Catalytic hydrolysis of cellobiose using different acid-functionalised Fe3O4 magnetic nanoparticles.

The present study demonstrated the preparation of three different acid-functionalised magnetic nanoparticles (MNPs) and evaluation for their catalytic efficacy in hydrolysis of cellobiose. Initially, iron oxide (Fe3O4)MNPs were synthesised, which further modified by applying silica coating (Fe3O4-MNPs@Si) and functionalised with alkylsulfonic acid (Fe3O4-MNPs@Si@AS), butylcarboxylic acid (Fe3O4-MNPs@Si@BCOOH) and sulphonic acid (Fe3O4-MNPs@Si@SO3H) groups. The Fourier transform infrared analysis confirmed the presence of above-mentioned acid functional groups on MNPs. Similarly, X-ray diffraction pattern and energy dispersive X-ray spectroscopy analysis confirmed the crystalline nature and elemental composition of MNPs, respectively. TEM micrographs showed the synthesis of spherical and polydispersed nanoparticles having diameter size in the range of 20-80 nm. Cellobiose hydrolysis was used as a model reaction to evaluate the catalytic efficacy of acid-functionalised nanoparticles. A maximum 74.8% cellobiose conversion was reported in case of Fe3O4-MNPs@Si@SO3H in first cycle of hydrolysis. Moreover, thus used acid-functionalised MNPs were magnetically separated and reused. In second cycle of hydrolysis, Fe3O4-MNPs@Si@SO3H showed 49.8% cellobiose conversion followed by Fe3O4-MNPs@Si@AS (45%) and Fe3O4-MNPs@Si@BCOOH (18.3%). However, similar pattern was reported in case of third cycle of hydrolysis. The proposed approach is considered as rapid and convenient. Moreover, reuse of acid-functionalised MNPs makes the process economically viable.