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Biomass gasification kinetic model plays an integral role in the analysis and application of biomass gasification process. Compared with the isothermal method, the non-isothermal method possesses the advantages of high computational effectiveness, multiple methods, and simple operation. However, there were limited reports associated with non-isothermal methods. In this paper, the pyrolysis kinetics of coffee grounds at a heating rate of 5–40 K/min and lignite at a heating rate of 5–40 K/min were analyzed by non-isothermal thermogravimetric analysis, respectively. A simpler parameter solving method, exponential substitution elimination method (ESE), was proposed. The activation energy of coffee grounds was 270 kJ/mol and that of lignite was 310 kJ/mol, which was basically consistent with that obtained by the traditional KSA and FWO methods. At the temperature of 1000–1273 K, the activation energy parameters calculated by ESE calculation were substituted into the random pore model RPM model for model fitting, and the fitting results showed that the newly proposed ESE calculation method was in line with the reality.

Microbial fuel cell (MFC) can be used as a potential technology for degradation of organic contaminant. In order to improve the efficiency of MFC treating the biogas slurry (BS), a comparison between the pretreatments of aerobic static culture and aeration was studied. The nitrogen and chemical oxygen demand (COD) removal and electricity production capacity of BS-MFC was investigated. The results showed that the total degradation rate of NH4+-N in BS after the aeration coupled with MFC treatment reached 95.70 %, which was 12.97 % higher than that of the aerobically statically cultivated BS. The coulombic efficiency (CE) of the aeration-treated BS participating the reaction in MFC was always higher than that of the aerobically cultivated group. The relative abundance of Chloroflexi, which plays an important role in nitrogen metabolism, accounted for a smaller proportion in the MFC reaction effluent after aeration treatment. While, the denitrification bacteria Patescibacteriawas slightly enhanced. The aeration-treated BS also stimulated the growth of electrochemically active microorganisms Gammaproteobacteriain the MFC system. The results of this study showed that pretreatment of the BS with aeration was more favorable to improve the efficiency of the BS-MFC, which provided informative suggestions for the improvement of MFC.

Heavy metal pollution is a severe environmental challenge, posing significant threats to ecosystems and human health. Heavy metals like cadmium, lead, and mercury can disrupt food chains and degrade soil and water quality at high concentrations, impacting ecological balance. For human health, heavy metal pollution can cause chronic poisoning and increase cancer risks. Thus, developing rapid and sensitive detection techniques for heavy metal ions is crucial. Electrochemical techniques, compared to traditional methods, offer high selectivity, fast analysis, simplicity, and cost-effectiveness. Biomass-derived carbon material-modified electrodes, with their low cost and high sensitivity, are widely applied in heavy metal ion detection. This review summarizes three primary green synthesis methods for carbon materials: hydrothermal carbonization, pyrolytic carbonization, and sol-gel synthesis. It explores how factors in green synthesis influence the structure and performance of biomass carbon in detecting heavy metal ions, guiding the development of rapid, highly sensitive, and selective electrochemical detection techniques.

Anaerobic digestion pretreatment was conducted to assist electrocatalyst preparation.The biological pretreatment succeeded in carbohydrates decomposition and nitrogen enrichment.Pretreatment derived biochar significantly increased the ORR activity and microbial fuel cell performance.

Hydrogenation of phenol is an important strategy to produce cyclohexane or cyclohexanol as both of them are raw materials for the synthesis of nylon-6 and nylon-66. Herein, we report a novel method for the selective hydrogenation of phenol to cyclohexane or cyclohexanol over a bifunctional Pd/NaY catalyst by regulating the solvent polarity. It was found that solvent polarity has a strong influence on the hydrogenation reaction mechanism. Under the identical conditions, 100% selectivity to cyclohexane could be obtained when reacting in n-octane (nonpolar solvent), while 92.3% selectivity to cyclohexanol was achieved in EtOH (polar solvent). The polarity of the solvent not only affects the competitive adsorption capacity but also the adsorption manner of phenol over the acid sites and the Pd nanoparticles in the Pd/NaY catalyst. DFT calculations show that different solvents have an almost negligible effect on the reaction energy barriers but highly affect the hydration reaction of cyclohexanol if the trace amount of water formed could not be timely removed from the catalytic system. This solvent-driven catalysis exhibits good recyclability, showing great promise for industrial applications. These findings not only provide new insights into the hydrogenation mechanism of phenolics, but also might help to develop facile strategies for the selective conversion of other phenolics into desired products.

