Photocatalytic removal of emerging organic pollutants in water

Abstract

The presence of emerging organic pollutant in water is of great threat for ecosystems and human health, highlighting the persistence of antibiotic leading to antibiotic resistance. Removal of such pollutants plays a crucial role to tackle this issue, so finding simple cost-effective methods for wastewater treatment. This work proposes the evaluation of nanostructured BiOI as a photocatalyst to activate peroxymonosulfate (PMS) for degrading and mineralizing organic pollutants in water. The preparation of BiOI nanofilms is carried out through an electrodeposition process. Annealing treatment of BiOI-films is used investigate the effect of temperature on the catalyst’s effectiveness. The organic pollutant used to perform the experiments is tetracycline. Experiments are conducted at two pH levels, 6 and 8. Examination of TC degradation and mineralization in absence of catalyst was performed under artificial visible light, PMS and the combination of both parameters. Solution at pH=6 demonstrated increased rates in comparison to pH=8. The merge of PMS and visible light resulted the highest performance. Once determined, it is applied in the presence of the BiOI photocatalyst. BiOI annealed at three different temperatures is also studied to find out whether temperature variations also affect mineralization and degradation rates. Then reusability of such catalyst is explored. Finally, the study of the photocatalysts activity on three additional pollutants plus a mixture of pollutants is evaluated for its applicability. BiOI annealed at 520 ºC (highest temperature studied) resulted the highest mineralization and degradation rates although reusability did not yield the same results. Consequently, BiOI-films at 420 and 250 ºC prove to be the most suitable for both its reusability and efficiency.