Comparative Kinetic Evaluation of Resin Immobilized TiO₂ and ZnO Photocatalysts in a Continuous Fixed-Bed System for Industrial and Food Wastewater Treatment

Hidayah, Euis Nurul; Mukharomah, Nur Laili Alfiatin; Puspitasari, Ika Nawang; Wibisono, Moch. Andy; Darmawan, Arya

doi:10.22059/poll.2026.409175.3258

Comparative Kinetic Evaluation of Resin Immobilized TiO₂ and ZnO Photocatalysts in a Continuous Fixed-Bed System for Industrial and Food Wastewater Treatment

Articles in Press

Document Type : Original Research Paper

Authors

Euis Nurul Hidayah ¹

Nur Laili Alfiatin Mukharomah ²

Ika Nawang Puspitasari ³

Moch. Andy Wibisono ²

Arya Darmawan ²

¹ Environmental Engineering Department, Faculty of Engineering and Science, Universitas Pembangunan Nasional Veteran Jawa Timur

² Environmental Recearch Center, Universitas Pembangunan Nasional Veteran Jawa Timur, Surabaya, Indonesia

³ Department of Chemical Engineering, Faculty of Engineering and Science, Universitas Pembangunan Nasional Veteran Jawa Timur, Surabaya, Indonesia

10.22059/poll.2026.409175.3258

Abstract

Electroplating wastewater contains toxic Cr⁶⁺, while tofu wastewater has a high organic load that degrades water quality. Advanced oxidation processes (AOPs) based on photocatalysis have been extensively developed, including fixed-bed reactors. However, the application of continuous systems remains limited due to the prevalence of batch scale studies, uneven flow distribution, and limited contact between pollutants and the photocatalyst. This study employs a continuous fixed-bed photocatalytic reactor as the primary innovation to address these limitations. The performance of resin immobilized TiO₂ and ZnO was evaluated for Cr⁶⁺ removal and COD reduction. The resin immobilized TiO₂ and ZnO was synthesized via a stirring method under dark conditions. Mass variations of 10, 20, and 30 g were used in the reactor which was operated under UV-C irradiation (40 W/m²) at a flow rate of 60 mL/min. Samples were analyzed from 0 to 180 minutes for Cr⁶⁺, COD, and pH parameters. The results showed that resin immobilized ZnO provided better performance, with Cr⁶⁺ removal of 71.36% and COD reduction of 92.61%, compared to resin immobilized TiO₂, which achieved 70.80% and 84.89%. Acidic conditions enhanced process effectiveness through the formation of hydroxyl radicals and redox reactions. Kinetic analysis indicated that the COD reduction followed first-order kinetics, whereas Cr⁶⁺ removal followed second-order kinetics, reflecting differences in reaction mechanisms. Overall, the developed continuous fixed-bed system demonstrated stable performance and holds potential for sustainable wastewater treatment applications.

Keywords

COD

hexavalent chromium

photocatalysis

semiconductor catalyst

wastewater treatment

Subjects