In this study, silica nanoparticles are initially synthesized using the Stöber method. The synthesized nanoparticles are functionalized with cyanuric chloride and bis(3-aminopropyl) amine molecules and dendrimer molecules are formed. The synthesized nanostructure is applied as a copper ion recognition element in a carbon paste electrode. The presented sensor is applied to identify the amount of copper ions from aqueous solutions of cooling tower of thermal power plant. The structural, morphological and size of the synthesized particles are investigated using XRD, FTIR, FE-SEM, TEM, EDX, TGA and UV-Vis techniques. In order to optimize the performance of the copper ion monitoring sensor, the parameters including graphite, paraffin and detector composition are investigated. The optimum sensor response is achieved at 75% graphite, 20% paraffin and 5% nanostructure. The electrochemical behavior of copper ions is monitored by cyclic voltammetry and the oxidation peak is obtained in the 0.1 V for copper oxidation. The obtained sensor has a detection limit of 10-5 M and a linear range of 0.1-1 mM in the differential pulse voltametric method. The proposed sensor is capable of application in real complex samples such as cooling tower of power plants. The results of this method are in accordance with the atomic absorption reference method for cooling tower sample. The proposed method is able to measure copper ions in the cooling tower sample with very high accuracy and precision.