Synthesis and Properties of Carbon Microspheres from Waste Office Paper.

As a kind of biomass resource, waste office paper can be used as a carbon precursor to prepare carbon materials. In this work, carbon microspheres with regular shape, uniform particle size and high carbon content were successfully prepared from waste office paper via a hydrothermal synthesis method with sulfuric acid as the catalyst. The effects of reaction temperature and sulfuric acid dosage on the morphology of the carbon microspheres were studied. The formation mechanism of the carbon microspheres was investigated by analyzing the structure and composition of the products. The results show that the hydrolysis of cellulose in waste paper under hydrothermal conditions was the key for the formation of carbon microspheres. The temperature of hydrothermal reaction and the use of sulfuric acid can affect the morphology of carbon microspheres. The carbon microspheres synthesized at 210 °C with 10 mL sulfuric acid have the best surface morphology, with uniform particle size and higher dispersion. Cyclic voltammetry and electrochemical impedance spectroscopy show that the carbon microspheres have good capacitance performance and can be used in capacitors. This study provides a low-cost precursor for carbon microspheres as well as a new method for the recycle of waste paper.

Preparation of Low Volatile Organic Compounds Silver Paste Containing Ternary Conductive Fillers and Optimization of Their Performances.

Conductive silver paste is a key material in the fields of printed circuits and printed electronic devices. However, the preparation of conductive silver paste with low-cost and volatile organic compounds (VOCs) is still a challenge. In this work, conductive silver pastes with excellent comprehensive performances were developed by using water-borne polyurethane (WPU) as the bonding phase and using the ternary mixture of Ag microflakes (Ag MFs), Ag nanowires (Ag NWs), and Ag nanoparticles (Ag NPs) as the conductive phase. WPU endowed conductive silver pastes with the adhesion along with releasing a few VOCs during the curing. Results showed that a small amount of Ag NPs or Ag NWs dramatically enhanced the electrical conductivity of silver paste paint film filled only with Ag MFs. The electrical resistivity for optimal ternary mixture conductive silver paste was 0.2 × 10-3 Ω∙cm, and the conductive phase was composed of 20.0 wt% Ag MFs, 7.5 wt% Ag NWs, and 2.5 wt% Ag NPs. Meanwhile, the adhesive strength and hardness of silver paste paint film were effectively improved by increasing the curing temperature. The optimal overall performance of the conductive silver pastes was achieved at the curing temperature of 160 °C. Therefore, this work can provide a new route for preparing conductive silver pastes with high performances.

Facile preparation of robust dual MgO-loaded carbon foam as an efficient adsorbent for malachite green removal.

This study developed a facile approach for the fabrication of dual MgO-loaded carbon foam (DMCF) via carbonization of a cured MgO/cyanate ester resin mixture, which underwent self-foaming of the resin followed by the carbothermal reduction of MgO. The features of the prepared DMCF prepared were characterized by FESEM, TEM, XRD, FTIR, XPS and so on, and the effects of adsorption conditions, adsorption isotherms, kinetics, and thermodynamics on malachite green (MG) removal using the DMCF as adsorbents were investigated through batch adsorption experiments. Results demonstrate that the DMCF possesses a unique dual loading of MgO particles which are not only loaded onto its foam walls but also filled within the walls with a graphene-wrapped core-shell structure. The experimental maximum adsorption capacity of MG reaches up to 1874.18 mg/g with a partition coefficient of 10.87 mg/g/µM. The adsorption process can be better described with Langmuir, pseudo-second-order, and intraparticle diffusion models. Moreover, the DMCF exhibits a removal percentage of 84.85% after five reuses, indicating that it is an efficient and promising adsorbent for MG adsorption.

Application of fractional calculus methods to viscoelastic behaviours of solid propellants.

