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With the utilization of used newspaper into the paper making industry, bleaching has been an area of concern to obtain a balance between desired brightness and the amount of treatment it requires. Motivation of this study was to optimize bleaching of recycled newsprint fibers in terms of five variables namely hydrogen peroxide charge, amount of sodium hydroxide employed, pulp consistency, bleaching temperature, and bleaching time. Experimental work was conducted in the laboratory to simulate bleaching plant and it was found that higher peroxide charge is better for improvement in brightness, but it is uneconomical to increase peroxide charge indefinitely. The amount of hydrogen peroxide is added so that the residual peroxide at the end of the reaction is not less than 10% of the initially added peroxide. Sodium hydroxide provides alkalinity which is very important for making the fibers flexible and softening of ink particles but it also contributes to pulp yellowing if residual hydrogen peroxide contents are lesser than the minimum required value. So, for 16 kg t−1 of hydrogen peroxide, 6 kg t−1 of sodium hydroxide prevented the brightness reversion in this study. Higher pulp consistency is better but unavailability of very high consistency pulp mixer in the industry is a limiting factor for higher than 30% pulp consistency. Temperature and time are quite interrelated and, with the given bleaching conditions, a temperature of 95 °C with 10 min residence time was found to be optimum for this study. It was also observed that multiple pre-washings increase brightness and save bleaching chemicals.

Using conductive interlayers to act as the "upper current collector" is a common strategy to suppress the shuttle effect in lithium-sulfur batteries. However, the current widely used interlayers generally have the disadvantages of poor conductivity and complicated fabrication. Herein, we report a novel carbon paper prepared by simple wet laid method. The as-prepared carbon paper exhibits excellent conductivity of 11.9 S/cm and 3D conductive structure. Finally, the carbon paper as an interlayer for lithium-sulfur batteries displays an initial capacity of 1091 mAh g-1 at C/5 rate, and remains 631 mAh g-1 after 200 cycles with a decay rate of 0.21% per cycle.

The authors of the title paper (Mater. Res. Express 6 (2019) 116213) claim to have grown a nickel boro phthalate (NBP) crystal by the slow evaporation method. A critical analysis of the paper reveals that the so-called NBP is an improperly characterized material. A reinvestigation of the crystal growth reaction has been performed to unambiguously characterize the product. In this letter to the Editor, it is proved that nickel boro phthalate neither contains nickel nor phthalate but is, in fact, boric acid.

Low concentration of biomarkers (proteins, nucleic acids, metabolites) is a major concern in early disease diagnosis due to the very low concentration of these biomarkers at the early stage of any disease. This challenge can be addressed by preconcentrating the biomarkers to improve the sensitivity of the diagnostic device. This paper describes a novel method to preconcentrate the charged molecules on paper using greenly synthesized iron nanoparticles. The iron nanoparticles were synthesized by utilizing plant extract as stabilizing agent, which both minimizes the cost and protects the environment. Three different samples of the nanoparticles were prepared by changing the charge or attaching a functional group (amine) to the surface. The iron nanoparticles act as a charged nanoporous membrane when deposited on the paper pads inducing electrostatic forces around the membrane leading to the concentration of the charged analytes near the boundary of the membrane. Crystal violet was used as a surrogate for the charged biomolecule. We report ∼24-fold increase in the concentration of crystal violet dye within 120 seconds using the positively charged membrane and the 0.2 mM dye solution. The developed experimental set-up eliminates the need for external pumping device and complex fabrication processes making the proposed method cost-effective, environment-friendly, and simple to use.

Sodium hyaluronate (HA) stabilized curcumin-Ag (Cur-Ag) hybrid nanoparticles were prepared in the water–ethanol mixture under constant mechanical stirring condition. The obtained HA stabilized Cur-Ag hybrid nanoparticles were characterized by fourier transform infrared spectroscopy, UV–visible spectroscopy, and x-ray diffraction to confirm the formation and structural interactions. The obtained Cur-Ag hybrid nanoparticles showed spherical shape with their size range 5–12 nm that was increased with the increasing a amount of silver ions as confirmed by transmission electron microscopic analysis. Further, a fibrous cellulose filter paper was impregnated with these hybrid nanoparticles and chitosan (CS) as biopolymer via polyelectrolyte complexation. The morphological analysis confirmed the uniform distribution of hybrid nanoparticle system onto the cellulose fibers of the fibrous filter paper. As per disc diffusion method, the Cur-Ag hybrid nanoparticles impregnated CS-coated filter paper exhibited excellent antibacterial properties against gram-negative Escherichia coli (E.coli) bacteria compared to HA stabilized Cur only. Moreover, as prepared hybrid nanoparticles impregnated biocomposite system is eco-friendly with efficient antibacterial property and have good potential to be used in medical applications.

In this paper, a simple method for preparing high stability superhydrophobic paper with pH-induced wettability transition was proposed. Firstly, the pH-responsive monomer 2- (dimethylamino) ethyl methacrylate (DMAEMA), the silicon-containing crosslinking monomer 3-trimethoxysilyl propyl methacrylate (TSPM) and the fluorine-containing monomer hexafluorobutyl methacrylate (HFMA) were polymerized to prepare the pH-responsive polymer PHFMA-PTSPM-PDMAEMA. Afterwards, the amino-modified SiO2 was grafted onto the polymer to provide roughness and then coated on the paper to prepare the superhydrophobic paper with pH-responsive properties. Further research found that the modified paper prepared by this method not only has strong stability and transparency, but also can realize the reversible regulation of superhydrophobic & lipophilic and super-oleophobic & hydrophilic properties under different pH-induction, and it has important application value in the field of oil-water separation in industrial applications.

