal as well as concentration of short-chain fatty acids among all the digesters were not significant. Microbial communty analysis showed that addition of glycerol increased abundance of Methanothrix soehngenii GP6 that was capable of participating in DIET and sugar/amino acid-fermenting bacteria (Fastidiosipila sanguinis and Brevefilum fermentans). Electrochemical Fourier transform infrared spectra and electron transfer coefficient showed that addition of glycerol increased electron transfer efficiencies of digestates, and the gaps were further widened with the increase in the concentration of glycerol. Conversely, addition of glycerol lowered electron transfer efficiencies of humic and protein-like substances extracted from digestates. These results suggested the potential mechanisms on competing electrons with humic and protein-like substances via DIET for highefficiency methane production from WAS with glycerol.

Phenol is a toxic chemical widely found in industrial wastewater, yet its impacts on waste activated sludge (WAS) anaerobic digestion and the underlying microbial feedbacks under long-term stress remain unclear. This study systematically investigated the extracellular-to-intracellular mechanisms of phenol during WAS anaerobic digestion. Short-term results revealed a distinct dose-dependent response: low phenol exposure (25mg/g TSS) enhanced solubilization, boosting maximum methane yield by 51%, whereas high concentrations (100-200mg/g TSS) triggered severe volatile fatty acids (VFAs) accumulation and system failure. Mechanistic investigations demonstrated that proteins are the first extracellular polymeric substances (EPS) component to respond to phenol stress. The combination of phenol with proteins causes the secondary structure of the proteins to become denatured, thereby destroying the EPS matrix and releasing the bound organic substrates. However, excessive phenol caused EPS physical barrier failure, disrupting cell membranes and altering cell physiological states. Crucially, Long-term operation over 120 days provided insights into the adaptive strategies of the microbial community under sustained phenol stress. Phenol-tolerant bacteria belonging to the order Aminicenantales were enriched during the acclimation period. Concurrent metagenomic analysis revealed upregulation of pathways associated with the Stickland reaction (grd, +41.99%) and the rate-limiting methanogenic enzyme (mcr, +39.91%), suggesting a potential role of these pathways in sustaining methanogenesis under phenol stress.

In this study, a novel green tea polyphenol-iron composite material (GTPI) was successfully synthesized via the co-precipitation method, aiming to enhance the performance of anaerobic digestion (AD) of waste activated sludge (WAS). The research findings demonstrated that the introduction of GTPI significantly improved methane yield (240.0 mL/g VS), representing increases of 21.0% and 8.8% over the control and Fe3O4-added reactor, respectively, while effectively promoting organic matter degradation. Material characterization revealed that the incorporation of green tea polyphenols enriched the material surface with oxygen-containing functional groups, such as C--O and O-H groups, thereby enhancing its electrochemical activity. Additionally, GTPI mitigates the surface passivation of iron oxides during dissimilatory iron reduction (DIR), thereby enhancing iron reduction efficiency and increasing microbial bioavailability. Microbial community analysis revealed that GTPI enriched iron-reducing bacteria (e.g., Geobacter) and hydrogenotrophic methanogenic archaea (Methanomassiliicoccus), and concurrently stimulated the associated enzymatic activities for hydrolysis, acidification, methanogenesis, and electron transfer. In this study, a novel GTPI was developed and applied to improve the anaerobic digestion of WAS. By using natural polyphenols to regulate the surface redox reactions of iron-based materials, GTPI provides a potential strategy for alleviating iron passivation and enhancing sludge anaerobic digestion performance.

The depletion of fossil fuels is driving the biorefineries to produce biofuel from lignocellulosic biomass resulting in the massive generation of lignin holding a significant potential to be converted to value-added products. In this study, enzymatic hydrolysis residue (EHR) from corncob furfural production process was used for the preparation of N-doped activated carbon (AC). It consisted of dehydration of the EHR with H3PO4, amination of the dehydrated EHR through Mannich reaction and activation of the aminated lignin with H3PO4. The composition and structure variations of the samples in these processes were elucidated by means of proximate analysis, ultimate analysis, FTIR, TGA, SEM, XRD, and XPS. It is indicated that the dehydration increased the reactivity of lignin for amination and increased its thermal stability during the activation. The Mannich reaction, which was conducted by reacting dehydrated lignin with hexamethylenediamine and furfural in the presence of H3PO4 effectively resulted in amine incorporation into lignin structure. The activation of aminated lignin with H3PO4 enhanced the porosity and converted amine to pyridinic-N and pyrrolic-N. At the activation temperature of 500 degrees C, an AC (AEHLC500) with surface area (SBET) of 690.1 m2/g and N content of 2.59 wt % was prepared in a yield of 64%. As it was used for reactive yellow (RYD-145) removal, an adsorption capacity of 113.80 mg/g for the dye was observed. The adsorption process fitted well to the Langmuir isotherm (R2 = 0.997) and the pseudo second order kinetic model (R2 = 0.993), revealing its chemisorption and monolayer characteristics.

