Polyquaternium-6 (PQ6) as the water-soluble polymer was used for complexing the anion forms of tungsten (Ⅵ) before ultrafiltration. Tungsten (Ⅵ)-PQ6 complex was retained by polysulfone hollow fiber ultrafiltration m...Polyquaternium-6 (PQ6) as the water-soluble polymer was used for complexing the anion forms of tungsten (Ⅵ) before ultrafiltration. Tungsten (Ⅵ)-PQ6 complex was retained by polysulfone hollow fiber ultrafiltration membrane in the complexation-ultrafiltration process. Effects of various operating parameters such as polymer metal ratio(PMR), pH and chloride ion concentration on permeate flux (J) and tungsten rejection coefficient (R) were investigated. The integration of four experiments including concentration, decomplexation, diafiltration and reuse of regenerated polymer was carried out. In the process of concentration, J declines slowly and R is about 1 at PMR of 3 and pH of 7. Tungsten concentration in the retentate increases linearly with volume concentration factor. Tungsten is concentrated efficiently with the membrane. The concentrated retentate was used further for the decomplexation. It takes about 6 min to reach the decomplexation equilibrium at chloride ion concentration of 50 mg·L-1 . The decomplexation percentage of tungsten (Ⅵ)-PQ6 complex reaches 56.1%. In the diafiltration process, tungsten (Ⅵ) can be extracted effectively by using 50 mg·L-1 chloride ion solution, and the purification of the regenerated PQ6 is acceptably satisfactory. The regenerated PQ6 was used to bind tungsten (Ⅵ) at various pH values. The binding capacity of the regenerated PQ6 is close to that of fresh PQ6, and the recovery percentage of binding capacity is higher than 90%.展开更多
Long-term air contamination and pollution challenges in particulate matter(PM) have raised fervent concerns for public health, e.g., the PM physical damage or the bacteria and virus carried by the PM. The desired air ...Long-term air contamination and pollution challenges in particulate matter(PM) have raised fervent concerns for public health, e.g., the PM physical damage or the bacteria and virus carried by the PM. The desired air filter, seeking both high filtration efficiency and low pressure drop remains challenging. Here, we report a bio-inspired spindle-knot halloysite nanotube microsphere-incorporated nanofiber(HNM-NF) filter with the assembly and shape structures of the spider silk. The resulting HNM-NFs exhibit integrated properties of high surface energy, hydrophilicity and strong PM capture. The spindle-knot structures could shrink the outer pore size on two-dimensional(2 D) surface and construct the fluffy 3 D reticular architecture, facilitating high-efficiency air pollutant capture(>85.0%) while maintaining low resistance to airflow(~39 Pa). The spindle-knot construction method was applicable to various materials(i.e.,Al_(2)O_(3), ZnO and TiO_(2)) and volume production of the microsphere-incorporated NF cartridge. The diversified spindleknot construction will be valuable for adapting to meet different filtration requirements.展开更多
基金Supported by the National Natural Science Foundation of China (20976040)Science and Technology Planning Project of Hunan Province of China (2009SK3036)
文摘Polyquaternium-6 (PQ6) as the water-soluble polymer was used for complexing the anion forms of tungsten (Ⅵ) before ultrafiltration. Tungsten (Ⅵ)-PQ6 complex was retained by polysulfone hollow fiber ultrafiltration membrane in the complexation-ultrafiltration process. Effects of various operating parameters such as polymer metal ratio(PMR), pH and chloride ion concentration on permeate flux (J) and tungsten rejection coefficient (R) were investigated. The integration of four experiments including concentration, decomplexation, diafiltration and reuse of regenerated polymer was carried out. In the process of concentration, J declines slowly and R is about 1 at PMR of 3 and pH of 7. Tungsten concentration in the retentate increases linearly with volume concentration factor. Tungsten is concentrated efficiently with the membrane. The concentrated retentate was used further for the decomplexation. It takes about 6 min to reach the decomplexation equilibrium at chloride ion concentration of 50 mg·L-1 . The decomplexation percentage of tungsten (Ⅵ)-PQ6 complex reaches 56.1%. In the diafiltration process, tungsten (Ⅵ) can be extracted effectively by using 50 mg·L-1 chloride ion solution, and the purification of the regenerated PQ6 is acceptably satisfactory. The regenerated PQ6 was used to bind tungsten (Ⅵ) at various pH values. The binding capacity of the regenerated PQ6 is close to that of fresh PQ6, and the recovery percentage of binding capacity is higher than 90%.
基金supported by the National Natural Science Foundation of China (21878341,51804343,41572036 and 51225403)the Natural Science Foundation of Hunan Province(2018JJ3670)the Key R&D Program of Hunan Province(2017GK2251)。
文摘Long-term air contamination and pollution challenges in particulate matter(PM) have raised fervent concerns for public health, e.g., the PM physical damage or the bacteria and virus carried by the PM. The desired air filter, seeking both high filtration efficiency and low pressure drop remains challenging. Here, we report a bio-inspired spindle-knot halloysite nanotube microsphere-incorporated nanofiber(HNM-NF) filter with the assembly and shape structures of the spider silk. The resulting HNM-NFs exhibit integrated properties of high surface energy, hydrophilicity and strong PM capture. The spindle-knot structures could shrink the outer pore size on two-dimensional(2 D) surface and construct the fluffy 3 D reticular architecture, facilitating high-efficiency air pollutant capture(>85.0%) while maintaining low resistance to airflow(~39 Pa). The spindle-knot construction method was applicable to various materials(i.e.,Al_(2)O_(3), ZnO and TiO_(2)) and volume production of the microsphere-incorporated NF cartridge. The diversified spindleknot construction will be valuable for adapting to meet different filtration requirements.
