Hydrophilic Polyvinylidene fluoride (PVDF) hollow fiber ultrafiltration membranes were prepared by wet-spinning method. The effects of technical parameters of acrylic acid grafted onto PVDF on the performance of hydrophilic PVDF membranes were investigated via orthogonal test, the technical parameters of preparation of hydrophilic PVDF membranes were determined, and hydrophilic PVDF membranes were prepared. Then hydrophilic PVDF membranes were characterized in terms of breaking strength, breaking elongation, rupture pressure, pure water flux and rejection. The fouling properties and the conditions of acrylic acid grafted onto PVDF were also examined. The results showed that acrylic acid had been grafted onto PVDF, the breaking strength and rupture pressure improved greatly, and the fouling properties were better than PS hollow fiber UF membrane.

Hydrophilic polyvinylidene fluoride (PVDF) flat ultrafiltration membranes were prepared by wet-spinning method. The effects of technical parameters of acrylic acid grafted onto PVDF on the performance of hydrophilic PVDF membranes were investigated, the technical parameters of preparation of hydrophilic PVDF membranes were determined, and hydrophilic PVDF flat membranes were prepared. Then, hydrophilic PVDF membranes were characterized in terms of pure water flux, contact angle, infrared spectroscopic analysis and scanning electron microscope (SEM). The results showed that acrylic acid had been grafted onto PVDF, and the hydrophilic performance of the modified membrane was better than the traditional one.

The 2-thiol benzothiazole was blended in Polyvinylidene fluoride (PVDF) membrane to prepare a kind of PVDF modified ultrafiltration membrane that could be used to remove mercury ion in water treatment. The water flux and retention rate of BSA of obtained PVDF modified ultrafiltration membrane was 222 L/m2·h and 92.33% respectively. The membrane performance were characterized by infrared spectroscopy (FT-IR) and water contact angle measurement. The results showed that, the PVDF modified membrane presented better adsorption ability for mercury ion than the traditional PVDF membrane. After 4 phases of adsorption/desorption, the modified membrane maintained a mercury ion adsorption amount of 0.264 mg/cm2and the desorption rate could reached 94%.

In this paper, a novel nanocomposite forward osmosis membrane (nTiO2-CTA/CA) was fabricated by introducing nanotitaniumdi oxide (nTiO2) into the cellulose triacetate/cellulose acetate (CTA/CA)-based casting solution using phase inversion methods. Casting composite and preparation--nTiO2 content, blend temperature and coagulating bath temperature--were tested for their effects on pure water flux and salt rejection of membranes. Results revealed that the FO membrane prepared under optimized composition showed excellent desalination performance (high water flux = 5.38 L/m2·h and salt rejection > 97 %). Moreover, SEM images showed that addition of nTiO2 resulted in nanocomposite forward osmosis membrane with a smoother surface. The contact angle of the membranes decreased from 76o to 51° with increase nTiO2 concentration from 0% to 0.10%.

Boiler is a complicated control object with multi-variable, strong coupling and uncertain time-delay. It is hard to get ideal control effect with normal controller. This paper presents the overview of advanced control techniques in traditional process control of boiler, such as PID multiplex control system, modern control system, intelligent control system, decoupling control system and robust control system. The future of advanced control research and application is also discussed.