Photocatalytic Evaluation of Ag2CO3 for Ethylparaben Degradation in Different Water Matrices

Abstract

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 kapp 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.

Overview of Catalytic Removal of Parabens from Water and Wastewater

“…59 Moreover, AgCl/Ag 3 PO 4 held superior stability and regeneration capacity for MeP degradation (5th cycle, only 6% reductions in removal) than pristine Ag 3 PO 4 (5th cycle, 74% reductions) (Figure 3c,e). 59 In the same line, modification of Ag 2 O via C doping has been carried out, whereby the widening of the band gap (1.3 to 2.46 eV) enabled 55% of EtP degradation (55%) under visible light 60 (Figure 3b). 71,72 Similar to Ag 3 PO 4 , CB of Ag 2 CO 3 consists of hybridized Ag ions in the s orbital (Ag s−Ag s), which decreases the effective mass of e − 's and enhances the migration of charged species.…”

“…74,75 It is also important to mention that under acidic conditions, Ag-based metal oxide complexes (Ag 2 CO 3 and Ag 3 PO 4 ) leached into the solution, thus affecting the stability/recyclability (Figure 3f). 60,76 The main bottleneck in the Ag-based photocatalysts is aggregation. Thus, it is recommended to use capping agents like graphene oxide (GO) or reduced graphene oxide (rGO) to reduce the aggregation phenomenon of Ag-based catalysts.…”

“…It should be noted that HA (100 mg L –1 ) gradually enhanced the degradation kinetics (0.320 min –1 ) compared to real WW (0.082 min –1 ) (Figure d) for Ag 2 CO 3. This is because of the self-oxidation behavior of the catalyst, whereby the transfer of e – ’s to the Ag 2 CO 3 or abstraction of e – ’s delays the e – –h + recombination and increases EtP degradation. , It is also important to mention that under acidic conditions, Ag-based metal oxide complexes (Ag 2 CO 3 and Ag 3 PO 4 ) leached into the solution, thus affecting the stability/recyclability (Figure f). , The main bottleneck in the Ag-based photocatalysts is aggregation. Thus, it is recommended to use capping agents like graphene oxide (GO) or reduced graphene oxide (rGO) to reduce the aggregation phenomenon of Ag-based catalysts. , …”

“…Panel b reproduced with permission from ref . Copyright Elsevier, 2013 and panels d–f reproduced with permission from ref . Creative Commons Attribution License.…”

Microwave Irradiation vs. Structural, Physicochemical, and Biological Features of Porous Environmentally Active Silver–Silica Nanocomposites

“…Moreover, the antimicrobial effect resulted from releasing silver ions due to the dissolution of silver particles in the suspension or after visible light illumination [ 28 , 29 ]. Other applications of silver carbonate are focused on pollution removal, fuel production [ 30 , 31 , 32 ], and the photodegradation of rhodamine B (RhB) [ 33 , 34 ], methylene blue [ 35 , 36 ], and ethylparaben [ 37 ].…”