Fabrication of Multifunctional Cotton Fabrics with Antibacterial, Hydrophobic, and Dyeing Performance.

Cotton fibers have received considerable attention owing to their functional properties. Current research endeavors have shifted toward devising straightforward and versatile approaches for modifying cotton fibers. Herein, a simple and feasible method was proposed for preparing multifunctional cotton fibers. This method entailed subjecting cotton fibers to alkaline conditions, prompting the epoxy group in epoxidized soybean oil to engage in a ring-opening reaction with the hydroxyl group in cotton fibers and the amino group in polyhexamethylene guanidine hydrochloride. Epoxidized soybean oil acted as a bridge, forming a covalent bond between polyhexamethylene guanidine hydrochloride and cotton fibers, thereby facilitating the cationization of cotton fibers. Structural changes in the modified cotton fibers were characterized using Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and energy-dispersive X-ray spectroscopy. The modified cotton fibers were also evaluated for their dyeing, antibacterial, and hydrophobic properties. The results demonstrated that the dye exhaustion and total dye utilization of modified cotton in salt-free dyeing were much higher than those of raw cotton in conventional dyeing. The water contact angle of the modified cotton fiber reached 139.5°, and their antibacterial properties were partially improved. Importantly, this chemical modification was performed under mild conditions, highlighting its simplicity and environmentally friendly nature.

Atomic layer deposition of Pt nanoparticles onto Co/MoN nanoarrays for improved electrochemical detection of H2O2.

The design and preparation of advanced nanocatalysts for the sensitive electrochemical detection of H2O2 is of great significance. Herein, a facile Pt@Co/MoN sensing platform was fabricated by depositing Pt nanoparticles onto Co/MoN nanoarrays using atomic layer deposition (ALD) technology. Benefitting from the unique nanostructure and the strong interaction between Pt and the nitride support, the prepared Pt@Co/MoN exhibited excellent performance in the electrochemical detection of H2O2. This work provides an interesting strategy to fabricate low-Pt electrocatalysts on a nanoarray support for future applications in electroanalysis.

Investigation on dyeing mechanism of modified cotton fiber.

Cotton fabrics have been chemically modified with two cationic compounds. They were 3-chloro-2-hydroxypropyltrimethylammonium chloride and the copolymer of dimethyl diallyl ammonium chloride and allyl glycidyl ether, respectively. Under the conditions of no inorganic salt, two modified cotton fabrics were dyed with reactive dyes. The dyeing mechanism of two modified cotton fabrics was investigated in comparison with traditional dyeing of untreated cotton fabrics. It involved the adsorption type, adsorption thermodynamics, and adsorption kinetics between reactive dyes and modified cotton fabrics in the dyeing process. The color-fixing process of modified cotton fibers was also studied in detail. The results showed that there were obvious distinctions between the salt-free dyeing mechanism of modified cotton fabrics and traditional dyeing of untreated cotton fabrics. The adsorption isotherm model of the two modified cotton fabrics conformed to the Langmuir-model. The kinetic model of two modified cotton fabrics conformed to the pseudo-second-order kinetic model. The adsorption of modified cotton fabrics was an endothermic process. The adsorption of unmodified cotton fabrics was an exothermic process. These will serve as a theoretical basis of the industrial production of salt-free dyeing of modified cotton fiber.

Enhancement of desulfurization by hydroxyl ammonium ionic liquid supported on active carbon.

Power plants emit sulfur dioxide (SO2) during combustion, which is typically removed via wet flue gas desulfurization, but this process produces numerous secondary pollutants. Ionic liquids (ILs) can potentially be used to remove SO2, but they suffer from poor mass transfer rates. Hydroxyl ammonium ILs are classical cheap ILs that contain electron-rich O and N sites that favor high absorption capacities. To accelerate mass transfer, two hydroxyl ammonium ILs, triethanolamine citrate and triethanolamine lactate, were immobilized on activated carbon (SILs) and used to capture SO2 from simulated flue gas. They exhibited excellent adsorption at low SO2 partial pressures due to the presence of a large gas-liquid interface. The molar adsorption ratios reached 7.65 and 2.40 mol/mol at 10 kPa SO2. The SILs possessed good SO2 selectivity in SO2/CO2 and SO2/O2 mixtures, because of the only 8% reduction in the total adsorption of SILs at 60 °C. And they exhibited excellent reversibility in which their total adsorption capacities were unaffected after 5 adsorption-desorption cycles. The mechanism analysis revealed that chemical adsorption was the major adsorption route, although physical adsorption also occurred. The main reactive sites included C-O and N-H groups in the ionic liquid. These SILs may potentially replace traditional chemical absorption materials for the separation of SO2 from flue gas.

