Concentration Of Functional Groups Research Articles

Selection of kraft lignin fractions as a partial substitute for phenol in synthesis of phenolic resins: Structure-property correlation

In this work, a strategy was proposed aiming to describe an efficient kraft lignin (KL) fractionation method to extract large amounts of low molar mass lignin to partially replace non-renewable phenol with the KL fractions in the synthesis of phenolic resins. KL from Eucalyptus urograndis wood was refined by a fractionation process in ethyl acetate (EtAc). The lignin-phenol-formaldehyde (LPF) resins were formulated by replacing 25% and 50% of phenol with the fractionated lignin. The lignin employed were KL, fraction of KL insoluble in EtAc (LFIns) and fraction of KL soluble in EtAc (LFSol). The LFSol and LFIns fractions were analyzed for composition, functional group content, and thermal properties. Gel Permeation Chromatography (GPC) results indicated that the lower molar mass lignin fractions (LFSol) showed higher solubility in EtAc. The total hydroxyl groups content (by 31 P NMR) of the soluble EtAc fraction increased to 4.73 mmol.g −1 after fractionation. The phenolic resin based on monomers derived from LFSol showed adhesion strength, glass transition temperature and thermal stability with values close to commercial phenolic resins. The better homogeneity of the LPF resin produced from LFSol at 25% phenol substitution resulted in adhesion properties similar to the control resin. On the other hand, LFSol could successfully directly replace 15% of the commercial PF resin (corresponding to > 30% phenol replacement) showing the performance similar to the commercial PF control and significantly higher than the LFIns and non-fractionated KL. • Extraction method of low molar mass kraft lignin. • Structure-performance correlation of selection of kraft lignin fractions. • Partial replacement of non-renewable phenol by lignin fractions. • Improved performance of the soluble lignin fraction as an adhesive.

Feasible synthesis of bifunctional polysilsesquioxane microspheres for robust adsorption of Hg(II) and Ag(I): Behavior and mechanism.

The pollution of Hg(II) and Ag(I) to water system exerts hazardous effect to aquatic ecosystem and public security. Simple strategy for constructing adsorbents to efficient remove them is greatly desired. Thus, a series of thiol and amino groups containing bifunctional polysilsesquioxanes (ASPSS) microspheres with adjustable porous structure and functional group content were synthesized by one-step feasible sol-gel process. The adsorption behavior and mechanism of ASPSS microspheres toward Hg(II) and Ag(I) was thoroughly determined. The maximum adsorption capacity of ASPSS for Hg(II) and Ag(I) are 4.32 and 3.86mmol·g-1 under 25℃. The as-prepared ASPSS microspheres can 100% selectively capture Hg(II) with the coexisting of Mn(II), Co(II), Pb(II), Cd(II), Cu(II), Fe(III). And they can 100% adsorb Ag(I) with the presence of Cd(II), Pb(II), Co(II), Ni(II), and Zn(II). Moreover, the ASPSS microspheres exhibit good removal efficiency for Hg(II) and Ag(I) from simulated industrial wastewater with the coexistence of multiple pollutants. Adsorption mechanism suggests the adsorption for Hg(II) and Ag(I) is the synergistic coordination effect of amino and thiol groups. The excellent adsorption selectivity for Hg(II) and Ag(I) is attributed to the super binding ability of these functional group. ASPSS microspheres also exhibit good regeneration ability and could be reused for removing Hg (II) and Ag(I) from aqueous solution with practical value.

Growth mechanism of glucose-based hydrochar under the effects of acid and temperature regulation.

Improving the tailorability of hydrochar synthesis is an effective way to enhance its performance and utilization efficiency. In this study, the growth rate, morphology, and molecular structure of hydrochar were controlled by regulating the pH and temperature of the hydrothermal carbonization process. Growth process analysis indicates that hydrochar has three growth periods: induction, rapid, and stable growth periods. It is mainly controlled by 5-hydroxymethylfurfural (HMF), which is formed by converting glucose and its transformation products. The regulation of acid can significantly shorten the induction period of hydrochar, even under low-temperature conditions (<180℃), and increase the growth rate of hydrochar. However, the degree of hydrochar adhesion varies: the lower the temperature, the greater the degree of its adhesion. Molecular structural analysis demonstrates that hydrochar mainly consists of furan structural domains and aromatic clusters, and its surface is rich in oxygen-containing functional groups. The degree at which hydrochar was aromatized was improved by increasing the reaction temperature (160-220℃); whereas the regulation of acid reduced it and increased the content of oxygen-containing functional groups on the hydrochar surface. Based on these results, it is proposed that hydrochar formation has five stages and three growth periods with or without acid regulation.