A three-branch viscoelastic model based on fractional derivatives is proposed for the viscoelastic behaviours of solid propellants. The simulation results show a satisfactory agreement with the stress relaxation modulus and complex modulus of solid propellants. As a comparison, the static modulus is also characterized by traditional viscoelastic model with integer-order derivatives. Results show that the application of the fractional derivatives to the viscoelastic constitutive model can effectively reduce the number of the required parameters while giving an accurate prediction of viscoelastic behaviours of solid propellants. Moreover, a simple and effective direct search method based on simulated annealing and Powell's mothed is proposed for the data fitting. This article is part of the theme issue 'Advanced materials modelling via fractional calculus: challenges and perspectives'.

A stiff ZnO/carbon foam composite with second-level macroporous structure filled ZnO particles for heavy metal ions removal.

A stiff zinc oxide/carbon foam (ZnO/CF) composite as a desirable adsorbent for heavy metal ions was innovatively designed and fabricated by loading ZnO particles into a carbon foam with capsule-like second-level macropores. The features of the resulting composite were characterized by FESEM, XRD, BET, FTIR, and XPS. The effects of adsorption parameters on the Pb(II), Cr(III), and Cu(II) ions removal were studied through batch experiments. Results show that the ZnO/CF composite possesses a second-level macroporous structure filled ZnO particles, which has both mesoporous structure and Zn-O-C bond with the strongly synergistic effect. And meanwhile, it has a relatively high compression strength of 2.18 MPa at a density of 0.18 g cm-3. The experimental maximum adsorption capacities for Pb(II), Cr(III), and Cu(II) ions reach 170.85 mg g-1, 168.74 mg g-1, and 104.61 mg g-1 with relatively high partition coefficients of 5.803 mg g-1 µM-1, 1.169 mg g-1 µM-1, and 0.648 mg g-1 µM-1, respectively. The experimental data are in accordance with Langmuir isotherm and pseudo-second-order kinetic model. Moreover, the composite still exhibits a good adsorption performance even after five cycles.

Hes3 Enhances the Malignant Phenotype of Lung Cancer through Upregulating Cyclin D1, Cyclin D3 and MMP7 Expression.

Hes3 is a basic helix-loop-helix factor gene, which was found to be involved in neural cell differentiation. Expression and clinicopathological significance of Hes3 in non-small cell lung cancer was not clear. In this study, we used immunohistochemistry to examine Hes3 expression in normal human lung and non-small cell lung cancer tissues. Hes3 expression was detected in cytoplasm and nucleus. Hes3 expression in bronchial epithelial cells and epithelial cells of submucosal glands was relatively weak and the positive rate was of 30.3% (10/33). Hes3 expression in non-small cell lung cancer tissues (51.8% (58/112)) was significantly higher than that in normal lung tissues (p < 0.05). Hes3 expression in cancer tissues was significantly associated with poor differentiation, advanced TNM stages, lymph node metastasis, and a shorter patient survival time (p < 0.05). In vitro study showed that overexpression of Hes3 in A549 cells significantly promoted cancer cell proliferation and invasion, while inhibition of Hes3 expression significantly downregulated cancer cell proliferation and invasion (p < 0.05). Western blotting showed that overexpression of Hes3 significantly upregulated expression of Cyclin D1, Cyclin D3, and MMP7 in A549 cells, while inhibition of Hes3 expression in LK2 cells significantly downregulated the expression of these molecules (p < 0.05). These results indicated that Hes3 may contribute to the malignant phenotype of non-small cell lung cancer, possibly through regulation of Cyclin D1, Cyclin D3, and MMP7, and may be a promising cancer marker.

Influences of operating parameters on liquefaction performances of Tetra Pak in sub-/supercritical water.

Liquefaction performances of waste Tetra Pak in sub-/supercritical water were evaluated in micro-batch reactors. The influences of temperature (300-420 °C), pressure (16-24 MPa), residence time (5-60 min) and feed concentration (5-40 wt%) on bio-oil yield, high heating value (HHV), and functional groups in bio-oil were investigated. The results showed that bio-oil yield firstly increased with increasing temperature and then decreased when the temperature exceeded 360 °C. Reaction time longer than 30 min gave a negative effect on bio-oil yield. The influence of pressure on bio-oil yield increased markedly from 16 MPa to 22 MPa, and then stabilized. The feed concentration higher than 20 wt% showed little influence on bio-oil yield. Maximum bio-oil yield of 35.55% was found at 360 °C, 22 MPa, 30 min and feed concentration of 20 wt%. HHV and energy recovery efficiency increased significantly with temperature, and maximum HHV of 48.747 MJ/kg and energy recovery efficiency of 46.49% were found at 420 °C, 20 MPa, 30 min and feed concentration of 20 wt%. The main compounds in bio-oil and morphology of the solid residue were also analyzed, and the possible liquefaction pathways of Tetra Pak were proposed.

