Characterization and biosorption of silver by biomass waste from the alginate industry

Abstract

In this work, biosorption of silver by a waste product from the alginate production industry was investigated. The biosorbent was submitted to treatment with nitric acid and experiments were performed using the non-acidified and acidified biosorbent. The results showed that the acidification was a successful step to enhance the silver biosorption. SEM micrographs showed the presence of diatoms in the outer structure of the biosorbent, and the sodium ion concentration was reduced after silver uptake. The kinetic experiments revealed that stationary phase was reached after 300 min, while the kinetic curves presented a hump of Ag(I) removal, which is related to the presence of the ion exchange mechanism. The silver biosorption capacity verified for the acidified biosorbent at 293 K was 2.92 mmol g−1, and the isotherms at 313 K could be described by the Ion Exchange model.