Effect of Flow Rate on Hexavalent Chromium Reduction in Electroplating Wastewater Using TiO2 Immobilized Resin

This study aims to analyze the effect of flow rate on the reduction of hexavalent chromium (Cr6+) in electroplating wastewater treated with a TiO2-immobilized resin in a continuous fixed-bed reactor. The electroplating wastewater, characterized by Cr6+, was treated with RIPT-TiO2 functioning as a catalyst to enhance the contaminant degradation process. The flow rate was then examined to observe the effect on the reduction of Cr6+ concentration during the reaction. The results showed that increasing the flow rate within the range of 40–70 mL/min affected the reduction of Cr6+, and ultimately influenced the photocatalytic efficiency. The flow rate affected the contact time between the wastewater and the catalyst. The best removal efficiency, reaching 50.83% at 180 minutes, was obtained at a lower flow rate. This study provides important contributions to the development of sustainable and efficient electroplating wastewater treatment technology using a continuous reactor system with a TiO2-immobilized resin.