Fine extraction of cellulose from corn straw and the application for eco-friendly packaging films enhanced with polyvinyl alcohol.

Biomass materials substituting for petroleum-based polymers occupy an important position in achieving sustainable development. Cellulose, a typical biomass material, stands out as the primary choice for producing eco-friendly packaging materials. However, it is still a challenge to efficiently utilize cellulose from waste biomass materials in practice. Herein, cellulose-based films were prepared by pretreating waste corn straw, separating straw husk, straw pith and straw leaf, and extracting cellulose through alkali and sodium chlorite treatment to improve its mechanical properties using the cross-linked polyvinyl alcohol (PVA) method in this work. The prepared composite films were characterized by Fourier transform infrared spectrometer (FTIR), X-ray diffraction instrument (XRD), Scanning electron microscopy (SEM), Thermogravimetric (TG) and mechanical properties. The results indicated that corn straw husk exhibited the highest cellulose content of 31.67 wt%, and obtained husk cellulose had the highest crystallinity of 52.5 %. Compared to corn straw, the crystallinity of husk cellulose, pith cellulose and leaf cellulose increased by 19.5 %, 16.4 % and 44.1 %, respectively. Husk cellulose/PVA composite films were the most thermally stable, with a maximum weight loss temperature of 346.8 °C. In addition, the husk cellulose/PVA composite film had the best tensile strength of 37 MPa. Meanwhile, the composite films had good UV shielding, low water vapor transmission rate and biodegradability. Therefore, this work provides a fine utilization route of waste corn straw, and as-prepared cellulose based films have potential application in eco-friendly packaging materials.

Antimicrobial Properties of Carboxymethyl Cellulose/Starch/N'N Methylenebisacrylamide Membranes Endowed by Ultrasound and Their Potential Application in Antimicrobial Packaging.

Cellulose is used widely in antimicrobial packaging due to its abundance in nature, biodegradability, renewability, non-toxicity, and low cost. However, how efficiently and rapidly it imparts high antimicrobial activity to cellulose-based packaging materials remains a challenge. In this work, Ag NPs were deposited on the surface of carboxymethyl cellulose/starch/N'N Methylenebisacrylamide film using ultrasonic radiation. Morphology and structure analysis of as-prepared films were conducted, and the antibacterial effects under different ultrasonic times and reductant contents were investigated. These results showed that Ag NPs were distributed uniformly on the film surface under an ultrasonic time of 45 min. The size of Ag NPs changes as the reducing agent content decreases. The composite film demonstrated a slightly better antibacterial effect against E. coli than against S. aureus. Therefore, this work can provide valuable insights for the research on antimicrobial packaging.

Recent Progresses in Pyrolysis of Plastic Packaging Wastes and Biomass Materials for Conversion of High-Value Carbons: A Review.

The recycling of plastic packaging wastes helps to alleviate the problems of white pollution and resource shortage. It is very necessary to develop high-value conversion technologies for plastic packaging wastes. To our knowledge, carbon materials with excellent properties have been widely used in energy storage, adsorption, water treatment, aerospace and functional packaging, and so on. Waste plastic packaging and biomass materials are excellent precursor materials of carbon materials due to their rich sources and high carbon content. Thus, the conversion from waste plastic packaging and biomass materials to carbon materials attracts much attention. However, closely related reviews are lacking up to now. In this work, the pyrolysis routes of the pyrolysis of plastic packaging wastes and biomass materials for conversion to high-value carbons and the influence factors were analyzed. Additionally, the applications of these obtained carbons were summarized. Furthermore, the limitations of the current pyrolysis technology are put forward and the research prospects are forecasted. Therefore, this review can provide a useful reference and guide for the research on the pyrolysis of plastic packaging wastes and biomass materials and the conversion to high-value carbon.

