•A novel two-stage process is proposed to recovery of Zn and Pb from waste zinc smelting slag.•Brick with low bulk density and high compressive strength is made by zinc smelting slag and clay.•The ...leaching toxicity of sintered brick is below the regulatory thresholds of Chinese National Standards.
Novel lightweight bricks have been produced by sintering mixes of zinc smelting slag and clay. A two-stage sintered process has been proposed to recovery of Zn and Pb and reutilization of the zinc smelting slag. In the first stage of the process, called reduction and volatilization procedure, zinc and lead were reduced by the carbon contained in the zinc smelting slag and volatilized into the dust, and the dust can be used as a secondary zinc resource. In the second stage of the process, called oxidation sintering procedure, a lightweight brick was produced. Samples containing up to 60wt.% zinc smelting slag and 40wt.% kaolin clay were reduced at 1050°C for 6h, and then sintered at 1050°C for 4h. The recoveries of Zn and Pb from the brick are 94.5±0.6% and 97.6±0.2%, respectively. Low bulk density (1.42gcm−3) and relatively high compressive strength (22MPa) sintered bricks were produced, and the leaching toxicity of the sintered bricks was below the regulatory thresholds of Chinese National Standards.
Corncob is a potential feedstock for biorefineries to produce cellulosic ethanol and other chemicals. Densifying lignocellulosic biomass with chemicals followed by autoclave (DLCA) has been confirmed ...an efficient and economical pretreatment method, and it was applied in the present work for conversion of corncob to bioethanol. The dosage of sulfuric acid, solid loading of biomass, and autoclave time for pretreatment were investigated. Enzymatic hydrolysis at 25–35% solids loadings resulted in 91–97% sugar conversions. Fermentation of the resulted hydrolysates went well with the highest ethanol titer reaching 75.71 g/L at 35% solid loading. Simultaneous saccharification and co-fermentation was applied to further improve xylose consumption at high solids loadings and the ethanol titer was enhanced to 82.0 g/L at 35% solid loading with an ethanol yield of 21.67 kg/100 kg corncob. This study demonstrated DLCA provided a highly digestible and highly fermentable corncob for biorefinery.
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•The pretreatment-severity-dependent inhibition is mainly due to phenolics.•A QSAR model was built to describe the phenolics caused inhibition.•Electrophilicity and hydrophobicity of ...phenolics determine the inhibition potential.•Phenolics bind to cellulases by hydrophobic interactions, hydrogen/covalent bonds.•The inhibition of cellulose hydrolysis by phenolics was greatly alleviated in-situ.
The lignin-derived phenolics are highly inhibitory toward lignocellulose enzymatic hydrolysis, while the relationship between phenolic structure and inhibitory effect is still not fully understood. In this study, the compositions of phenolics from dilute acid pretreated wheat straw were analyzed and their impact on cellulose hydrolysis was studied. With increase of pretreatment severity, more toxic phenolics were produced from lignin degradation reactions, which were the major contributor to the increased inhibitory effect of pretreatment hydrolysate towards cellulases. Through analyzing the relationship of phenolic structure and their inhibitory effect, a useful model was developed to predict the phenolics-caused inhibition by combining the indexes of electrophilicity and hydrophobicity. Further, through understanding the interactions between phenolics and cellulases, a novel biocomponent alleviator was rationally designed to block the phenolics-cellulase interactions, the degree of improvement of enzymatic hydrolysis reached as high as 135.8%. This study provides directions for developing more effective pretreatment and detoxification methods.
Separation-free sugar-platform biorefinery from lignocellulose has drawn increasing attention due to its feasibility. However, the presence of lignin-derived phenolics within the whole slurry after ...pretreatment, is highly inhibitory toward enzymatic hydrolysis of lignocellulose especially at high solid loadings. Developing effective methods to mitigate the phenolics-caused enzyme inhibition in-situ can further improve the cellulose hydrolysis, while the relevant studies are limited. In this study, the effects of different kinds of additives on mitigating the phenolic-caused inhibition was determined and the synergy among the additives were systematically evaluated. Based on the analysis, we developed novel binary additives to alleviate the phenolic-caused inhibition of cellulose hydrolysis in-situ. In addition to surfactants, a reducing agent (l-cysteine) was introduced to enhance the enzymatic hydrolysis of cellulose and the strong synergism between the reducing agent and the surfactant was firstly demonstrated. Further, the mechanism study indicated that these additives could prevent the strong interactions between phenolics and cellulase and improve the major cellulase activities. Finally, with the addition of the binary additives, the cellulose hydrolysis for acid/alkaline pretreated corn stover were significantly improved with low enzyme loading without detoxification. This study provides directions for designing novel additives to improve the enzymatic hydrolysis of pretreated lignocellulosic biomass.
