Photocatalytic Evaluation of Ag₂CO₃ for Ethylparaben Degradation in Different Water Matrices

• Main Authors: Athanasia Petala, Athanasia Nassiou, Dionissios Mantzavinos, Zacharias Frontistis
• Format: Article
• Language: English
• Published: MDPI AG 2020-04-01
• Series: Water
• Subjects: advanced oxidation; endocrine disrupting compounds; waters; visible-light active materials
• Online Access: https://www.mdpi.com/2073-4441/12/4/1180

The present study examines the photocatalytic properties of silver carbonate (Ag₂CO₃) for ethyl paraben (EP) degradation under simulated solar irradiation. Ag₂CO₃ was prepared according to a solution method and its physicochemical characteristics were studied by means of X-ray diffraction (XRD), the Brunauer–Emmett–Teller (BET) method, diffuse reflectance spectroscopy (DRS), and transmission electron microscopy (TEM). Complete EP (0.5 mg/L) removal was achieved after 120 min of irradiation with the use of 750 mg/L Ag₂CO₃ in ultrapure water (UPW), with EP degradation following pseudo-first-order kinetics. The effect of several experimental parameters was investigated; increasing catalyst concentration from 250 mg/L to 1000 mg/L led to an increase in EP removal, while increasing EP concentration from 0.25 mg/L to 1.00 mg/L slightly lowered k_app from 0.115 min⁻¹ to 0.085 min⁻¹. Experiments carried out with the use of UV or visible cut-off filters showed sufficient EP degradation under visible irradiation. A series of experiments were performed in real water matrices such as bottled water (BW) and wastewater (WW), manifesting Ag₂CO₃’s equally high photocatalytic activity for EP degradation. To interpret these results different concentrations of inorganic anions (bicarbonate 100–500 mg/L, chloride 100–500 mg/L) present in aqueous media, as well as 10 mg/L organic matter in the form of humic acid (HA), were added sequentially in UPW. Results showed accelerating effects on EP degradation for the lowest concentrations tested in all cases.