Preparation of Lignin-Based Magnetic Adsorbent From Kraft Lignin for Adsorbing the Congo Red

The utilization of lignin from different lignocellulosic biomass is the hot topic for the biorefinery of biomass. In this paper, magnetic lignin nanoparticles (MLN) were prepared by kraft lignin from bamboo residue and Fe3O4 with different ratios via Mannich reaction. The surface morphology and structure of magnetic lignin were characterized and analyzed by X-ray powder diffraction, Fourier transform infrared spectroscopy, and transmission electron microscopy, which confirmed that the MLN were successfully prepared. The performance of MLN adsorbents was evaluated by adsorbing Congo red solution at different initial concentrations and contact times. The results showed that Fe3O4@lignin (1:0.5) had the best adsorption effect on Congo red solution. When the concentration of Congo red reached 0.6 g/L, Fe3O4@lignin (1:0.5) had the best adsorption effect on Congo red, reaching 95.5% in only 30 min. As lignin is modified by Fe3O4, it can be recovered by magnetic substances after adsorption and has good reuse performance. The results of adsorption kinetics and adsorption isotherm showed that except for the adsorption process of Fe3O4@lignin (1:0.5), which is consistent with the chemical adsorption of the multimolecular layer, the adsorption process of other adsorbents is in accordance with the chemical adsorption of the monomolecular layer. In terms of environmental protection and adsorption efficiency, and MLN has become an ideal adsorbent for Congo red dyes due to its simple preparation, superior performance, and convenient recovery.

Features of adsorption processes for wastewater treatment from zinc ions

The results of adsorption properties of complex natural sorbents in relation to the neutralization of zinc ions from wastewater are presented. The adsorption isotherm of Zn2+ ions on complex sorbents (clinoptilolite-shungite) (1:1) according to Langmuir and Freundlich models is constructed, the type of adsorption isotherms according to S. Brunauer classification is established. The value of the maximum sorption capacity of Gmax complex sorbents for Zn2+ ions is calculated. The peculiarities of the sorption process of zinc ions with the formation of a monomolecular layer based on the calculated coefficients of the Langmuir and Freundlich were found. The optimal conditions for the dependence of the degree of absorption of Zn2+ ions by complex sorbents on the duration of the sorption process are determined. The ratio "solid (complex sorbent) - liquid" was determined experimentally.

2D Monomolecular Nanosheets Based on Thiacalixarene Derivatives: Synthesis, Solid State Self-Assembly and Crystal Polymorphism

Synthetic organic 2D materials are attracting careful attention of researchers due to their excellent functionality in various applications, including storage batteries, catalysis, thermoelectricity, advanced electronics, superconductors, optoelectronics, etc. In this work, thiacalix[4]arene derivatives functionalized by geranyl fragments at the lower rim in cone and 1,3-alternate conformations, that are capable of controlled self-assembly in a 2D nanostructures were synthesized. X-ray diffraction analysis showed the formation of 2D monomolecular-layer nanosheets from synthesized thiacalix[4]arenes, the distance between which depends on the stereoisomer used. It was established by DSC, FSC, and PXRD methods that the obtained macrocycles are capable of forming different crystalline polymorphs, moreover dimethyl sulphoxide (DMSO) is contributing to the formation of a more stable polymorph for cone stereoisomer. The obtained crystalline 2D materials based on synthesized thiacalix[4]arenes can find application in material science and medicine for the development of modern pharmaceuticals and new generation materials.

Effect of the hydrochloric acid concentration on the surface-active and functional characteristics of linear alkylbenzenesulfonic acid

