Fluorination modification enhanced the water resistance of Universitetet i Oslo-67 for multiple volatile organic compounds adsorption under high humidity conditions: Mechanism study

The construction of metal-organic frameworks (MOFs) with highly efficient capture for volatile organic compounds (VOCs) adsorption under humid conditions is a significant yet formidable task. Herein, series of fluorinated UiO-67 modified with trifluoroacetic acid (TFA) and 4-fluorobenzoic acid were successfully synthesized for VOCs adsorption under high humidity conditions. Experiments results showed that UiO-67 modified with 4-fluorobenzoic acid (67-F) presented excellent adsorption capacity of 345 mg/g for toluene adsorption and exhibited great water resistance (10.0 vol% H2O, 374 mg/g toluene adsorption capacity). Characterization results indicated that the introduction of 4-fluorobenzoic acid induced the competitive coordination between 4-fluorobenzoic acid and 4,4-biphenyl dicarboxylic acid (BPDC) with Zr4+, causing the formation of abundant defects to provide extra adsorption sites. Meanwhile, the benzene ring in 4-fluorobenzoic acid enhanced the π-π conjugation, causing the further promotion of VOCs adsorption capacity. More importantly, the water resistance mechanism was investigated and elucidated that the introduction of F decreased the surface energy of 67-F and its affinity with water. Meanwhile, the metal complex induced by the fluorinated modification produced an electron-dense pore environment, which greatly improved its chemical and water stability. This work provided a strategy for preparing an adsorbent with high water resistance for real-world VOCs adsorption at high humidity conditions.

Seaweed-inspired underwater anti-oil-fouling and anti-fogging coating with mechanical durability

Ecofriendly fabrication of anti-oil-fouling materials is of interest. Surfaces with underwater superoleophobicity have been fabricated which exhibit limited mechanical durability and water resistance. In this study, we report on a bioinspired bilayer design of a transparent anti-oil-fouling coating. Seaweed surfaces show anti-oil-fouling in the sea due to its high surface hydration ability. Mussels can adhere tightly onto a surface with good stability in the sea by virtue of its levodopa-containing secretions. The surface layer was fabricated using a crosslinked combination of carboxymethyl cellulose (CMC) and sodium alginate (AlgS) inspired by seaweed, with the addition of calcium ions. Polydopamine (PDA), a derivative of levodopa, was used as the underlayer to enhance bonding strength and water resistance. Oil that adhered to the coated surface was spontaneously detached upon immersion in water. The mechanism underlying this anti-oil-fouling effect was elucidated using Gibbs free energy theory. The coating exhibited mechanical durability and water resistance. The coating is transparent and preserves the original color of the substrate. The coated glass showed stable anti-fogging and anti-frost performance. These coatings hold promise for a wide range of anti-oil-fouling applications.

Effects of different oil additives on water resistance of corn starch straws

To investigate the effect of oil additives on improving the water resistance of corn starch straws, corn oil (CO), soybean oil (SO), rapeseed oil (RO), peanut oil (PO), lard (LD) and coconut oil (CCO) were chosen and compared the structure and properties of starch straws with different oil additives. Corn starch straws (CS), and starch straws supplemented with CO, SO, RO, PO, LD and CCO were prepared by thermoplastic extrusion. The results showed that the incorporation of oils effectively enhanced the water resistance of starch straws such as water absorption, water solubility and water swelling performance. Meanwhile, the flexural strength of starch straws significantly increased. There was no significant linear relationship among starch chain length, oil unsaturation and straw performance. Among seven starch straws, S-SO had the strongest hydrogen bond interaction (3289 cm-1) and relaxation time (0.96 ms). The S-CO had the highest relative crystallinity (16.82 %) and degree of double helix (1.535), hence resulting in the lowest water absorption and solubility values, the highest flexural strength (23.43 MPa), the highest ΔT value (9.93 °C) and ΔH value (4.79 J/g). S-RO had the highest thermal transition temperatures.

Enhancing low-temperature CO removal in complex flue gases: A study on La and Cu doped Co3O4 catalysts under real-world combustion environment

Designing CO oxidation catalysts for complex flue gases conditions is particularly challenging in fire scenarios. Traditional flue gas simulations use a few representative gases but often fail to adequately evaluate catalyst performance in real-world combustion conditions. In this study, we developed doping strategies using La and Cu to enhance the water resistance of Co3O4 catalysts. Catalyst 0.1La-Co3O4-CuO/CeO2 exhibits exceptional low-temperature catalytic activity, achieving 100% conversion at 130 °C. This enhancement is largely due to the introduction of La, which increases the active Co3+/Co2+ ratio and suppresses hydroxyl group formation on the Co3O4 surface. Cu doping also changes the Co3O4 lattice structure, forming Cu+ as active sites and enhancing the activity at low temperatures. For the first time, steady-state tube furnace and fixed bed were employed to evaluate the catalytic performance of CO in actual combustion atmosphere. Catalyst 0.1La-Co3O4-CuO/CeO2 maintains excellent catalytic efficiency (T100 = 120 °C) under well-ventilated conditions. However, its activity significantly decreases in poorly ventilated environments, due to the competitive adsorption of small molecules at active sites, such as acetone, commonly found in smoke. This study provides valuable insights for designing water-resistant, low-temperature, non-noble metal catalysts and offers a methodology for evaluating CO catalytic activity in real-world environments.

High performance polyvinyl alcohol/lignin fibers with excellent mechanical and water resistance properties

To address the shortcoming of Polyvinyl alcohol (PVA) fibers for food or medical packaging materials including low mechanical strength and poor water resistance, lignin (LN) was used as raw material, acetone/H2O as solvent to self-assemble into lignin nanoparticles (LNP) by adverse solvent precipitation approach, and then PVA/LNP composite fibers with different LNP contents were fabricated successfully by wet and dry spinning. Herein, vast hydrophilic hydroxyl groups in PVA decreased owing to the hydrogen bond between LN and PVA, Especially, with only 0.5 wt% loading of LNP into the PVA/LNP fibers, the diameter was 94.4 dtex, tensile strength was 10.1 cN/dtex (1279.8 MPa), initial modulus was 94.7 cN/dtex (12.0 GPa), the crystallinity was 56.7 %, the orientation was 97.1 %, and water contact angle was 103.1°. Compared with pure PVA fibers, the tensile strength of PVA/LNP-0.5 fibers was increased by 44.2 % and the contact angle was increased 37°. This work provides novel insights into obtaining lignin-reinforced PVA composite fibers with strong mechanical properties and excellent water resistance properties, indicating the potential of the PVA/LNP fibers for food or medical packaging application.

Preparation and characterization on the eco-friendly corn starch based adhesive of with salient water resistance, mildew resistance

Starch adhesive is a commonly used bonding glue that is sustainable, formaldehyde-free and biodegradable. However, there are obviously some problems related to its high viscosity, poor water and mildew resistance. Hence, exploring a starch-based adhesive with good properties that satisfies the requirements of wood processing presents the context of the current research. Thus, corn starch was used as raw material to form oxidized starch (OCS) via oxidation using sodium periodate, it was reacted with a synthesis polyurea compound that prepared from hexanediamine-urea (HU) obtained by deamination to yield a oxidized starch-hexanediamine-urea adhesive (denoted hereafter as OCSHU). The oxidation process was optimized in terms of oxidant concentration, reaction time and temperature. Furthermore, the impact of HU addition on the mechanical properties of the adhesive was explored. Results indicate adhesive exhibited outstanding shear strength, when 13 % of NaIO4 was used as an oxidant to treat starch at 55 °C for 24 h, and involved in a subsequent reaction with 40 % of HU. The dry shear strength, 24 h cold water strength, 3 h hot water strength and 3 h boiling water strength are 1.84, 1.50, 1.32, and 1.31 MPa. Meantime, OCSHU adhesive solution revealed good storage stability whereas cured resin exhibited mildew resistance. The developed adhesive is a simple and green biomass wood adhesive.

