Yanbin Yun

Effects of amphiphilic additive Pluronic F127 on performance of poly (ether sulfone) ultrafiltration membrane

ABSTRACT The amphiphilic additive Pluronic F127 can effectively improve the hydrophilic character of membranes. This article reported the effects of Pluronic F127 additive, Pluronic F127/oxalic acid, and Pluronic F127/polyethylene glycol 4000 blended additives on morphology, separation properties and hydrophilic of poly (ether sulfone) (PES) ultrafiltration membrane. The membrane was made by liquid/solid phase inversion method. The results showed that the Pluronic F127 can improve the water flux and retention of PES ultrafiltration membrane, increase pore size and porosity, and change the cross-section structure. The flux of PES membrane with F127 was lower than that with oxalic acid at the same concentration. As the concentration of F127 increased, the flux increased, the retention showed undulation, and the hydrophilic improved. Compared with only F127, the flux of the membrane with F127 blended additives slightly increased and the effect of F127 is the major in the blending system, and the blended addi...

Synthesis and Adsorption Performance of Molecularly ImprintedMicrospheres for Quercetin by Suspension Polymerization

The preparation of molecularly imprinted microspheres for quercetin by aqueous suspension polymerization was first presented, in which quercetin is used as template molecule, methacrylic acid as functional monomer and ethylene glycol dimethacrylate as cross-linker. Morphological of the imprinted microspheres for quercetin was characterized by scanning electron microscopy. The imprinting effect of the imprinted microspheres was evaluated, and selectivity analysis suggests that the imprinted microspheres can selectively recognize quercetin from its structure analogues. In addition, adsorption kinetics and adsorption isotherm are used to investigate the binding characteristics of the imprinted microspheres. Results indicate that quercetin can be adsorbed rapidly by the imprinted microspheres, and the maximum theoretical static binding capacity is up to 96.5927 mg g-1.

Purification of Ginkgo biloba flavonoids by UF membrane technology

Abstract In order to enhance the recovery rate and reduce energy consumption, an ultrafiltration process was applied to purify the crude product of Ginkgo biloba extract as an alternative to conventional methods. The effect of membrane type, operation temperature, the transmembrane pressure, feed concentration on the permeate flux profile, solute rejection, and membrane fouling were investigated. By single factor experiments, the results showed that (1) flux increased obviously with enhancing the feed temperature or pressure; (2) flux decreased as the concentration of feed rose or runtime extended; (3) change regularity of the rejection (R) was different to that of the flux; (4) temperature was the most important factor; (5) poly (ether sulfone) membrane (MWCO, 10,000 Da) was better than the other membranes and improved the flavonoids content from 24 to 68%. The membrane fouling was analyzed by scanning electron microscopy and Fourier transform infrared spectroscopy.

Preparation and adsorption performance of molecularly imprinted polymers for Kaempferol

Abstract Molecularly imprinting polymers (MIPs) are a class of highly cross-linked polymer with specific binding sites for a target molecule. In this study MIPs were prepared by precipitation polymerization, using kaempferol as the template molecule, methacrylic acid as the functional monomer, azodiisobutyronitrile as the initiator, and ethylene glycol dimethacrylate as the cross-linker in acetonitrile solvent. The synthesized kaempferol-MIP and nonimprinted polymer (NIP) were analyzed by infrared spectroscopy and scanning electron microscope. In addition, the obtained polymers were evaluated by adsorption isotherms and dynamic curves with their selective recognition properties for kaempferol. The experimental results show that (1) the imprinted polymers are spherical morphology; (2) the adsorption dynamic curves of kaempferol-MIP and NIP indicate that the specific adsorption increases with time extension and reaches saturation in a short period, and the kaempferol-MIP exhibits a higher affinity for kaemp...

Evaluation of ultrafiltration membranes with the multimedia filter/ultrafiltration/reverse osmosis/NH3-N remover system to treat surface water

Abstract This study discussed the feasibility for the multimedia filter/UF/RO/NH3-N remover system to treat river Tang surface water, and three different polysulfone (PSf) membranes with molecular weight cut off of 80, 100, and 300 kDa were tested to select a UF membrane for low membrane fouling, higher flux, low transmembrane pressure and better quality of the permeate. The results showed that the multimedia filter/UF/RO/NH3-N remover combined system was able to remove all unwanted elements and to produce consistent and high-quality water. For the whole experiment, K of RO system basically stabilized at 2.8 L/m2 h·bar. RO system could effectively remove NH3-N and conductivity. Comparing results from three UF membranes experiments, it was found that three UF membranes could remove particles (colloids) and the 100 kDa PSf membrane was the most suitable membrane to treat the river Tang.