Wastewater contaminated with hydroxychloroquine (HCQ) poses a serious threat to the environment and human life. This study aimed to evaluate the ability of living microalgae to remove HCQ from an aqueous solution. Batch mode experiments were conducted under different conditions to investigate the effect of operating parameters on HCQ removal efficiency and mechanisms. Equilibrium, kinetic and thermodynamic study was also carried out to better describe the interactions between HCQ and microalgae. The maximum HCQ removal was 92.10 ± 1.25% obtained under optimal pH of 9.9 ± 0.1, a contact time of 45 min, a stirring speed of 300 rpm, an initial HCQ concentration of 20 mg/L, and a microalgae dose of 100 mg/L. The Langmuir isotherm and the pseudo-second-order kinetic model were best suited for the biosorption experiments, and the maximum biosorption capacity was 339.02 mg/g. The thermodynamic study showed that the biosorption process was exothermic and spontaneous. Experiments on real wastewater showed that the HCQ removal was not significantly affected by the presence of other contaminants in the water.
Practitioner Points• The best HCQ removal was 92.10 ± 1.25% obtained under optimal conditions. • The Langmuir isotherm and the pseudo-second-order kinetic model were best suited for the biosorption experiments.• The maximum biosorption capacity was 339.02 mg/g.• The thermodynamic study showed that the biosorption process was exothermic and spontaneous.• The microalgae studied can be successfully used in HCQ removal from water.
Using chloroquine (CQ) as a provisional treatment for COVID-19 patients generates more pharmaceutical waste, posing a potential environmental threat. The present study evaluates the feasibility of the electrocoagulation (EC) process in removing CQ from an aqueous solution. The experiment was performed in a laboratory-scale stirred tank reactor (STR). The effects of operating conditions were investigated. Equilibrium and kinetic experiments were also performed to describe CQ adsorption. The results showed that increasing both the applied current density and the EC reaction time increases the removal efficiency of CQ. The results showed that 95% of CQ removal efficiency was achieved at a current density of 66.89 mA/cm2, 600 rpm of agitation rate, 60 min of electrolysis time, an initial CQ concentration of 3 mg/L, and a pH of 6.5. For equilibrium and kinetic studies, the Langmuir isotherm and the pseudo-second-order provided the best fit to the experimental data. The optimal operating conditions led to a specific amount of dissolved aluminum electrodes and a specific energy consumption of 0.228 kg/m3 and 12.243 kWh/m3. These results suggest that the EC process is an excellent tool for effectively degrading CQ from wastewater with a low operating cost (2.48 USD/m3).
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