Nowadays, the production of biodiesel from various renewable sources is becoming increasingly urgent because fossil fuels are becoming less and less available and accessible. Biodegradability, non-toxicity, and low pollution emissions are merely some properties making biodiesel a more environmentally friendly fuel. Esterification/transesterification is the most commonly used method to produce the biodiesel, whose reaction products are water/glycerol and mixed fatty acid esters. The membrane separation methods are applied to remove water/glycerol, which is capable of upsetting the chemical equilibrium of esterification/transesterification controlled by thermodynamics and facilitating the reaction to proceed forward accordingly. The integrated membrane separation process is coupled with the chemical reaction, which could isolate a certain product from the reaction system with the reaction going on. That means that it is possible for the membrane separation technology to burst the restraints of original chemical equilibrium to gain the higher equilibrium conversion rate and yield. In comparison to other methods, the membrane separation technique coupled with chemical reaction has the ability to increase the reaction conversion rate, shorten the reaction time, and evenly reduce energy consumption.

A spherical composite aerogel adsorbent (CA/KCB aerogel) with excellent Pb2+adsorption performance was prepared by sol-gel method using calcium alginate (CA) and KMnO4modified cotton stalk biochar (KCB). The preparation parameters of CA/KCB aerogel were optimized by response surface methodology. The physicochemical properties and Pb2+adsorption characteristics of CA/KCB aerogel were systematically investigated. The CA/KCB aerogel before and after Pb2+adsorption was characterized by SEM, EDS, FTIR and XRD, and the adsorption mechanism was discussed. The optimal preparation parameters of CA/KCB aerogel are: the dosage of KCB was 6 g/L, the mass concentration of sodium alginate and CaCl2was 3% and 1% respectively. CA/KCB aerogel was rich in oxygen-containing functional groups, exchangeable cations and interconnected pores, and can exist stably in aqueous solutions with a wide pH range (2−12). The data of adsorption kinetics and adsorption isotherms can be well fitted by the pseudo-second-order model and Langmuir model, respectively. The maximum adsorption capacity of Pb2+was 664.6 mg/g. The adsorption process was an endothermic reaction dominated by monolayer chemisorption. The binding of CA and KCB in aerogel can promote the adsorption of Pb2+synergistically. Finally, CA/KCB aerogel was directly applied to the treatment of electroplating wastewater. The coexisting heavy metals (Pb, Cu and Zn) in the wastewater can be effectively removed when the adsorbent dose was 35 g/L. The conclusion is that CA/KCB aerogel has a promising application prospect as adsorbent for heavy metal removal.

•Research on kinetic compensation effect in non-isothermal gasification.•Influence of the method for calculating kinetic parameters on the compensation effect.•Influence of gas diffusion on kinetic compensation effects.•Dependence of kinetic compensation effects on diffusion.

•The efficient conversion of biomass into carbon catalyst via ZnCl2 activation.•The catalyst deriving from biomass possess a hierarchical structure.•The activation mechanism was clarified during the pyrolysis process.•The catalyst shows excellent performance for ORR in wide pH range.•They can be high-efficiency non-precious metal ORR electrocatalysts for fuel cells.