The surface-active (surface tension, adsorption, molecule cross-sectional area in the adsorption monomolecular layer) and colloidal (viscosity, critical micelle concentration, solubilization) properties in aqueous and hydrochloric acid solutions of anionic surfactant alkylbenzenesulfonic acid (ABSA) were studied. Surface activity of ABSA increases in the presence of hydrochloric acid. Two inflections were established on adsorption isotherms with inorganic acid content of 5 and 10 wt. %, which are indicative of stepwise micelle formation. The ABSA dissociation is suppressed in the presence of hydrochloric acid, and therefore it behaves as a nonionic surfactant, forming micelles at lower concentrations. Mixed micelles, formed by dissociated and non-dissociated surfactant particles, are organized with an increase of ABSA content in mixture. The value of the surfactant limiting adsorption increases significantly at small hydrochloric acid amounts in comparison with an aqueous solution. The formed monomolecular layer is denser in the presence of inorganic acid than in an aqueous solution. The solubilization of Sudan I dye in alkylbenzenesulfonic acid increases with increasing in solution acidity. The extremum points on isotherms of solubilizing ability with 5 and 10 wt. % HCl content are observed at surfactant concentrations corresponding to the beginning and end of the formation of micelles containing alkylbenzenesulfonate ion.

Approaching optimal hole transport layers by an organic monomolecular strategy for efficient inverted perovskite solar cells

We report a universal monomolecular layer-hole transport layer (ML-HTL) strategy, employing MLs of widely used organic hole transport materials to construct HTLs. A fill factor of 81.86% and champion PCE of 20.58% were achieved with a hydrophobic small molecule ML-HTL.

Surface Enhanced Raman Scattering Study of 1-H-2 (tolylazo) Imidazole (TaiH) Induced by Uncoupled Plasmon of Silver Nano Particles

Raman and SER spectra of 1-H-2 (tolylazo) imidazole (Tai H) are reported for the first time. Monomolecular layer of TaiH is formed on silver nano particles (SNPs) at a concentration of 4.93×10−6 M in Ag-sol. TaiH molecules are adsorbed on to SNPs the through the imidazole N atom and undergo trans-to-cis dark isomerization as evidenced by the appearance of signature cis-peaks and the UV-Vis absorption spectra. Stable non-aggregated SNPs are resulted by the interaction of TaiH and the particle size is significantly reduced. DFT calculations based on single Ag-atom model are in excellent agreement with experimental observations.

First-Principles Study of Structural and Electronic Properties of MoS1.5Se0.5 Alloy

The effects of relative positions of Se atoms in a monomolecular layer of MoS[Formula: see text]Se[Formula: see text] have been studied. It is demonstrated that the distribution of Se atoms between top and bottom chalcogen planes is most energetically favorable. For a more probable distribution of Se atoms this monolayer alloy is a direct semiconductor with the fundamental bandgap of 2.35[Formula: see text]eV. We have also evaluated the optical band gaps of the alloy at 77[Formula: see text]K (1.86[Formula: see text]eV) and room temperature (1.80[Formula: see text]eV), which are in a good agreement with the experimentally measured bandgap of 1.79[Formula: see text]eV.

Graphene-Induced Osteogenic Differentiation Is Mediated by the Integrin/FAK Axis

Graphene is capable of promoting osteogenesis without chemical induction. Nevertheless, the underlying mechanism(s) remain largely unknown. The objectives here were: (i) to assess whether graphene scaffolds are capable of supporting osteogenesis in vivo and; (ii) to ascertain the participation of the integrin/FAK mechanotransduction axis during the osteogenic differentiation induced by graphene. MSC-impregnated graphene scaffolds (n = 6) were implanted into immunocompromised mice (28 days). Alternatively, MSCs were seeded onto PDMS substrates (modulus of elasticity = 130, 830 and 1300 kPa) coated with a single monomolecular layer of graphene and cultured in basal medium (10 days). The ensuing expressions of FAK-p397, integrin, ROCK1, F-actin, Smad p1/5, RUNX2, OCN and OPN were evaluated by Western blot (n = 3). As controls, MSCs were plated onto uncoated PDMS in the presence of mechanotransduction inhibitors (echistatin, Y27632 and DMH1). MSC-impregnated graphene scaffolds exhibited positive immunoexpression of bone-related markers (RUNX2 and OPN) without the assistance of osteogenic inducers. In vitro, regardless of the stiffness of the underlying PDMS substrate, MSCs seeded onto graphene-coated PDMS substrates demonstrated higher expressions of all tested osteogenic and integrin/FAK proteins tested compared to MSCs seeded onto PDMS alone. Hence, graphene promotes osteogenesis via the activation of the mechanosensitive integrin/FAK axis.