MOF-Derived Fe-Doped Ni@NC Hierarchical Hollow Microspheres as an Efficient Electrocatalyst for Alkaline Oxygen Evolution Reaction.

The development of low-cost and efficient electrocatalysts for oxygen evolution reaction (OER) is of great importance for producing hydrogen via water splitting. Metal-organic frameworks (MOFs) provide an opportunity for the facile preparation of high-efficiency OER electrocatalysts. In this work, we prepared iron-doped nickel nanoparticles encapsulated in nitrogen-doped carbon microspheres (Fe-Ni@NC) with a unique hierarchical porous structure by directly pyrolyzing the MOF precursor for effectively boosting OER. The Fe doping has a significant enhancement effect on the catalytic performance. The optimized Fe (5%)-Ni@NC catalyst represents a remarkable activity with an overpotential of 257 mV at 10 mA cm-2 and superior stability toward OER in 1.0 M KOH.

Mechanistic Influence of Chemical Agglomeration Agents on Removal of Inhalable Particles from Coal Combustion.

Particle pollution has been a research topic attracting the attention of the researchers around the world because inhalable particles are hazardous to humans and the environment. The major resource of particle pollution is the combustion of coal and biomass. Dust collectors, electrostatic precipitators, and bag filters are required to remove particles from flue. Because of the large specific surface areas of inhalable particles, they easily agglomerate to form larger aggregates; therefore, improving the capture efficiency of dust collectors is of importance. Herein, chemical agglomeration agents were sprayed into a turbulent agglomeration chamber to improve the removal efficiency of inhalable particles. The results showed that the total removal efficiency of inhalable particles was 59.2% for the three-composition agglomeration agents of kappa carrageenans/Tween-80/NH4Cl (KC/TW/NH4Cl). The mean particle diameter increased from 2.8 µm before agglomeration to above 10.0 µm after agglomeration. In the agglomeration process, nonionic TW accelerates the wetting properties, in which the polymer, KC, or anion polyacrylamide, promotes prolongation of the contact time between droplets and particles. Two different removal mechanisms are proposed to explain the effect of chemical agglomeration agents. Immersion agglomeration described the agglomeration process of only fine particles, and distribution agglomeration supported the capture of large particles for fine ones in polydispersed aerosols.

Chemical Modification of Cotton Fabrics by a Bifunctional Cationic Polymer for Salt-Free Reactive Dyeing.

Cotton modification exhibited great potential in the fabric dyeing industry. A bifunctional cationic polymer with a moderate cationic degree and low molecular weight was achieved via free radical polymerization between dimethyl diallyl ammonium chloride and allyl glycidyl ether. Then, it was further utilized for the modification of cotton fabrics. The formation of the cationic polymer was identified using Fourier transform infrared and nuclear magnetic resonance spectroscopies. The structure and properties of both treated and untreated cotton were analyzed by X-ray photoelectron spectroscopy and scanning electron microscopy. The modified cotton fabrics could be salt-free dyed with reactive dyes at low temperatures. While obtaining satisfactory color fastness and leveling properties, the dyeability of the modified cotton was improved significantly compared with the conventional dyeing of native cotton. Besides, the prepared cationic polymer has good flocculating properties to avoid secondary pollution, suggesting high potential for achieving an economical and eco-friendly dyeing process.

[Rapid Synthesis of Metal Organic Framework and Its Adsorption Properties on Anonic Dyes].

The waste water containing dyes is difficult to be biochemically treated because of its deep color. Adsorption becomes an important treatment method for this kind of waste water. The iron organic framework was rapidly synthesized at room temperature, and characterized by IR and XRD. Adsorption properties of the materials were tested using four anonic dyes solutions. It was found that the iron organic framework could be formed rapidly, with higher surface area and pore volumes. The pH value of zero point charge was 3.7. The adsorption experiments showed that the iron organic material could remove more dyes in acid solution. The dye adsorption capacity increased with increasing dye concentration. These adsorption data fitted well with Langmuir thermoadsorption equation. The calculated parameter from Langmuir adsorption indicated that the adsorption process could be performed easily. The second order kinetic equation could describe the adsorption data. In addition, the structure of dyes could affect the adsorption process. The metal complex dyes could be quickly removed.