Efficacious destruction of typical aromatic hydrocarbons over CoMn/Ni foam monolithic catalysts with boosted activity and water resistance

Developing cost-effective monolith catalyst with superior low-temperature activity is critical for oxidative efficacious removal of industrial volatile organic compounds (VOCs). However, the complexity of the industrial flue gas conditions demands the need for high moisture tolerance, which is challenging. Herein, CoMn-Metal Organic Framework (CoMn-MOF) was in situ grown on Ni foam (NiF) at room temperature to synthesize the cost-effective monolith catalyst. The optimized catalyst, Co1Mn1/NiF, exhibited excellent performance in toluene oxidation (T90 = 239 °C) due to the substitution of manganese into the cobalt lattice. This substitution weakened the Co-O bond strength, creating more oxygen vacancies and increasing the active oxygen species content. Additionally, experimentally and computationally evidence revealed that the mutual inhibiting effect of three typical aromatic hydrocarbons (benzene, toluene and m-xylene) over the Co1Mn1/NiF catalyst was attributed to the competitive adsorption occurring on the active site. Furthermore, the Co1Mn1/NiF catalyst also presents outstanding water resistance, particularly at a concentration of 3 vol%, where the activity is even enhanced. This was attributed to the lower water adsorption and dissociation energy derived from the interaction between the bimetals. Results demonstrate that the dissociation of water vapor enables more reactive oxygen species to participate in the reaction which reduces the formation of intermediates and facilitates the reaction. This investigation provides new insights into the preparation of oxygen vacancy-rich monolith catalysts with high water resistance for practical applications.

Highly water-resistant paper via infiltration with polymeric microspheres from nanocellulose-stabilized plant oil-derived monomer

Sustainable strategies to improve the water resistance of cellulose paper are actively sought. In this work, polymeric microspheres (PMs), prepared through emulsion polymerization of cellulose nanofibers stabilized rubber seed oil-derived monomer, were investigated as coatings on corrugated medium paper (CMP). After infiltrating porous paper with PMs, the water-resistant corrugated papers (WRCPn) with enhanced mechanical properties were obtained. When 30 wt% PMs were introduced, WRCP30 turned out to be highly compacted with an increased water contact angle of 106.3° and a low water vapor transmission rate of 81 g/(m2 d) at 23 °C. Meanwhile, the tensile strength of WRCP30 increased to 22.2 MPa, a 4-fold increase from CMP. When tested in a well-hydrated state, 71% of its mechanical strength in the dry state was maintained. Even with a low content of 10 wt% PMs, WRCP10 also exhibited stable tensile strength and water wettability during the cyclic soaking-drying process. Thus, the plant oil based sustainable emulsion polymers provide a convenient route for enhancing the overall performance of cellulose paper.

Silver nanoparticles coated cellulose-based flexible membrane with excellent UV resistance, high infrared reflection and water resistance for personal thermal management

Designing of a green and multifunctionally integrated cellulose-based flexible wearable material with personal thermoregulation, water and ultraviolet (UV) resistance is essential for the development of personal thermal management and smart textiles. Herein, a hydrophobic silver nanoparticles cellulose-based membrane (H-AgNPs/CEPCM) was prepared through simple solution blending, spin-coating process and chemical vapor modification. The prepared membrane exhibited excellent UV resistance due to the synergistic effect of carbon quantum dots (CQDs) as well as UV-absorbing functional groups. The spin-coated AgNPs layer with high infrared reflectivity has great radiant insulation, and temperature was reduced by 3.4 °C compared with H-CEPCM in indoor environment. Furthermore, the mechanical properties of H-AgNPs/CEPCM were significantly improved by the introduction of amide and ether bonds, as well as a large number of hydrogen bonds. This led to a tensile strength of 23.21 MPa and an elongation at break of 16.57 %, while also providing water resistance. Additionally, the H-AgNPs/CEPCM exhibited outstanding thermal stability and hydrophobicity. This work may provide a feasible and promising strategy for the construction of multifunctional integrated cellulose membrane materials for radiant insulation, outdoor textiles and novel UV protection applications.

Molecular Crystals Constructed by Polar Molecular Cages: A Promising System for Exploring High-performance Infrared Nonlinear Optical Crystals

Polar molecular crystals, with their densely stacked polar nonlinear optical (NLO) active units, are favored for their large second harmonic generation (SHG) responses and birefringence. However, their potential for practical applications as Infrared (IR) NLO materials has historically been underappreciated due to the weak inter-molecular interaction forces that may compromise their physicochemical properties. In this study, we propose molecular crystals with polar molecular cages as a treasure-house for the development of superior IR NLO materials and a representative system, binary chalcogenide molecular crystals, composed of [P4 Sn ] (n=3-9) polar molecular cages, is introduced. These crystals may not only achieve wide band gap, large SHG response, and birefringence in a single structure, but also exhibit favorable physicochemical properties. We subsequently obtained a polar molecular crystal, α-P4 S5 , which demonstrated exceptional IR optical properties, including a strong SHG response (1.1×AGS), wide band gap (3.02 eV), large birefringence (0.134@2050 nm), and a broad transmission range (0.41-14.7 μm). Moreover, it showed excellent water resistance and hardness. These findings highlight the potential of polar molecular crystals as a promising platform for the development of high-performance IR NLO materials.

A combination of logical judging circuit and water-resistant ultrathin film PEDOT: PSS electrode for noninvasive ECG measurement

Heart disease-related deaths have increased in recent decades, with most patients dying of sudden cardiac arrest. In such instances, the effect of regular electrocardiogram (ECG) measurements is minimal. Therefore, long-term ECG monitoring has become increasingly important. In this paper, we report a non-adhesive high accuracy ECG monitoring system that can be used in various scenarios without interfering with daily activities. The ECG ultra-thin film electrode is made by water-resistant material based on poly(3,4-ethylenedioxythiophene) poly(4-styrenesulfonate) (PEDOT: PSS) electrode doped with ethylene glycol (EG) and xylitol, to improve the noise signal caused by sweat. The optimal ratio of the three ingredients of PEDOT: PSS/xylitol/EG was determined experimentally to accommodate the ECG monitoring. By using the proposed selectively closed multi-channel single-lead logic circuit, the noise of ECG signal received from the proposed film electrode can be successfully reduced during broad-area electrode measurements, thus to improve ECG measurement accuracy.

Water resistant, biodegradable and flexible corn starch/carboxymethyl cellulose composite film for slow-release fertilizer coating materials

The inherent limitations of Cornstarch (CS) and Carboxymethyl Cellulose (CMC) membranes, such as brittleness, fragility, and water solubility, limit their use in controlled-release fertilizers. This study reports on the synthesis of crosslinked CMC/CS-20-E composite membranes using the casting technique, with epichlorohydrin (ECH) as the crosslinking agent in an acidic environment to crosslink CS and CMC. The synthesized composite film demonstrates remarkable water resistance, as evidenced by the insignificant alteration in its morphology and structure post 72 h of water immersion. Its flexibility is reflected in its capacity to endure knotting and bending, with an elongation at break reaching 78.1 %. Moreover, the degradation rate surpasses 90 % within a span of seven days. The CMC/CS-20-E-x-urea controlled-release fertilizer was subsequently produced using a layer-by-layer self-assembly technique, where urea particles were incorporated into the crosslinked composite solution. This CMC/CS-20-E-x-urea controlled-release fertilizer displayed superior controlled-release performance over a duration of seven days when juxtaposed with pure urea. In particular, the CMC/CS-20-E-3 %-urea controlled-release fertilizer showed a cumulative release rate of 84 % by the seventh day. The controlled-release fertilizers developed in this study offer a promising strategy for creating eco-friendly options that are crucial for fertilizing crops with short growth cycles.