The lignin waste from lignocellulose biorefinery limits its green recycling development. Lignin is a kind of natural aromatic polymer with a complex three-dimensional amorphous structure. Catalytic pyrolysis technology has been employed to convert lignin waste into high-grade aromatic compounds, which can realize the full-component refining of biomass. However, the catalytic pyrolysis of lignin has faced problems such as low target product selectivity and poor catalyst stability, which affects the conversion efficiency and economy. This review aims to scope the latest developments the lignin waste valorization by catalytic pyrolysis from the aspects of lignin structure characteristics, catalytic pyrolysis mode, catalyst types, and catalytic pyrolysis reaction system, respectively. The latest aspects of catalyst and catalytic pyrolysis reaction system development in the lignin pyrolysis process have been emphatically analyzed. Based on a critical analysis of the scientific literature, the industrial symbiosis model of cross-industry comprehensive utilization of biorefinery lignin waste with a focus on catalytic pyrolysis technology was proposed for accurately incorporating catalytic pyrolysis technology into the biorefinery system. Finally, several perspectives on designing efficient and commercial application strategies of lignin waste energy utilization are addressed. This review can provide a scientific reference for further research studies on lignin waste residue produced by lignocellulose biorefinery.

Impacts of pyrolysis temperature of biochar on lead adsorption from aqueous solution and related mechanisms were investigated in this work. Biochars derived from cotton stalk were prepared under temperature from 250 to 650 ℃. The physicochemical properties and the Pb2+adsorption capacity (Qe) of biochar were characterized. The results revealed that Qe was positively correlated (p < 0.01) with ash content, pH, C content and average pore diameter, and negatively correlated (p < 0.01) with O content, O/C ratio, (N + O)/C ratio and yield of biochar, respectively. Batch adsorption were performed using the optimal biochar sample (CS550), and the effects of ambient temperature, initial pH, biochar dose, adsorption time and initial concentration of Pb2+on adsorption were explored. The results suggest that the pseudo-second-order model and Freundlich model fit the adsorption data well, and the maximum sorption capacity calculated by Langmuir model was 146.78 mg/g. SEM-EDS, FTIR and XRD were used to characterize the biochar before and after Pb2+adsorption. The results indicate that there are six adsorption mechanisms participate in the adsorption process, and precipitation, ion exchange with AAEMs, Pb2+-π interactions and complexation were found to be the main adsorption mechanisms. The regeneration experiment results indicate that biochar could be reused to remove Pb2+for at least 3 runs with a slight decrease in the adsorption capacity. The conclusion is that cotton stalk biochar is an environment-friendly adsorbent for the purification of wastewater containing heavy metals.

The reuse of process wastewater as a reaction medium in hydrothermal liquefaction (HTL) of biomass to enhance biocrude oil (BO) production has been investigated, but the interaction between the biomass and process wastewater has rarely been studied. In the present work, pyroligneous acid (PA) was used as the reaction medium and substrate during the HTL process of cornstalk (CS). Hydrothermal conversion of PA itself, HTL of CS with water, and coliquefaction of CS and PA were carried out in a high-temperature and high-pressure batch reactor. Effects of reaction temperature and PA on the yields and characteristics of products were investigated. The PA itself was hydrothermally converted into BO, solid residue (SR), an aqueous phase, and gases. Reaction temperature had a strong influence on the product distribution during the coliquefaction of CS and PA but little influence on products during PA hydrothermal conversion. The highest BO yield from PA hydrothermal conversion occurred at 300 °C (28.96 wt %). For the coliquefaction of CS and PA, the highest experimental BO yield was 31.29 wt % at 300 °C, exceeding its corresponding theoretical value by 3.28 wt %; the experimental SR yield at 350 °C was 13.01 wt %, with the highest increase of 3.34 wt % compared to its corresponding theoretical value. The synergistic effects of CS and PA occurred at high temperatures (300 and 350 °C), promoting BO formation and strengthening SR accumulation, possibly due to the interactions among the compounds dissolved in PA and the components of CS. The BOs obtained from CS and PA coliquefaction had similar C, H, and O contents and higher heating values (HHVs) than those of HTL of CS, suggesting that the reuse of PA in HTL did not compromise the oil quality. Compared with the HTL of CS with water, CS and PA coliquefaction resulted in reduced concentrations of phenols, N-containing compounds, and organic acids and higher concentrations of ketones, alcohols, and hydrocarbons. Hence, PA clearly affected the distribution of organic components in BOs. In addition, more carbonaceous SRs were produced from coliquefaction with C and O contents of 65.14–70.23 and 23.94–29.89 wt %, respectively, and HHVs of 22.77–26.99 MJ/kg.