Chelation mode impact of copper(II)- aminosilane complexes immobilized onto graphene oxide as an oxidative catalyst

Copper (II) was chelated with mono-, di-and tri-aminosilane functionalized graphene oxide ( GO) and denoted as CAT1, CAT2, and CAT3.GO/Cu(II)- aminosilane complexes were characterized by Fourier transform infrared, Xray diffraction, energy dispersive X-ray, thermogravimetric, and inductively coupled plasma, Brunauer-EmmettTeller, transmission and scanning electron microscopy techniques. The Cu(II) to ligand ratio was found nearly fixed about the value of 1: 2. The surface areas of CAT1, CAT2 and CAT3 were 61.14, 30.52, and 30.58 m(2) g(- 1). Indigo carmine dye (IC), as a model, was subjected to oxidative degradation utilizing the immobilized complexes as catalysts and H2O2 as an oxidant. The data were found to fit the second - order kinetics with respect to [ IC]. Different from Fenton-like process, an enhancement in the activation of H2O2 for oxidation was noticed in going from acidic to alkaline. Enthalpy-entropy compensation ( EEC) between these heterogeneous systems has been discussed. The reactivity of the suggested chelation modes was arranged in the order; mode 1 > mode 2 > mode 3. A complete decolorization with 94.9% degradation of 10(- 4) mol l(- 1) IC solution to inorganic end products at pH = 8 with H2O2 of 0.025 mol l(- 1) in the presence 80 mg l(- 1) of CAT1 and a rate constant of 6.74 x10(- 2) l mol(- 1) min(- 1) was confirmed by total organic carbon (TOC) technique. Stability tests and the possibility of recycling approved the validity of the catalysts in the real environmental applications.