Binderless zeolite X pellets were “one-pot” synthesized via in situ hydrothermal conversion of silica gel precursors in sodium aluminate solution. The conversion and crystallization kinetics were investigated as a function of synthesis time with a spectrum of techniques. It is found that four-membered (4R) and six-membered rings (6R) are formed by linking diffused Al species with dissolved Si species during the aging period, while the zeolite X frameworks are constructed via reorganization of β cages with double six-membered rings (D6R) in crystallization process. Furthermore, GCMC simulation was conducted to elucidate 1-hexene adsorption in zeolite X as ion species and exchange degree vary, in which adsorption capacity and guest – host interaction energy were evaluated. Incorporation of Mg2+ and Ca2+ enables higher adsorption capacity, while introduction of Co2+, Ni2+, Cu2+ and Zn2+ boosts adsorption and enhances interaction energy.