To find an effective method in separation of Cs(I), an advanced macroporous silica-based supramolecular recognition composite, (Calix[4] + MODB)/SiO2-P, was synthesized. It was done by impregnation and immobilization of 1,3-[(2,4-diethylheptylethoxy)oxy]-2,4-crown-6-calix[4]arene (Calix[4]arene-R14) and methyloctyl-2-di-methy-lbutanemide (MODB) into the pores of the SiO2-P particles. MODB was used to modify Calix[4]arene-R14. The adsorption of some typical fission products such as Mo(VI), Pd(II), La(III), Y(III), Ru(III), Rh(III), Cs(I), and Zr(IV) contained in highly active liquid waste (HLW) onto (Calix[4]+ MODB)/SiO2-P was investigated. It was performed by examining the effects of contact time, the concentration of HNO3 in the range of 0.3-7.0 M. and operation temperature on the adsorption of the tested metals. (Calix[4] + MODB)/SiO2-P showed strong adsorption ability and excellent selectivity for Cs(I) over all the tested metals. The separation of Cs(I) from a simulated HLW containing 5.0 mM of the tested elements was performed by (Calix[4] + MODB)/SiO2-P packed column at 298 K. Mo(VI), Pd(II), La(III), Y(III), Ru(III), Rh(III), and Zr(IV) showed no adsorption and were eluted into effluent along with 3.0 M HNO3. Cs(I) adsorbed by (Calix[4] + MODB)/SiO2-P was effectively eluted with water and then separated from the others. The results demonstrated that in 3.0 M HNO3, (Calix[4] + MODB)/SiO2-P is promising to apply in separation of Cs(I), one of the heat generators, from HLW in the SPEC (Strontium/Cesium Partitioning from HLW by Extraction Chromatography) process developed recently. (C) 2010 Elsevier B.V. All rights reserved.