RSC Advances

Gong, Runming; Ma, Zihao; Wang, Xing; Han, Ying; Guo, Yanzhu; Sun, Guangwei; Li, Yao; Zhou, Jinghui

doi: 10.1039/c9ra04568fpmid: 35528402

Waste newspaper is one of the most common cellulosic materials. Therefore, effective utilization of this commonly available biomass resource to prepare high-value carbon-based solid acid catalysts is an interesting and meaningful task. In this study we propose a new route for waste newspaper valorization, in which sulfonic-acid-functionalized carbon fiber can be directly produced from waste newspaper as a recyclable carbon based solid acid catalyst (WCSA) for the hydrolysis of cellulose. The as-prepared sulfonic-acid-functionalized carbon fiber contained –SO3H, –COOH, and phenolic –OH groups and exhibited good catalytic activity for the hydrolysis of cellulose. WCSA prepared under sulfonation conditions at a temperature of 100 °C and for a duration of 10 h has a higher sulfonic acid content. A total reducing sugars (TRS) yield of 58.2% was obtained with a catalyst/microcrystalline cellulose (MCC) ratio of 4 at 150 °C using a reaction time of 6 h. The recycling performance of the WCSA catalyst indicated that the TRS remained almost stable for five cycles during the hydrolysis of cellulose.

Chen, Hong; Qiu, Nan; Wu, Baozhen; Yang, Zhaoming; Sun, Sen; Wang, Yuan

doi: 10.1039/c9ra05508hpmid: 35528405

Ultrafine crystalline materials have been extensively investigated as high-rate lithium-storage materials due to their shortened charge-transport length and high surface area. The pseudocapacitive effect plays a considerable role in electrochemical lithium storage when the electrochemically active materials approach nanoscale dimensions, but this has received limited attention. Herein, a series of (Mg0.2Co0.2Ni0.2Cu0.2Zn0.2)O electrodes with different particle sizes were prepared and tested. The ultrafine (Mg0.2Co0.2Ni0.2Cu0.2Zn0.2)O nanofilm (3–5 nm) anodes show a remarkable rate capability, delivering high specific charge and discharge capacities of 829, 698, 602, 498 and 408 mA h g−1 at 100, 200, 500, 1000 and 2000 mA g−1, respectively, and a dominant pseudocapacitive contribution as high as 90.2% toward lithium storage was revealed by electrochemical analysis at a high scanning rate of 1.0 mV s−1. This work offers an approach to tune the lithium-storage properties of (Mg0.2Co0.2Ni0.2Cu0.2Zn0.2)O by size control and gives insights into the enhancement of pseudocapacitance-assisted lithium-storage capacity.

Panploo, Krittaya; Chalermsinsuwan, Benjapon; Poompradub, Sirilux

doi: 10.1039/c9ra06000fpmid: 35528441

To reduce the carbon dioxide (CO2) concentration in the atmosphere, natural rubber (NR) was developed as a rubber foam for CO2 adsorption. Although the CO2 adsorption capacity of the NR latex foam produced by mixing with a cake mixer (CM) was higher than that produced with an overhead stirrer (OS), both capacity values were still low. To improve the CO2 adsorption capacity, the use of unmodified and (3-aminopropyl)triethoxysilane-modified silica particles as fillers in the CM rubber foam matrix was examined. The highest CO2 adsorption capacity, from a mixed gas flow rate of 100 mL min−1 at ambient temperature and pressure, was obtained with the CM foam filled with 5 parts by weight per hundred parts of rubber filled with modified silica particles (4.08 mg g−1). The CO2 adsorption capacity of this foam was approximately 1.11- and 2.87-fold higher than that of the CM foam filled with unmodified silica particles (3.69 mg g−1) and unfilled CM rubber (1.42 mg g−1), respectively. Morphological analysis supported that the cell size and number of pores per cell of the NR latex foam, which were higher in the CM foams than the OS foams, were important factors for evaluating CO2 adsorption. In addition to physisorption between CM and CO2, chemisorption between the modified silica particles and CO2 increased the CO2 adsorption capacity.

