Robust and Durable Superhydrophobic Polyurethane Sponge for Oil/Water Separation

With the purpose of purging and recycling oil and organic solvent from a water surface, a superhydrophobic polyurethane (PU) sponge was fabricated through a combined method of interfacial polymerization (IP) and molecular self-assembly. The as-prepared sponge has a superwetting characteristic of superlipophilicity in atmosphere and superhydrophobicity both in atmosphere and under oil, and it can quickly and selectively absorb various kinds of oils up to 29.9 times its own weight. More importantly, because of a covalent combination of the sponge skeleton and the polyamide thin film from IP, the superhydrophobic sponges could be reused for oil/water separation over 500 cycles without losing its superhydrophobicity, showing the highest reusability among the reported absorptive materials. The superhydrophobic sponge also can be used in the continuous absorption and expulsion of oils and organic solvents from water surfaces with the help of a vacuum pump. All of these features make the sponge a promising candidate material for oil-spill cleanups

Robust and Durable Superhydrophobic Polyurethane Sponge for Oil/Water Separation

With the purpose of purging and recycling oil and organic solvent from a water surface, a superhydrophobic polyurethane (PU) sponge was fabricated through a combined method of interfacial polymerization (IP) and molecular self-assembly. The as-prepared sponge has a superwetting characteristic of superlipophilicity in atmosphere and superhydrophobicity both in atmosphere and under oil, and it can quickly and selectively absorb various kinds of oils up to 29.9 times its own weight. More importantly, because of a covalent combination of the sponge skeleton and the polyamide thin film from IP, the superhydrophobic sponges could be reused for oil/water separation over 500 cycles without losing its superhydrophobicity, showing the highest reusability among the reported absorptive materials. The superhydrophobic sponge also can be used in the continuous absorption and expulsion of oils and organic solvents from water surfaces with the help of a vacuum pump. All of these features make the sponge a promising candidate material for oil-spill cleanups

Robust and Durable Superhydrophobic Polyurethane Sponge for Oil/Water Separation

With the purpose of purging and recycling oil and organic solvent from a water surface, a superhydrophobic polyurethane (PU) sponge was fabricated through a combined method of interfacial polymerization (IP) and molecular self-assembly. The as-prepared sponge has a superwetting characteristic of superlipophilicity in atmosphere and superhydrophobicity both in atmosphere and under oil, and it can quickly and selectively absorb various kinds of oils up to 29.9 times its own weight. More importantly, because of a covalent combination of the sponge skeleton and the polyamide thin film from IP, the superhydrophobic sponges could be reused for oil/water separation over 500 cycles without losing its superhydrophobicity, showing the highest reusability among the reported absorptive materials. The superhydrophobic sponge also can be used in the continuous absorption and expulsion of oils and organic solvents from water surfaces with the help of a vacuum pump. All of these features make the sponge a promising candidate material for oil-spill cleanups

Structure Optimization of a Rotating Zigzag Bed via Computational Fluid Dynamics Simulation

3D physical and computational fluid dynamics models have been developed to describe the rotating zigzag bed (RZB). The pressure distribution in a RZB was investigated first. It was found that the simulations agreed well with experiments, so the reliability of the models was proved. The simulations suggest that the pressure drop decreases with the rotating bed thickness (<i>H</i>, the height between the rotating and stationary disks) within certain limits, particularly under a high gas flow rate. Also, the dead zones in the flow field are obviously reduced when we enlarge the rotor in the radial dimension. The optimal rotating bed thickness of 96 mm obtained by the principle of equal area was verified in the simulations. So, the principle can be used in the structural design of a RZB

SO₂ Capture Using pH-Buffered Aqueous Solutions of Protic Triamine-Based Ionic Liquid

In this work, a kind of aqueous solution of novel protic triamine-based ionic liquid was proposed for efficient SO₂ capture. The mixed absorbents were prepared by blending 1,1,4,7,7-pentaethyldiethylene (PEDETA) with sulfuric acid and water, and their physicochemical properties were studied by various methods. Remarkably, the viscosities of the mixed absorbents are in the range of 1.44–1.85 mPa s at 293.2 K, which is as low as water. Detailed SO₂ absorption experiments were carried out to investigate the influence of some important factors, including temperature (298.2, 313.2, and 328.2 K), SO₂ partial pressure (0–1 bar), and sulfuric acid proportion. It is worth noting that the mixed absorbents showed excellent absorption capacity, especially at a low partial pressure. All absorbed SO₂ could be released easily and completely by the method of heating reflux. More importantly, the absorbent could be reused for at least 5 cycles without noticeable changes in both absorption performance and chemical structure. A thermogravimetric analysis further confirmed its good thermal stability. The detailed absorption mechanism was proposed and demonstrated by an infrared spectrum. In the end, the p<i>K</i>_a values and reaction enthalpy of the protonation reaction of PEDETA were determined by acid titration and parameter analysis based on the reaction equilibrium model. In summary, the mixed absorbents, which possess low viscosities, good resistance to sulfuric acid, excellent capacity, and reusability, may have a good perspective in industrial SO₂ capture