Mechanical performance and water resistance of biochar admixture lightweight magnesium oxychloride cement

The applications of magnesium oxychloride cement (MOC) have been extensively studied recently due to its eco-friendly and high-strength nature. However, one of the significant limitations of MOC is its poor water resistance. To address this limitation, this study explored the prospect of incorporating biochar particles (up to 25 % of the dry mass of MgO) to form lightweight MOC with improved water resistance. The compressive (fc) and flexural (ff) strengths were investigated after 28-day curing and under 56-day water attack. The fc of MOC after immersion was determined under both wet (directly after immersion) and dry (air-dried to constant weights) conditions. The results indicated that the inclusion of 5 % and 10 % biochar increased the 28-day fc, while the addition of biochar decreased ff regardless of its dosage. Microscopic examination uncovered that the increase in strength resulted from the promoted production of phase 5 (5 Mg(OH)2·MgCl2·8H2O) and the reduction in unreacted MgO. The inclusion of 5 % and 10 % biochar increased the compressive and flexural strength retention ratios after 56-day immersion. The ff with 5 % biochar inclusion after immersion was higher compared to that of pure MOC. Moreover, the inclusion of biochar had minimal effects on the thermal degradation of MOC. The above results suggest that biochar can be a potential additive to enhance the mechanical behaviour and water resistance of MOC. As fc of immersed MOC increased during air-drying, a new equation was developed to describe variations in fc of MOC subject to different degrees of saturation during drying.

A multiple cross-linking strategy to develop an environment-friendly and water resistance wheat gluten protein wood adhesive

Wheat gluten (WG) shows great promise to synthesize environment-friendly wood adhesives. However, their weak bonding strength and poor water resistance have limited its application in the commercial wood-based panel industry. In this study, a novel WG-based adhesive was developed by constructing a multiple cross-linking network generated by covalent and non-covalent bonds. The potential mechanism was revealed by FT-IR analysis. Furthermore, their surface morphology, thermal stability, viscosity, and residual rate of adhesives with different compositions were systematically characterized and compared. The results showed that the hydrogen bonding, reactions between amine groups and tannin, and ring opening reaction of epoxy, synergistically contributed to generate a highly crosslinked network. The wet/boil water strength of the plywood prepared from WG/tannin/ethylene imine polymer (PEI)-glycerol triglycidyl ether (GTE) adhesive with the addition of 15 % GTE could reach 1.21 MPa and 1.20 MPa, respectively, and a mildew resistance ability was observed. This study provides a facile strategy to fabricate high-performance plant protein-based adhesives with desirable water resistance for practical application.

Ultrathin MnO2 with strong lattice disorder for catalytic oxidation of volatile organic compounds

Catalytic oxidation proves the most promising technology for volatile organic compounds (VOCs) abatement. Lattice disorder plays a crucial role in the catalytic activity of catalysts due to the exposure of more active sites. Inspired by this, we successfully prepared a series of ε-MnO2 with different lattice disorder defects via several simple methods and applied them to the catalytic oxidation of two typical VOCs (toluene and acetone). Various characterizations and performance tests confirm that the ultrathin (1.4-1.8 nm) structure and strong lattice disorder can enhance the low temperature reduction and reactive oxygen species, so that MnO2-R exhibits excellent toluene and acetone oxidation activities. In-situ DRIFTS tests were carried out to detect reaction intermediates in the toluene and acetone oxidation process on the catalyst surface. Moreover, we propose a possible synergistic mechanism for toluene and acetone mixtures catalytic oxidation. This work reveals the important role of lattice disorder defects in the catalytic oxidation of VOCs on Mn-based catalysts, and deepens the insights of the reaction path in toluene and acetone catalytic oxidation.

Optimization and characterization of reinforced biodegradable cellulose-based aerogels via polylactic acid/polyhydroxybutyrate coating

Vine shoots (VS) and waste eucalyptus paperboard (EP) have been used as cellulose sources (in the form of cellulose nanocrystals -CNCs- and cellulosic fibers respectively) for developing cellulose-based aerogels. Two different parameters including cellulose concentration (0.5 % and 2 % w/v) and freezing temperatures (-20 °C and -80 °C) were tested to evaluate differences in the porosity of the aerogels via Brunauer-Emmett-Teller (BET) and thermal conductivity analyses. In addition, a supplementary coating was applied to the raw aerogels by means of dipping the materials in either polylactic acid (PLA) or polyhydroxybutyrate (PHB) solutions (1 % w/v). Their microstructure was observed via SEM and the reinforcing capacity provided by the coating was measured by means of mechanical compressive tests (~10-fold improvement) and water resistance (contact angle >100°). Finally, aerogels' biodegradability was also confirmed according to the standard ISO 20200 thus providing a sustainable and high-performance alternative to conventional materials also following circular economy principles.

Synthesis of biomass hyperbranched polyamide resin from cellulose and citric acid for wood adhesive

Traditional wood adhesives have the problems of excessive dependence on fossil resources and environmental pollution. Cellulose, a renewable biomass resource with a low price and huge output, provides a basis for preparing biomass wood adhesives. In this study, a new type of polyamide resin was prepared by modifying microcrystalline cellulose and reacting with natural citric acid. Specifically, toluenesulfonyl cellulose (TS) was synthesized, and functional amino cellulose (AC) was prepared by a nucleophilic substitution reaction with hyperbranched polyamide (HP). Then cellulose-based hyperbranched polyamide resin (CHP) was prepared by polycondensation with citric acid. The structure of CHP resin was investigated by FTIR, XPS, 13C NMR and GPC, and plywood was prepared to study its mechanical properties. Due to the formation of hyperbranched cross-linked network structure inside the resin, the prepared plywood has excellent properties. The dry shear strength reaches 2.24 MPa, and the strength reaches 1.25 and 1.31 MPa after soaking in water at 63 °C and 93 °C for 3 h. The resin in this study has a simple preparation process and excellent performance, which provides a solid foundation for developing high-performance cellulose-based wood adhesives.

One-step fabrication of eco-friendly multi-functional amphiphobic coatings for cellulose-based food packaging

Plastic and fluorine-containing oil and water resistant packaging materials have been gradually replaced by non-toxic and harmless bio-based materials because of their hazard to environment and human health. In this study, chitosan/carnauba wax emulsions (CS/CWs) were firstly prepared by one-step and used as oil and water resistant coating for cellulose-based food packaging paper. The impacts of emulsion components on stability of the emulsions and barrier performance of the coated paper were investigated. The results showed that the viscosity, particle size and polydispersity index of the emulsions were greatly dependent on the concentration of CS and CW, and the coated paper had the best comprehensive performance in water and oil resistance when the concentration of CS was 3 % and the amount of CW was 90 % of the total solid content (CS3/CW90). The particle size of CS3/CW90 was in the range of 0.5-0.7 μm, and the Cobb60 value, water contact angle and the kit ratings of paper coated with CS3/CW90 achieved 7.5 g/m2, 130.9° and 12/12, respectively, and the coated paper also exhibited excellent thermal stability and high antibacterial rate of 99.1 %, demonstrating its great potential for application in multi-functional food packaging.

A fully bio-based soy protein wood adhesive modified by citric acid with high water tolerance

Despite the widespread application prospect of soybean meal flour (SF) as a non-toxic and renewable wood adhesive, the practical application is limited by its poor mechanical properties and water resistance. In this work, a novel SF-based wood adhesive (CSP) was developed using citric acid (CA) as a modifier, which was further designated to produce plywood on a laboratory scale. Moreover, the effects of the mass ratio of CA/SF, hot-pressing temperature, and hot-pressing time on the bonding properties and water resistance of the resulting plywood were investigated in detail. As a result, under the optimal hot-pressing conditions (180 °C, 5 min), high-performance plywood bonded by CSP (CA/SF = 15/100) adhesive was fabricated, whose dry shear strength, cold-water wet shear strength (20 °C for 24 h), and hot-water wet shear strength (63 °C for 3 h) reached 1.65 MPa, 1.99 MPa, and 1.58 MPa, respectively. Due to the easy preparation process, sustainability, and favorable properties, the proposed fully bio-based CSP wood adhesive has great potential for the large-scale fabrication of eco-friendly wood panels in industry.