N-Doped porous carbons obtained from chitosan and spent coffee as electrocatalysts with tuneable oxygen reduction reaction selectivity for H2O2 generation.

Nitrogen-containing porous carbons prepared by the pyrolysis of adequate biopolymer-based precursors have shown potential in several electrochemical energy-related applications. However, it is still of crucial interest to find the optimal precursors and process conditions which would allow the preparation of carbons with adequate porous structure as well as suitable nitrogen content and distribution of functional groups. In the present work we suggested a straightforward approach to prepare N-doped porous carbons by direct pyrolysis under nitrogen of chitosan : coffee blends of different compositions and using KOH for simultaneous surface activation. The synthetized carbon materials were tested for the electrochemical oxygen reduction to hydrogen peroxide (H2O2). A higher fraction of chitosan in the precursor led to a decrease in meso- and nano-porosity of the formed porous carbons, while their activity towards H2O2 generation increased. The nitrogen species derived from chitosan seem to play a very important role. Out of the synthesized catalysts the one with the largest content of pyridinic nitrogen sites exhibited the highest faradaic efficiency. The faradaic efficiencies and current densities of the synthesized materials were comparable with the ones of other commercially available carbons obtained from less renewable precursors.

Remarkable synergy between sawdust biochar and attapulgite/diatomite after co-ball milling to adsorb methylene blue.

Biochar has been recognized as a promising sustainable adsorbent for removing pollutants from wastewater. In this study, two natural minerals, attapulgite (ATP) and diatomite (DE) were co-ball milled with sawdust biochar (pyrolyzed at 600 °C for 2 h) at ratios of 10-40% (w/w) and examined the ability of methylene blue (MB) to be removed from aqueous solutions by them. All the mineral-biochar composites sorbed more MB than both ball milled biochar (MBC) and ball milled mineral alone, indicating there was a positive synergy in co-ball milling biochar with these minerals. The 10% (w/w) composites of ATP:BC (MABC10%) and DE:BC (MDBC10%) had the greatest MB maximum adsorption capacities (modeled by Langmuir isotherm modeling) and were 2.7 and 2.3 times that of MBC, respectively. The adsorption capacities of MABC10% and MDBA10% were 183.0 mg g-1 and 155.0 mg g-1 at adsorption equilibrium, respectively. These improvements can be owing to the greater content of oxygen-containing functional groups and higher cation exchange capacity of the MABC10% and MDBC10% composites. In addition, the characterization results also reveal that pore filling, π-π stacking interactions, hydrogen bonding of hydrophilic functional groups, and electrostatic adsorption of oxygen-containing functional groups also contribute prominently to the adsorption of MB. This, along with the greater MB adsorption at higher pH and ionic strengths, suggests the roles in MB adsorption was an electrostatic interaction and an ion exchange mechanism. These results demonstrate that mineral-biochar composites prepared by co-ball milling treatment were promising sorbents of ionic contaminants for environmental applications.

A study of silver sorption from aqueous solutions by solid-phase modified poly(n-thiocarbamoyl-3-aminopropyl silsesquioxane)

