Development of novel uv led photocatalytic reactor and performance evaluation of fluorescent dye degradation using graphene oxide

Abstract

Fluorescent dyes present in textile wastewater are problematic due to its high molecular weight and stability. In the research arena, out of all dye degradation studies, only around 1% of works were about the fluorescent dye degradation. Advanced oxidation processes proved to be one of the most effective techniques for fluorescent dye degradation. Heterogeneous photocatalysis is one of the advanced oxidation processes widely evaluated nowadays. There are three main components of heterogeneous photocatalysis viz., pollutant, photocatalyst and light. The fourth component is very significant for the enhancement of the photocatalytic efficiency. In the review of literature, five benchmarks were used for the comparison of photocatalytic reactors are apparent kinetic constant (kapp), Space time yield (STY), Photocatalytic space time yield (PSTY), Specific removal rate (SRR) and Electrical energy consumption (EEC). The STY is the volume throughput of pollutant processed from 100mM to 0.1mM for a particular reactor per day. The PSTY is estimated by dividing STY by volume normalised lamp power. From the literature review, it is observed that Micro-reactors (MR) have high STY, whereas Packed bed reactors (PBR) have high PSTY. In this research, efforts were made to design and develop a novel UV-LED photocatalytic reactor to balance both STY (value representing pollutant removal performance) and PSTY (value representing energy efficiency). The distance between light and substrate was optimized using ray tracing algorithm. The photocatalyst Graphene oxide was procured and photocatalyst characterisation was carried out for X-Ray Diffraction (particle size), Fourier Transform Infrared Spectroscopy (molecular vibrations), Diffuse Reflectance Spectroscopy (band gap), Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy (morphology with composition) iv and Brunaur Emmett Teller analysis (specific surface area). Optimization experiments were carried out using two fluorescent dyes viz., Acridine orange (AO) and E