Paper is a fascinating material for electronic platform devices due to being an inexpensive and environment friendly material. Terahertz wave is able to penetrate paper, thus paper-based terahertz metamaterial will be great terahertz devices. Creating multiple symmetrical Split Ring Resonator (SRR) on upper side paper and depositing metallic plane on back side paper yield terahertz metamaterial absorber. The maximum of absorbance peak for numerical and analytical results are 98% at 0.92 THz and 99% at 0.92 THz, respectively. The superposition of multiple reflections of terahertz wave generated on paper and yielding destructive interference phenomenon. Numerical and analytical works have been carried out in this works and showed good agreement.

Present work reports the green synthesis of highly stable, non-toxic, environmental friendly, fluorescent carbon quantum dots (CQD) via simple synthetic route using the waste carbon paper as their precursor. The as-synthesized CQD were post-synthetically modified with (3-Aminopropyl)triethoxysilane (APTES) as a nitrogen source for amine functionalized CQD (NCQD) formation. When excited at wavelength λex = 350 nm, the maximum emission intensity of NCQD was observed at wavelength λem = 450 nm. The QDs show blue colored luminescence with significant photoluminescence quantum yield (~5.1%). Transmission electron microscopy and Energy-dispersive x-ray spectroscopy data show their size about 4.8 nm and the presence of nitrogen in elemental composition respectively. XRD and selected area electron diffraction patterns reveal their amorphous nature. This NCQD based sensing probe selectivity displays the high sensitivity for trinitrotoluene (TNT) in 4.4 nM to the 26.4 μM range. The probe delivers a 7.4ppb detection limit at 1.3% relative standard deviation.

This paper presents a novel boron diffusion process using boron paper as the boron source to form a p+ layer. It was found that sheet resistance was invariable with changing the distance between boron paper and Si wafers, and diffusion uniformity was the best at a distance of 0.3 cm. Sheet resistance (Rs) decreased with increasing diffusion temperature, showing a value of 6.9 ?/ at 1050 ?C with a high diffusion uniformity of 99.173%. The junction depth increased from 195 nm to 517 nm with diffusion temperature raised from 900 ?C to 1050 ?C. The influence of diffusion time on the performance of B diffusion from boron paper was similar with that of temperature.

Porous conducting carbon fiber paper (PCCFP) is one of the vital component of the gas diffusion layer (GDL) in a fuel cell. This PCCFP serves as the most suitable substrate for the GDL due to its electrical conductivity, mechanical properties, and porosity. In this approach, carbon fiber composite papers were developed by incorporating different fractions of natural graphite (NG) in the matrix phase, i.e. Phenolic resin, and using the combined process of paper making and carbon–carbon composite formation technique. These prepared samples were then heat treated at 1800 °C in an inert atmosphere. The effect of natural graphite incorporation was ascertained by characterizing porous carbon paper by various techniques i.e. X-ray diffraction, Raman spectroscopy, Scanning electron microscopy, electrical and mechanical properties, and I–V performance in a unit fuel cell assembly. The inclusion of NG certainly enhance the properties of the carbon matrix as well as improving the conductive path of carbon fibers. In this study addition of 1 wt.% of natural graphite demonstrated a significant improvement in the electrical conductivity and performance of PCCFP and resulted in the improvement of power density from 361–563 mW cm−2. This paper reports that the uniform dispersion of NG was able to generate a maximum number of macrosize pores in the carbon paper that strengthened the flexural modulus from 4 to 12 GPa without compromising the porosity required for the GDL.

Recycled cellulosic paperboards may include mineral oils after the recycle process, which together with their poor water resistance limit their use as food packaging materials. In this work, we demonstrate that a proper functionalization of the recycled paper with two successive polymer treatments, imposes a mineral oil migration barrier and simultaneously renders it waterproof and grease resistant, making it an ideal material for food contact. The first poly (methyl methacrylate) treatment penetrates the paper network and creates a protective layer around every fiber, permitting thus the transformation of the paperboard to a hydrophobic material throughout its thickness, reducing at the same time the mineral oil migration. Subsequently, the second layer with a cyclic olefin copolymer fills the open pores of the surface, and reduces the mineral oil hydrocarbons migration at levels below those proposed by the BMEL. Online liquid chromatography-gas chromatography coupled with flame ionization detection quantitatively demonstrate that this dual functional treatment prevents the migration of both saturated (mineral oil saturated hydrocarbons) and aromatic hydrocarbon (mineral oil aromatic hydrocarbons) mineral oils from the recycled paperboard to a dry food simulant.

In the present work, a free-standing paper-like sample made of a three-dimensional web of multiwall carbon nanotubes that exhibit cross-linking and wall sharing is characterized with respect to its electrical, electrochemical, surface and wetting properties. All these parameters are studied simultaneously to assess the potential of the sample for demanding applications with multiple material requirements. It is observed that many characteristics of the one-dimensional counterpart are retained by the three-dimensional web. In addition, the properties of this nanostructured material are compared against zero-, one- two- and three-dimensional carbon-based materials, while potential applications that require high electrical conductivity and energy storage capabilities and related properties, are discussed.