Sorption properties of poly(3-aminopropylsilsesquioxanes) modified with thiourea groups were studied to predict the possibility of using poly(n-thiocarbamoyl-3-aminopropylsilsesquioxanes) (TCPS) in separation and concentration techniques. The sorbents were synthesized by the sol-gel method followed by solid-phase modification using ammonium thiocyanate or thiosemicarbazide as modifiers. It was established that sorbents with the highest content of thiocarbamide functional groups (modified with ammonium thiocyanate) enabled quantitative and selective recovery of Ag (I) from strongly acidic solutions. The degree of Ag (I) recovery slightly decreases at pH&gt;5, which is associated with increasing competitive sorption of Cu (II), Ca (II), Mg (II), Mn (II) and Fe (III). The highest recovery of Ag (I) for TCPS-0.63 and TCPS-0.68 was achieved at pH ranging from 4 to 8 (degree of recovery was 55–68% (TCPS-0.63); 21–26% (TCPS-0.68 )); at the same time, there was a predominance of competitive sorption of Ca (II), Mg (II), Mn (II), and Fe (III). Based on the aforementioned, it can be concluded that the sorbents modified with ammonium thiocyanate are characterized by high concentration of attached thiocarbamide groups that make them suitable for the selective recovery of Ag (I) ions from multicomponent solutions at pH 1–2.

Effect of ionic liquids on the microstructure and combustion performance of Shengli lignite.

To ensure the safe transportation and efficient utilisation of lignite, it is important to inhibit its spontaneous combustion. In this study, Shengli lignite (SL+) was used as the research object and ionic liquids (ILs) were used to pretreat the lignite to investigate their effect on the combustion performance of lignite. On this basis, the relationship between the structure and combustion performance of lignite with different structures (heat treatment, oxidation) after ILs treatment was investigated. Results indicated that the combustion of lignite treated with ILs shifted towards higher temperatures. The most pronounced effect was observed in coal samples treated with [BMIM]Cl (1-butyl-3-methylimidazolium chloride), with the maximum combustion rate corresponding to a temperature increase of approximately 57 °C compared to that of the untreated lignite. For the heat-treated lignite, the temperature corresponding to the maximum combustion rate was approximately 38 °C higher than that of the untreated lignite. After [BMIM]Cl treatment, the combustion performance of the heat-treated lignite changed very slightly. In contrast, for oxidised lignite, the temperature corresponding to the maximum combustion rate decreased by approximately 54 °C compared with that of the untreated lignite and increased by approximately 135 °C after treatment with [BMIM]Cl. The characterisation results show that the content of aliphatic hydrogen and oxygen-containing functional groups decreased in the heat-treated lignite, while the content of hydroxyl and carboxyl groups increased in the oxidised lignite. The microstructure of the heat-treated lignite after [BMIM]Cl treatment changed slightly. In contrast, in the oxidised lignite after [BMIM]Cl treatment, the content of hydroxyl and carboxyl groups decreased, whereas the content of ether (C-O-) structures increased. The increased content of ether (C-O-) structures improved the stability of the coal samples. It is believed that the inhibition of lignite combustion is mainly attributed to the high stability of the ether (C-O-) structures. The kinetic analysis demonstrated that the ILs treatment increased the activation energy of lignite combustion.

Enzymatic surface modification of banana fabric with cellulase: Characterization and antimicrobial finishing with plant extracts

The current study examined the effect of cellulase enzyme bio-scouring on the banana fabric and the improvement in the antimicrobial property of the same fabric with the natural plant-based extract. Pre-treatment of banana fabric with cellulase enzyme was optimized with different parameters, namely enzyme concentration (2%), pH (5.5), MLR (Material to Liquid Ratio) (1:20), time (60 min), and temperature (55 °C). Effect of the enzyme bio-scouring on surface properties was studied using characterization techniques such as Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) Spectroscopy, Scanning Electron Microscopy (SEM), X-Ray Photoelectron Spectroscopy (XPS), Wet-out time, Water contact angle and Hydrophilicity test. The changes in bulk properties due to the enzymatic treatment were studied by Weight Loss (%), X-Ray Diffraction (XRD), Thermal Attenuated Gravimetric Analysis (TGA), and Tensile Strength Measurement. The ATR-FTIR spectroscopy and XPS characterization revealed enhancement in the concentration of polar functional groups like -CHO, -COOH, -OH on the surface of the cellulase-treated banana fabric. For the antimicrobial finish, leaf extracts of Camellia sinensis (Green Tea) and Ocimum sanctum (Tulsi) were applied to cellulase-treated banana fabric in different percentages, coupled with citric acid as a cross-linking agent. Antimicrobial testing was done using the Agar plate method and the altered Hoenstein test against one gram-positive bacteria (Staphylococcus aureus) and one gram-negative bacteria (Escherichia coli). In the case of cellulase enzyme treated banana fabric, 97% reduction for S. aureus and 92% reduction for E. coli were achieved. The durability of the finish was tested, and the antimicrobial finish persisted up to three cycles of washing in the case of the cellulase enzyme-treated banana fabric. In contrast, the antimicrobial finish was lost after the first washing of untreated fabric. According to the findings, the cellulase enzyme treatment can be used as an environmentally acceptable method for improving surface properties and adsorption of the antimicrobial extracts, thereby enhancing the antimicrobial property of the banana fabric. • Value addition to banana fabric-a natural cellulosic fabric derived from commodity crops' byproducts/waste. • Cellulase enzyme pre-treatment of banana fabric and its effect on the surface and bulk properties. • Characterization of treated fabric with advanced techniques and optimization of process parameters. • Antimicrobial finishing of enzyme-treated banana fabric with natural extracts Camellia sinensis and Ocimum sanctum . • Enhanced uptake/better durability of finishing: Sustainable approach for improving competitiveness and market potential of banana fabric.

