*3.3. Degradation Procedure*

RhB degradation was used to assess the degradation activity of the prepared samples. For the Fenton-like reaction, 20 mg of the prepared catalyst samples was added into the RhB solution (20 ppm, 50 mL), and the solution was stirred in the dark for 30 min. At 10 min before adding Na2S2O8, the absorbance at its characteristic absorption peak of 550 nm was measured to check the adsorption ability of the prepared samples. Subsequently, 100 µL of Na2S2O<sup>8</sup> (2 M) was added to dye solution. After a given time interval, 1 mL of suspension was sampled with a plastic pipette and this aliquot was quenched immediately by adding 10 µL NaN<sup>3</sup> (1 M) and filtered by a 0.22-µm syringe filter organic membrane to remove catalyst particles. The concentration of RhB was measured using a Synergy H1 hybrid multimode microplate reader (BioTek Instruments, Winooski, VT, USA) at its characteristic absorption peak of 550 nm. Similar processes were performed for other catalysts (Cu2S and FeS2), dyestuffs (R6G, MB, and MO), and organic pollutant (BPA). After the experiment, TOC concentration was determined on an Elementar Acquray TOC analyzer (Elementar Analysensysteme GmbH, Langenselbold, Germany) to evaluate the extent of mineralization.
