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Advances in Materials Science and Engineering
Volume 2013 (2013), Article ID 274245, 7 pages
Research Article

Preparation of Modified Kaolin Filler with Cesium and Its Application in Security Paper

1Cellulose and Paper Department, National Research Centre (NRC), Dokki, Giza 11622, Egypt
2Chemistry Department, Faculty of Science, Helwan University, Ain Helwan, Cairo 11975, Egypt
3National Centre for Nuclear Safety & Radiation Control (NCNSRC), Egyptian Atom Energy Authority (AEA), Nasr City, Cairo, Egypt
4Research Counterfeiting and Forgery Department, Forensic Medical Authority, Ministry of Justice, Cairo, Egypt

Received 26 May 2013; Accepted 7 July 2013

Academic Editor: Wen-Hua Sun

Copyright © 2013 Houssni El-Saied et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


In this study, cesium was added intentionally during paper manufacture for protecting the papers against forgery and counterfeiting by sorbing cesium ions (Cs+) on kaolin, used as special filler in papermaking. The sorption of cesium from aqueous solution by kaolin was studied as a function of pH, shaking time, cesium initial concentration, and mass of kaolin using batch technique. The results showed that a solution containing 10 mg/L Cs+ and 250 mg of kaolin at pH 6 can be used to modify the kaolin. Paper handsheets were prepared containing various percentages of the modified kaolin. The mechanical and optical properties of paper handsheets were studied. The prepared paper handsheets were irradiated by gamma irradiation using different doses. Fourier transform infrared (FTIR) spectroscopy was used to study the effect of kaolin modification by cesium and gamma irradiation on paper handsheets properties. The results indicated that modified kaolin enhanced the mechanical and optical properties of paper handsheets. Electron spin resonance (ESR) spectroscopy and laser-induced breakdown spectroscopy (LIBS) were also used. They provided rapid, sensitive and nondestructive techniques in differentiating between different questioned documents. This study presents a new concept in manufacturing security papers and anticounterfeiting applications.