## 6 Removal of Pharmaceutical Pollutants in Wastewater by Nanosorbents
### Removal of Non-Steroidal Anti-Inflammatory Drugs
Ibuprofen adsorption occurs due to the presence of amino groups in the L-cysteine molecule, which can be implicated in ibuprofen attachment. At pH 6.0, a maximum ibuprofen elimination effectiveness of 82.90% was recorded with 30 mg of nanomaterial dose. Instead of L-cysteine, an amine functionalized magnetic silica nanocomposite was studied for the removal of ibuprofen from aqueous streams ([PERSON] and [PERSON] [140]). The adsorption process was observed to attain equilibrium during the first 15 min, with ibuprofen adsorption efficiency ranging between 94 and 97%. At pH 7.0 at room temperature, the adsorption capacity of the nanocomposites for ibuprofen was 58-59 mg/g. The adsorption process was discovered to follow pseudo-second-order kinetics and matched well with the Langmuir isotherm model, indicating adsorption on the nanocomposite's homogeneous surface. Adsorption of diclofenac by magnetic adsorbent was lower in the beginning, suggesting that physical bonds formed solely on the surface of the nanoparticles, and when diclofenac amount and adsorption time increased, the pollutant diffused into the pores [141]. The maximum contact duration was 120 min, after which saturation of free sites on the sorbent was observed, which was utilized to determine that the process followed a pseudo-first-order kinetic model. Thermodynamic investigations revealed that diclofenac assimilation increased with increasing temperature, indicating an endothermic and entropically driven reaction, since a negative value for entropy change was observed [141]. Optimal sorption occurred at 298 K, and thermodynamic analysis demonstrated positive enthalpy and entropy. The latter suggest that pollutant removal rises with increasing temperature and that the sorbent-sorbate interacts well. A magnetic adsorbent composed of genipin-crosslinked chitosan/-graphene oxide-SO\({}_{3}\)H was produced and utilized as an ibuprofen adsorbent. When analyzed using chitosan nanoparticles, the sorption process appeared to fit ideally with the Freundlich isotherm and pseudo-second-order kinetics, showing single layer-based attachment with persistent homogeneous contact with the adsorbent sites. Ibuprofen's maximal adsorption capacity improved from 113.27 to 138.16 mg/g when the temperature increased from 298 to 313 K. Thermodynamic research revealed that ibuprofen adsorption reduced with increasing temperature, due to the formation of a physical link between the polymer and the ibuprofen, which is destroyed by high temperatures. The adsorption capacity was stable at 85% after five cycles of adsorption-desorption with a simple 0.01 M NaOH solution treatment [106]. Activated carbons have been the most often utilized sorbent for the removal of pharmaceuticals from wastewater, and several functionalization processes have been developed throughout the years [142]. Activated carbon derived from beer industry waste with a specific surface area of 364 m\({}^{2}\)/g was used to successfully remove acetaminophen from wastewater [142]. The process best resembled the Langmuir model, illustrating a monolayer contact with the recycled adsorbent. It can be deduced that there is an interaction with a particular spot on the sorbent, with no internal acetaminophen reactions. Naproxen removal from wastewater was investigated using activated carbon made from Indian gooseberry seed shells combined with surface-modified graphite powder and silver nanoparticles [93]. The adaption of several methods of interaction, primarily through electrostatic interaction between the anions of pharmaceuticals and the positively charged groups of the sorbent, was enhanced by pseudo-second-order kinetics. Adsorption regeneration with simple acidic washing revealed an \(\sim\)18.2% drop in desorption efficiency across the cycles [93]. Biochar is a by-product waste from the syngas manufacturing process that was magnetized and utilized for ibuprofen adsorption [103]. Adsorption was shown to be a quick process for a contact duration of 5 min, after which the sorption sites were entirely used up.