Photocatalytic degradation of paracetamol using aluminosilicate supported TiO₂

The continuous growth of the pharmaceutical drug industry has escalated the problem of pharmaceutical waste disposal, and subsequent contamination of aquatic bodies. Paracetamol is one of the most prescribed and purchased drugs that has been widely detected in wastewater and surface water. The present study investigated paracetamol degradation by photocatalytic treatment in a batch system using TiO₂ supported on aluminosilicate recovered from waste LED panel (ATiO₂). The prepared ATiO₂ catalyst was characterized for morphology, elemental composition and crystallinity using scanning electron microscope (SEM) with electron dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD), respectively. ATiO₂ was spherical in morphology with a predominance of the anatase phase of TiO₂ and an average size of ∼15 nm. Subsequently, the effects of operating parameters, viz., initial paracetamol concentration (1-10 mg/L), catalyst dosage (0.5-4.0 g/L) and pH (4-10) on paracetamol degradation were investigated using central composite design (CCD). A polynomial model was developed to interpret the linear and interactive effect of operating parameters on the paracetamol degradation efficiency. About 99% degradation efficiency of paracetamol was obtained at optimum conditions (Initial paracetamol concentration ∼2.74 mg/L, ATiO₂ dosage ∼2.71 g/L and pH ∼ 9.5). The mechanism of paracetamol degradation was adsorption on aluminosilicate and subsequent degradation by TiO₂. ATiO₂ could be effectively reused up to 3 cycles, with <5% decrease in the degradation efficiency.