Extracellular electron transfer (EET) by type I Methanosarcina is relevant to bioenergy recovery, greenhouse gas emissions, environmental remediation and metal corrosion. However, its extracellular respiration is limited by low methanophenazine (MP) levels in the cell membrane, resulting in poor conductivity and restricted electron flux. Here, we grew Methanosarcina barkeri, the most studied species in type I Methanosarcina, with methanol as a sole electron donor and anthraquinone-2,6-disulfonate (AQDS) as a sole electron acceptor. Nearly all AQDS was reduced in the presence of magnetite nanoparticles, whereas less than 50% was reduced in their absence. The increase in concentration of cell proteins and number of gene copies of mcrA was accompanied by the increase in concentration of magnetite nanoparticles. Cell morphology showed that magnetite nanoparticles highly aggregated to form a single sheet and covered on cell surface, and did not penetrate the cells. When magnetite nanoparticles were replaced by semiconductive α-hematite nanoparticles, the AQDS-dependent extracellular respiration was also facilitated, but the increase was significantly weaker. Conducting atomic force microscopy (CAFM) and scanning electrochemical microscope (SECM) showed that magnetite nanoparticles formed conductive magnetite nanoparticle-membrane complexes on the cell surface, thereby enhancing extracellular electron transfer. Transcriptomics showed that expression of most of genes for membrane-bound MP-dependent hydrogenase (Vht), F420H2 dehydrogenase (Fpo) and heterodisulfide reductase (HdrDE) was significantly upregulated. These results suggest a novel model for AQDS-dependent extracellular respiration in M. barkeri induced by magnetite nanoparticles, improving mechanistic understanding of conductive nanoparticle-mediated extracellular electron transfer in this archaeon.

Eliminating Ni-organic complexes while recovering valuable Ni remains challenging in complex wastewater. Herein, we developed a Mn2O3-assisted electro-peroxone system, namely Mn2O3-EP, by integrating a Mn2O3 anode with an activated carbon fiber cathode for selective decomplexation and simultaneous Ni recovery. Mn2O3-EP completely decomplexed Ni-EDTA within 30 min and recovered ∼98% Ni on the cathode as Ni(OH)2 and Ni0. Compared with conventional EP, the decomplexation and Ni recovery rate constants increased by 2.54 and 1.79 times, respectively. Mechanistic analyses confirmed that singlet oxygen (1O2) generated from Mn2O3-mediated O3 activation and hydroxyl radicals (·OH) produced from cathodic peroxone jointly promoted Ni-EDTA decomplexation, contributing 57.7% and 36.7%, respectively. The Mn(III)/Mn(IV) cycle and oxygen vacancies on Mn2O3 further favored O3 activation toward 1O2 formation. Mn2O3-EP showed good tolerance to representative matrix components, including Cl-, NO3-, and humic acid, and was also effective for Ni complexes with NTA, citrate, and tartrate. In real electroplating wastewater, Mn2O3-EP reduced dissolved Ni from 9.38 to 0.73 mg L-1 and achieved >90% Ni recovery, with a decomplexation rate constant four times higher than that of conventional EP. A preliminary life cycle assessment suggested lower environmental impacts per unit Ni recovered under the selected system boundary, while ozone utilization and electrode preparation remain targets for further optimization. The new synergistic 1O2-·OH process offers a selective, robust pathway for coupled decomplexation and resource recovery from complex wastewaters.

