ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Bulgarian natural diatomites: modification and characterization

Paunka S. Vassileva, Madlena S. Apostolova, Albena K. Detcheva, and Elisaveta H. Ivanova

Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, bl. 11, Acad. G. Bontchev str., BG-1113, Sofia, Bulgaria

E-mail: albena@svr.igic.bas.bg

Abstract: Natural Bulgarian diatomite modified by oxidation with sulfuric acid and H₂O₂ or by coating with manganese oxide was characterized considering its chemical composition, surface area, pore volume, and structure. Modified diatomites displayed larger surface area and pore volumes in comparison with untreated natural diatomite, which favored their sorption behavior. Sorption properties of diatomites towards Fe³⁺, Pb²⁺, Cu²⁺, Cd²⁺, Mn²⁺, Ni²⁺, Co²⁺, Cr³⁺, Pd²⁺, Ca²⁺, and Mg²⁺ were investigated and their sorption capacities were determined. Sorption properties of manganese oxide-modified diatomite were superior to those of diatomite modified by oxidation. Owing to its high sorption capacity towards Co²⁺, Ni²⁺, Pb²⁺, Cr³⁺, Fe²⁺, Cu²⁺, and Cd²⁺, the manganese oxide-modified diatomite is a promising low-cost sorbent for selective removal of milligram amounts of these toxic metal ions from contaminated water.

Keywords: natural diatomites – modification – adsorption – toxic metal ions

Full paper is available at www.springerlink.com.

DOI: 10.2478/s11696-012-0272-x

Chemical Papers 67 (3) 342–349 (2013)