[Adsorption kinetic mechanism of ionic soluble dye mixture on fly ash].

The fly ash from coal combustion was used as adsorbent for the removal of binary mixtures of dyes from aqueous solution. The binary solution included reactive red 23 and one of reactive blue 4, reactive yellow 4, acid black 1 and acid blue 193. The experimental findings show the removal efficiency of reactive red 23 is about 60% -70% while the removal of acid dyes exceeds 90%. The removal value of reactive blue 4 is about 85%, while the value is only 50% for reactive yellow 4. The adsorption kinetic data are good fitted with the pseudo-second-order kinetic model. The external diffusion coefficient solution is in the order of 10(-4) cm x s(-1), while the intraparticle diffusion coefficient is in the order of 10(-8) cm2 x s(1). Because all B(N) numbers are smaller than 100, adsorption of dyes on fly ash is mainly controlled by the external diffusion mechanism.

Chemical modification of cotton fabrics for improving utilization of reactive dyes.

The cotton fabric was chemically modified with the acrylamide through Michael addition reaction and Hoffman degradation reaction. And the optimum chemical modification conditions were determined. The molecular structure of the modified cotton fabric was identified by Fourier transform infrared spectroscopy (FTIR). The structures of both the raw and modified cotton fabrics were investigated by X-ray diffraction and scanning electronic microscopy. The raw and modified cotton fabrics were dyed using commercial reactive dyes with vinyl-sulfone groups. The results showed that the total dye utilization of modified cotton fabrics in the salt-free dyeing was higher than that of raw cotton fabrics in the conventional dyeing. And the color fastness properties and tear strength of modified fabrics were both satisfactory.

Adsorption of anionic dyes from aqueous solution on fly ash.

The adsorption behavior of two reactive dyes (Reactive Red 23 and Reactive Blue 171) and two acid dyes (Acid Black 1 and Acid Blue193) from aqueous solution on fly ash was investigated in order to identify the ability of this waste-material to remove colored textile dyes from wastewater. For this purpose a series of batch tests were carried out as a function of solution pH value, contact time, dye concentration and adsorption temperature. The experimental findings showed that the removal of four dyes on fly ash was a pH-dependent process with the maximum adsorption capacity at the initial solution pH of 7.5-8.5 for reactive dyes and 5-6 for acid dyes. Adsorption equilibriums of each anionic dye on fly ash could be reached within 60 min at respective optimum pH at 293 K. An increase in the initial dye concentration enhanced the adsorption capacity, but failed to increase the dye removal efficiency. The adsorption capacity for Reactive Red 23, Reactive Blue 171, Acid Blue193 and Acid Black 1 was found to be 2.102, 1.860, 10.937 and 10.331 mg g(-1), respectively. Kinetic studies of four dyes followed the pseudo-second-order modal. Freundlich isotherm described the equilibrium data of acid dyes on fly ash better than Langmuir isotherm, but Langmuir isotherm showed better fit to the equilibrium data of reactive dyes. Different thermodynamic parameters such as the free energy, enthalpy and entropy of adsorption of the dye-fly ash systems were evaluated and it was found that the reaction was spontaneous and endothermic in nature.

Investigation into dyeing acceleration efficiency of ultrasound energy.

The acceleration efficiency of ultrasound was investigated by different application of ultrasound during dyeing process in an ultrasound cleaner. Actual energy dissipated into the dyeing bath was measured to ensure the formation of ultrasound cavatiation. The experimental findings showed ultrasound pretreatment could improve slightly the dye exhaustion and fixation, but failed to improve fastness of dyed fabrics. Obvious enhancement effects on dye exhaustion and fixation were achieved in continuous and intermittent ultrasound dyeing processes, and slight improvement effects on some fastness properties of fabrics dyed in ultrasound fields were observed. A comparison of the efficiencies in two ultrasound dyeing processes revealed the dyeing process in intermittent ultrasound field would benefit to making full use of ultrasound energy.