Food packaging films based on ionically crosslinked konjac glucomannan incorporating zein-pectin nanoparticle-stabilized corn germ oil-oregano oil Pickering emulsion

This study addresses the limitations of konjac glucomannan (KGM) films in mechanical properties, hydrophobicity and antibacterial activities. For the first time, a zein-pectin nanoparticle-stabilized corn germ oil-oregano essential oil Pickering emulsion (ZPCEO) was incorporated into KGM, with the resulting film being further ionically crosslinked with Ca2+, Cu2+ or Fe3+. FTIR, SEM and EDS results showed that the metal ions were crosslinked with the hydroxyl and carbonyl groups of polysaccharides and uniformly distributed throughout the films (degree of crosslinking: Fe3+ > Cu2+ > Ca2+). Compared with pure KGM films, the ionic crosslinked ZPCEO/KGM (IL-ZPCEO/KGM) films have superior water resistance mechanical properties, and exhibit unique UV-blocking properties, antioxidant and antibacterial activities. The ZPCEO/KGM-Fe3+ film offered the best all-round properties, including the highest tensile strength, water resistance, UV-blocking capacity, and antimicrobial activity. Thus, ionic crosslinking of ZPCEO/KGM films can be applied to the preparation of food packaging for use in high humidity environments.

Valorization of sewage sludge for facile and green wood bio-adhesives production

A method is presented herein for the design of wood bio-adhesives using sewage sludge extracts (SSE). SSE was extracted from SS using deep eutectic solvents and processed with glycerol triglycidyl ether (GTE) to disrupt the secondary structure of proteins. An additive was also used to improve mechanical performance. The resulting bio-adhesive (SSE/GTE@TA) had a wet shear strength of 0.93 MPa, meeting the Chinese national standard GB/T 9846-2015 (≥0.7 MPa). However, the high polysaccharide content in SSE would weaken the mechanical properties of wood bio-adhesives. The key to improve bio-adhesive quality was the formation of a strong chemical bond via Maillard reaction as well as higher temperatures (140 °C) to reduce polysaccharide content via dehydration. This approach has lower environmental impact and higher economic efficiency compared to incineration and anaerobic digestion of sewage sludge. This work provides a new perspective on the high-value utilization of SS and offers a novel approach to developing bio-adhesives for the wood industry.

Effect of benzoic acid and dopamine hydrochloride as a modulator in the water resistance of Universitetet i Oslo-67: Adsorption performance and mechanism

The severe hazards on ecological environment and human body caused by volatile organic compounds (VOCs) have attracted worldwide substantial attention. In this research, a series of novel modified Universitetet i Oslo-67 (UiO-67) with water resistance were prepared and characterized, which had modified by benzoic acid and dopamine hydrochloride (67-ben-DH). On this basis, the adsorption performance, adsorption kinetics, defect engineering and water resistance of adsorbent were investigated. The results indicated that the excellent pore structure and specific surface area of 67-ben-DH-6 (molar ratio of Zr4+ to DH was 1:6) were retained while the adsorption performance and water resistance of the adsorbent were improved. Due to more defects, excellent adsorption diffusion and strong π-π interactions of 67-ben-DH-6, it performed the maximum adsorption capacity of toluene (793 mg g-1). Furthermore, the outstanding water resistance was attributed to the fact that N element of DH reduced the affinity of the adsorbent with water. Finally, the density functional theory (DFT) calculations showed that the adsorbent 67-ben-DH-6 had the maximum adsorption energy for toluene (-99.4 kJ mol-1) and the minimum adsorption energy for water (-17.8 kJ mol-1). Thus, the potential mechanism of 67-ben-DH for efficient toluene adsorption and water resistance was verified from a microscopic perspective.

Synthetic effect of supports in Cu-Mn-doped oxide catalysts for promoting ozone decomposition under humid environment

The escalating levels of surface ozone concentration pose detrimental effects on public health and the environment. Catalytic decomposition presents an optimal solution for surface ozone removal. Nevertheless, catalyst still encounters challenges such as poisoning and deactivation in the high humidity environment. The influence of support on catalytic ozone decomposition was examined at a gas hourly space velocity of 300 L·g-1·h-1 and 85% relative humidity under ambient temperature using Cu-Mn-doped oxide catalysts synthesized via a straightforward coprecipitation method. Notably, the Cu-Mn/SiO2 catalyst exhibited remarkable performance on ozone decomposition, achieving 98% ozone conversion and stability for 10 h. Further characterization analysis indicated that the catalyst's enhanced water resistance and activity could be attributed to factors such as an increased number of active sites, a large surface area, abundant active oxygen species, and a lower Mn oxidation state. The catalytic environment created by mixed oxides can offer a clearer understanding of their synergistic effects on catalytic ozone decomposition, providing significant insights into the development of water-resistant catalysts with superior performance.

Study on application and environmental effect of phosphogypsum-fly ash-red mud composite cemented paste backfill

Phosphogypsum (PG) cementitious paste backfill (CPB) was prepared by using PG and fly ash (FA) as the main raw materials, red mud (RM) as the alkaline activator, Portland cement (OPC) as the binder, and silica fume (SF) as the additive, and its properties were investigated to achieve the objective of "treating harm with waste." The results showed that the addition of OPC facilitated the flowability of the slurry, while the addition of RM and SF had the opposite effect. The slurry presented ideal flowability when the water/binder ratio was 0.2 and the superplasticizer (SP) content was 0.7%. The mechanical properties and water resistance were improved significantly with increasing OPC, RM, and SF doping. The strength of the CPB material exceeded 22 MPa after curing at room temperature for 28 days, which met the mine filling requirements. Changes in the ion concentrations of the solution were first monitored during immersion. The dissolution rules of Ca2+ and SO42- at different immersion ages confirmed that RM promoted the continuous hydration of CPB, which was the key to improve water resistance. Microstructural analysis showed that the main hydration products were AFt and C-S-H, which played an important role in the strength development of the material. The leaching results demonstrated that the metal ion content satisfied the requirements of the III categories of Chinese environmental standards (GB/T 14848-2017), indicating that the technology is a reliable and environmentally friendly technology for PG, FA, and RM recovery that can simultaneously support safe mining.

Effective and eco-friendly safe self-antimildew strategy to simultaneously improve the water resistance and bonding strength of starch-based adhesive

Starch adhesive, as a sustainable biomass-based adhesive, could be used to solve environmental problems from petroleum-derived adhesive. But its application is hindered by poor water resistance, mildew resistance, and storage stability. Here, a fully bio-based citric acid-starch adhesive (CASt) with high properties was successfully introduced by a simple method. Liquid chromatography/mass spectrometry (LC-MS), and Fourier Transform Infrared spectroscopy (FT-IR) determined that esterification of citric acid (CA) and starch (St) occurred to form a stable three-dimensional crosslinking structure, which strengthened water resistance and bonding strength of the starch adhesive. Compared with native starch (100 %), the soluble content of cured CASt was 1-16 %. CASt adhesive has well storage stability and high mildew resistance. Even after being stored for 5 months, the CASt-1 adhesive (mass ratio of CA/St = 1:1, and reaction time = 1 h) still have good liquidity. And its hot water strength (1.05 ± 0.22 MPa) also satisfied the standard requirements (≥0.7 MPa). The exhibited CASt adhesive is eco-friendly with components from plant resources, which performed as a bright alternative that can substitute petroleum-based adhesives in the artificial board industry.

