Poly(sodium styrene sulfonate)-Grafted Graphene Oxide: A Novel Carrier for Horseradish Peroxidase Immobilization

Horseradish peroxidase (HRP) was successfully immobilized on a novel enzyme carrier, hydride composite of graphene oxide grafted sodium styrene sulfonate (GO-g-PSStNa), and used for removal of phenol from water. Hydride composite (GO-g-PSStNa) was synthesized using graphene oxide (GO) and sodium styrene sulfonate (SStNa) by atom transfer radical polymerization (ATRP). The morphologies and chemical composition of the resulted samples were investigated by SEM, FTIR and XPS. The results showed that the hydrophilic monomer SStNa was grafted onto the surface of the GO. HRP was immobilized on the surface of hydride material and its loading reached 8.0 mg/g under the immobilization conditions of pH 7 at 0 °C. The removal efficiency of phenol for immobilized HRP had an optimum pH 6, which was shifted to 8 for free enzyme. Both the free and immobilized enzyme shared the same optimal temperature at 40 °C. Immobilized HRP exhibited higher removal efficiency for phenol compared with free HRP. The best immobilization effect could be reused at least eight times. The high phenol removal can be resulted by improvement of catalytic activity of immobilized HPR with adsorption on GO-g-PSStNa support.