Author:
Mentor:
Abel E Navarro PhD
Abstract:
The gold market keeps growing over the years and the search of new mines and less expensive extraction as well as purification techniques are a top priority. The highly toxic extraction with cyanide is still used in developing countries, causing severe impacts in human health and ecosystems. This issue urges us to develop new techniques for the recovery and capture of gold ions from aqueous systems. This project studied the uptake of gold (III) ions from aqueous solutions using marine algae from Peruvian beaches, Lessonia nigrescens Bory (L13) and Sargassum nodossum Bory (S12). Batch equilibrium studies were conducted at room temperature to evaluate the role of initial solution pH, adsorbent dose, particle size and ionic strength on the adsorption of trivalent gold ions. Adsorption kinetics and isotherms report maximum adsorption capacities of 224 and 59 mg of Au(III) per gram of L13 and S12, respectively; according to the theories of Langmuir. Adsorption of Au(III) was maximized at an initial solution pH between 4 and 5 and the process is slightly favored in the presence of sodium nitrate and with smaller particle sizes of the adsorbents. Scanning electron microscopy indicates that L13 and S12 pose favorable morphological and textural properties for the uptake of metal ions.