Preparation and characterization of the bonding performance of a starch-based water resistance adhesive by Schiff base reaction

Starch is one of the important raw materials for the preparation of biomass adhesives for its good viscosity and low-cost properties. However, the drawbacks of poor water resistance and bonding performance seriously restrict its application in the wood industry. To resolve those problems, an environment-friendly renewable, and high water resistance starch-based adhesive (OSTH) was prepared with oxidized starch and hexanediamine by Schiff base reaction. In order to optimize the adhesive preparation process, the effect of different oxidation times and oxidant addition on the mechanical performance of plywood were investigated. In addition, the curing behavior characteristics, thermomechanical properties, and thermal stability of the OSTH adhesives were analyzed by differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and thermogravimetric analysis (TG). Fourier-transform infrared (FTIR) spectrometry and Liquid Chromatography-Mass Spectrometry (LC-MS) were used to explain the reaction mechanisms involved. The results show this adhesive has an excellent bonding performance at the oxidation time of 12 h with 11 % (w/w, dry starch basis) NaIO4 as an oxidant. The dry shear strength, 24-hour cold water, and 3-hour hot water (63 °C) soaking shear strength of the plywood bonded with this resin were respectively 1.87 MPa, 0.96 MPa, and 0.91 MPa, which satisfied the standard requirement of GB/T 9846-2015 (≥0.7 MPa). Thus, this study provided a potential strategy to prepare starch-based wood adhesives with good bonding performance and water resistance.

Catalysts for highly water-resistant catalytic decomposition of ozone: Hausmannite Mn3O4 on exposed (101) crystal surface

Recently, ozone pollution has gradually replaced PM2.5 as the main pollutant affecting air pollution. In this study, we synthesized a series of Mn₃O₄ catalysts by hydrothermal method changing the precursors and tested their activities at different relative humidity, gas volume space velocity of 150,000 h^-1 and 5 ppm ozone. Remarkably, Mn₃O₄-SO₄ prepared with MnSO₄ as precursor showed excellent catalytic ozone decomposition activity, almost completely converting 5 ppm of ozone at different relative humidity ranges. Finally, the most active Mn₃O₄-SO₄ catalyst was tested for its usability limit at RH= 90%, after 28 h of testing under high humidity conditions, it had retained successfully the complete decomposition of low concentrations of ozone. The catalysts were characterized by XRD, Raman, HRTEM, XPS, BET, H₂O-TPD and in situ IR NH₃ adsorption. The characterization analysis revealed that the Mn₃O₄-SO₄ surface could exposed a highly active (101) crystalline surface with high specific surface area, excellent hydrophobicity as well as ozone adsorption capacity, which were highly favorable for ozone decomposition under high humidity conditions. In this work, Mn₃O₄ exhibits good catalytic activity, which provides an additional option for future studies of manganese oxides.

High-performance bamboo composites based on the chemical bonding of active bamboo interface and chitosan

Nowadays, green, clean, and efficient sustainable development has become the world's mainstream industrial development. However, the bamboo/wood industry is still in the status quo with high fossil resource dependence and significant greenhouse gas emissions. Herein, a low-carbon and green strategy to produce bamboo composites is developed. The bamboo interface was modified directionally to a bamboo carboxy/aldehyde interface by using a TEMPO/NaIO₄ system, and then chemically cross-linked with chitosan to produce active bonding bamboo composite (ABBM). It was confirmed that the chemical bond cross-linking (CN, N-C-N, electrostatic interactions, hydrogen bonding) in the gluing region was helpful to obtain the excellent dry bonding strength (11.74 MPa), water resistance (5.44 MPa), and anti-aging properties (decreased by 20 %). This green production of ABBM solves the problem of poor water resistance and aging resistance of all-biomass-based chitosan adhesives. It can replace bamboo composites produced using fossil-based adhesives to meet the requirements of the construction, furniture, and packaging industries, changing the previous situation of composite materials requiring high temperature pressing and highly dependent on fossil-based adhesives. This provides a greener and cleaner production method for the bamboo industry, as well as more options for the global bamboo industry to achieve green and clean production goals.

Influence of silylated nano cellulose reinforcement on the mechanical, water resistance, thermal, morphological and antibacterial properties of soy protein isolate (SPI)-based composite films

The aim of this research work is to improve the mechanical and water-resistance properties of soy protein isolate (SPI) biofilm. In this work, 3-aminopropyltriethoxysilane (APTES) coupling agent modified nanocellulose was introduced into the SPI matrix in the presence of citric acid cross-linker. The presence of amino groups in APTES facilitated to form cross-linked structures with soy protein. The incorporation of a citric acid cross-linker made the cross-linking process more productive, and the surface smoothness of the film was confirmed by a Scanning Electron Microscope (FE-SEM). From the study of the mechanical and thermal properties and water resistance of the film, it was confirmed that the results were highly satisfactory for the modified nanocellulose incorporated film compared to the non-modified one. Additionally, coating of citral essential oil onto SPI nanocomposite film displayed antimicrobial properties due to the presence of various phenolic groups in the citral oil. The Tensile Strength and Young's Modulus of silane-modified nanocellulose containing film were enhanced by ~119 % and ~ 112 %, respectively on incorporation of 1 % APTES-modified nanocellulose. Consequently, this work is expected to offer an effective way for silylated nano-cellulose reinforcing soy protein isolate (SPI) based bio nanocomposite films for packaging applications. As an example, we have demonstrated one of the application as wrapping films for packing black grapes.

Tannin-based wood adhesive with good water resistance crosslinked by hexanediamine

As a biomass material, tannins are used in the preparation of wood adhesives, but their poor strength and water resistance has greatly limited their application. Therefore, it is necessary to prepare tannin-based wood adhesives with good water resistance. In the present study, tannin and hexanediamine were simply mixed at room temperature to prepare tannin-hexanediamine (TH) adhesive and then used to prepare plywood. Effects of mass ratio of hexanediamine to tannin and pH value of TH adhesive are studied. The results indicating the effects of mass ratio and pH value are apparent on shear strength. When the mass ratio is above 25 % and the pH value is above 9, the plywood shows good water resistance. Fourier transform-infrared (FTIR), X-ray photoelectron spectroscopy (XPS), liquid chromatography-mass spectrometry (LCMS) and X-ray diffraction (XRD) are used to determine the structures of TH adhesive, confirmed the reaction between tannin and hexanediamine to form macromolecules. Simultaneous thermal analyzer (TG-DSC) and Dynamic mechanical analysis (DMA) are used to analyze the thermal properties, indicate TH resin contains a good storage module and heat resistance. Therefore, with its good shear strength and water resistance, this newly developed tannin-based adhesive has the potential to application in wood-based panel industry, as an alternative of formaldehyde-based adhesive.

Development of water-resistant paper using chitosan and plant-based wax extracted from banana leaves

On being exposed to water, cellulose paper swells and its mechanical properties become weak. In this study, natural wax with an average particle size of 12.3 μm extracted from banana leaves was mixed with chitosan to prepare coatings applied on paper surfaces. Chitosan efficiently dispersed banana leaf-extracted wax on paper surfaces. The mixed chitosan and wax coatings considerably influenced paper properties, including yellowness, whiteness, thickness, wettability, water and oil sorption, and mechanical properties. The coating induced hydrophobicity in the paper, resulting in a significant increase in the water contact angle from 65.1 ± 7.7° (uncoated paper) to 123.2 ± 2.1°, and a decrease in water absorption by ⁓64 % to 52.6 ± 1.9 %. The coated paper demonstrated an oil sorption capacity of 212.2 ± 2.8 %, which was ⁓43 % greater than that of the uncoated paper, and the tensile strength of the coated paper improved by 43 % under wet conditions compared to the uncoated paper. Additionally, a separation of oil in water was observed for the chitosan/wax coated paper. Based on these promising results, the paper coated with chitosan and wax could be used for direct-contact packaging applications.