Spectroscopic Approach on Bulk and Surface Properties of Fungal Biomass-Clay Adsorbents: Effect of Temperature and Amount of Clay during Synthesis

The physicochemical properties of an enhanced adsorbent material generated by clays and fungal biomass can be modified systematically. We used spectroscopic techniques to investigate the interaction mechanisms between biomass and clay and how surface properties change with synthesis temperature and clay amounts. Biomass-clay complexes were synthesized and either shock-frozen and freeze-dried or dried at 60 °C in the oven. Surface and bulk properties were analyzed by scanning electron microscopy, attenuated total reflectance-Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and by wettability and surface charge measurements. Interactions of specific biomass-related molecules with clay and changes in physicochemical properties were observed. Higher amounts of clay caused a decrease in particle aggregation while the biomass arranged more evenly. XPS proved interactions due to exchange reactions between Na from the clay and biomass external organic compounds. FTIR, wettability, surface charge, and XPS indicated a less ordered arrangement of the biomass on the clay when drying was performed at 60 °C. The properties of these types of materials define their potential use in future applications. These results indicate the possibility of the selective creation of bioclays: more hydrophobic, with a higher content of organic matter or more specific functional groups on the surface.

Chemical properties of biochars prepared from corn and wheat straw at different temperatures

In this study, biochar produced by anaerobic combustion of wheat straw and corn straw in Henan Province at 300 ℃, 500 ℃ and 700 ℃ was used. The chemical properties of wheat biochar and corn biochar, such as pH and infrared spectra, were studied with the increase of temperature. The chemical properties of wheat and corn biochars were compared based on the related literatures.It was found that the pH of biochar from wheat straw and corn straw combustion increased with the increase of temperature. Through the analysis of infrared spectra, it was found that the pH change of the two biochars may be related to the content of functional groups in the biochars themselves. With the increase of temperature, the spectra showed that the functional groups of the two biochars, such as hydroxyl and carboxyl,The main reason is that the chemical bonds of the above functional groups are broken with the increase of temperature. Resulting in a decrease in the number of acidic functional groups and an increase in the alkalinity of the biochar.

Enhancing the mechanical properties of calcium silicate hydrate by engineering graphene oxide structures via molecular dynamics simulations

ABSTRACT It has been proved that the incorporation of graphene oxide (GO) can improve the mechanical and durability performance of cementitious matrix to varying degrees. However, it is unclear how defects, functional group content, and composition, as well as other factors, affect the enhancing effect of GO on the mechanical characteristics of calcium-silicate-hydrate (C–S–H). In this paper, molecular dynamics (MD) simulation is employed to engineer the mechanical properties of the GO/C–S–H composite. The effects of defect type and size, functional group content and composition on the mechanical properties of GO/C–S–H composite are investigated. The results show that (i) GO sheets with quadrilateral and hexagonal defects can effectively strengthen GO/C–S–H composites, but GO sheets with triangular defects cannot be enhanced. And the enhancement effect grows with the increase in defect sizes; The tensile strength of both perfect GO/C–S–H composites and defective GO/C–S–H composites increases significantly with increasing strain rate; (ii) increasing the functional group content of GO can improve the tensile strength of GO/C–S–H; (iii) the mechanical properties of GO/C–S–H composites can be tuned by changing the ratio of hydroxyl and epoxy groups. These findings inspire the optimal design of GO/C–S–H composites using nanotechnology.

