Yongjun Sun,Qu Wu,Xiaoqi Li,Wenquan Sun,Jun Zhou,Kinjal J. Shah
In this work, a composite flocculant (polyferric titanium sulfate–polydimethyldiallylammonium chloride [PFTS–PDMDAAC]) with a rich spatial network structure was prepared for the treatment of simulated wastewater containing polystyrene (PS) micro–nanoparticles. Characterization results showed that the surface of the PFTS–PDMDAAC was a three-dimensional network polymer of chain molecules that exhibited good thermal stability and formed an amorphous polymer containing multiply hydroxyl-bridged titanium and iron. When n(OH − ) : n(Fe) = 1:2, n(PO 4 3− ) : n(Fe) = 0.35, n(Ti) : n(Fe) = 1:8, n(DMDAAC) : n(Fe) = 5:100, and the polymerization temperature is 60°C, the prepared composite flocculant has the best effect. The effects of dosage, pH, and agitation intensity on the flocculation properties of PFTS–PDMDAAC were also studied. The optimal removal rates of PS-μm and haze by PFTS–PDMDAAC were 85.60% and 90.10%, respectively, at a stirring intensity of 200 rpm, a pH of 9.0, and a PFTS–PDMDAAC dosage of 20 mg/L. The flocs produced by the PFTS–PDMDAAC flocculation were large and compact in structure, and the flocculation mechanism was mainly based on adsorption bridging. Kaolin played a promoting role in the process of PS-μm removal by PFTS–PDMDAAC floc and accelerated the formation of large and dense flocs. This study provided a reference for the coagulation method to remove micro–nanopollutants in the actual water treatment process. Practitioner Points A composite flocculant with rich spatial network structure (PFTS–PDMDAAC) was prepared. PFTS–PDMDAAC can effectively remove micro–nano polystyrene (PS) in wastewater. The floc produced by PFTS–PDMDAAC is large and compact in structure. The flocculation mechanism of PFTS–PDMDAAC is mainly adsorption bridging.
There is a demand for composite films with excellent hydrophobic properties in inertial confinement fusion (ICF) physics experiments. In this paper, we prepared fluorinated polyimide hydrophobic films using spinning and plasma etching methods. The experimental results indicate that the water contact angle for the perfluorodecyltrichlorosilane (PFTS) treatment polyimide (PI) film is 112.0 ∘ , which is larger than the pure PI film ( 6 9 . 0 ∘ ) . The rap oil contact angle is 84.2 ∘ , which is also much larger than the contact angle of PI film ( 1 2 . 0 ∘ ) . Moreover, the surface roughness of the prepared films was measured by white light interferometry (WLI). The surface roughness (Ra) of pure PI is 9.79 nm, but with the application of FSiO 2 particles, the Ra of the films increases to 65.05 nm. After plasma treatment, the Ra of the PI/FSiO 2 composite film increases to 186.71 nm because plasma treatment can scratch the film surface and increase its roughness. However, treating the PI/FSiO 2 composite film with the plasma and PFTS, the Ra is only 88.90 nm. This decrease in Ra is due to the PFTS, which is able to reduce the surface roughness. The development of composite films, compared to pure PI films, could prove to be an extremely valuable material in ICF experiments.
Super-wetting fibrous membranes have been widely researched for the separation of oil-water mixtures and light oil-water emulsions. However, reusable oil-water separation membranes for heavy oil with high viscosity and high density have proved to be extremely challenging. Herein, superhydrophobic, flexible, and foldable polyimide (PI) nanofiber membranes for heavy oil separation were prepared by using electrospinning method combined with surface modification to build a stable nano-scale roughness on the fiber surface. The results demonstrated that the fibrous membranes modified by fumed silica and 1H, 1H, 2H, 2H-perfluorooctyl trichlorosilane(PFTS) not only had excellent mechanical robustness, but also achieved both ultra-high oil-water selectivity and separation performance. The as-prepared PI fibrous membranes showed the ultra-high gravity-driven light/oil-water emulsion separation flux of 3904.7 L m −2 h −1 and 22474.7 L m −2 h −1 with and without emulsifier stabilization, and the flux of heavy oil can reached 271.36 L m −2 h −1 under 25KPa. The mechanically robust and reusable PI fibrous membranes with high efficient oil-water emulsion and heavy oil separation performance exhibit great potential for practical applications for oily wastewater and oil spill treatment.
危险品化学品经营许可证（带存储）