OICC Press Iranian Journal of Catalysis 2345-4865 6 5 2024 02 03 Nano cotton-shape mesoporous (NCSM) modified by Fe3O4: Green, magnetic and reusable catalytic system for dechlorization of bromothymol blue (BTB) EN Hamid Aliyan Department of Chemistry, Shahreza Branch, Islamic Azad University, 86145-311, Iran. Journal Article 2024 02 03 Fe3O4-containing cotton-like mesoporous silica system (Fe3O4@NCSM) was studied with regard to its performance towards the photodecolorization of bromothymol blue (BTB) aqueous solution. The surface properties of the functionalized catalyst were analyzed by a series of characterization techniques like FTIR, XRD, BET, SEM and TEM. The N2 Adsorption–desorption analysis shows that the mesostructure of silica remains intact after Fe3O4 modifications, while the spectral technique shows the successful encapsulating of the neat Fe3O4 inside the porous silica support. The optimum values of the experimental parameters which affect the degradation efficiency were obtained as: 0.15 g L−1 of the photocatalyst, 25 ppm dye concentration and pH 5.6.