2003 Volume 36 Issue 4 Pages 506-510
The removal of harmful organic materials in water has been carried out using the adsorption and desorption characteristics of a temperature-sensitive polymer gel which is synthesized from polyvinylalcohol (PVA). Two types of polymerization degrees (1700 and 2500) of PVA were used in this experiment. The gel volume in water was induced at around 310 K for 1700 and 320 K for 2500. At higher temperatures, the temperature sensitive polymer gel shrinks because of discharging water, whereas, in contrast, at lower temperatures, the gel swells as a result of absorbing water. The reversibility of the volume change of the synthesized polymer gel is confirmed by changing temperature.
The adsorption behavior of organic compounds onto PVA polymer gels in water was investigated at various temperatures. The amount of adsorption of organic compounds increases remarkably at temperatures higher than about 310 K for 1700 and 320 K for 2500. The organic compound in water could be adsorbed and desorbed reversibly onto PVA polymer gel by the temperature swing. The mechanism of adsorption and desorption of organic compounds onto gel can be explained by the hydration and dehydration of the polymer gel. The driving force of the adsorption is thought to be the hydrophobic interaction between PVA polymer gel and organic compounds.
