## 3 Pharmaceuticals Pollutants
### Detection, Sample Preparation and Analysis of NsaIDs and ARV Drugs
#### Factors Affecting Adsorption  
Initial concentration, contact time, adsorbent dosage, type of catalyst, irradiation time, pH, and temperature are some of the factors that influence the adsorption of pharmaceutical compounds into nanoparticles. The reaction rate is determined by the relative initial concentrations of adsorbent and adsorbate [80]. Higher concentrations of adsorbate result in lower removal efficiency of pharmaceutical compounds, while higher concentrations of adsorbent result in higher removal efficiency. The contact time between the adsorbent and the adsorbate is crucial in determining the removal efficiency of a specific nanomaterial. This is because it provides the information on the adsorbate's sorption kinetics for a given initial dosage of the adsorbent [81]. For instance, insight into the reaction rate and the sorption mechanism during adsorption involving mass transfer, diffusion, and reaction on the adsorbent surface [82]. In general, the amount of solute adsorption rises with increasing adsorbent concentration. This is as a result of higher adsorbent concentration, which translates to more active adsorption sites. However, the total solute adsorption per unit weight of an adsorbent might decrease when adsorbent concentration increases. This is due to interference produced by adsorbent active site interaction. Therefore, adsorption studies should incorporate the effect of dosage in order to obtain desired adsorption efficiency. The optimal adsorbent dosage is mostly determined by the availability of active sites, which is linked to the existence of surface area and functional groups [83]. In terms of the effects of pH, the pH of the solution is significant since it might affect the adsorption process. It affects the amount of adsorbate ionization and hence the surface properties of an adsorbent. The chemical equilibrium for estimating each adsorbate speciation should be within the pH range of 1-12 in order to understand adsorbent behavior in solution [83]. Yet, the temperature of the solution is the dominant influence on the adsorption process. Since it affects the adsorbent enlargement, adsorbate mobility, and the solid/liquid interface. The latter can be explained in terms thermodynamic parameters, such as Gibbs free energy (DG0), enthalpy (DH0), and entropy (DS0). For instance, negative DG0 values indicate that the adsorption process is spontaneous, whereas positive DH0 values suggest that the process is endothermic. Furthermore, the amount of DH0 appears to be connected to the kind of sorption, namely, physisorption (DH0 50 kJ/mol) and chemisorption (DH0 > 50 kJ/mol) [84]. In the of DS0, the positive DS0 values can be explained as an increase in entropy caused by the exchange of metal ions for more mobile ions during the adsorption process.  
The affinity of pharmaceutical compounds is a key factor in regulating the mechanism of nanoparticles, and affinity is determined by the adsorbate molecules' properties. The higher the affinity of the adsorbate molecule for the adsorbent, the more likely the adsorption process will occur [85]. The electrostatic movement between the adsorbate and the adsorbent was governed by the electrostatic movement of ionic pharmaceutical compounds. It was discovered that the electrolyte solution could be used to modify the strength of adsorbent-adsorbate interactions [86].  
Adsoorbent and adsorbate physicochemical properties also have a significant impact on the adsorption process. Changing the surface of the adsorbed using thermal or chemical activation procedures results in a more porous structure with more oxygenated functional groups [87]. The chemical composition and molecular structure change as a result of the various activation processes, which are then used to remove specific pharmaceuticals. The adsorbate molecules attack the adsorbent's corners first, resulting in a variety of interactions [88]. This means that the more surface area a nanoparticle has, the better its chances of interacting with adsorbate molecules.