Mass-producible in-situ amorphous solid/electrolyte interface with high ionic conductivity for long-cycling aqueous Zn-ion batteries

Although aqueous Zn-ion batteries (aZIBs) have garnered significant attention, they are yet to be commercialized due to severe corrosion and dendrite growth on Zn anodes. In this work, an artificial solid-electrolyte interface (SEI) with amorphous structure was created in-situ on the anode by immersing Zn foil in ethylene diamine tetra(methylene phosphonic acid) sodium (EDTMPNA5) liquid. This facile and effective method provides the possibility for Zn anode protection in large-scale applications. Experimental results, combined with theoretical calculations, indicate that the artificial SEI remains intact and adheres tightly to the Zn substrate. The negatively-charged phosphonic acid groups and disordered inner structure offer adequate sites for rapid Zn²⁺ transference and facilitate [Zn(H₂O)₆]²⁺ desolvation during charging/discharging. Due to the synergistic effect of the aforementioned advantages, the artificial SEI endows high Coulombic efficiency (CE, 99.75%) and smooth Zn deposition/stripping under the SEI. The symmetric cell exhibits a long cycling life of over 2400 h with low-voltage hysteresis. Additionally, full cells with MVO cathodes demonstrate the superiority of the modified anodes. This work provides insight into the design of in-situ artificial SEI on the Zn anode and self-discharge suppression to expedite the practical application of aZIBs.

A starch-based, crosslinked blend film with seawater-specific dissolution characteristics

Existing biodegradable plastics may not be ideal replacements of petroleum-based single-use plastics owing to their slow biodegradation in seawater. To address this issue, a starch-based blend film with different disintegration/dissolution speeds in freshwater and seawater was prepared. Poly(acrylic acid) segments were grafted onto starch; a clear and homogenous film was prepared by blending the grafted starch with poly(vinyl pyrrolidone) (PVP) by solution casting. After drying, the grafted starch was crosslinked with PVP by hydrogen bonds, owing to which the water stability of the film is higher than that of unmodified starch films in fresh water. In seawater, the film dissolves quickly as a result of disruption of the hydrogen bond crosslinks. This technique balances degradability in marine environment and water resistance in everyday environment, provides an alternative route to mitigate marine plastic pollution and could be potentially useful for single-use applications in different fields such as packaging, healthcare, and agriculture.

Construction of a cellulose-based high-performance adhesive with a crosslinking structure bridged by Schiff base and ureido groups

Biomass-based adhesives are considered to be the preferred alternative to formaldehyde-type wood adhesives due to their wide range of sources, low cost, and sustainability. Herein, an environmentally friendly Schiff base cross-linked compact three-dimensional network structure bio-adhesive (DAC-PEI-U) derived from polyethyleneimine (PEI), urea, and cellulose was successfully prepared, verifying by detailed FTIR, NMR, and XPS analysis. Schiff base bridging between aldehyde groups in dialdehyde cellulose (DAC) and amino groups in polyurea (PEIU) not only constructed crosslinking networks but also endowed adhesives with good adhesion property. The dry bond strength of DAC-PEI-U adhesive reached 2.71 MPa, and the wet shear strength was 1.51 MPa (hot water) and 1.34 MPa (boiling water), respectively. It not only improves the water resistance and bonding process, but also displays simple synthesis and low cost. The improved performance of DAC-PEI-U adhesive is attributed to the generation of hyperbranched cross-linking structure in the adhesive system, which results in increased cross-linking density and promotes the formation of dense cross-sections in the curing adhesive. This work paves a solid way for developing cellulose-based wood adhesives with wet bonding properties, thus holding great potential as an alternative to formaldehyde-type adhesives in wood-based panel and indoor panel bonding industries.

Mechanical, water resistance and environmental benefits of magnesium oxychloride cement incorporating rice husk ash

Magnesium oxychloride cement (MOC) has received extensive attention as an eco-friendly cement, but its poor water resistance limits its engineering applications. In this study, MOC mixture (MOCM) was modified with 10-50 % rice husk ash (RHA) (wt% of MgO), and the development of their fresh properties, mechanical strength and microstructure was investigated. The results show that the incorporation of RHA to MOCM increases the setting time of the mixture and reduces its flowability. Due to the fine particle size and high reactivity of RHA, the incorporation of an appropriate amount of RHA to MOCM improves the matrix compactness, thereby enhancing the compressive strength of the samples. Although the microstructure of MOCM deteriorates and the strength decreases after immersion in water, the strength retention coefficient of MOCM with 50 % RHA increases by 24.57 % compared with that of plain MOCM. The incorporation of RHA not only reduces the relative content of magnesium oxide in MOCM, but also generates Mg-Cl-Si-H gel, which is beneficial to improve the water resistance of MOCM. Meanwhile, with the increase of RHA content, the carbon emission of MOCM also decreases. Compared with other modification methods, RHA-modified MOCM performs better in terms of water resistance, environmental benefits and strength enhancement.

Durability assessment of external thermal insulation composite systems in urban and maritime environments

External Thermal Insulation Composite Systems (ETICS) are multilayer solutions which provide an enhanced thermal performance to the building envelope. However, significant anomalies can be detected on ETICS facades, in some cases shortly after the application of these systems. This study intends to evaluate and compare the durability of six commercially available ETICS after two years of outdoor exposure at both urban and maritime conditions in Portugal. The systems were characterized by means of non-destructive testing (i.e., visual and microscopic assessment, water transport properties, thermal conductivity, surface roughness), thus allowing to evaluate the performance loss throughout natural aging. The bio-susceptibility and aesthetic properties (color and gloss) were also investigated. Results showed that the performance and durability of the complete system is significantly affected by the rendering system formulation. The lime-based specimens obtained the highest rate of mold development after one year of aging in a maritime environment, becoming considerably darker and with lower surface gloss. Fungal analysis of this darkish stained area indicated the presence of mold species of the genera Alternaria, Didymella, Cladosporium and Epicoccum, and yeasts of the genera Vishniacozyma and Cystobasidium. An increase of both capillary water absorption and water vapor permeability was also registered for the aged lime-based specimens. Acrylic-based systems obtained lower capillary water absorption after aging and greater dirt deposition on their surfaces, especially in urban conditions. These systems had also higher color variation and surface gloss decrease and slightly higher mold growth, when compared with those aged in a maritime environment. Finally, no mold growth was detected on the silicate-based specimens after two years of aging. However, these specimens obtained higher capillary water absorption and lower vapor permeability after aging, possibly leading to moisture accumulation within the system. Results contribute towards the development of ETICS with enhanced performance and durability.

Revealing the mechanism of high water resistant and excellent active of CuMn oxide catalyst derived from Bimetal-Organic framework for acetone catalytic oxidation

Environmental H₂O is an influential factor in the low-temperature catalytic oxidation of volatile organic compounds (VOCs), and it significantly impacts the reaction process and mechanism. Here, a series of rod-like Cu-Mn oxides were synthesised by pyrolysing Cu/Mn-BTC for acetone oxidation. The results confirm that the formation of multiphase interfaces have more excellent catalytic performance compared to single-phase catalysis. This phenomenon can be attributed to the formation of multiphase interfaces, which resulted in the synthesized catalysts with more active oxygen species and defective sites. The CuMn₂O_x catalyst exhibited superior catalytic performance (T₉₀ = 150 °C), high water resistance and long-term stability. Furthermore, in situ diffuse reflectance infrared Fourier transform spectroscopy and thermal desorption-gas chromatography-mass spectrometry results indicated that the degradation pathway of acetone was as follows: acetone ((CH₃)₂CO*) → enolate complexes ((CH₂) = C(CH₃) O*) → acetaldehyde ((CH₃CHO*) → acetate (CH₃COO*) → formate (HCOO*) → CO₂ and H₂O. At a low-temperature, water vapour dissociated a large number of activated hydroxyl groups on the multiphase interface, which promoted the dissociation of enolate complexes and acetaldehyde species. This composite oxide is a promising catalyst for removing oxygenated VOCs at high humidity.