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•Cellulose hydrolysis at high solid loading was strongly inhibited by phenolics.•Strong synergism was firstly demonstrated between l-cysteine and Tween 40.•The additives can prevent the strong interactions between phenolics and cellulases.•The addition of the additives significantly improved the cellulose hydrolysis.
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•DLCA pretreatment effectively disrupts biomass structure at low temperatures.•Temperature contribution to conventional pretreatment severity was underestimated.•Modified severity ...factor improves xylan hydrolysis evaluation in DLCA pretreatment.•Mathematical model accurately predicts pretreatment efficiency and enzymatic hydrolysis.
DLCA(sa) pretreatment (densifying lignocellulosic biomass with sulfuric acid followed by autoclave treatment), featured with low treatment temperature and densification, demonstrate high efficiency in biomass pretreatment. In this study, the effects of temperature, acid loading, time on the hydrolysis of xylan, cellulose and lignin during DLCA(sa) pretreatment were systematically investigated. It was shown that DLCA(sa) pretreatment can effectively solubilize xylan, achieving an 84% xylose recovery under mild conditions (130 °C, 30 min, and 0.125 g/g acid loading). The conventional pretreatment severity factor correlated and further modified to improve the accuracy in evaluating the xylan hydrolysis. Additionally, a mathematical model based on the xylan hydrolytic kinetics was proposed to predict the enzymatic hydrolysis. Kinetic model suggested that mechanical densification facilitates the penetration of acid into the biomass matrix, leading to increased accessibility of xylan to acid catalysis.
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•Fractal kinetics describe enzymatic hydrolysis of cellulose at various solid loadings.•Mixture design model simulates effects of various feeding modes on sugar release.•Feeding ...dosages and feeding times synergistically influence sugar release.•Customized fed-batch strategies boost sugar release from high solid hydrolysis.•255 g/L sugar concentration was achieved with a model optimized fed-batch strategy.
Achieving high sugar concentrations through enzymatic hydrolysis of pretreated lignocellulose with low enzyme loadings is crucial for reducing the costs of lignocellulosic biorefineries. However, the adverse effects of the “solid effect” pose essential challenges in this regard. In this study, the objective is to improve the sugar concentrations through enzymatic hydrolysis of Densifying Lignocellulose with Ca(OH)2 or H2SO4 followed by Autoclave pretreated corn stover (DLCA(ch)-CS or DLCA (sa)-CS) at 40 % w/w solid loading through kinetic analysis and a statistically designed fed-batch feeding strategy. Initially, the hydrolysis kinetics of different pretreated biomass were analyzed using fractal kinetic modeling, aiming to elucidate the reasons for the observed differences in hydrolysis. Furthermore, leveraging the kinetic differences, the optimal initial solid loading was determined, and statistical models were employed to optimize feeding modes for enzymatic hydrolysis. The result revealed that compared with H2SO4, Ca(OH)2 serves as an better catalyst for improving the hydrolysability of biomass, enhancing cellulose accessibility to cellulases and reduce the mass transfer rate during enzymatic hydrolysis. Interestingly, the optimal feeding mode for less digestible substrate (DLCA(sa)-CS) is different from the more digestible substrate (DLCA(ch)-CS). Notably, by using the optimized fed-batch feeding mode, the sugar concentration can reach a maximum of 255 g/L, with glucan conversion of 89.8 %, at low enzyme loading (10 mg protein/g glucan). This is the highest total sugar concentration achieved through 72 h enzymatic hydrolysis with low enzyme loadings using a fed-batch strategy. This approach proves highly effective in designing fed-batch strategies for pretreated biomass and has great potential to serve as a universal tool for designing suitable feeding schemes for various bionconversion process.
