Factors affecting treatment of TFT‐LCD wastewater by fenton and electro‐fenton processes

Abstract

The TFT‐LCD screen (thin film transistor liquid crystal display) industry has been growing rapidly in Taiwan in recent years. The wastewater from this industry contains many non‐biodegradable pollutants and high strength nitrogen and sulfur containing compounds which are difficult to degrade. Fenton and electro‐Fenton with double‐cathode processes were used to treat the high COD content of real TFT‐LCD wastewater which cannot be removed by conventional processes. The effect of operating parameters such as pH, Fe 2+ , H 2 O 2 concentration and electrical current on COD removal were determined. The electro‐Fenton process rapidly degraded the TFT‐LCD wastewater in the first 20 minutes while in the Fenton process, the rapid degradation occurred in the first 60 min. This showed that electro‐Fenton process could degrade the TFT‐LCD wastewater faster than the Fenton process. The highest COD removal efficiency was found to be 100% at 120 min at pH = 4, [Fe 2+ ] = 3.5 mM, [H 2 O 2 ] = 285 mM and 1.5 A of electrical current of electro‐Fenton process. © 2015 American Institute of Chemical Engineers Environ Prog, 35: 368–373, 2016