Integrated-electrochemical Approaches Powered by Photovoltaic Energy for Detecting and Treating Hydroxychloroquine in Water

Abstract

Hydroxychloroquine (HCQ), a derivative of 4-aminoquinolone, is prescribed as an antimalarial prevention drug and to treat diseases such as rheumatoid arthritis, and systemic lupus erythematosus. Recently, the treatment of Coronavirus (COVID-19) was authorized by national and international medical organizations in certain hospitalized patients by chloroquine and hydroxychloroquine. However, its use for treating COVID-19 is only an unproven hypothesis still being investigated. Consequently, the high risk of natural water contamination due to the large production and utilization of HCQ is a key issue to overcome urgently. For this reason, the monitoring its concentration in water and the treatment of polluted effluents with HCQ are needed to minimize its hazardous effects. Then, in this study, an electrochemical measuring device and electrochemical water treatment are integrated for their environmental application on HCQ control. In the former, raw cork-graphite electrochemical sensor was prepared and a simple differential pulse voltammetric (DPV) method was developed for the quantitative determination of HQC. Meanwhile, the degradation of HCQ was carried out with BDD anode by applying 15, 30, and 60 mA cm-2 over 90 min of treatment, in the latter. The decay and degradation of HCQ were monitored by DPV, and HPLC measurements. Results indicated that, the electrochemical device exhibited a clear current response, allowing to quantify the analyte in the 2.5–25 ppm range. Alternatively, BDD-electrolysis demonstrated to be an efficient process for removing organic matter from the drug compound effluent via the production of strong oxidizing species. Lower HCQ concentrations were detected, using the electrochemical sensor, when higher current densities and sulfate concentrations were used in BDD-electrolysis, demonstrating the applicability of integrated-technologies. The evolution of short-carboxylic acids (oxalic, formic, oxamic, maleic, acetic, and glycoxylic) was observed at 15 mA cm-2 but all of them were eliminated after 120 min. Inorganic ions (NH4 + and NO3 -) were also detected under these experimental conditions, confirming that the pollutant was mineralized. Finally, lower energy requirements were estimated for all experimental conditions; however, solar photovoltaic (PV) renewable energy has been utilized to power these electrochemical technologies, decreasing the investment cost.