Adsorption and photocatalytic degradation performances of methyl orange-imprinted polysiloxane particles using TiO2 as matrix

Combining molecular imprinting technique with titanium dioxide (TiO₂) photocatalysis technique can improve the degradation ability and selectivity of TiO₂ nanoparticles towards pollutants. In this work, methyl orange-imprinted polysiloxane particles (MIPs) were synthesized using TiO₂ as matrix and silane as functional monomers. The adsorption capacity (Q_e) of MIPs was 20.48 mg·g⁻¹, while the imprinting efficiency (IE) was 3.4. Such MIPs exhibited stable imprinting efficiencies and adsorption efficiencies towards methyl orange (MO) in the multi-cycle stability test. Photocatalytic degradation performances of both MIPs and non-imprinted polysiloxane particles (NIPs) were investigated. Compared with NIPs, MIPs exhibited better photocatalytic degradation performance towards MO, with the degradation efficiency of 98.8% in 12 min and the apparent rate constant (K_obs) of 0.077 min⁻¹. The interaction between silane and MO was also studied through molecular dynamics simulation. This work provides new insights into the use of silane for the synthesis of MIPs as well as the molecular imprinting technique for applications in the field of TiO₂ photocatalysis.