Self-assembled poly(N-methylaniline)-lignosulfonate spheres: from silver-ion adsorbent to antimicrobial material.

Self-assembled poly(N-methylaniline)-lignosulfonate (PNMA-LS) composite spheres with reactive silver-ion adsorbability were prepared from N-methylaniline by using lignosulfonate (LS) as a dispersant. The results show that the PNMA-LS composite consisted of spheres with good size distribution and an average diameter of 1.03-1.27 µm, and the spheres were assembled by their final nanofibers with an average diameter of 19-34 nm. The PNMA-LS composite spheres exhibit excellent silver-ion adsorption; the maximum adsorption capacity of silver ions is up to 2.16 g g(-1) at an adsorption temperature of 308 K. TEM and wide-angle X-ray results of the PNMA-LS composite spheres after absorption of silver ions show that silver ions are reduced to silver nanoparticles with a mean diameter of about 11.2 nm through a redox reaction between the PNMA-LS composite and the silver ions. The main adsorption mechanism between the PNMA-LS composite and the silver ions is chelation and redox adsorption. In particular, a ternary PNMA-LS-Ag composite achieved by using the reducing reaction between PNMA-LS composite spheres and silver ions can be used as an antibacterial material with high bactericidal rate of 99.95 and 99.99% for Escherichia coli and Staphylococcus aureus cells, respectively.

Abnormal expression of Pygopus 2 correlates with a malignant phenotype in human lung cancer.

BACKGROUND: Pygopus 2 (Pygo2) is a Pygo family member and an important component of the Wnt signaling transcriptional complex. Despite this data, no clinical studies investigating Pygo2 expression in lung cancer have yet been reported. METHODS: In the present study, the expression patterns of Pygo2 were evaluated by immunochemistry in 168 patients with non-small cell lung cancer (NSCLC). We used small interfering RNA (siRNA) to specifically silence Pygo2, and investigated its effect on cell growth by an 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and flow cytometry analysis in human lung cancer cell lines. RESULTS: Immunohistochemical analysis showed low expression of Pygo2 in normal lung tissues and increased nuclear expression in lung cancer tissues, either with or without perinuclear expression. Abnormal Pygo2 expression was associated with poor differentiation and a high Tumor (T), Node (N) and Metastases (M) stage in NSCLC patients, and correlated with poor prognosis. Using MTT assay we observed that Pygo2 downregulation inhibited cell proliferation; in addition, flow cytometry analysis showed that Pygo2 knockdown induced apoptosis and increased numbers of G1-phase cells and a reduction in S-phase cells. CONCLUSIONS: We therefore conclude that abnormal Pygo2 protein expression may be a marker for advanced NSCLC. Furthermore, Pygo2 knockdown suppresses cell growth.

Research Progress on Up-Conversion Fluorescence Probe for Detection of Perfluorooctanoic Acid in Water Treatment.

Perfluorooctanoic acid (PFOA) is a new type of organic pollutant in wastewater that is persistent, toxic, and accumulates in living organisms. The development of rapid and sensitive analytical methods to detect PFOA in environmental media is of great importance. Fluorescence detection has the advantages of high efficiency and low cost, in which fluorescent probes have excellent fluorescence properties, excellent bio-solubility, and remarkable photostability. It is necessary to review the fluorescence detection routes for PFOA. In addition, the up-conversion of fluorescent materials (UCNPs), as fluorescent materials to prepare fluorescent probes with, has significant advantages and also attracts the attention of researchers, however, reviews related to their application in detecting PFOA and comparing them with other routes are rare. Furthermore, there are many strategies to improve the performance of up-conversion fluorescent probes including SiO2 modification and amino modification. These strategies can enhance the detection effect of PFOA. Thus, this work reviews the types of fluorescence detection, the design, and synthesis of UCNPs, their recognition mechanism, properties, and their application progress. Moreover, the development trend and prospects of these detection probes are given.

