Mahlambi, Precious Nokwethemba.Rochat, Sebastien.Baker, Ben.Simelane, Lindokuhle Anele.2025-02-012025-02-0120232023https://hdl.handle.net/10413/23602Masters Degree. University of KwaZulu-Natal, Pietermaritzburg.The current study was directed to the synthesis and application of low-cost adsorbent for the removal of antiretroviral drugs (ARVDs) such as nevirapine, abacavir and efavirenz in wastewater samples. The study involved the modification and application of liquid chromatography photo diode array (LC-PDA) for the detection of the ARVDs of interest. The good separation of ARVDs was achieved using a gradient elution 50 % ACN: 50 % H2O (0-2 minutes), 70 %ACN: 30 % H2O (3-20 minutes).The macadamia nutshells, Platanus acerifolia leaves (London plane) were explored as easily accessible and eco-friendly adsorbents. The single synthetic route and high surface area of the polymer of intrinsic microporosity number-1(PIM-1) were the distinct properties that were ideal for exploring this adsorbent for removal of ARVDs in wastewater samples. The adsorbents were synthesized and characterized using Fourier transform infrared spectroscopy (FTIR),Scanning electron microscopy (SEM), Brunauer Emmett Teller (BET), Powder X-ray diffraction (PXRD). The results obtained from macadamia nutshell and Platanus acerifolia adsorbent for FTIR characterization were functional groups such O-H, C=O and C=C and many others whereas Platanus acerifolia adsorbent had additional N-H from in addition to one obtained in macadamia adsorbent. The PIM-1 showed CN, C=O and C-H functional groups. SEM showed rod-folded structure and flaky-folded structure for macadamia nutshell adsorbent and Platanus acerifolia leaves adsorbent respectively, whereas PIM-1 exhibited microporous to mesoporous pore on adsorbent surface. The BET showed a surface area, pore diameter and pore volume of 0.1180 m2/g, 27.98 nm, and 8.3×10-5 cm3/g for macadamia nutshells adsorbent and 1.14 m2/g, 0.0024 cm3/g and 4.09 nm for Platanus acerifolia leaves adsorbent. The PIM-1 had a surface of 557.39 cm2/g, pore volume 0.4123 cm3/g and pore diameter 2.96 nm. The PXRD of macadamia and Platanus acerifolia adsorbents had native crystalline cellulose structure whereas PIM-1 had an amorphous material. These characterization results indicated that the adsorbents have the potential to efficiently remove the ARVDs from in contaminated wastewater. Prior to the application of adsorbents, parameters such as adsorption time (5-240 minutes), solution pH (2-10), initial concentration (0.2-2 mg/L), adsorbent mass dosage (0.2-10 mg) and adsorption temperature (15-40°C) were investigated to access the removal efficiency of all the synthesized adsorbents on their ability to remove ARVDs in wastewater samples. Under optimum conditions the adsorption was conducted using 10 mg of the adsorbent in 10 mL wastewater sample spiked at a concentration 1.0 mg/L, at a pH of 7 and stirred at 150 rpm at 30°C. These conditions yielded a removal efficiency greater than 80 %, 90 % and 86 % using macadamia nutshells, Platanus acerifolia leaves and PIM-1 adsorbent, respectively in all ARVDs of interest. The study of adsorption kinetics, adsorption isotherms and thermodynamic model was essential for designing an efficient adsorption process to remove ARVDs which are pollutants of emerging concern. The results obtained showed that pseudo-second-order model well defined the kinetic data, and the adsorption isotherms was well fitted in Langmuir isotherm and adsorption process was exothermic in nature for macadamia nutshells and Platanus acerifolia leaves adsorbent. For PIM-1 adsorbent, the pseudo-second-order was dominant, and the adsorption isotherm was well defined by Freundlich model. Thermodynamic parameters showed that the adsorption was thermodynamically favored, spontaneous, and exothermic in nature. The adsorbents were then applied under optimum conditions and the amount adsorbed of ARVDs from wastewater samples were 94.41, 88.84 and 83.06 mg/g for nevirapine, abacavir and efavirenz respectively for macadamia nutshell adsorbent. For Platanus acerifolia leaves adsorbent, 97.56, 84.75 and 81.56 mg/g amount adsorbed of nevirapine, abacavir and efavirenz. On the other hand, PIM-1 adsorbent had an adsorption capacity of 83.65, 93.83 and 94.56 mg/g amount for nevirapine, abacavir and efavirenz, respectively. Overall, the macadamia nustshells, Platanus acerifolia leaves and PIM-1 adsorbents have illustrated to be efficient and cost-effective adsorbents for removal ARVDs in wastewater samples. However, the two agricultural adsorbents, macadamia nutshell and Platanus acerifolia leaves adsorbents could be highly recommended since their usage is able to reduce land and water pollution which is compromises water quantity which is already at stake across the globe.enAntiretrovirals.Low-cost.Kinetics.Thermodynamics.Isotherms.Thesis