The term decolorization as used in the pharmaceutical industry is a misnomer. It does not mean to literally remove color. That would be too simple, too literal. Rather, to decolorize in the pharmaceutical industry means to remove impurities of one sort or another. In the decolorization of a fermented product process stream one often uses ion exchange resins. However, a superior solution lies in the use of specially designed activated alumina. Activated alumina has the ability to effectively remove impurities. The degree of color removal can be programmed by altering pore size, pH and particle size. Materials which can be decolorized by using activated alumina are as diverse as hydrocarbon oils, food oils such as olive oil, fatty acid derived nitriles, azo and other textile dyes, poly vinyl chloride, industrial carbon and antibiotics such as daunomycin and vancomycin.
Within the textile industry decolorization is reflective of the removal of color. The textile industry utilizes more than 10,000 different dyes and pigments, with the azo class of synthetic dyes representing more than 50% of all dye production. There are more than 2,000 structurally different azo dyes in commercial use. For both environmental and health reasons it is essential to completely removed these azo dyes before they reach to effluent stream as they may become carcinogenic in oxygen depleted settings. The advantage of using activated alumina to bind and decolorize azo dyes lies in the amphoteric properties of alumina. Both acid and basic dyes are able to bind on to the same particle. This unique property of decolorizing alumina, coupled with the ability to reactivate alumina at temperatures in excess of 400 C and reuse the alumina makes this the most cost efficient method for azo dye extraction.
DynaPharma™ Pyrogen Product Info | Azo Dye Decolorization by Chemical, Physical and Biological Techniques | Utilization of Specialized Activated Alumina for Decolorization