Pretreatment of Color Filter Wastewater towards Biodegradable by Fresnel-Lens-Assisted Solar TiO2 Photocatalysis

Abstract EN

The pretreatment of color filter wastewater towards biodegradable by Fresnel-lens-enhanced solar TiO2 photocatalytic process was investigated.

The experimental design of response surface methodology (RSM) was employed to assess the effect of critical process parameters (including initial pH, TiO2 dosage, and reaction time) on pretreatment performance in terms of BOD5/COD, COD and TOC removal efficiency.

Appropriate reaction conditions were established as an initial pH of 7.5, a TiO2 dosage of 1.5 g/L with a reaction time of 3 h for increasing the BOD5/COD ratio to 0.15, which implied that the treated wastewater would be possibly biodegradable.

Meanwhile, the efficiency of COD and TOC removals reached 32.9% and 24.4%, respectively.

With the enhancement of Fresnel lens, the required reaction time for improving the biodegradability of wastewater to 0.15 was 1 h only.

Moreover, the efficiency of COD and TOC removals was promoted to 37.4% and 25.8%, respectively.

This could be mainly due to the concentrated effect of Fresnel lens for solar energy, including an increase of 2 times of solar irradiation and a raising of 15–20°C of wastewater temperature.

Consequently, solar TiO2 photocatalytic process with the use of a PMMA Fresnel lens could offer an economical and practical alternative for the pretreatment of industry wastewater containing diversified biorefractory pollutants with a high concentration of COD such as color filter wastewater.