## 6 Removal of Pharmaceutical Pollutants in Wastewater by Nanosorbents
### Removal of Antiretroviral Drugs in Water  
In the case of ARV drugs, a nanofiber from _Mondia Whitei_/Poly vinyl alcohol (MW/PVA) blend and a first ever graphene-based material (graphene wool) were investigated [55]. The effect of adsorbent dose on ARV and associated drugs elimination was by nanofiberMW/PVA was studied. According to the results obtained by [55], a substantial decrease in drug removal was seen when the adsorbent dose was changed from 10 to 60 mg while other parameters remained constant (pH 7, initial concentration of 0.5 mg L\({}^{-1}\), agitation speed of 125 rpm, and contact period of 30 min). This reduction in removal was attributed to adsorption active site aggregation or overlaps [145]. At a dose of 10 mg, the greatest clearance efficiency was in the range of 22.3-38.1 mg g\({}^{-1}\). Taking the percentage elimination into account, 40 mg was employed for further optimization of the remaining parameters. The rate-limiting stage in the adsorption of ARVs were found to be chemisorption. Although the experimental results fitted the pseudo-second order model well, they could not describe the adsorption mechanism. The intraparticle diffusion kinetic model was used to overcome this constraint. The adsorbate transfer in a solid-liquid adsorption process is frequently characterized by film diffusion (also known as external diffusion), surface diffusion, pore diffusion, or mixed surface and pore diffusion. Isoniazid removal was consistent between pH 5 and 9, owing to its neutrality under these circumstances. Both isoniazid and the nanofiber surface were positively charged at pH lower than pK2 (pH = 5), resulting in a decreased percentage elimination due to electrostatic repulsive forces. Finally, where isoniazid and nanofibers were negatively charged, there was a considerable drop in % removal at pH greater than pK3. Except at pH 12, similar tendencies were seen for the remaining nine medicines with two pKa values. Because pH 12 is lower than their pK2 value, the remaining nine medicines existed as neutral/zwitterionic forms, resulting in a higher % elimination than isoniazid. The maximal percentage removal at the optimal pH of 5 was in the range of 75.1-92.8 [55].  
A full risk-based evaluation of graphene has been explored but is currently unavailable; nonetheless, many researchers feel that the material does not offer a major health risk based on its composition, although it may pose a concern due to its thin and lightweight nature. With regard to inhalation concerns, graphene is particularly concerning in the particle form [146]. As a result, the physical structure of the graphene-based material and the production procedure are important. In the case of graphene wool, the quartz wool substrate functions as a solid support, facilitating with graphene immobilization [146]. The results of this work show that graphene wool may be employed as an efficient adsorbent for the removal of antiretroviral medication pollutants, notably efavirenz and nevriapine, from aqueous solution. Not enough studies have been conducted to mitigate the presence of ARV drugs in our water system. Many studies have identified and quantified these drugs in our water systems, but a lack of removal technologies to mitigate this issue has been observed. Table 2 Depicts the adsorption capacity, surface area and order of adsorption values of various nanosorbents for the removal of NSAIDs and ARVs in water as discussed.  
\begin{table}
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