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Poly (β-L-malic acid) (PMLA) is attracting industrial interest for its potential application in medicine and other industries. In this study, electrolytic stimulation assisted PMLA production was developed. Firstly, it was found that the pentavalent nitrogen source (i.e., NO

A nanofiltration (NF) membrane with high salt permeation and high retention of small organics is appealing for the treatment of high-salinity organic wastewater. However, the conventional negatively charged NF membranes commonly show high retention of divalent anions (e.g., SO

As the world is faced with the coronavirus disease 2019 (COVID-19) pandemic, photocatalytic antibacterial ceramics can reduce the consumption of disinfectants and improve the safety of the public health environment. However, these antibacterial ceramics are often limited by poor stability and low light utilization efficiency. Herein, an antibacterial ceramic was developed via the method of facile in situ etching of upconversion glass-ceramics (UGC) (FIEG) with HCl, in which the BiOCl nanosheets were in situ grown on the surface of GC to improve its stability and antibacterial activity. The results suggest that the upconversion antibacterial ceramics can harvest and utilize near-infrared (NIR) photons efficiently, which display notable antibacterial activity for

Identification of adsorption centers with atomic levels of adsorbents is crucial to study the adsorption of formaldehyde (HCHO), especially for an in-depth understanding of the mechanism of HCHO capture. Herein, we investigate the HCHO adsorption performance of one-dimensional (1D) nanoporous boron nitride (BN) fiber, and explore the adsorption mechanism by density functional theory (DFT) calculations, including adsorption energy change and Bader charge change, and experimental study as well. Research shows that the 1D nanoporous BN fiber possesses a high concentration of Lewis pairs, which act as Lewis acid and Lewis base sites associated with the fiber's electron-deficient and electron-rich features. It is worth noting that the HCHO removal efficiency of a typical sample is as high as 91%. This work may open the door to the field of adsorption of other pollutants by constructing Lewis pairs in the future.

Chemical cleaning is indispensable for the sustainable operation of nanofiltration (NF) in wastewater treatment. However, the common chemical cleaning methods are plagued by low cleaning efficiency, high chemical consumption, and separation performance deterioration. In this work, a chemoenzymatic cascade reaction is proposed for pollutant degradation and polyamide NF membrane cleaning. Glucose oxidase (GOD) enzymatic reaction in this cascade system produces hydrogen peroxide (H

To remove stubborn pore fouling, Fenton catalysis with interfacially designed Fe3O4 nanoparticles is used to clean polyamide nanofiltration membrane, and such magnetic cleaning agent is easily recovered and reused for green membrane cleaning.

It is critical to detect Fe3+ and Al3+ rapidly and accurately due to their high risk to human and ecological environment. In this work, a kind of Terbium-based metal-organic framework...

Sugarcane bagasse was pretreated with lewis acid-mediated glycerol, results showed that 98.47% glucan recovery, 95.31% xylan removal and 49.69% delignification were achieved by pretreatment using 80 wt% aqueous glycerol combined with 1.0 wt% AlCl3 at 150 °C for 1 h. Reutilization experiments of acidified glycerol showed that its pretreatment efficiency was relatively well maintained during four consecutive cycles. Enzymatic in situ saccharification of pretreated bagasse led to about 50% glucose yield at 16 wt% glycerol concentration. After pretreatment, the lignin distributed in pretreatment hydrolysate and pretreated solid residue (referred to as organosolv lignin (OL) and cellulolytic enzyme lignin (CEL), respectively) demonstrated contrasting effect on enzymatic hydrolysis with OL slightly increasing while CEL decreasing cellulose conversion, which could be explained by their differences in hydrophobicity and surface charge. Further analysis of the structure and molecular weights of two lignin samples indicated their great potential for valorization into value-added products.