Water durability modification of cerium-manganese oxide by tin shell for efficient airborne benzene oxidation

Single or cooperative incorporation of Ce and Sn elements into α-MnO₂ parent were tried to update the catalytic benzene oxidation performance, and the successive modification via Ce doping and Sn deposition was demonstrated to be a promising methodology to offer high mineralization and avoid moisture-aroused inactivation. Ce doping caused lattice distortion, increased Mn³⁺ content to 2.7 times that of the pristine MnO₂ and weakened Mn-O bonds due to electron transfer from Ce³⁺ to lattice oxygen, thus facilizing oxygen vacancy formation. Further, Sn deposition on CeMn substrate induced strong metal support interaction (SMSI) due to the core-shell like structure of Sn@CeMn, which promoted the construction of active oxygen vacancies to an even larger extent (1.2 and 2.5 times that of the CeMn and pristine MnO₂, respectively). The thus-formed larger amount of reactive oxygen species rendered the Sn@CeMn simultaneously with high CO₂ yield and low CO production. Also benefited from the SMSI effect, the Sn@CeMn's ability to continuously activate O₂ and H₂O into reactive oxygen species (e.g.,·OH radicals) was enhanced, which could offset the negativity caused by water vapor, thereby keeping > 95% removal during 5.5 h water switch on/off investigation at 200 °C. Reaction pathways were uncovered with designed experimentations.

Promotional effects of calcination temperature and H2O on the catalytic activity of Al-substituted MnAlO catalysts for low-temperature acetone oxidation

In order to enhance the role of Al in the materials, Al-substituted MnAlO catalysts were synthesized via the hydrothermal-redox method at different calcination temperatures for acetone oxidation. There were Al-substituted α-MnO₂ and amorphous aluminum oxide existed with homogeneous dispersion of elements in the catalysts. The surface property, reaction rate, CO₂ yield and water resistance of MnAlO catalysts were greatly affected by calcination temperatures. MnAlO-450 catalyst exhibited the best catalytic performance (acetone conversion of 90% at 165 °C) with CO₂ yield higher than 99.7%, which was mainly related to the weaker Mn-O bond strength, lower temperature reducibility and abundant Lewis acid sites. The acetone conversion of MnAlO-450 increased by as much as 16% in the presence of 1 vol% H₂O compared to that in the absence of H₂O at T₅₀ (the temperature for 50% conversion of acetone). The acceleration consumption of ethanol as the main by-product by H₂O improved the catalytic performance. This work would shed light on the Al substitution based catalysts for OVOC oxidation with highly efficient and water resistance.

Improvement mechanism of water resistance and volume stability of magnesium oxychloride cement: A comparison study on the influences of various gypsum

The development of magnesium oxychloride cement can effectively utilize the waste of potash industry and reduce its harm to the environment. Although magnesium oxychloride cement paste (MOCP) has excellent performance in dry environment, its performance is greatly deteriorated in water or humid environment, which severely limits its practical application. In order to improve the water resistance of MOCP, MOCP was modified by various gypsum in this study, and the intrinsic mechanism was explored. Results showed that replacing MgO with gypsum delayed the setting time of MOCP and effectively improved its volume stability. Although the incorporation of gypsum reduced the 14-d air-cured compressive strength of MOCP, waste gypsum was able to significantly improve the water resistance of MOCP compared to natural gypsum. When 80% flue gas desulfurization gypsum and phosphogypsum (weight of magnesium oxide) were incorporated into MOCP, the 14-d air-cured compressive strength of MOCP was only decreased by 14.49% and 15.94% compared with the control group, but its 28-d water immersion strength retention coefficient (SRC) could still reach 61.02% and 46.55%, respectively. However, for the control group and MOCP with 80% natural gypsum, the 28-d SRC were only 28.99% and 8.41%. The incorporation of high-volume waste gypsum to MOCP not only reduced the relative content of MgO, but also improved the stability of the 5-phase in water, which was beneficial to improve the water resistance of MOCP. In addition, high-volume waste gypsum-modified MOCP had lower cost and carbon emissions, and exhibited superior water resistance and sustainability compared to existing MOCP compositions.

Preparation of a high bonding performance soybean protein-based adhesive with low crosslinker addition via microwave chemistry

Human health and environmental protection demand wood-based panel industry for innovative soy-based adhesives with high production efficiency, straightforward synthesis processes, non-toxicity, and high bonding performance. A simple and efficient microwave pretreatment process and low addition of bio-derived crosslinking agent was used in this study to prepare a non-toxic and high-bonding performance soybean protein-based adhesive. After 4 min of microwave pretreatment time, the complex quaternary structure of soybean protein molecule unfolds, the soybean protein disperses evenly and stably, and active groups of soybean protein molecules are exposed. After adding 3.85% crosslinking agent, the moisture absorption rate of the soybean protein-based adhesive decreases by 41.77%, the residual rate increases by 3.68%, and the wet shear strength of the resultant plywood increases to 1.12 MPa, which satisfies requirement of interior use plywood. Compared with previously reported soy-based adhesives, this adhesive is dependent on fewer chemical reagents, but has good bonding performance. The 204.41% of relative cell viability indicates the resultant adhesive was non-toxic. The proposed high-efficiency, high-performance, non-toxic biomass adhesive has great prospects for the industrial application.

Chitosan/zein bilayer films with one-way water barrier characteristic: Physical, structural and thermal properties

Chitosan (C) and zein (Z) were used to develop bilayer films with a characteristic one-way water barrier using a layer-by-layer (LBL) casting method. The effects of mass ratios (C:Z_1:1, C:Z_1:2, C:Z_1:3, C:Z_3:1, C:Z_2:1) on the microstructure and physicochemical properties of bilayer films were investigated. Bilayer films had uniform microstructures, and C:Z = 1:3 showed a firmer structure as the Z aggregates were distributed in the continuous phase of C. The intermolecular interactions between the C and Z layers were observed using FTIR and XRD analysis. TGA demonstrated that adding Z layer enhanced the thermal stability of C films. LBL coating gave the C/Z bilayer film an increased elongation and tensile strength, as well as a decreased water vapor and oxygen permeability, especially for C:Z = 1:3 which had better properties. The results suggested that C and Z bilayer films may be a promising material for food packaging with the desired water resistance.

Preparation of durable magnesium oxysulfate cement with the incorporation of mineral admixtures and sequestration of carbon dioxide

To reduce the consumption of energy and raw materials caused by the production of Portland cement and enhance the carbon dioxide sequestration of building materials, this paper aims to manufacture durable and green magnesium oxysulfate cement based on incorporating mineral admixtures (fly ash (FA) or ground granulated blast-furnace slag (GGBFS)) and CO₂ curing treatment. Compressive strength, flexural strength, resistance to water and wetting-drying cycles of magnesium oxysulfate (MOS) were evaluated. Phase compositions and microstructures of typical samples were measured by X-ray diffraction (XRD), differential scanning calorimetry (DSC-TG), and scanning electron microscope (SEM) techniques. The results showed that mechanical strength and strength retention after wetting-drying treatment of MOS cement was increased by the sequestration of carbon dioxide. Both FA and GGBFS could improve the water resistance due to restrainting the phase conversion of MgO into Mg(OH)₂. However, the addition of FA or GGBFS deteriorated the compressive strength of MOS cement samples after wetting-drying treatment, owing to the formation of more magnesium hydroxide crystals and decomposition of 5 Mg(OH)₂·MgSO₄·7H₂O (5·1·7 phase). Furthermore, about 5% carbon dioxide can be captured by MOS cement paste during 24 h accelerated carbonation treatment. Therefore, the incorporation of mineral admixtures and sequestration of carbon dioxide was suggested as an effective method in manufacturing the highly durable and cleaner magnesium oxysulfate cement.

