Jacob White^1,, Whitney Smith¹

Congo red, a conjugated diazo dye which is a derivative of benzidine and napthionic acid, has experienced commercial success because of its ability to dye cotton easily. The unregulated disposal of textile dyes, such as Congo red, has created a challenge for environmental chemists to determine effective, inexpensive treatment processes for remediating contaminated water. Studies involving semiconductors such as titanium dioxide (TiO₂) and zinc oxide (ZnO) have investigated their affects on wastewaters after being irradiated. However, few reports have described the influence temperature has on such systems. The objective of this study was to briefly characterize, via UV-Visible spectroscopic techniques, the temperature-dependency of the photocatalytic degradation of Congo red using zinc oxide and an inexpensive radiation source. The results indicate that the rate of degradation is catalytically dependent, photo-induced, and potentially temperature dependent with the greatest rate of degradation observed in trials conducted at low (~5°C) temperature. The results may also suggest the prevalence of aggregate dye formation at elevated (~40°C) temperature, although photocatalytic degradation is likely to occur concurrently.

Congo red, textile dye, water remediation, water treatment, photocatalysis