Ether-Functionalized Ionic Liquids with Low Viscosity for Efficient SO₂ Capture

Three kinds of ionic liquids (ILs) with ether-functionalized cations and bis­(trifluoromethanesulfonyl)­imide anions were synthesized in our laboratory, and the SO₂ absorption capacities of those three kinds of ILs were measured at temperature from 20 to 50 °C and 1 bar. High capacity of SO₂, excellent reversibility, and high selectivity were achieved by the interaction between the ILs and SO₂. The absorption and desorption processes are very fast, and SO₂ can be removed completely from the ILs. Thermal stability was tested, and the decomposition temperatures of the three kinds of ILs were all higher than 420 °C. NMR investigations and computer simulation studies also show that SO₂ absorption by these ILs is a physical process by forming weak hydrogen bonds between the oxygen atoms in the SO₂ and the hydrogen atoms in the ILs. This work further investigated how the water content affects the solubility of SO₂ in the ILs. These ILs exhibit significant improvements over traditional absorbents and indicate green, efficient, and energy-saving methods for industry applications in SO₂ separation

Hydrodynamics and Mass-Transfer Analysis of a Distillation Ripple Tray by Computational Fluid Dynamics Simulation

A 3D two-phase computational fluid dynamics model in the Eulerian–Eulerian framework was developed to predict the hydrodynamics, mass-transfer behaviors, and tray efficiency of dual-flow trays: ripple trays. Interaction between the two phases occurs via interphase momentum and mass transfer. Mass-transfer coefficients were estimated using the Higbie penetration theory model. The simulated results were compared with the experimental data obtained from distillation of cyclohexane and <i>n</i>-heptane at total reflux. The results show that vapor and liquid flow countercurrently through the tray holes and four main hydrodynamic regimes are distinguished at different vapor/liquid loadings (<i>F</i>_s factor). It was found that the mass transfer of the spray zone above the froth was also significant, especially at lower loadings. In addition, the results indicated that the efficiency of a ripple tray was a strong function of the open hole area and <i>F</i>_s factor

Efficient Demulsification of Diesel-in-Water Emulsions by Different Structural Dendrimer-Based Demulsifiers

A series of amine-based dendrimer polyamidoamine (PAMAM) demulsifiers with different initial cores were synthesized and investigated in the demulsification process of diesel-in-water emulsions. With the aim of systemic evaluation of their demulsification performance, some important factors of the demulsification processes were investigated including demulsifier dosage, settling time, temperature, oil content, and kinds of diesel. The demulsifier with the triethylenetetramine (TETA) initial core provided excellent demulsification performance by removing oil with less dosage and at relatively low temperature in short periods and reached 96.66% demulsification efficiency for catalytic cracking diesel emulsion. The results showed its good application prospects. In order to gain insight into the demulsification process and mechanism, some measurement methods were adopted. Micrograph and droplet size distribution of emulsions illustrated that the PAMAM demulsifier could lead to the breakup of diesel-in-water emulsions by flocculation and coalescence. The surface tension and interfacial tension gave a basic understanding of the demulsification mechanism. Zeta potential indicated that emulsion had been broken up. The conductivity measurement explained the demulsification mechanism from the aspect of the electrostatic interactions of moving droplets. The dendrimer and SDS had strong aggregation interactions in the system according to the results of hydrodynamic radium

A Novel Copper(I)-Based Supported Ionic Liquid Membrane with High Permeability for Ethylene/Ethane Separation

For the separation of an ethylene/ethane mixture, a novel copper­(I)-based supported ionic liquid membrane (SILM) with high permeability has been fabricated. This SILM was prepared from a polyvinylidene fluoride microporous membrane impregnating the copper­(I) based IL which formed by the cuprous chloride (CuCl) and 1-butyl-3-methylimidazolium chloride ([Bmim]­[Cl]). Scanning electron microscopy, attenuated total reflection Fourier transform infrared spectroscopy, and time of flight mass spectroscopy were used to characterize the SILM. Pure and mixed gas permeation experiments were carried out to investigate the influences of ILs composition, trans-membrane pressure, temperature, and time upon the separation performance. This SILM showed comparable C₂H₄ permselectivity but outstanding permeability with a long-term stability beyond the reported polymeric membrane upper bound. At the CuCl/[Bmim]­[Cl] ratio of 2, the C₂H₄ permeability and permselectivity reached 2653 barrer and 11.8, respectively. Furthermore, the facilitated transport effect was studied by ¹H NMR and quantum mechanical calculations. The anionic species formed by sp hybridization of Cu⁺ possesses unfilled attachment sites to selectively complex with C₂H₄ and weaken the interionic hydrogen bond of [Bmim]­[Cl], thus lowering the system’s viscosity

Silver-Based Deep Eutectic Solvents as Separation Media: Supported Liquid Membranes for Facilitated Olefin Transport

Supported liquid membranes (SLMs) have exhibited great potential as interesting materials for the separation of olefin/paraffin mixtures. To further improve the performance of SLMs, novel and sustainable silver-based deep eutectic solvents (DESs) constructed from trifluoromethanesulfonate (AgCF₃SO₃) and acetamide (CH₃CONH₂) were synthesized as membrane liquids for the first time. Their formation mechanism and structure were investigated intensively, confirming that multiple coordination and hydrogen-bonding interactions yielded homogeneous and stable liquids that contained free silver ions and silver-containing cationic complexes as carriers for the facilitated transport of C₂H₄. The as-prepared DES-SLMs were characterized by SEM and ATR-FTIR and their separation performances were investigated by C₂H₄/C₂H₆ separation experiments. The effects of the composition of the silver-based DESs, the operating temperature, and the transmembrane pressure were also investigated systemically. The permeability selectivity, solubility selectivity, and diffusivity selectivity were also quantitatively analyzed. Compared with previously reported results, the as-prepared DES-SLMs exhibited excellent permeabilities of C₂H₄ and comparable selectivities of C₂H₄/C₂H₆, thus exceeding the upper bound. This investigation might provide alternatives for the development of high-performance SLMs for olefin/paraffin separations and insights into the formation mechanism of silver-based DESs for further design and strengthening