Construction of PDA-PEI/ZIF-L@PE tight ultra-filtration (TUF) membranes on porous polyethylene (PE) substrates for efficient dye/salt separation.

Tight ultra-filtration (TUF) membranes were constructed by in situ growing zinc imidazole frameworks micro-crystalline leaves (ZIF-L) in polyethylene imine (PEI) and polydopamine (PDA) deposit layers on porous polyethylene (PE) substrates. The effects of preparation conditions on the surface physical and chemical structures as well as on the dye/salt separation performance of the formed TUF membranes were systematically investigated. By inserting selective water permeation channels and increasing contacting surface areas, in situ-grown ZIF-L arrays tightly cross-linked in the coating matrix greatly increased water permeation without trading off dye/salt retention selectivity. The morphology of the included ZIF-L particles could be varied by adjusting the ligand/Zn molar ratio (α) in the preparation processes. Optimized PDA-PEI/ZIF-L@PE TUF membranes containing ZIF-L of cross-cross block morphology showed very high pure water permeability of 180 ± 20 L·m-2·h-1·bar-1 (LMHB) and retention selectivity (SCR/Na2SO4 and SMB/Na2SO4) of 267 and 43, respectively, as well as excellent stability and anti-fouling properties.

Development of coin-shaped ZIF-7 functionalized superhydrophobic polysulfone composite foams for continuous removal of oily contaminants from water.

Development of efficient absorbent materials for oil spillage clean-up and environmental pollution remediation is highly desired but remains a challenge. In this work, superhydrophobic/superoleophilic polysulfone based ZIF-7 composite (SPZ) foams were fabricated via chemical modification of polysulfone and integrating with hydrophobic coin-shaped ZIF-7 particles. The synergistic approaches provided the SPZ foams with high porosity, low density and superhydrophobic/superoleophilic features (θwater=162.3°, θoil=0°) and outstanding self-cleaning property. The as-prepared SPZ foams exhibited highly selective absorption capacity (up to 3800 wt%) for various kinds of oils and organic solvents. Furthermore, the SPZ foams still maintained 95.2% of its pristine absorption capacity and the θwater remained at 143.6° after ten absorption/distillation cycles. The SPZ foam showed outstanding separation ability towards different types of emulsions with separation efficiency all above 97%. The high oil/water separation efficiency and robust reusability made the SPZ foams promising absorbent in dealing with practical oil spills.

Superhydrophobic three-dimensional porous ethyl cellulose absorbent with micro/nano-scale hierarchical structures for highly efficient removal of oily contaminants from water.

The development of efficient absorbent materials is of global importance for oil spillage cleanup and environmental protection. In this work, a novel superhydrophobic micro/nano-scale hierarchical structured ethyl cellulose sponge was successfully fabricated via an eco-friendly salt-templating method followed by immobilizing silver nanoparticles on the surface and subsequent modification with long-chain alkanethiols. The as-prepared sponge with unique micro-nano structure and porous interconnected network exhibited low density (<17 kg m-3), high porosity (>98%) and robust superhydrophobicity (θwater = 161.3°, θoil = 0°, sliding angle = 3.6°). The sponge could collect a wide range of organic solvents and oils with absorption capacity of 36-48 times of its own weight. Furthermore, the absorption capacity decreased slightly to 89.8% of its initial value after 50 cycles, demonstrating excellent recyclability of the sponge. It was believed that the superhydrophobic/superoleophilic sponge would be a promising absorbent material for the selective oil removal and recovery in environmental remediation.

Superhydrophobic/Superoleophilic and Reinforced Ethyl Cellulose Sponges for Oil/Water Separation: Synergistic Strategies of Cross-linking, Carbon Nanotube Composite, and Nanosilica Modification.

Superhydrophobic/superoleophilic and reinforced ethyl cellulose (SEC) sponges were prepared by cross-linking EC with epichlorohydrin (ECH) and complexing with silanized carbon nanotubes (Si-CNTs) followed by coating nanosilica on the surface of porous sponges and subsequent modification with hexadecyltrimethoxysilane (HDTMS). These synergistic strategies endowed the SEC sponges with the superhydrophobic/superoleophilic properties (θwater = 158.2°, θoil = 0°, sliding angle = 3°) and outstanding mechanical properties (could bear the pressure of 28.6 kPa without damage). The unique micronanostructures and properties of the porous sponges were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and water contact angle measurements. The as prepared SEC sponges with high mechanical strength were able to collect a wide range of oils and organic solvents with absorption capacity up to 64 times of their own weight. Furthermore, the absorption capacity of the sponges decreased slightly to 86.4% of its initial value after 50 separation cycles, suggesting their excellent recyclable performance. The high efficiency and endurability of the sponges during oil/water separation made them ideal absorbent in oil spillage cleanup.

Environmental-friendly and magnetic/silanized ethyl cellulose sponges as effective and recyclable oil-absorption materials.

Ethyl cellulose (EC), owing to its wide availability, environmental-friendliness, and intrinsic hydrophobicity/oleophilicity, was used as an absorbent material for the first time. The superhydrophobic magnetic EC sponges with low density and high porosity were facilely prepared via freeze-drying method. The superhydrophobicity and magnetism of the sponges were achieved by silanization EC with hexadecyltrimethoxysilane and mixing with ferroferric oxide (Fe3O4) nanoparticles. The as-prepared magnetic silanized EC (MSEC) sponges showed stable superhydrophobicity (θwater>150°, rolling contact angle: 7°) in several kinds of solutions. Furthermore, the sponges exhibited high separation efficiency and good mass absorption capacity for a wide variety of oils and organic solvents (37-51 times of their own weight). Benefitting from the robust superhydrophobicity and good self-cleaning property of the sponges, the absorption capacity could be well maintained upon repeated use, demonstrating the superior recyclability. These advantages made the sponges ideal absorbents for oil spillage cleanup.

UV light- and thermo-responsive supramolecular aggregates with tunable morphologies from the inclusion complexation of dendritic/linear polymers.

UV light- and thermo-responsive supramolecular aggregates with tunable morphologies were obtained through the inclusion complexation between a ß-CD containing dendritic host polymer and an azobenzene containing linear guest polymer. Morphologies of the aggregates could be adjusted by changing the molar ratio of host/guest polymers in the supramolecular polymers.

[Ultrafine particle number concentration and size distribution of vehicle exhaust ultrafine particles].

Ultrafine particle (UFP) number concentrations obtained from three different vehicles were measured using fast mobility particle sizer (FMPS) and automobile exhaust gas analyzer. UFP number concentration and size distribution were studied at different idle driving speeds. The results showed that at a low idle speed of 800 rmin-1 , the emission particle number concentration was the lowest and showed a increasing trend with the increase of idle speed. The majority of exhaust particles were in Nuclear mode and Aitken mode. The peak sizes were dominated by 10 nm and 50 nm. Particle number concentration showed a significantly sharp increase during the vehicle acceleration process, and was then kept stable when the speed was stable. In the range of 0. 4 m axial distance from the end of the exhaust pipe, the particle number concentration decayed rapidly after dilution, but it was not obvious in the range of 0. 4-1 m. The number concentration was larger than the background concentration. Concentration of exhaust emissions such as CO, HC and NO showed a reducing trend with the increase of idle speed,which was in contrast to the emission trend of particle number concentration.