As a cheap, biodegradable, and nontoxic chemical, choline chloride (ChCl) is widely used in animal feed. In this study, acid and alkali catalyzed ChCl pretreatments of corn stover (CS) were investigated. Compared with single aqueous ChCl pretreatment, H2SO4 acidified aqueous ChCl pretreatment was more effective in removing lignin (69.5%) and xylan (84.9%). NaOH alkalified aqueous ChCl pretreatment demonstrated better performance of delignification (76.8%) but weaker capability of removing xylan (46.2%) than acidified aqueous ChCl pretreatment. Following enzymatic digestibility of pretreated CS, glucose yield from acidified ChCl pretreatment was 72.1%, significantly lower than that of alkalified ChCl pretreatment (89.4%). However, the highest glucose yield of 98.6% resulted from solitary alkali pretreatment. Correlation studies between change in physico-chemical properties of pretreated solids and corresponding enzymatic digestibility indicated high delignification and bigger cellulose crystallite size were mainly responsible for high enzymatic hydrolysis efficiency. Additionally, the properties of extracted lignin from single and combined pretreatments with ChCl and alkali or acid were analyzed. Acidified ChCl pretreatment increased, whereas alkaline ChCl pretreatment decreased molecular weight and phenolic hydroxyl groups of separated lignin in comparison to individual acid and alkali pretreatment. These findings would provide useful information in understanding biomass pretreatments with aqueous ChCl.

Nanofiltration (NF) with advantages of high efficiency and low‐cost has attracted increasing attentions in bio‐separation. However, the large‐scale application is limited by the inferior molecular selectivity, low chemical stability and serious membrane fouling. Many efforts, thus, have been devoted in NF materials design for specific applications to enhance the separation efficiency of bio‐products and increase membrane life‐time, as well as reduce the operating cost. This review summarized the recent progress of NF applications in bio‐separation, discussed various demands for NF membrane in the bio‐products purification and corresponding material innovations, finally proposed several practical suggestions for future research, which provided directions and guidance toward further product development and process industrialization.

Available literature on Chinese medicinal herbal residues (CMHRs) bioconversion highlights pretreatment prior to saccharification with cellulase without considering the presence of starch constituent. Herein, four commonly found CMHRs were tested for starch content, and it was found they all contained starch with content ranging from 4.74% to 16.78%. Hydrolysis of raw CMHRs with combined cellulase and amylolytic enzymes yielded increments of 16.85% to 26.51% in 48-h glucan conversion compared to cellulase alone. Further study showed 48-h glucan conversion of raw CMHRs outperformed that pretreated by water-ethanol successive extraction, ultrasound and acid, but underperformed alkali-pretreated CMHRs. Although increasing 48-h glucan conversion in the range of 7.40% to 24.10% compared to raw CMHRs, alkaline pretreatment demonstrated low glucose recovery and incurred additional cost, making it unfavorable. Saccharification of the four raw CMHRs with combined enzymes seems like a preferred option considering the elimination of high-cost pretreatment step.

Application of nanofiltration membranes in industries still has to contend with membrane fouling that causes a significant loss of separation performance. Herein, an innovative approach to design antifouling membranes with a narrowed pore size distribution by interfacial polymerization (IP) assisted by silane coupling agents is reported. An aqueous solution of piperazine anhydrous (PIP) and γ-(2,3-epoxypropoxy) propytrimethoxysilane (KH560) is employed to perform IP with an organic solution of trimesoyl chloride and tetraethyl orthosilicate (TEOS) on a porous support. In accordance with the results of molecular dynamics and dissipative particle dynamics simulations, the reactive additive KH560 accelerates the diffusion rate of PIP to enrich at the reaction boundary. Moreover, the hydrolysis/condensation of KH560 and TEOS at the aqueous/organic interface forms an interpenetrating network with the polyamide network, which regulates the separation layer structure. The characterization results indicate that the polyamide-silica membrane has a denser, thicker, and uniform separation layer. The mean pore size of the polyamide-silica membrane and the traditional polyamide membrane is 0.62 and 0.74 nm, respectively, and these correspond to the geometric standard deviation (namely, pore size distribution) of 1.39 and 1.97, respectively. It is proved that the narrower pore size distribution endows the polyamide-silica membrane with stronger antifouling performance (flux decay ratio decreases from 18.4 to 3.8%). Such a membrane also has impressive long-term antifouling stability during cane molasses decolorization at a high temperature (50 °C). The outcomes of this study not only provide a novel one-step multiple IP strategy to prepare antifouling nanofiltration membranes but also emphasize the importance of pore size distribution in fouling control for various industrial liquid separations.

