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Removal of five pharmaceutical products classified as emerging pollutants in aqueous medium using the vetiver species (Chrysopogon zizanioides)

Abstract:

Pharmaceutical products constitute a unique group of emerging pollutants of great interest because their frequent presence in surface waters, groundwater, and drinking water have been determined. Due to incomplete metabolism and absorption in the human body, many of these drugs are excreted and released to the environment through wastewater. Therefore, this work's objective was to evaluate the potential of the vetiver species (Chrysopogon zizanioides) to eliminate five commonly prescribed and over-the-counter pharmaceuticals from the aquatic environment, such as ciprofloxacin, ibuprofen, sulfamethoxazole, diclofenac, and acetaminophen. The species was acclimated in wintering to carry out the experiments under standard temperature conditions and a pH of 6.5. The samples were analyzed using UV-Vis spectrophotometry to read the absorbances of each pharmaceutical product directly. For the statistical analysis of the data, the response surfaces methodology was used to find the models that help determine optimal times and concentrations where the absorption of each drug is maximized and obtain the growth slopes to determine where the optimum should be sought. Statistical software R version 3.6.0 and RStudio version 1.1.453 were used. The results obtained indicate that C. zizanioides more efficiently removed ciprofloxacin (98.3%) at a concentration of 3mg/L over a time of 149h, followed by ibuprofen and diclofenac with a maximum removal of 73.33% and sulfametaxazole with 66.53%, obtaining the lowest percentage of removal for acetaminophen of 38.49% at 192h, where samples were taken every 48 hours of the solutions of each drug at different concentrations (3 mg/L, 6 mg/L, 9 mg/L, 12 mg/L). In this research work, the removal capacity of Chrysopogon zizanioides of the five drugs studied in an aqueous medium under controlled conditions was demonstrated, envisaging great potential in the field of environmental biotechnology for tertiary wastewater treatment.