Establishing direct interspecies electron transfer (DIET)-based methanogenic pathway is likely to address the technical bottlenecks involved in long periods and low rates of methanogenesis during anaerobic digestion of lignocellulose. However, the efficiency of DIET is limited by low abundance of electroactive bacteria and electron competition with conventional methanogenic pathway. Here, we combined cow manures with paddy soils/marine sediments as initial inocula, and constructed two simplified microbial consortia (DIETsimp) for conversion of lignocellulose to methane via a 'top-down' selection. Both DIETsimp dramatically shortened periods of methanogenesis (ca. 15-16 vs 25-40 d, this study vs present level) and increased methane production rates (ca. 32 vs 10-25 mL/gVS·d). Lowering pH dramatically increased conductivity of both DIETsimp, similar to that was found in electrically conductive pili of Geobacter sulfurreducens. Meanwhile, the intensities of characteristic peaks in electrochemical Fourier transform infrared spectra associated with c-type cytochrome in both DIETsimp dramatically increased. Metagenomic analysis showed that, Methanosarcina mazei, capable of accepting electrons via DIET, and electroactive species, Sphaerochaeta globosa and Clostridium aceticum, were the dominant archaea and bacteria in both DIETsimp, respectively. The potential DIET-based methanogenic pathway during anaerobic digestion of lignocellulose that S. globosa and C. aceticum metabolized intermediates (e.g. xylose, glucose, pyruvate and acetate) and transferred electrons to M. mazei for the reduction of CO2 to methane was proposed. At last, we optimized culture conditions (including inoculum ratio, C/N and period) to maximize the performances of both DIETsimp via combining the single-factor experiments with response surface methodology.

Physically tight structure of methanogenic aggregates formed by syntrophic microbes that exchange electrons via interspecies hydrogen/formate transfer (IHT/IFT) can activate defensive attack from type VI secretion system (T6SS), which has been recognized as the primary cause for poor stability. Direct interspecies electron transfer (DIET) may alleviate the technical bottleneck of proximity-triggered defensive attack from T6SS, since syntrophic microbes function long-distance electron transfer via electrically conductive pili (e-pili) or its displayed c-type cytochromes. Here, three up-flow anaerobic sludge blanket reactors, respectively with ethanol, propionate, and butyrate as a sole substrate, were used to culture DIET- and IHT/IFT-based aggregates. DIET-based aggregates were generally larger and exhibited a looser, porous structure compared to IHT/IFT-based aggregates. However, rheological behavior showed that they possessed higher rigidity and toughness, attributed to the structural support of the conductive pili network. 3D reconstruction and imaging of a single DIET-based aggregate by nano-industrial computed tomography showed that syntrophic microbes did not display a pronounced localized aggregation pattern. Conductivity-temperature/pH response showed that the DIET-based aggregates exhibited a metallic-like conductance similar to that found in e-pili. Meanwhile, the surface-enhanced Raman spectra showed that the intensities of characteristic peaks associated with c-type cytochromes in DIET-based aggregates were higher than those in IHT/IFT-based aggregates. Analysis of metagenomic and metaproteomic data showed that in DIET-based aggregates expression of key proteins of T6SS was suppressed. These results demonstrated that in DIET-based aggregates syntrophic microbes did not aggregate to form a physically tight structure, eluding defensive attack from T6SS and strengthening their stabilities.

Amine functionalized lignin has been prepared from enzymatic hydrolysis residue (EHR) obtained from corncob furfural production process by using the Mannich reaction. Dehydration of EHR with phosphoric acid (H3PO4) has been employed to enhance its reactivity for amine functionalization. For amine functionalization of dehydrated lignin (DEHL), hexamethylenediamine (HMDA) and diethylamine (DEA) have been used as amine sources, while furfural has been used as an aldehyde source. The structural changes during the dehydration and amine functionalization processes were elucidated using proximate analysis, elemental analysis, FTIR, SEM, EDS, BET, and XPS analysis. The Mannich reaction conditions were optimized to obtain amine functionalized lignin (AEHL) with a high N content. Amine type and the Mannich reaction temperature were found to be the most influential factors affecting N content. Optimized AEHL exhibited the highest N content of 7.04%. The adsorption performance of the optimized AEHL was evaluated for the adsorption of reactive yellow dye (RYD-145). The effect of various factors, including adsorbent dosage, pH, temperature, time, and initial dye concentration, on removal efficiency was evaluated. The maximum adsorption capacity of AEHL for RYD-145 was found to be 37.52 mg/g following Langmuir and pseudo-second order kinetics.

