Investigation of the Photocatalytic Degradation Efficiency of a Refractory Organic Pollutant using a Phytotoxicological Approach

The present study aims to explore the efficiency of applying a photocatalytic process based on the use of ZnO/UV-vis system for the degradation and removal of toxicity generated by an emerging pharmaceutical contaminant from aqueous solutions. The focus compound considered in this research is a drug used as a vasodilator, identified as refractory and persistent. The photocatalytic process conditions involved the use of the compound pentoxifylline and zinc oxide as photocatalyst. A series of preliminary phytotoxicity tests were carried out using a superior plant species, Lepidium sativum, to examine the likelihood of any environmental impact of the reaction intermediates that may be released during the photocatalytic process. The data obtained showed that the untreated solution (40 mg/L of pollutant) causes an inhibition of both seed germination (80%) and radicle and leaves length, which is probably due to the recalcitrance of pollutant and its toxicity. Also, the ecotoxicological results achieved for the tests performed on the solutions resulted after the photocatalytic process confirmed the treatment efficiency in terms of elimination of toxic reaction intermediates.