Construction of self-assembled bilayer core-shell V2O3 microspheres as absorber with superior microwave absorption performance.

The design and preparation of heterogeneous structures of dielectric materials has been the mainstream direction for the construction of superior microwave absorption materials (MAMs). We report a facile and efficient procedure combination of hydrothermal process and subsequent heat treatment for successfully prepared bilayer core-shell structure self-assembled V2O3 microspheres (BCSV). The microstructure, defects, dielectric properties and microwave absorption (MA) properties of BCSV were systematically investigated, and the effect of bilayer core-shell structure on the MA properties was discussed. By varying the heat treatment temperature, it is feasible to regulate the thickness of V2O3 bilayer and its unique structure defects, hence enhancing the attenuation and multiple polarization loss of electromagnetic waves inside the microspheres. Self-assembled V2O3 microspheres with bilayer core-shell structure exhibit high-performance MA property. The reflection loss (RL) gets to - 67.12 dB at 11.69 GHz covering the whole X-band after heat treatment at 600 °C, and the broad effective absorption bandwidth is 5.49 GHz with a thickness of 2.20 mm. The conductivity loss, multiple polarization loss and dielectric loss are ascribed to the specific bilayer core-shell structure. Thus, our work provides a good perspective on how to create vanadium oxide-based MAMs with effective absorption and broad bandwidth.

A facile, alternative and sustainable feedstock for transparent polyurethane elastomers from chemical recycling waste PET in high-efficient way.

Polymers with excellent optical and mechanical performance fabricated from renewable resources, have been paid an increasing attention in recent years. Here, high-performing polyurethane elastomers with significant mechanical properties, crystallinity, excellent stretchability and good transparency are prepared by a synergistic molecular design in the soft and hard segments. Using the liquid glycolysis degradation product (LGOP) as a chain extender, polyurethane elastomer is synthesized from polyethylene terephthalate (PET) waste bottles. The results suggest that the degradation products from waste PET can be directly used as feedstock for preparing polyurethane elastomers with significant performance. The polyurethanes exhibited excellent optical transparency of near 90%, and can be stretched up to 670% without any treatment to return to original size. It is assumed that the symmetrical hard domain composed of aromatic rings and ester groups in LGOP creates sufficient chain fluidity for the dynamic exchange of hydrogen bonds and urethane. This paper has devoted to achieve a complete and mature system from waste PET to polyurethane products, to create a closed loop of waste PET plastic recycling and regeneration, and to realize the polyurethane industrial chain of raw material self-supply.

Research Progress of Treatment Technology and Adsorption Materials for Removing Chromate in the Environment.

Cr is used extensively in industry, so the number of Cr (VI) hazards is increasing. The effective control and removal of Cr (VI) from the environment are becoming an increasing research priority. In order to provide a more comprehensive description of the research progress of chromate adsorption materials, this paper summarizes the articles describing chromate adsorption in the past five years. It summarizes the adsorption principles, adsorbent types, and adsorption effects to provide methods and ideas to solve the chromate pollution problem further. After research, it is found that many adsorbents reduce adsorption when there is too much charge in the water. Besides, to ensure adsorption efficiency, there are problems with the formability of some materials, which impact recycling.

Surface charge regulation of imidazolium salts/starch/carboxymethyl cellulose ternary polymer blend films for controlling antimicrobial performance and hydrophobicity.

Starch (SR)/carboxymethyl cellulose (CMC) based antimicrobial films have been widely applied in packaging field. As a high-effect antimicrobial agent, the surface charge of imidazolium salt plays an important effect on antimicrobial performances of starch/carboxymethyl cellulose. Here in, the surface charge of dodecyl imidazolium bromide salt was regulated via thiol-ene reaction. Furthermore, antibacterial films were prepared by mixing imidazolium salts with SR/CMC via solution casting method. Under the optimized ratio of CMC to SR, the antibacterial activity for as-prepared ternary polymer blend films was enhanced with the increasing of surface charge of imidazolium salt. The sample of ADSC-01 film with highest surface charge showed best antibacterial properties for E. coli and S. aureus with the inhibition zone of 3.20 cm and 3.00 cm, respectively. In addition, hydrophobic property exhibited similar positive correlation with the surface charge. Therefore, this work provides a new route to regulate the antibacterial activity of bio-based ternary polymer blend films in the packaging.