Biological hydrolysis has been widely recognized as an effective method for the pretreatment of crop straw. However, due to the complex structure and composition of straw, hydrolysis efficiency is often low, particularly because of the presence of lignin. In this study, a top-down approach involving continuous subculture was employed to construct a synthetic bacterial consortium derived from saline-alkali paddy soil, aiming to achieve high hydrolysis efficiency for rice straw (RS) and wheat straw (WS). Within this saline-alkali-tolerant synthetic bacterial consortium, Pontibacter, Lysobacter, and Bacillus were common to both the RS and WS groups. Sphingoaurantiacus (4.70%), Sericytochromatia (3.32%), Paenibacillus (2.84%), Paludisphaera (2.71%), and the S0134_terrestrial_group (2.26%) were specifically enriched in the RS group, while Microbacterium (10.05%), Domibacillus (3.45%), Azospirillum (2.39%), Sumerlaea (1.91%), and Aminobacter (1.85%) were enriched in the WS group. Ultimately, the hydrolysis efficiencies reached 71.12% for RS and 78.04% for WS. Notably, both groups achieved high lignin hydrolysis efficiencies exceeding 60%. The enhanced straw hydrolysis efficiency can also be attributed to the enrichment of functional hydrolytic enzymes. Specifically, hydrolysis efficiencies for hemicellulose and cellulose were higher in the RS group, whereas lignin hydrolysis efficiency was higher in the WS group. The primary hydrolysis products-reducing sugars and beta-ketoadipate-represent key raw materials for the production of high-value energy and chemical products. The high efficiency of lignin hydrolysis in this study addresses a common limitation observed in other research. This finding provide a possible approach to solve the low hydrolysis efficiencies for lignin by synthetic bacterial consortium from saline-alkali paddy soil.

Direct interspecies electron transfer (DIET) is recognized as a novel path for anaerobic digestion (AD) of organics, e.g. ethanol. Biochar has been used to enhance DIET, due to its good conductivity, while the existence of Na+ could influence transmembrane electron transfer of anaerobic microorganisms. However, the potential synergistic effects of salinity and biochar on improving DIET-based AD have not been extensively explored. In this study, it was found that increasing Na+ concentrations from 0 to 5.0 g/L significantly promoted COD removal and methane production with ethanol as substrate. The addition of biochar further enhanced AD performance. When the hydraulic retention time (HRT) was reduced to 12 h, reactor R1 (the control reactor, without Na+) experienced system collapse, while reactors R2 and R3 (the saline reactors with and without biochar) maintained COD removal rates above 90 %, especially in reactor R3. Larger microbial aggregates formed in reactors R2 and R3, with electroactive microorganisms such as Desulfovibrio becoming dominant. But the abundance of Desulfovibrio in reactors R2 and R3 showed obvious difference (P < 0.05). These findings suggest potential synergistic effects of salinity and biochar in enhancing ethanol-fed AD under elevated organic loading. This study proposes feasible strategies for AD facing to high organic loading or acid stress condition.

Mercury removal from coal combustion flue gas remains a significant challenge for environmental protection due to the lack of cost-effective sorbents.In this study,a series of red mud(RM)-based sorbents impregnated with sodium halides(NaBr and NaI)are presented to capture elemental mercury(Hg0)from flue gas.The modified RM underwent comprehensive characterization,including analysis of its textural qualities,crystal structure,chemical composition,and thermal properties.The results indicate that the halide impregnation substantially impacts the surface area and pore size of the RM.Hg0 removal performance was evaluated on a fixed-bed reactor in simulated flue gas(consisting of N2,O2,CO2,NO and SO2,etc.)on a modified RM.At an optimal adsorption temperature of 160 ℃,NaI-modified sorbent(RMI5)offers a removal efficiency of 98%in a mixture of gas,including O2,NO and HCl.Furthermore,pseudo-second-order model fitting results demonstrate the chemisorption mechanism for the adsorption of Hg0 in kinetic investigations.

Anaerobic digestion is an important approach for reducing the volume of urban sludge and achieving resource recovery. However, conventional anaerobic digestion is limited by the diffusion of hydrogen and formic acid, which can easily lead to metabolic blockage, eventual acidification, and system collapse. Direct interspecies electron transfer (DIET) has been proven to effectively mitigate these issues and enhance the efficiency of anaerobic digestion. Previous studies have shown that the addition of a small amount of glycerol can enrich electroactive microorganisms and promote DIET. However, the use of exogenous glycerol increases operational costs. To address this, the present study combined alkali pretreatment and yeast fermentation to produce glycerol in situ from urban sludge, thereby promoting DIET and supporting efficient methane production. The results showed that the optimal duration for alkaline pretreatment was 10 hours, which increased the soluble sugar content by 43.4% compared to untreated sludge. The optimal inoculation ratio for yeast fermentation was 10%, and the optimal fermentation duration was 9 hours, during which glycerol accounted for 2.43% of the total chemical oxygen demand (COD) of the sludge. Anaerobic digestion performance was evaluated based on indicators such as methane yield, volatile solids (VS) removal rate, and organic matter conversion efficiency. Compared with the control group, the yeast fermentation group and the combined alkaline pretreatment and yeast fermentation group achieved increases in methane production of 11.8% and 15.4%, respectively. The VS removal rate was similar across all groups (approximately 45%), while the organic matter conversion efficiency for the yeast fermentation group and the combined group increased by 5.80% and 9.30%, respectively. Furthermore, analysis of the electron transfer coefficient (ETC) revealed the intrinsic mechanism of system enhancement. Compared to the control group, the discharging ETC in the yeast fermentation group and the combined pretreatment group increased by 11.1% and 16.8%, respectively. Similarly, the charging ETC in these groups increased by 11.1% and 17.3%, respectively. Finally, microbial community analysis indicated that Methanothrix soehnenii GP6 and Fastidiosipila sanguinis were enriched in the combined pretreatment group, suggesting their potential involvement in DIET.