Xu, Yanru; Guo, Lifang; Zhang, Haonan; Zhai, Huamin; Ren, Hao

doi: 10.1039/c9ra06487gpmid: 35528406

The synthesis process of the phenolic resin adhesive was developed in the 19th century, and its excellent environmental resistance and high bonding strength make it one of the main wood adhesives. With the development of industry, phenolic resin adhesive is not only used in plywood, wood processing and laminate, but also in automobile, aerospace, composite materials and other fields. Herein we review the main synthetic processes and latest research progress for phenolic resin adhesives, the capacity distribution of major domestic phenolic resin enterprises, analysis of domestic phenolic resin consumption, import and export volume and price, Chinese plywood production, and the main production and export markets. Furthermore, research and discussion on the commercial application of domestic phenolic resin adhesives in plywood were carried out, which provides a reference for development of better phenolic resin adhesives that meet the development needs of the country, along with quality and economic competitiveness.

Begum, Farzana; Ikram, Muhammad; Twamley, Brendan; Baker, Robert J.

doi: 10.1039/c9ra04863dpmid: 35528399

The synthesis of two types of phosphine ligands that feature perfluorinated ponytails is reported. A bidentate (RfCH2CH2)2PCH2CH2P(CH2CH2Rf)2 (Rf = CF3(CF2)n; n = 5, 7) and an alkoxyphosphine made by ring opening a fluorous epoxide, RfCH2CH(OH)CH2PR2 (Rf = CF3(CF2)7), have been prepared and spectroscopically characterised. The electronic effects of the fluorous chains have been elucidated from either the 1JPt–P or 1JP–Se coupling constants in Pt(ii) or phosphine selenide compounds. Whilst the bidentate phosphines do not give stable or active Pd catalysts, the hybrid ligand does allow Susuki, Heck and Sonogashira catalysis to be demonstrated with low catalyst loadings and good turnovers. Whilst a fluorous extraction methodology does not give good performance, the ligand can be adsorbed onto Teflon tape and for the Suzuki cross coupling reaction the catalytic system can be run 6 times before activity drops and this has been traced to oxidation of the ligand. Additionally the crystal structure of the hybrid phosphine oxide is reported and the non-covalent interactions discussed.

Procházková, Lenka; Vaněček, Vojtěch; Čuba, Václav; Pjatkan, Radek; Martinez-Turtos, Rosana; Jakubec, Ivo; Buryi, Maksym; Omelkov, Sergey; Auffray, Etiennette; Lecoq, Paul; Mihóková, Eva; Nikl, Martin

doi: 10.1039/c9ra04421cpmid: 35528437

Heat treatment is needed to increase the luminescence intensity of ZnO:Ga particles, but it comes at the cost of higher particle agglomeration. Higher agglomeration results in low transparency of scintillating powder when embedded in a matrix and constitutes one of the biggest disadvantages, besides low light yield and low stopping power, of ZnO:Ga powder. Limiting ZnO:Ga particle size is therefore a key step in order to prepare highly luminescent and transparent composites with prospects for optical applications. In this work, SiO2 coating was successfully used to improve luminescence intensity or limitation of crystallite size growth during further annealing. Furthermore, ZnO:Ga and ZnO:Ga-SiO2 core–shells were embedded in a polystyrene matrix.

Li, Hongliang; Deng, Mingxiang; Hou, Hongshuai; Ji, Xiaobo

doi: 10.1039/c9ra02663kpmid: 35528413

Recently, Sb2S3 has drawn extensive interest in the energy storage domain due to its high theoretical capacity of 946 mA h g−1. However, the inherent disadvantages of serious volume expansion and poor conductivity restrict the development of Sb2S3 for its application in SIBs. In addition, chemical synthesis is a main method to prepare Sb2S3, which is commonly accompanied by environmental pollution and excessive energy consumption. Herein, the natural stibnite mineral was directly applied in SIBs after modification with graphite via an effective and facile approach. The novel composites exhibited excellent electrochemical properties with higher reversible capacity, better rate capability and more outstanding cycling stability than the bare natural stibnite mineral. Briefly, this study is anticipated to provide a reference for the development of natural minerals as first-hand materials in energy storage and a new approach to improve natural stibnite mineral composites for their application as anodes in SIBs.