Effect of the Structure of Magnetic Nanocomposite Adsorbents on the Lysozyme Separation Efficiency.

In this study, we prepared various anionic magnetic adsorbents through the carboxyl functionalization of core/shell-structured Fe3O4/SiO2 (FS) particles by either succinic anhydride (FSC), low-molecular-weight (MW 1800) polyacrylic acid (PAA) (FSP1), or high-molecular-weight (MW 100,000) PAA (FSP2), and then, investigated the effect of the structure of adsorbents and operational parameters on their performance for the lysozyme separation. The type and size of functional molecules have significant effects on the surface concentration of functional carboxyl groups onto the adsorbent particles (increase in the order of FSP2 > FSP1 > FSC), and consequently on the adsorption efficiency (AE) (∼100, 98, and 62%, respectively) and adsorption capacity (AC) (∼1000, 980, and 621 mg·g-1, respectively) of the adsorbents. However, the loss of the antibacterial activity of separated lysozyme molecules due to the molecular conformational change increased in the order of FSP2 > FSP1 = FSC, as compared to the free lysozyme. The application of basic buffer solutions for the elution of adsorbed enzyme molecules resulted in more adverse effects on the enzyme activity. The obtained results recommend that FSP1 can be used as a suitable anionic adsorbent for the isolation of positively charged proteins, owing to its high adsorption capacity, excellent reusability, and structural stability, as well as the high purity, structural stability, and activity recovery of the isolated proteins.

A novel method to greener carbon material for CO2 adsorption

This study explores the chemical activation using K2CO3 and Fe(NO3)3 to alter the porous structure and a novel nitrogen functionalisation biomass derived carbon using cold plasma. The results showed that the obtained walnut shell carbon demonstrated a remarkable CO2 adsorption capacity of 5.69 mmol g−1 at 0°C, 1 bar and 3.94 mmol g−1 at 25°C, 1 bar. Further assessment of adsorption capacities at high pressures (up to 4 bar) demonstrated the adsorption capacity of 8.03 mmol g−1 at 0°C, 4 bar and 6.33 mmol g−1 at 25°C, 4 bar. Cold plasma is a novel method to increase the nitrogen functional group content to 10.37 at%. This study showed that, however, surface nitrogen functional groups do not contribute to CO2 adsorption, and despite the presence of nitrogen groups, physisorption is the dominant factor controlling the CO2 adsorption of walnut shell derived carbon.

Multistage Activation of Anthracite Coal-Based Activated Carbon for High-Performance Supercapacitor Applications

An anthracitic coal-derived activated porous carbon is proposed as a promising carbon electrode material for supercapacitor (SC) applications. The specific capacitance of this activated carbon SC electrode is related to the characteristics, such as specific surface area, pore size distribution, wettability, and conductivity. In the present work, a series of anthracite-based activated carbons (ABAC) were prepared via a multistage activation process and used as electrode materials for SCs. The multistage activation experiment was developed by exploring different activation temperatures, precursor/activating agent mass ratios, and process treating environments. The electrochemical performance of ABACs was evaluated in a three-electrode testing system. Multiple electrolytes were utilized, such as 1 M sulfuric acid (H2SO4) and 1 and 6 M potassium hydroxide (KOH) solutions. An optimum ABAC electrode was obtained, characterized by its largest wettability and superior conductivity, and achieved excellent electrochemical performance. The three-electrode system exhibited a specific capacitance of 288.52 and 260.30 F/g at 0.5 A/g in the 1 M H2SO4 and 6 M KOH electrolytes, respectively. It was found that moderate multistage activation temperatures are beneficial for the electrolyte uptake which enhances the specific capacitance. The high content of the oxygen functional groups on the activated carbon surface greatly improved its specific capacitance due to the increase in wettability. In the 1 M H2SO4 electrolyte, the working electrode exhibited better performance than in 1 M KOH because the ion diameter in the acidic electrolyte was more suitable for pore diffusion. The concentrated KOH electrolyte leads to an increase in specific capacitance due to increased ions being adsorbed by a certain number of the hydrophilic pores. Moreover, the specific capacitance of the optimum ABAC sample remained at 95.4% of the initial value after 1000 galvanostatic charge–discharge tests at 0.5 A/g, which is superior to the performance of SC grade commercial carbon.

