## 4 Removal of Pharmaceuticals during Wastewater Treatment
### Removal of Different Pharmaceuticals by Advanced Oxidation Processes  
[PERSON] et al. [29] describe advanced oxidation processes (AOPs) as aqueous phase oxidation methods. These AOPs are characterized by the use of high energy and the generation of hydroxyl radical (\"OH) as a very strong oxidant [7; 89; 90; 91]. Researchers have repeatedly recognized that AOPs effectively degrade pharmaceuticals in wastewater and other aquatic systems. Photochemical, ozone-based (O\({}_{3}\)/H\({}_{2}\)O\({}_{2}\), O\({}_{3}\)/UV), and photo-Fenton processes are generally more effective than ozonation alone due to the photon-initiated carbon-halogen bond cleavage and increased generation of hydroxyl free radicals [92]. In addition, UV or visible irradiation can generate reactive excited states of pharmaceuticals. The main problem associated with AOPs is the generation of toxic oxidation products that can remain in the sanitized water [93]. The literature outlined various types of heterogeneous photocatalysts, mechanisms, synthesis methods of the photocatalyst, the nature of the pharmaceutical compound, and photocatalytic reactor designs and their operating parameters, as well as the effect of the water matrices on the degradation [94; 95]. The removal of paracetamol and acetaminophen ACE, as NSAID products, was mentioned by many studies [96; 97; 98]. [PERSON] et al. [99] and [PERSON] et al. [96] used two totally different photocatalytic processes for the elimination of acetaminophen ACE. In fact, the photo-electrocalolytic (PEC) degradation of ACE using TiO\({}_{2}\) nanotubes as photocatalysts demonstrated that the photodegradation of ACE was quicker at pH = 3, and a higher degree of mineralization was achieved [99]. In comparison, analyzing by photocatalysis using mixed Ti-Zr metal-organic frameworks under solar irradiation showed total removal of ACE, and high reusability of the photocatalyst had been noted that facilitated the utilization of this photocatalyst in real wastewater treatment [96]. Among analgesics, paracetamol was mentioned in Table 3 for a full degradation at pH 9 [98]. However, using photo-degradation for paracetamol resulted in 98% of removal under solar irradiation, using ferroivalate for 2 mg/L as a concentration for 5 min of treatment once in an aqueous solution [97]. According to [PERSON] et al. [100], using TiO\({}_{2}\) heterogeneous photocatalysts with UV-LEDs was efficient to remove IBU from pharmaceutical industry wastewater and from ultrapure water in natural pH (between 5 to 5.3) and less efficient in treating the wastewater from the municipal WWTPs. In real urban wastewater, they found a percentage between 89.83% and 100% of degradation after 40 min of treatment. [PERSON] et al. [101] used light-driven AOPs, which is a good treatment process for three different pharmaceuticals products: ibuprofen, carbamazepine, and ciprofloxacin in real urban wastewater. They demonstrated a removal of 80.4% to 100% of carbamazepine, an antidepressant drug, after 40 min of treatment in real urban wastewater, also from 89.83% to 100% for ibuprofen and a total removal for ciprofloxacin. [PERSON] et al. [102] also noted the efficiency of the photocatalysis process over photolysis, which was faster and characterized by a higher elimination of pharmaceutical products in wastewater: 74% removal of carbamazepine and 100% removal of both propranolol and DIC. For the other NSAIDs, [PERSON] et al. [103] also studied aqueous solution by TiO\({}_{2}\) photocatalyst. They showed a total degradation and mineralization of DIC after 2 h of irradiation. Moreover, for NPX pharmaceutical compounds, [PERSON] et al. [104] proved that their removal in ultrapure water by a photocatalytic process is more efficient than photolysis. In fact, the TiO\({}_{2}\)-UV process results in higher removals of NPX with 98% and chemical oxygen demand COD of 25%. However, for photolysis at pH initial 6.5, the COD was 83% and 11% after 3 h, whereas [PERSON] et al.