Jiang, Xiangyi; Wu, Gaochan; Zalloum, Waleed A.; Meuser, Megan E.; Dick, Alexej; Sun, Lin; Chen, Chin-Ho; Kang, Dongwei; Jing, Lanlan; Jia, Ruifang; Cocklin, Simon; Lee, Kuo-Hsiung; Liu, Xinyong; Zhan, Peng

doi: 10.1039/c9ra05869apmid: 32089839

The HIV-1 capsid (CA) protein plays crucial roles in both early and late stages of the viral life cycle, which has intrigued researchers to target it to develop anti-HIV drugs. Accordingly, in this research, we report the design, synthesis and biological evaluation of a series of novel phenylalanine derivatives as HIV-1 CA protein inhibitors using the Cu(i)-catalyzed azide and alkyne 1,3-dipolar cycloaddition (CuAAC) reaction. Among this series of inhibitors, compound II-10c displayed a remarkable anti-HIV activity (EC50 = 2.13 μM, CC50 > 35.49 μM). Furthermore, surface plasmon resonance (SPR) binding assays showed that compounds II-10c and PF-74 (lead compound) have similar affinities to HIV-1 CA monomer. Further investigation showed that the weak permeability and water solubility of representative compounds were probably the important factors that restricted their cell-based activity. Preliminary structure–activity relationships (SARs) were inferred based on the activities of these compounds, and their known structure. The most promising new compound was studied with molecular dynamics simulation (MD) to determine the preferred interactions with the drug target. Finally, the activities of members of this series of inhibitors were deeply inspected to find the potential reasons for their anti-HIV-1 activity from various perspectives. This highlights the important factors required to design compounds with improved potency.

Wang, Liqun; Hu, Wei; Deng, Jiao; Liu, Xin; Zhou, Jun; Li, Xiangzhou

doi: 10.1039/c9ra05338gpmid: 35528448

Litsea cubeba essential oil (LCEO) extracted from the fruit of the Litsea tree is a broad-spectrum bacteriostatic agent that has been used to treat ailments for thousands of years in China. The objective of our study was to assess the inhibitory effect of LCEO on Botrytis cinerea, a fungus that causes the putrification of fruits and vegetables. After being treated with 1.0% LCEO, the electrical conductivity of the fungal cells increased, and the contents of soluble reducing sugars and proteins slowly increased over treatment time. After being treated for 48 h with 1.0% LCEO, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images clearly showed damage to hyphae cells when compared with the normal growth of the control groups. Additional studies showed that the ergosterol content in the cell membrane significantly decreased with an increase in the LCEO concentration, and the electrophoretic bands of the proteins assayed using the sodium dodecyl sulfate-polyacrylamide gel electrophoresis method significantly changed at different LCEO concentrations. LCEO damaged the cell membrane and changed the cell membrane permeability, leading to the changes in some components in the cytoplasm, such as soluble reducing sugars, proteins, and ergosterol. In general, the antimicrobial activity of LCEO is attributable to a unique pathway and involves a series of events both on the surface and within the cytoplasm of the fungal cell.

Bai, Jing-Wen; Chen, Xing-Ru; Tang, Yang; Cui, Wen-Qiang; Li, Da-Long; God'spower, Bello-Onaghise; Yang, Yu

doi: 10.1039/c9ra04662cpmid: 35528391

A microwave assisted extraction technology was used to extract chrysophanol from rhubarb. The present study will focus on the optimum extraction conditions of chrysophanol and discuss the inhibitory effect of chrysophanol on the biofilm formation of Streptococcus suis (S. suis). A Box–Behnken design based on single-factor experiments was applied to optimize the microwave assisted extraction process and to study the factors' relationships with each other. The results showed that a microwave temperature of 56 °C, ethanol concentration of 70%, microwave power of 540 W and liquid to raw material ratio of 55 mL g−1 were the optimal conditions for the microwave method. The yield of chrysophanol was 2.54 ± 0.07% under the optimal conditions, which was in agreement with the predicted value (2.64%). Then, the chemical structure of the extracted chrysophanol was identified by LC-MS. In addition, in vitro experiments showed that chrysophanol has an inhibitory effect on S. suis (minimum inhibitory concentration was 1.98 μg mL−1) and was shown to significantly inhibit the capability of S. suis to form a biofilm using crystal violet staining. Finally, scanning electron microscopy analysis showed that the three-dimensional structure of the biofilm deposited by the S. suis community was destroyed by chrysophanol.