SARS-CoV-2 pharmaceutical drugs: a critical review on the environmental impacts, chemical characteristics, and behavior of advanced oxidation processes in water.

This review summarizes research data on the pharmaceutical drugs used to treat the novel SARS-CoV-2 virus, their characteristics, environmental impacts, and the advanced oxidation processes (AOP) applied to remove them. A literature survey was conducted using the electronic databases Science Direct, Scopus, Taylor & Francis, Google Scholar, PubMed, and Springer. This complete research includes and discusses relevant studies that involve the introduction, pharmaceutical drugs used in the SARS-CoV-2 pandemic: chemical characteristics and environmental impact, advanced oxidation process (AOP), future trends and discussion, and conclusions. The results show a full approach in the versatility of AOPs as a promising solution to minimize the environmental impact associated with these compounds by the fact that they offer different ways for hydroxyl radical production. Moreover, this article focuses on introducing the fundamentals of each AOP, the main parameters involved, and the concomitance with other sources and modifications over the years. Photocatalysis, sonochemical technologies, electro-oxidation, photolysis, Fenton reaction, ozone, and sulfate radical AOP have been used to mineralize SARS-CoV-2 pharmaceutical compounds, and the efficiencies are greater than 65%. According to the results, photocatalysis is the main technology currently applied to remove these pharmaceuticals. This process has garnered attention because solar energy can be directly utilized; however, low photocatalytic efficiencies and high costs in large-scale practical applications limit its use. Furthermore, pharmaceuticals in the environment are diverse and complex. Finally, the review also provides ideas for further research needs and major concerns.

As and [Formula: see text] cooccurrence in drinking water: critical review of the international scenario, physicochemical behavior, removal technologies, health effects, and future trends.

Drinking water contaminated with As and [Formula: see text] is increasingly prevalent worldwide. Their coexistence can have negative effects due to antagonistic or synergistic mechanisms, ranging from cosmetic problems, such as skin lesions and teeth staining, to more severe abnormalities, such as cancer and neurotoxicity. Available technologies for concurrent removal include electrocoagulation ~ adsorption > membranes > chemical coagulation > , and among others, all of which have limitations despite their advantages. Nevertheless, the existence of competing ions such as silicon > phosphate > calcium ~ magnesium > sulfate > and nitrate affects the elimination efficiency. Mexico is one of the countries that is affected by As and [Formula: see text] contamination. Because only 10 of the 32 states have adequate removal technologies, more than 65% of the country is impacted by co-presence problems. Numerous reviews have been published concerning the elimination of As or [Formula: see text]. However, only a few studies have focused on the simultaneous removal. This critical review analyzes the new sources of contamination, simultaneous physicochemical behaviors, available technologies for the elimination of both species, and future trends. This highlights the need to implement technologies that work with actual contaminated water instead of aqueous solutions (55% of the works reviewed correspond to aqueous solutions). Similarly, it is necessary to migrate to the creation of pilot, pre-pilot, or prototype scale projects, because 77% of the existing studies correspond to lab-scale research.

Photo-electrooxidation treatment of Acetaminophen in aqueous solution using BDD-Fe and BDD-Cu systems.

In this study, acetaminophen (ACT) in aqueous solution was treated with electrooxidation and photo-electrooxidation processes (PEO). An electrochemical cell was used for the treatment of different concentrations of ACT (10, 50 and 80 mg L-1). A 23 factorial design was proposed, and the variables studied were current intensity 0.5 A (45.45 mA cm-2) and 1.0 A (90.91 mA cm-2), electrode configuration (anode:BDD, cathode:Fe or Cu) and presence/absence of UV light; NaCl 0.043 M (2.5 g L-1) was used as supporting electrolyte, the initial pH was 5.5, and the treatment time was 3 h. The aqueous solutions were characterized before and after the treatment using infrared spectroscopy (FT-IR), Ultraviolet-visible spectroscopy (UV-Vis), chemical oxygen demand (COD), total organic carbon (TOC), total carbon (TC), and fluorescence spectroscopy. The optimal operating conditions using an initial ACT concentration of 80 mg L-1 were 1.0 A, BDD-Fe configuration and UV light (254 nm). The removal efficiencies were 100% of ACT and 82.75% of TOC after 15 min of treatment. At concentrations of 50 and 10 mg L-1, 77.16% and 50.29% of TOC were removed after 10 and 5 min of treatment, respectively. Finally, the kinetic study showed an increase in the rate constants when the UV light was applied.

Defluoridation of drinking water by magnesium and aluminum electrocoagulation in continuous flow-rate: a response surface design.

The goal of this research is to apply an electrocoagulation process in continuous flow for the defluoridation of drinking water. Two sampling sites were studied, Temascalcingo (T), Mexico state and Jerecuaro (J), Guanajuato, with fluoride (F-) concentrations above the norms (2.3 mg L-1 and 4.5 mg L-1, respectively). In addition, a second Temascalcingo sample was enriched (TE) to 9.2 mg L-1 F- to study the effect of the F- concentration. A response surface design was proposed through a Box-Behnken model, and the variables studied were electrode system, flow-rate and current intensity. 51 experiments were performed with T-site to determine the best operating conditions for the system. These conditions were applied to the J-site. The experiments for T, Al/Al system achieves an F- concentration within permissible limits (0.72 mg L-1 F-) at 10 min of treatment, 0.2 A (Current density j 48.78 A m-2) and 10 mL min-1 with a removal efficiency of 68.69%, and after 160 min, the removal increased to 99.56%. AlMg/AlMg needs 10 min to achieve a concentration of 0.75 mg L-1 F- at 0.2 A (j 25 A m-2), 16 mL min-1 with a removal efficiency of 67.39%, and after 100 min, the removal is increased to 92.17%. An important and novel advantage is the use of AlMg allows an acceptable removal of F- (<1.5 mg L-1) at high and low concentrations in short periods of time; this also allows save energy costs and the effluent is free of residual aluminum, avoiding side effects.