A comparison between adsorption and photocatalytic degradation for the management of sulfamethoxazole in water

Sulfamethoxazole (SMX) is one of the majority of vital antibiotic medications and is widely employed for the treatment of bacterial infections. This pharmaceutical residue has been detected in surface water and sewage wastewater treatment plants (WWTP). Moreover, it has negative impacts on humans and ecosystems. The main aim of this work is to remediate water from SMX using two different water treatment techniques i.e. adsorption and photocatalytic degradation by using silver phosphate (Ag₃PO₄). The materials were characterized using structural (e.g. elemental dispersive X-ray spectroscopy (EDX), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD), and morphological (Brunauer-Emmett-Teller (BET), and scanning electron microscopy (SEM)) analytical methods. The percentage of elimination of SMX at optimum solution pH, adsorbent dose, initial drug concentration and equilibrium time, was 95.15% by adsorption which corresponds to a maximum adsorption capacity (Q_max) of 1299.7 mgg^-1 and the removal percentage of SMX was 98.2% according to the photocatalytic degradation. Fritz-Schlunder model is the best to describe the adsorption of SMX onto Ag₃PO₄. Ag₃PO₄ can be efficiently recycled as an adsorbent using distilled water up to 4 cycles followed by ethanol 70% and turmeric extract. For the recycling of Ag₃PO₄ as a photocatalyst, 0.1 M NaOH is the best solvent followed by water, ethanol 70%.