Hydrophobic modification of silica-coated magnetic iron sand with MTES, PTES, and HDTMS for enhanced adsorption of benzene, toluene, and xylene

The issue of oil pollution in aquatic environments necessitates a solution by developing an efficient, and cost-effective adsorbent. This research studied the adsorption characteristics of oil pollutant component representatives (benzene, toluene, and xylene) on silica-coated magnetic iron sand (MIS@SiO 2 ) modified with three types of hydrophobic organosilanes, including methyltriethoxysilane (Me), phenyltriethoxysilane (Ph), and hexadecyltrimethoxysilane (Hd), denoted MIS@SiO 2 /Me, MIS@SiO 2 /Ph, and MIS@SiO 2 /Hd, respectively. The organosilane concentrations were varied at 5, 10, 15, and 20 mmol, with a constant weight of 0.5 g MIS and 1 mol NaSiO 3 . The results showed that the optimal contact times for benzene, toluene, and xylene were 210, 150, and 180 min, respectively, with optimal concentrations of 150 mg/L, 100 mg/L, and 50 mg/L. The maximum adsorption capacities obtained were 99.64 mg/g for benzene and 114.29 mg/g for toluene using MIS@SiO 2 /Hd3 (15 mmol), and 135.71 mg/g for xylene using MIS@SiO 2 /Ph2 (10 mmol). The adsorption kinetics followed the pseudo-second-order model, while the adsorption isotherm conformed to the Freundlich model. These findings highlight the potential of the developed material as an effective adsorbent for mitigating oil pollution in aquatic environments. • Hydrophobic adsorbents were synthesized from silica-coated magnetic iron sand and organosilanes. • Maximum adsorption: benzene 99.64 mg/g, toluene 114.29 mg/g, xylene 135.71 mg/g. • Adsorption followed the pseudo-second-order kinetics and the Freundlich isotherm. • The material shows strong potential for treating oil pollution in water systems.