“…The RB5 solution was scanned by a spectrophotometer (Metertech, SP-830, Taiwan) from 320 nm to 900 nm, and the optical absorption curve plotted. Decolourization of RB5 was determined using the characteristic peak absorbance (598 nm), a similar method was reported for detecting the dyes 7 and RB5 mineralization was determined by results of a TOC analyzer (Tekmar, Dohrmann Phoenix 8000, USA). The Zeta potential of the magnetic catalyst (SiO 2 /Fe 3 O 4 ) in the aqueous phase was measured using a Zetasizer Nano Instrument (Nano ZS, Red badge ZEN 3600, UK) with the solution pH adjusted between 2 and 7.5 by adding NaOH and HCl.…”