Mechanical fracture of electrodes will occur during lithiation caused by large volume changes, which leads to the capacity loss of the lithium-ion battery. Herein, we present a new analytical model ...to investigate the effect of creep deformation on stress relaxation and fracture of the lithiated tin (Sn) electrode under the galvanostatic and potentiostatic operation. Interestingly, it is found that the presence of creep can improve fracture resistance and toughness of the Sn electrode. In addition, the surface effect has the capacity to weaken the creep deformation effectively. And the different size of the Sn electrode shows different effects for creep deformation. This conclusion explains the difference in charging conditions, and the mechanism of stress change inside the electrode is also different. Deeply, the base on our model, the stress strength factor, and critical size of the electrode have been evaluated under galvanostatic and potentiostatic operation with creep deformation effects. Finally, the safety area during lithiation is established to determine the critical size of the Sn electrode. And the presence of creep deformation may significantly increase critical dimensions of the electrode. These results will provide a valuable basis to design the durable electrodes.
In lithium-ion batteries, the volume change of anode materials will result in fracture of solid electrolyte interphase (SEI) during continuous lithiation and delithiation. Herein, an analytical model ...has been developed to determine the fracture mechanism of the SEI and the fatigue in lithium-ion batteries. The evolution of diffusion-induced stresses and concentration have been evaluated. In addition, surface effects are found to effectively reduce the stresses and the crack propagation in SEI during lithiation. With combined energy release rate, the critical thickness of SEI is also established to prevent crack propagation. Finally, the capacity fade of lithium-ion batteries during cycling may be predicted using fatigue model. It is found that the depths of discharge (DODs) are closely related to the capacity fade of lithium-ion batteries. Overall, this work may provide physical understanding for optimized structural design to alleviate the SEI fracture and the fatigue of the lithium-ion batteries.
Developing value-added lignin-based biomaterials for enzyme immobilization has drawn great attention. This study developed a cost-effective and eco-friendly one-pot strategy to synthesize the ...rod-like lignin@zeolitic imidazolate framework-8 (ZIF-8) hybrid nanomaterial by using lignin derived from lignocellulosic biofuel production. The incorporation of lignin into the ZIF-8 network not only altered the morphology, but also modified the surface properties of the material, making it an ideal support for enzyme immobilization. The synthesized nanoscale hybrid materials were used to immobilize beta-glucosidase (BG) with high immobilization capacity and about 92–166 mg/g of BG was immobilized through physical adsorption. The immobilized BG exhibited good stability, catalytic activity and recycling properties, and was reused under acidic conditions for more than 8 cycles with more than 60% activity kept. The as-prepared hybrid material can serve as a great carrier for immobilizing various biomolecules.
•A one-pot strategy was developed to synthesize the rod-like lignin@ZIF-8.•The morphology and surface properties of lignin@ZIF-8 were characterized.•The immobilization capacity of lignin@ZIF-8 for beta-glucosidase (BG) was about 92–166 mg/g.•The relative activity of immobilized BG was more than 60% after 8 times reuse.
Lignin nanoparticles have gained increasing attention as a potential antimicrobial agent due to their biocompatibility, biodegradability, and low toxicity. However, the limited ability of lignin to ...act as an antibacterial is a major barrier to its widespread use. Thus, it is crucial to develop novel approaches to amplify lignin's biological capabilities in order to promote its effective utilization. In this study, we modified lignin nanoparticles (LNPs) with photo-active curcumin (Cur), zinc oxide (ZnO), or a combination of both to enhance their antimicrobial properties. The successful modifications of LNPs were confirmed using comprehensive characterization techniques. The antimicrobial efficacy of the modified LNPs was assessed against both gram-positive and gram-negative bacterial strains. The results showed that the modification of LNPs with Cur and ZnO have much higher antibacterial and antibiofilm activities than unmodified LNPs. Moreover, photo illumination resulted in even higher antibacterial activity. Furthermore, atomic force microscopy revealed bacterial cells lysis and membrane damage by ZnO/Cur modified LNPs. Our research demonstrates that ZnO/Cur modified LNPs can serve as novel hybrid materials with enhanced antimicrobial capabilities. In addition, the photo-induced enhancement in antibacterial activity not only demonstrated the versatility of this hybrid material but also opened up interesting potential for bioinspired therapeutics agents.
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