Jia-Hui Xu,Xi Yan,Yan Chen,Xiao-Jing Guo,Wan-Zhong Lang
In the daily life of human beings, sewage discharge and oil spill accidents occur from time to time. New types of controllable oil/water separation interface materials have received more attention. In this study, we proposed a simple and environmentally friendly method to prepare a Nickel filter with switchable wettability . The final product is prepared by high temperature calcination and soaked with stearic acid ethanol solution. The prepared filter screen has selective separation performance for oil/water mixture with switchable surface wettability between superhydrophobic and superhydrophilic. The separation efficiency is higher than 99.50%, and the flux rate is as high as 46.25 L m −2 s −1 for water-removing process and 40.22 L m −2 s −1 for oil-removing process. The wettability conversion of the membrane can be achieved through heating treatment and soaking treatment, and it still has good oil/water separation performance. After 20 times of cycles, the separation efficiency remains unchanged, and the flux remain above 40.06 L m −2 s −1 for oil removal and 36.81 L m −2 s −1 for water removal process. The results show that the prepared nickel filter screen has good practical application prospects such as water reclamation and oil spill treatment.
Xinwang Cao,Meiling Huang,Bin Ding,Jianyong Yu,Gang Sun
Conventional ultrafiltration (UF) or nanofiltration (NF) filters for water treatments are based on porous membranes, where the torturous porosity usually results in a relatively low flux rate , typically manufactured by the phase immersion method. Electrospun (ES) nanofibrous membranes with a high flux rate evoked a considerable interest in the ultrafiltration or nanofiltration applications, because of their high porosity, good interconnectivity and high specific surface area. Herein, we developed a novel double layers of polyacrylonitrile (PAN) electrospun nanofibrous membranes (with an average fiber diameter of 173 nm) reinforced with TEMPO (2, 2, 6, 6-tetramethylpiperidine-1-oxyl radical) selectively oxidized jute cellulose nanowhiskers (with a diameter in the range of 3–10 nm). From FE-SEM images, the presence of evenly coated thin layer of cellulose nanowhiskers on the PAN ES nanofibers is evident. The versatile PAN/cellulose ES composite membranes with superior mechanical properties and high filtration efficiency of 7–40 nm particles would be particularly useful for applications in the domestic drinking water and industrial waste water treatment.
Aikifa Raza,Bin Ding,Ghazala Zainab,Mohamed El-Newehy,Salem S. Al-Deyab,Jianyong Yu
Creating a practical and energy-efficient method with high efficacy to separate oil–water mixtures, especially those stabilized by surfactants, has proven to be extremely challenging. To overcome this challenge, a novel and scalable strategy was developed for the synthesis of superhydrophilic and prewetted oleophobic nanofibrous membranes by the facile combination of in situ cross-linked polyethylene glycol diacrylate nanofibers supported on polyacrylonitrile/polyethylene glycol nanofibrous (x-PEGDA@PG NF) membranes. The as-prepared x-PEGDA@PG NF membranes have shown superhydrophilicity with ultralow time of wetting and promising oleophobicity to achieve effective separation for both immiscible oil–water mixtures and oil-in-water microemulsions solely driven by gravity. These new membranes having a good mechanical strength of 14 MPa and mean pore sizes between 1.5 and 2.6 μm have shown a very high flux rate of 10 975 L m−2 h−1 with extremely high separation efficiency (the residual oil content in filtrate is 26 ppm). More importantly, the membranes exhibit high separation capacity, which can separate 10 L of an oil–water mixture continuously without a decline in flux, and excellent antifouling properties for long term use, thus making them important candidates for treating wastewater produced in industry and daily life. Such membranes are also ideal for high viscosity oil purification such as purification of crude oil.