Adsorption Behavior of Acid Yellow G by highly-crosslinked amphoteric starch

A series of crosslinked amphoteric starches with different degrees of substitution (DS) synthesized by a hemi-dry process are used to adsorb Acid Yellow G. Some factors, such as pH, dose of amphoteric starches, and initial concentration of dye, adsorption time, adsorption temperature and DS of anionic groups are investigated. The results show that the adsorption capacity of amphoteric starch changes obviously with the different conditions, while it is not affected greatly by DS of anionic groups. The adsorption capacity reaches 149.6, 145.9 and 140.9 mg/g, respectively for three absorbents, whose DS of the cationic group is 0.3, and DS of the anionic group is 0.12, 0.20, 0.33, respectively when the initial concentration of Acid Yellow is 140 mg/l. the thermodynamic data show that the adsorption process is exothermic, thus low temperature benefits the adsorption process.