Our goal for this study is to investigate the use of eco-friendly geopolymer cement in the treatment of wastewater that contains heavy elements and dyes using an immobilization technique to offer a new suggested method for dealing with these wastes. Our data indicates that using the prepared slag-based geopolymer pastes, the reactive yellow-145 dye's colour completely disappeared as well as the presence of copper ions in the leaching solution. Our data suggests that we were able to decrease pollutants and purifying the water in the industrial system. We investigated the removal efficiency of both organic dye pollutant reactive yellow-145 and copper ions with two different concentrations (700 ppm & 2700 ppm) using geopolymer mix [90% slag-10% fly ash] in the presence of 15% wt sodium silicate : 15% wt sodium hydroxide as an alkali activator, at varied hydration ages up to 14 days. The quantity of pollutant dye that was immobilised was measured using UV-Vis spectrophotometric analysis. On the other hand, the quantity of leachate of copper ions measured by atomic absorption spectroscopy We also investigate how a mix of reactive dye and copper ions affects slag-based geopolymer paste hydration characteristics. The effects of the reactive dye, Cu2+ ions, and a combination of both on the microstructure of the geopolymer pastes were studied using FTIR and XRD measurements