Effect of Different Silane Coupling Agents on Properties of Waste Corrugated Paper Fiber/Polylactic Acid Composites.

The surface of plant fibers was modified by silane coupling agents to prepare plant fiber/polylactic acid (PLA) composites, which can improve the dispersion, adhesion, and compatibility between the plant fibers and the PLA matrix. In this work, three silane coupling agents (KH550, KH560, and KH570) with different molecular structures were used to modify the surface of waste corrugated paper fibers (WFs), and dichloromethane was used as the solvent to prepare the WF/PLA composites. The effects of different silane coupling agents on the microstructure, mechanical properties, thermal decomposition, and crystallization properties of the composites were studied. The mechanical properties of the composites treated with 4 wt% KH560 were the best. Silane coupling agents can slightly improve the melting temperature of the composites, and WFs can promote the crystallization of PLA. The modification of WFs by silane coupling agents can increase the decomposition temperature of the WF/PLA composites. The content and type of silane coupling agent directly affected the mechanical properties of the WF/PLA composites. The interfacial compatibility between the WFs and PLA can be improved by using a silane coupling agent, which can further enhance the mechanical properties of WF/PLA composites. This provides a research basis for the further improvement of the performance of plant fiber/PLA composites.

Construct of CoZnO/CSP biomass-derived carbon composites with broad effective absorption bandwidth of 7.2 GHz and excellent microwave absorption performance.

Biomass-carbon materials have excellent electromagnetic wave attenuation properties, which is one of the essential factors for developing ultra-thin matched-thickness, and high-performance microwave absorption materials. This study reports a two-step procedure consisting of carbonization and subsequent in-situ growth for preparing a wrinkle-like multilayer biomass-derived composites with magnetic Co particles and ZnO particles (CoZnO/C-X). The synergistic effect of a wrinkle-like multilayer structure and Co and ZnO particles, as well as the existence of many heterogeneous interfaces in the composites structure, and efficiently creates multiple scattering and reflections, which gives the composites the strong microwave absorption properties. The minimum reflection loss value (RLmin) of CoZnO/C-X reaches - 54.90 dB with a thickness of 1.8 mm, and the effective absorption bandwidth (lower than - 10 dB) is 7.2 GHz covering from 10.8 GHz to18.0 GHz with matching thickness of 2.0 mm. Furthermore, the reasonable dielectric/magnetic losses, optimized impedance matching and enhanced polarization loss play an indispensable role among improving microwave absorption performance. Thus, this result provides a good potential method for preparation of magnetic particle/metal oxide/biomass-derived carbon microwave absorbing structural materials.

Self-assembly of porous cellulose fibers and the incorporation of graphene carbon quantum dots for stable luminescence.

Porous fibers as excellent carriers can be used to prepare photoluminescence materials. Herein, cellulose nanocrystals (CNCs) were derived from microcrystalline cellulose (MCC) by sulfuric acid hydrolysis. After CNCs were squeezed into a coagulating bath containing silicon precursors obtained by the hydrolysis of tetraethyl orthosilicate, porous cellulose fibers were constructed through self-assembly and then incorporated with graphene carbon quantum dots (GQDs) to prepare porous photoluminescence cellulose fibers. The silicon precursor amount, self-assembly time, and corrosion time were optimized. In addition, the morphology, structure and optical properties of the products were investigated. These results showed that as-prepared porous cellulose fibers with mesopores presented loose and porous mesh. Interestingly, the porous photoluminescence cellulose fibers exhibited blue fluorescence, and the maximum emission peak appeared at 430 nm under the excitation wavelength of 350 nm. Furthermore, the relative fluorescence intensity of the porous photoluminescence cellulose fibers was significantly enhanced compared with nonporous photoluminescence cellulose fibers. This work provided a new method to prepare environmentally and stably photoluminescence fibers, which had potential applications in anti-counterfeit packaging and smart packaging.