When dye is present in wastewater, it is considered a hazardous organic pollutant and must be eliminated. The goal of the current study was to evaluate the elimination of Malachite green (MG) and Methyl violet (MV) dyes using Ni foam (NiF) as an anode, along with stainless steel mesh electrodes as cathodes, and alum sludge (AS) as a third particle electrode in a three-dimensional electrocoagulation-flotation system (3DECF). With an electrolysis period of 30 minutes and pH = 7, response surface method was used to estimate the optimum conditions of studied parameters. These parameters were current density within the range of 1–5 mA/cm², concentration of NaCl within the range of 0.4 –1 g/L, and air flow rate within a range of 1–5 L/min. After 30 minutes of electrolysis, a dye removal of 93.151% was achieved at 5 mA/cm², 1 g/L NaCl, and an air flow rate of 3.7 L/min. The energy consumed was 67.847 kWh/kg of dyes. The model for dye removal is highly significant, with an F-value and P-value of 78.63 and 0.000, respectively, and the treatment process can be accurately described by this model. The R2 multiple correlation value was 0.9930, and there was a very good value of the adj. R2 (0.9804) and the pred. R2 (0.8879). EDX and FESEM were applied to examine the morphology of the surface and structure of the NiF electrode and alum sludge. Due to the excellent 3D structure of the foam electrode, this economical 3DECF system with the NiF anode and stainless-steel mesh as the cathode has demonstrated its high effectiveness in removing MG and MV dye with a low amount of NaCl. This makes the foam electrode an excellent choice. The results overall indicate that the 3DECF of dyes in binary systems may be an effective method with positive socioeconomic and environmental impacts. It can also increase efficiency when used in connection with another process.
