A Study Of Adsorption Purification In Ultra High Purity Hydrogen Peroxide Preparation

The ultra high pure hydrogen peroxide is one of the critical chemical materials for wet chemical process in the microelectronic industry. The biggest microelectronic chip market will appear in China in 2010 year, consequently purity and cleanliness of the hydrogen peroxide are critical to yield. Therefore, it is significant to prepare ultra high pure hydrogen peroxide solution to the international criterion via purifying industrial hydrogen peroxide.It is very severe to the demand of product quality when preparing the ultra high pure hydrogen peroxide. Existing technology of purification were limited for strong oxidation-reduction, themo-sensitive, and instability of hydrogen peroxide. Therefore, purification technique of the ultra high pure hydrogen peroxide becomes the one of key technology. Reported in this thesis, is a new technique to prepare the ultra high pure hydrogen peroxide of SEMI-C8 standard. With activeated carbon (AC) as adsorption of organic impurities, purification technique used to remove certain amount of metallic and nonmetallic ions through ion exchange method, and low catalytic decomposition of hydrogen peroxide based on the modification of AC loaded organic chelate.The pore structure performance and surface chemical properties of AC were tested and analyzed. The effects of pore structure performance and surface acidic groups of AC on adsorption performance were studied as well. The phase equilibrium of organic impurities in hydrogen peroxide solution adsorbed by AC was mensurated via intermittent static method. The results showed that the adsorption ability of AC on organic impurities from hydrogen peroxide solution was greatly affected by pore structure properties of AC. The organic molecules in hydrogen peroxide solution were mainly adsorbed by pore diameter of 1-3nm.The thermodynamics and dynamics of adsorption process were analyzed the interrelated formulas of thermodynamics and dynamics were founded, and adsorption thermodynamics was investigated. The mechanism of adsorption was discussed by combining the infrared spectral analysis and the effects of adsorption temperature, adsorption time, TOC original concentration, and AC dosage on hydrogen peroxide concentration. According to the results of infrared spectral analysis, pore structure and surface chemical properties of AC, the mechanism of decomposition of hydrogen peroxide during AC adsorption was discussed as well. As a result, the idea that the concentration of hydrogen peroxide was not only affected by surface acidic groups of AC, but also by the pore structure of AC was given, which offered the theoretic guideline for the preparation technique of ultra high pure hydrogen peroxide of electronic grade.The effects of different kinds of AC and conditions on removal of organic matter from hydrogen peroxide were investigated. The results showed that AC2, the organic impurities in industrial hydrogen peroxide solution (concentration of 35%) could be reduced effectively to below 20ppm and meet the standard of ultra high pure hydrogen peroxide of SEMI-C8 level, while concentration loss of hydrogen peroxide could be less than 5 percentage points during adsorption process.The loaded active carbon-based chelated adsorben adapted to the hydrogen peroxide system was designed and prepared the loaded active carbon-based chelated adsorben acts well in removal of metallic ions which could easily decompose hydrogen peroxide in hydrogen peroxide solution. The chelated adsorbent could restrain effectively decomposition of hydrogen peroxide in contrast with carrier AC.Ion exchange in hydrogen peroxide solution was investigated. The ion exchange resins adapt to hydrogen peroxide system were chosen. The mass transfer parameters were investigated by analyzing breakthrough curves for ions into fixed exchange pole via the breakthrough function method.The integration technique of removal TOC and ion exchange was proposed. The ultra high pure hydrogen peroxide of SEMI-C8 l standard of was successfully prepared by using two stage adsorption and combinate ion exchange of combined bed and mixed bed.