Simultaneous adsorption of iron and sulfate ions on the chitosan surface via crystallization

Abstract

As a consequence of mining, heavy metal ions as well as oxyanions like sulfate and phosphates get discharged into the environment and hence contaminate ground water and surface water. The iron hydroxide deposition occurs as a red brownish sludge changing the whole appearance of the river, for example river Spree. Additionally, the pH of the river changes due to the increasing amount of sulfate pollution. One way of eliminating the iron hydroxide deposition and increasing the water quality is the application of Chitosan particles. Chitosan is a naturally occurring and environmental biopolymer with the property of a superadsorber. For the first time, iron ions as well as the oppositely charged sulfate ions were both adsorbed simultaneously on chitosan. Both were adsorbed in a high amount as iron sulfate and iron hydroxide aggregates on the surface of the chitosan particles.