Decolorization is important for wastewater treatment and product purification. Compared to an adsorption method using activated carbon and ion-exchange resin, nanofiltration (NF) is a sustainable t...

β-poly(L-malic acid) (PMLA) has attracted industrial interest for its potential applications in medicine and other industries. For a sustainable PMLA production, it requires replacing/reducing the CaCO3 usage, since the residual CaCO3 impeded the cells’ utilization, and a large amount of commercially useless gypsum was accumulated. In this study, it was found that more glucose was converted into CO2 using soluble alkalis compared with CaCO3 usage. Moreover, since the high ion strength and respiration effect of soluble alkalis also inhibited PMLA production, they could not effectively replace CaCO3. Furthermore, comparing the fermentations with different neutralizers (soluble alkali vs. CaCO3), it was found that the differential genes are mainly involved in the pathway of starch and sucrose metabolism, pentose and glucuronate interconversions, histidine metabolism, ascorbate and aldarate metabolism, and phagosome. In detail, in the case with CaCO3, 562 genes were downregulated and 262 genes were upregulated, and especially, those genes involved in energy production and conversion were downregulated by 26.7%. Therefore, the irreplaceability of CaCO3 was caused by its effect on the PMLA metabolic pathway rather than its usage as neutralizer. Finally, a combined pH shift control strategy with CaCO3 addition was developed. After the fermentation, 64.8 g/L PMLA and 38.9 g/L biomass were obtained with undetectable CaCO3 and less CO2 emission. • The effect of CaCO3 on PMLA metabolic pathway resulted in its irreplaceability. • A pH shift control strategy with CaCO 3 addition was developed. • Undetectable CaCO 3 and less CO 2 emission were detected with the new strategy.

Nanofiltration (NF) membranes, especially polyamide (PA) ones, are widely applied in water treatment, food processing, and resource recovery thanks to their excellent separation selectivity to smal...

Nanofiltration plays an increasingly large role in many industrial applications, such as water treatment (e.g., desalination, water softening, and fluoride removal) and resource recovery (e.g., alkaline earth metals). Energy consumption and benefits of nanofiltration processes are directly determined by the selectivity of the nanofiltration membranes, which is largely governed by pore-size distribution and Donnan effects. During operation, the separation performance of unmodified nanofiltration membranes will also be impacted (deleteriously) upon unavoidable membrane fouling. Many efforts, therefore, have been directed toward enhancing the selectivity of nanofiltration membranes, which can be classified into membrane fabrication method improvement and process intensification. This review summarizes recent developments in the field and provides guidance for potential future approaches to improve the selectivity of nanofiltration membranes.

Biocatalytic membrane takes advantages of reaction–separation integration as well as enzyme immobilization, which has attracted increasing attentions in online detection and biomanufacturing. However, the high preparation cost, inferior comprehensive performance, and low stability limit its applications. Thus, besides enzyme immobilization, more efforts should be made in biocatalytic membrane configuration design for a specific application to enhance the synergistic effect of reaction and separation and improve its operating stability. This review summarized the recent progress on biocatalytic membrane preparation, discussed different membrane configurations for various applications, finally proposed several challenges and possible solutions, which provided directions and guides for the development and industrialization of biocatalytic membrane.

Owing to severe water pollution problems and intrinsic disadvantages of separation membranes, a catalytic membrane that realizes reaction–separation coupling and catalyst reuse becomes an increasing research hotspot in water treatment as it can improve both catalytic and separation efficiency, enhance contaminant removal, and alleviate membrane fouling. In recent years, many investigations have been reported on catalytic membrane preparation for the removal of aqueous contaminants. In this chapter, we briefly introduce the basic principles of different types of catalytic membranes (e.g., traditional oxidative catalytic membranes, photocatalytic membranes, electro-catalytic membranes, and bio-catalytic membranes) for contaminant removal, and summarize recent progress in membrane materials and preparation methods, as well as their applications in various contaminants’ removal. Perspectives on future research for catalytic membrane are also provided.