Photoelectrotrophic denitrification (PEDeN) is an innovative denitrification process with great potential for nitrate (NO3-) removal from carbon-deficient wastewater. However, the inevitable presence of reactive oxygen species (ROS) significantly undermines the sustainability of PEDeN, including inducing substantial nitrous oxide (N2O) accumulation and declining system's performance. This work demonstrates a proof-of-principle of a photovoltaic (PV)-type PEDeN reactor, where the dominant ROS, including hydrogen peroxide and hydroxyl radicals, are completely isolated from denitrifiers. This way enabled NO3- to be selectively reduced (100%) to nitrogen with minimal N2O emission. The maximum accumulated N2O-N relative to input NO3--N was 11.3%, significantly lower than that in hybrid systems, such as Thiobacillus denitrificans-CdS (72.1%) and Thiobacillus denitrificans-AQS (95.5%). After eliminating ROS, the NO3- removal efficiency in each cyclic experiment reached 100% and the nitrogenous intermediators, such as nitrite and N2O, could be minimized via enhancing the photocurrent. Importantly, NO3- reduction continued even when no chemicals was added, indicating that water can serve as the end electron donor. This study introduces a PV-type PEDeN reactor concept for sustainable nitrate removal via mitigating the toxic effects of ROS and it will offer a cost-effective, environmentally friendly, and scalable technology for removing NO3- pollutants from carbon-deficient wastewater.

The Buchwald-Hartwig (B-H) reaction graph, a novel graph for deep learning models, is designed to simulate the interactions among multiple chemical components in the B-H reaction by representing each reactant as an individual node within a custom-designed reaction graph, thereby capturing both single-molecule and intermolecular relationship features. Trained on a high-throughput B-H reaction data set, B-H Reaction Graph Neural Network (BH-RGNN) achieves near-state-of-the-art performance with an R2 score of 0.971 while maintaining low computational costs. Using a perturbation-based analysis, the model reveals significant insights into the relationship between bases and reaction yields, identifying key characteristics of bases influencing yields, which provides valuable guidance for base selection in the B-H reaction. This work demonstrates the effectiveness of tailored graph representations in advancing GNN applications for chemical reaction modeling, offering a promising tool for predicting reaction yield and identifying key reaction factors.

This paper proposes a smartphone-based electrochemical detection instrument, combined with a microfluidic device using Microelectromechanical systems (MEMS) technology integrating a thin-layer flow cell and a modified ITO electrode to successfully construct a portable multiple metal ions detection system. This effectively addresses the issues of poor portability, complex operation, and strong reliance on the laboratory environment of traditional detection equipment. The electrochemical detection instrument realizes the highly sensitive detection of metal ions through the integrated hardware circuit design and the collaborative work of software algorithms. The hardware circuit is based on an STM32 microcontroller as the core, combined with a constant potential circuit and low-pass filtering circuit, which realizes high-precision acquisition of weak current signal and anti-interference processing, and the low-pass filtering makes the signal-to-noise ratio of cyclic voltammetry curves significantly improved. The application (APP) software for smartphones was developed to improve the data quality based on cubic spline interpolation and smoothing algorithm, and the Levenberg-Marquardt nonlinear fitting algorithm was used to optimize the parameters of the model so that the R2 value of data fitting was more than 0.99, which improves the analytical accuracy and ensures the reliability of the measurement. Further, a microfluidic device modified by single-walled carbon nanotubes (SWCNTs)/conductive carbon black (CB) was devised and built, combined with a detection instrument with a fluidic control unit to promote sample diffusion and enhance sensitivity. According to the results, the detection limits of the system for the metal ions, Cu, Pb, and Cd were 88 μg/L, 0.73 μg/L and 2.3 μg/L, respectively, which verified its effectiveness and potential application in the immediate detection of metal ions and can meet the needs of the point-of-use (POU).