Biochar-derived dissolved black carbon accelerates ferrihydrite microbial transformation and subsequent imidacloprid degradation

The effects of an electron shuttle (dissolved black carbon (DBC) derived from biochar) on the microbial reduction of ferrihydrite and subsequent imidacloprid (IMI) degradation were studied. The results showed that DBC addition enhanced the microbial reduction of Fe(III) in ferrihydrite and increased the quantity of Fe(II) released into the liquid phase. The electron transfer capacity of DBC was significantly influenced by the content of redox-active oxygen-containing functional groups (e.g., quinone, hydroquinone, and polyphenol groups), which was dependent on the pyrolysis temperature. The electrochemical characteristics of DBC resulted in enhanced electron transfer, which promoted Fe(III) reduction and mediated the microbial transformation of ferrihydrite. The microbial transformation of ferrihydrite resulted in the formation of secondary minerals such as siderite and vivianite. The IMI degradation efficiency was related to the Fe(III) reduction rate and the pyrolysis temperature used in DBC production, and the degradation pathways were nitrate reduction and imino hydrolysis induced by the Fe(II) generated from the reduction of Fe(III) in ferrihydrite. The results obtained in this study provide new data for understanding the multifunctional roles of biochar-derived DBC in the redox and transformation processes of iron minerals induced by iron-reducing bacteria, the related biogeochemical cycles of iron and the fate of pollutants.

Amphoteric cellulose microspheres for the efficient remediation of anionic and cationic dyeing wastewater

Amphoteric cellulose porous microsphere adsorbents (ACM) with high contents of functional groups were prepared by carboxylation and amination reactions. The obtained ACM possess similar contents of carboxyl groups (1.52 mmol/g) and amino groups (1.51 mmol/g). In addition, the modified microspheres exhibited excellent mechanical properties benefiting from the dense porous structures. The ACM could simultaneously remove the cationic dye methyl orange (MO) as well as the anionic dye methylene blue (MeB) with adsorption capacities as high as 345.32 mg/g and 616.12 mg/g, respectively. Another the microspheres are also with good regeneration that the adsorption capacities still maintained more than 90 % after 8 cycles.

Chitosan – dextran phosphate carbamate hydrogels for locally controlled co-delivery of doxorubicin and indomethacin: From computation study to in vivo pharmacokinetics

The development of synergistic drug combinations is a promising strategy for effective cancer suppression. Here, we report all-polysaccharide biodegradable polyelectrolyte complex hydrogels (DPCS) based on dextran phosphate carbamate (DP) and chitosan (CS) for controlled co-delivery of the anticancer drug doxorubicin (DOX) and the non-steroidal anti-inflammatory drug indomethacin (IND). IND can induce more apoptosis in tumor cells by reducing the level of multidrug resistance-associated protein 1. Based on calculations using density functional theory and zeta potential analysis data, carriers with high drug loading were obtained. The release profile of both drugs from the hydrogels was tuned by changing the molecular weight and functional groups content of the polysaccharides. The optimized DPCS showed a steady release of DOX both in vitro and in vivo, and a gradual release of IND, which constantly induced the action of DOX. Considering all of these benefits, DOX- and IND-loaded DPCS offer a promising long-acting polysaccharide-based antitumor platform.

Fungal-Modified Lignin-Enhanced Physicochemical Properties of Collagen-Based Composite Films.

