The present study is an attempt to synthesize and explore the applications of the synthetic nano-zeolites (nZ) and its composites with graphene oxide (GO) for water purification. The modified Hummer's method and hydrothermal methods were applied for the synthesis of the graphene oxide and nano zeolites respectively, followed by the preparation of the composite with the ultrasonic method. The Scanning electron microscopy, Energy dispersive analysis of X-rays, Fourier transform infrared spectroscopy and X-ray fluorescence was used for physico-chemical characterization of the composite. The various parameters like adsorbent dose, contact time, initial and final pH of solution were optimized for the removal of calcium hardness. The results indicate optimum removal (98%) can be reached at pH 7 while the removal is highly adsorbent dose-dependent. The nZGO removal data were investigated by pseudo-first-order, pseudo-second-order, Elovich, and Intraparticle diffusion. In that, pseudo-second-order and Intraparticle diffusion models are best fitted to experimental data. The experimental data were also analysed by Langmuir, Freundlich and Temkin isotherms, the experimental data follows Langmuir isotherm with determination coefficient is 0.99.