Preparation of zeolitic imidazolate framework-67/wool fabric and its adsorption capacity for reactive dyes.

Zeolitic imidazolate framework-67 (ZIF-67) formed by Co2+ and 2-methylimidazole (MIM) is widely used for adsorption and separation of pollutants. However, there are some disadvantages for ZIF-67 powder, such as strong electrostatic interaction and difficulty in recovery from the liquid phase. The available way to solve the above problems is choosing a suitable substrate to load ZIF-67. The amino and hydroxyl of wool fabrics effectively capture and fix ZIF-67, making it easy to separate ZIF-67 by taking out the composite materials from aqueous solution. In this study, ZIF-67/Wool fabric (ZW) was successfully prepared. The results show that ZIF-67 has better adsorption performance for reactive dyes with more sulfonic groups, higher molecular weight and lower steric resistance. The equilibrium adsorption capacity of ZW for reactive red 195 was 4.15 mg g-1. The adsorption accorded with pseudo-second-order kinetic model and Langmuir isotherm. This study improved the application of ZIF-67, which provided a treatment method for dyeing wastewater and made it possible to recycle waste wool.

Synergistic Effects of Alpha Olefin Sulfonate and Sodium Alginate on Inkjet Printing of Cotton/Polyamide Fabrics.

Bicomponent or multicomponent fiber fabrics are important materials for manufacturing high-performance textiles. However, the printing and dyeing of these fabrics are very difficult because the dyeability of different fibers varies greatly. The present study investigated the inkjet printing performance of interwoven fabrics of cotton and polyamide 6. The surfactant alpha olefin sulfonate (AOS) was incorporated into the sodium alginate (SA) solution to pretreat the fabrics to improve the color effects of printed fabrics. The results indicate that fabric pretreatment using 5% alpha olefin sulfonate and 2% sodium alginate significantly enhanced the image colors through increasing the hydrophilicity of the film formed on polyamide fibers and changing the surface morphology of both the fibers. The molecules of AOS interacted with the macromolecules of SA to form the composite films, where the AOS concentration gradient increased outward and SA concentration gradient increased inward. The synergistic pretreatment of alpha olefin sulfonate and sodium alginate endowed the fabrics with high inkjet printing performance, satisfactory color fastnesses, and durability.

Synergy between nanozymes and natural enzymes on the hybrid MoS2 nanosheets/graphite microfiber for enhanced voltammetric determination of hydrogen peroxide.

A biosensor for hydrogen peroxide (H2O2) has been developed based on the use of MoS2 nanosheets and graphite that are assembled to form a microfiber hybrid structure. The MoS2 nanosheets are synthesized in situ on a graphite microfiber. The chemical composition and surface morphology of the microfiber hybrid structure has been characterized. The microfiber is shown to display peroxidase-mimicking activity. In the next step, horseradish peroxidase, methylene blue, and chitosan are co-immobilized on the microfiber electrode. The use of MoS2 nanosheets warrants high electrochemical activity of immobilized enzyme on the electrode surface. The modified microfiber electrode, best operated at a voltage of - 0.3 V (vs. Ag/AgCl), can be used to sense H2O2 with a linear response in the 0.1 to 90 µM concentration range and with a determination limit of 30 nM (at S/N = 3). The good response is attributed to the synergistic enhancement of the synthetic nanozymes (few-layered MoS2 nanosheets) and immobilized natural horseradish peroxidase (HRP). Grapical abstract.

Piezoelectric Polyacrylonitrile Nanofiber Film-Based Dual-Function Self-Powered Flexible Sensor.

To meet the growing demands in flexible and wearable electronics, various sensors have been designed for detecting and monitoring the physical quantity changes. However, most of these sensors can only detect one certain kind of physical quantity based on a single mechanism. In this paper, we have fabricated a multifunctional sensor made from carbonized electrospun polyacrylonitrile/barium titanate (PAN-C/BTO) nanofiber film. It can detect two physical quantities (pressure and curvature), independently and simultaneously, by integrating piezoresistive, piezoelectric, and triboelectric effects. For flex sensing with the impedance change of PAN-C/BTO nanofiber films during bending, it had a sensitivity of 1.12 deg-1 from 58.9° to 120.2° and a working range of 28°-150°. For self-powered force sensing, it had a gauge factor of 1.44 V·N-1 within the range of 0.15-25 N. The sensor had a long stability over 60 000 cycles at both sensing modes. The inclusion of barium titanate nanoparticles (BTO NPs) into the nanofiber film had an over 2.4 times enhancement of sensitivity for pressure sensing because of the synergy of piezoelectric and triboelectric effects. On the basis of multifunction and modularity, a series of potential applications of the sensor were demonstrated, including sensing human's swallowing, walking gaits, finger flexure, and finger-tapping. The self-powered flexible dual-mode sensor has great application potential in human-computer interactive and smart wearable sensing systems.