Renewable and biodegradable materials have attracted broad attention as alternatives to existing conventional plastics, which have caused serious environmental problems. Collagen is a potential material for developing versatile film due to its biosafety, renewability, and biodegradability. However, it is still critical to overcome the low mechanical, antibacterial and antioxidant properties of the collagen film for food packaging applications. To address these limitations, we developed a new technology to prepare composite film by using collagen and fungal-modified APL (alkali pretreatment liquor). In this study, five edible and medical fungi, Cunninghamella echinulata FR3, Pleurotus ostreatus BP3, Ganoderma lucidum EN2, Schizophyllum commune DS1 and Xylariaceae sp. XY were used to modify the APL, and that showed that the modified APL significantly improved the mechanical, antibacterial and antioxidant properties of APL/Collagen composite films. Particularly, the APL modified by BP3, EN2 and XY showed preferable performance in enhancing the properties of the composite films. The tensile strength of the film was increased by 1.5-fold in the presence of the APL modified by EN2. To further understand the effect of fungal-biomodified APL on the properties of the composite films, a correlation analysis between the components of APL and the properties of composite films was conducted and indicated that the content of aromatic functional groups and lignin had a positive correlation with the enhanced mechanical and antioxidant properties of the composite films. In summary, composite films prepared from collagen and fungal biomodified APL showed elevated mechanical, antibacterial and antioxidant properties, and the herein-reported novel technology prospectively possesses great potential application in the food packaging industry.

A hydrophobic and hierarchical porous resin-based activated carbon modified by g-C3N4 for toluene capture from humid conditions

The synthesis of hydrophobic and hierarchical porous activated carbon (AC) used for toluene capture from a humid atmosphere still remains a challenge. In this work, a novel hydrophobic and hierarchical porous AC was prepared from resorcinol-formaldehyde resin spheres using g-C3N4 as a new pore-forming agent. By the proper participation of g-C3N4, the obtained adsorbent GNHRC-1.5 was endowed with an excellent toluene adsorption capacity (10 mmol/g) under low pressure of P = 0.2 kPa, which was 54% higher than that of nonmodified resin-based AC. By DIH (Difference of Isosteric Heats) prediction, the adsorption selectivity of GNHRC-1.5 to toluene/water was further enhanced to 139.55, higher than that of other reported adsorbents. Toluene breakthrough tests and kinetic analysis showed that GNHRC-1.5 possessed a faster intraparticle diffusion and outstanding reusability, which was ascribed to its a certain amount of mesopores. Grand Canonical Monte Carlo and molecular dynamics simulation were applied to explore the competitive adsorption mechanism of toluene and water vapor from the perspective of pore size and surface functional groups. The results indicated that the competitive adsorption was controlled by Van der Waals energy, intramolecular energy and electrostatic energy. Both the higher content of narrow micropores below 1 nm and carboxyl are not beneficial for toluene adsorption under humid conditions. For GNHRC-1.5, an appropriate micropore distribution, a certain amount of mesopores, and a lower content of oxygen functional groups, afford it excellent adsorption selectivity for toluene and fast adsorption kinetics under humid conditions.

Optimization and Characterization of the F-LSR Manufacturing Process Using Quaternary Ammonium Silanolate as an Initiator for Synthesizing Fluorosilicone.

Due to the growing demand for versatile hybrid materials that can withstand harsh conditions (below -40 °C), fluorosilicone copolymers are becoming promising materials that can overcome the limited operating temperature of conventional rubber. In order to synthesize a fluorosilicone copolymer, a potent initiator capable of simultaneously initiating various siloxane monomers in anionic ring-opening polymerization (AROP) is required. In this study, tetramethyl ammonium silanolate (TMAS), a quaternary ammonium (QA) anion, was employed as an initiator for AROP, thereby fluoro-methyl-vinyl-silicone (FVMQ) and fluoro-hydrido-methyl-silicone (FHMQ) were successfully synthesized under optimized conditions. FT-IR, NMR, and GPC analyses confirmed that the chain length and functional group content of FVMQ and FHMQ are controlled by changing the ratio of the components. Moreover, fluorine-involved liquid silicone rubber (F-LSR) was prepared with FVMQ as the main chain and FHMQ as a crosslinker. The tensile strength, elongation, and hardness of each F-LSR sample were measured. Finally, it was confirmed through TGA, DSC, TR-test, and embrittlement testing that elastic retention at low temperatures improved even though the heat resistance slightly decreased as the trifluoropropyl group increased in F-LSR. We anticipate that the optimization of fluorosilicone synthesis initiated by QA and the comprehensive characterization of F-LSRs with different fluorine content and chain lengths will be pivotal to academia and industry.