Spectroscopic Studies of the Biosorption of Gold(III) by Dealginated Seaweed Waste

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• 作者：MarÍ ; a E. Romero-Gonzá ; lez ; Ceri J. Williams ; Philip H. E. Gardiner ; Steve J. Gurman ; and Stephen Habesh
• 刊名：Environmental Science & Technology
• 出版年：2003
• 出版时间：September 15, 2003
• 年：2003
• 卷：37
• 期：18
• 页码：4163 - 4169
• 全文大小：193K
• 年卷期：v.37,no.18(September 15, 2003)
• ISSN：1520-5851

文摘

Gold biosorption by dealginated seaweed waste has beenstudied to elucidate the mechanisms of metal uptakefrom solution. Dealginated seaweed was able to retain upto 1 mmol g^-1 of Au from solution at pH 3. FT-IR showedthe presence of carboxylate groups on the surface of thebiosorbent; however, the changes observed for the Au-bound samples suggested very little sorption to the carboxylmoieties. Colloidal Au formed on the surface of dealginatedseaweed by reduction of Au(III) to Au(0) was observedusing ESEM and four different types of particles were clearlyidentified. The Au distribution matched closely thatobtained for S atoms indicating a possible link betweenthese elements. EXAFS measurements showed that colloidalAu is present on the surface of the biosorbent. Evidenceof gold reduction from Au(III) to Au(I) and Au(0) was alsoconfirmed by the measured bond distances characteristicof the metal. The coordination number obtained byEXAFS indicated that approximately 75% of the Au on thesample was present in the colloidal form and the remainingAu was bound to S as nearest neighbor. The proposedmechanisms for Au removal from solution are reduction ofAu species by components on the surface of the biosorbentto form colloidal metal followed by retention of theionic Au(I) species at the sulfur containing sites. Theresults show that dealginated seaweed can be used forthe cleanup of gold-containing effluents.