In this book, the utilization possibility of nickel oxide nanoparticles-modified diatomite (NONMD) has been studied as an adsorbent for the removal of Colored Pollutants from an aqueous medium in the industrial effluent . Nickel metal can be a good choice for degrading the dyes and other pollutants from aqueous solutions. The equilibrium and kinetics study are investigated and the effects of various process parameters such as solution pH, adsorbent dosage, adsorbent size, initial dye concentration, temperature, contact time and salt were examined. The mean size and the surface morphology of the adsorbent were characterized by SEM, BET, FTIR, XRD, EDX and elemental analysis. Equilibrium data are attempted by various adsorption isotherms including Langmuir, Freundlich and Brunauer-Emmett-Teller (BET) isotherms in order to select an appropriate isotherm model. Moreover, a kinetics study of the adsorption process is also considered to describe the rate of sorption.