A novel Fe-Co double-atom catalyst with high low-temperature activity and strong water-resistant for O3 decomposition: A theoretical exploration

Developing catalysts with high activity, durability, and water resistance for ozone decomposition is crucial to regulate the pollution of ozone in the troposphere, especially in indoor air. To overcome the shortcomings of metal oxide catalysts with respect to their durability and water resistance, Fe-Co double-atom catalyst (DAC) is proposed as a novel catalyst for ozone decomposition. Here, through a systematic study using density functional theory (DFT) calculations and microkinetic modeling, the adsorption and catalytic decomposition of O₃ on Fe-Co DAC have been examined based on adsorption configuration, orbital hybridization, and electron transfer. Based on Eley-Rideal (E-R) and Langmuir-Hinshelwood (L-H) reaction mechanisms, the mechanisms of ozone decomposition on Fe-Co DAC were explored by analyzing reaction paths and energy variations. To confirm the water-resistant of Fe-Co DAC, competitive adsorption behavior between O₃ and dominant environmental gases was discussed through ab initio molecular dynamic (AIMD) simulation. The dominant reaction mechanism of ozone decomposition is L-H and the rate-determining step is the desorption of the first oxygen molecule from the surface of Fe-Co DAC which has an energy barrier of 0.78 eV. Due to this relatively low energy barrier and high turnover frequency (TOF), the optimal operation window of catalytic O₃ decomposition on Fe-Co DAC is <500 K suggesting that catalytic decomposition of O₃ on Fe-Co DAC can occur at room temperature. This theoretical study provides new insights for designing novel catalysts for ozone decomposition and fundamental guidance for subsequent experimental research.

Anchor and bridge functions of APTES layer on interface between hydrophilic starch films and hydrophobic soyabean oil coating

One of the well-recognized weaknesses of starch-based materials is their sensitivity to moisture, which limits their expanding applications. Natural materials, soyabean oils have been used as a coating for starch film, but the poor interface between hydrophilic starch and hydrophobic soyabean oil needs to be improved. In this work, (3-Aminopropyl) triethoxysilane (APTES) was used to reinforce the bonding between starch matrix and the coating of bio-based acrylated epoxidized soyabean oil (AESO). Study results show that APTES interacted effectively with both starch films via hydrogen bonding, and chemical bonds with AESO through the Michael addition reaction. Pull adhesion and cross-cutting tests demonstrated that the interfacial adhesion was significantly improved after treating their surface with APTES. The interfacial adhesion strength increased over 4 times after treating with 1.6 wt% APTES. The starch films treated with APTES and AESO coating were intact after soaking in water for more than 2 h.

A novel γ-like MnO2 catalyst for ozone decomposition in high humidity conditions

MnO₂ catalysts have been widely studied for catalytic gaseous ozone decomposition. However, their poor moisture resistance often leads to undesirable catalytic effects in the presence of high humidity. In this study, a novel catalyst with γ-like MnO₂ was synthesized using the selective dissolution method on LaMnO₃ perovskites. The as-prepared catalyst exhibited quite stable ozone conversion of ~90% within 12 h under 75% relative humidity (400-800 ppm of ozone, 30 °C, 150 000 mL·g^-1·h^-1 of WHSV). In contrast, traditional γ-MnO₂ catalyst showed deficient resistance to H₂O and sensitivity to space velocity. Detailed characterizations showed that the larger number of oxygen vacancies induced by structure reconstruction of the γ-like MnO₂ and residual La³⁺ cations facilitated ozone decomposition in humid atmosphere. Finally, the reaction rate of ozone decomposition was proposed by a kinetic study, which further proved that the amount and hydrophilicity of oxygen vacancies are the determinants of the first-order reaction rate constant.

Engineering cellulose nanopaper with water resistant, antibacterial, and improved barrier properties by impregnation of chitosan and the followed halogenation

This work demonstrated a facile and sustainable approach to functionalize cellulose nanopaper (CNP) by impregnation of chitosan (CS) and the followed halogenation. It was found that the tensile strength of the functionalized CNP (CNP/CS-Cl) was enhanced by 38.3% and 512.6% at dry and wet conditions, respectively. Meanwhile, the total transmittance (at 550 nm) of CNP/CS-Cl was increased from 75% of pure CNP to 85%, with 35% decrease in optical haze. Moreover, the CNP/CS-Cl exhibited significant enhancement in barrier properties. Importantly, part of the amino groups on CS were transformed into N-halamines during the halogenation process, which endowed the CNP/CS-Cl with excellent antibacterial performance against both S. aureus and E. coli with 100% bacterial reduction after 10 min of contact. Thus, this work provides a simple and efficient approach to functionalize CNP with water resistance, high transparency, excellent antibacterial and barrier properties, which will expand the potential applications of CNP.

Simple strategy for the construction of oxygen vacancies on α-MnO2 catalyst to improve toluene catalytic oxidation

A strategy simple, safe and suitable for large scale production of α-MnO₂ catalyst with high activity in VOCs oxidation is crucial for its application. The catalytic reactivity of α-MnO₂ catalyst is largely related with its oxygen vacancy. Herein, we report effective construction of oxygen vacancies on α-MnO₂ through simply adjusting precipitation temperature of a redox precipitation process. The key role of surface oxygen vacancies in toluene oxidation and the formation of different amount and distribution of the oxygen vacancies over the α-MnO₂ catalysts were revealed by characterizations together with DFT calculations. The best catalyst (α-MnO₂-60) exhibited significantly improved catalytic activity of α-MnO₂ catalyst in toluene oxidation (T₉₀ = 203 ℃) and excellent water resistance. The richest surface oxygen vacancies of α-MnO₂-60 contributed to its best catalytic activity, despite of its relatively lower specific surface area. This work may provide a new perspective for the rational design of high efficient VOCs catalysts.

Hyaluronic acid nanofibers crosslinked with a nontoxic reagent

The poor water resistance of the eletrospun hyaluronic acid (HA) nanofibers prevents their biomedical applications. In this manuscript, we crosslinked HA nanofibers with the periodate oxidation - adipic acid dihydrazide (ADH) crosslinking strategy. Quantification results showed that ∼ 57 % of aldehydes in oxidized HA were crosslinked by ADH and the crosslinking density could reach 75.7 %. Correspondingly, the crosslinked HA nanofiber mats exhibited wet tensile strength up to 0.88 MPa and could maintain their nanofibrous morphology after 14 days in simulated body fluid. Although ∼ 28 % of the aldehydes in oxidized HA were unreacted, the crosslinked HA nanofibers did not cause toxicity to L929 fibroblast cells, possibly because that the unreacted aldehyde groups were linked on macromolecular fragments and could not go across cell membranes. The water resistant and biocompatible HA nanofibers are expected to seek extensive applications in biomedical fields such as wound healing, adhesion prevention, and tissue engineering.

Sandcastle worm-inspired phytic acid and magnesium oxychloride cement copolymerization for performance enhancement

The development of magnesium oxychloride cement (MOC) can convert wastes in the potash industry into valuable products and reduce CO₂ emission. The use of acid radicals has the potential to enhance the water resistance of MOC. However, because of the internal stress formed during the crystallization process, the occurrence of cracks accompanied by a significant decrease in the mechanical properties is inevitable. Inspired by the sandcastle worm and organic-inorganic copolymerization, a novel strategy was proposed, which employed phytic acid (PA) to copolymerize with phase 5 crystals to reduce the internal stress and prevent crack generation. XPS and TG-DSC analyses revealed that organic-inorganic copolymers were successfully produced. Furthermore, the compressive strength (CS) and water resistance of MOC-PA were significantly enhanced. The enhanced properties were associated with the coordination bonds and high tension of the rigid rings in phytic acid, which was sufficient to overcome the internal stress. Additionally, the repeated hydrolysis of rod-like phase 5 generated a gel-like phase from the outside inward, enhancing their water resistance. Compared with MOC-0, MOC-0.6 showed a 17.8% increase in CS and a 102.3% increase in water resistance. The microscopic mechanisms of the enhanced CS and water resistance of high-performance greener cements were proposed.