Condensed-Phosphate Imprinted Resins Prepared by a Surface Template Polymerization Method

Abstract

The eutrophication of lakes and ponds has been among the environmental problems for the last two decades. Since eutrophication is caused by nitrogen and phosphorus incoming in excess over those concentrations loaded in nature, it is required to suppress the level of nitrogen and phosphorus in wastewater. Removing such elements through biological processes has been studied. 1,2 Nitrogen removal by nitrification 2 has been well investigated, but phosphorus removal does not seem to be simple and facile in view of the variety of conditions which have to be met in practice. 1 In view of this, the removal of phosphorus using an adsorptive resin could be a method of choice. A molecular imprinting or template polymerization method seems to be promising for the preparation of such resins, because the resins are easily prepared and could catch the target molecules (ions) selectively. An elaboration of the technique may even produce resins of highly refined selectivity that could handle trace phosphorus species in water for analytical procedures like collections and pretreatments.An imprinting method is based on the polymerization of functional monomers that surround or molecularly recognize the guest molecule in the presence of matrix-forming monomers. After polymerization, the guest molecule is removed from the resin, and the resultant resin retains the structure complementary to the guest molecule. The polymer matrix memorizes the shape and the chemical properties of "templated" guest; the resin is "imprinted" with the guest molecule. A template polymerization technique was proposed by Wulff 3,4 for the preparation of resins capable of resolving optically active compounds. Templated resins were prepared for polyvalent metal ions 5 and for the drugs. 6 Some such resins have found application to biometrics sensors. 7 In a traditional template polymerization technique, polymerization was carried out in organic solution, preferably in the presence of porogen.On the other hand, we proposed a new imprinting technique, surface imprinting, which was designed to introduce templated sites on the surface of cross-linked, tiny polymer resin particles. Figure 1 shows the concept of surface template polymerization in a schematic manner. An essential process involved is that the functional surfactant monomers (oleylamine) and the target molecules interact with each other on the oil/water interface available in an "oil in water" type emulsion polymerization mixture (2). Then, the "host-guest complex" is immobilized by polymerization of matrix monomers (divinylbenzene) that are present in large excess over the functional surfactant monomers (3). However, a co-surfactant monomer was used to increase the emulsion stability as well as to help make the imprinting effective through cooperation among functional groups of different nature. It is to be noted that although oleylamine or oleyl alcohol contains one double bond, this bond does not effectively take part in ordinary vinyl polymerization. Thus, under our surface imprinting conditions,...

Preparation of Ferrocyanide-Imprinted Pyridine-Carrying Microspheres by Surface Imprinting Polymerization

“…7 The ferrocyanide solutions were prepared by dissolving potassium ferrocyanide just before use. Pure water was obtained from a Ferrocyanide-imprinted pyridine-carrying microspheres were prepared using ferrocyanide ions as a template.…”

“…6,7 The resin (0.100 g) and 0.01 M aqueous potassium chloride solution (10 ml) containing 0.05 mM ferrocyanide ion and appropriate acid and alkaline solutions were mixed in a ∼12 ml plastic tube. The tube was shaken for 12 h at 25˚C, and the pH of the solution was measured.…”

“…2,3 Imprinted polymers have also been applied to sensors 4 and catalysts. 5 We have studied the preparation of inorganic anion-imprinted polymers 6,7 by surface template polymerization technique using oleylamine as a surfactant molecule that served also as an anchoring group for the template molecule to be bound on the surface of the resultant resin. This time, we applied the anionimprinting technique to the surfaces of microspheres.…”

Amino-functionalized Nano-size Composite Materials for Dispersive Solid-Phase Extraction of Phosphate in Water Samples

“…1,2 It is well known that trace amounts of phosphorus in water can lead to eutrophication problems. 3 The phosphate concentration is regulated, and the maximum permissible is limited to 10 μg L -1 to escape eutrophication problems. 4,5 Today, various analytical methods are available for the determination of phosphate, such as spectrophotometry, [6][7][8] ion chromatography, 9,10 electrochemisty 11 and capillary electrophoresis.…”

Preparation of an Organic Acid-imprinted Resin by a Surface Imprinting Method

“…and condensed-phosphate, 9 by using oleylamine. Since this method produces spherical micro-particles, grinding and sieving of the resultant resin are not necessary.…”