A novel iron-glutamate-silicotungstate ternary complex (FeШGluSiW) was synthesized from ferric chloride (FeIII), glutamic acid (Glu), and silicotungstic acid (SiW), and used as a heterogeneous Fenton-like catalyst for 4-chlorophenol (4-CP) degradation at neutral pH value. The prepared FeШGluSiW was characterized using inductively coupled plasma atomic emission spectroscopy, thermogravimetry, Fourier-transform infrared spectroscopy, ultraviolet-visible diffuse reflectance spectroscopy, X-ray diffraction, and field-emission scanning electron microscopy. The results showed that FeШGluSiW has the formula [Fe(C5H8NO4)(H2O)]2SiW12O40·13H2O, with glutamate moiety and Keggin-structured SiW12O404- heteropolyanion. The catalyst showed high catalytic activity in 4-CP degradation in the dark and under irradiation. Under the conditions of 4-CP 100 mg/L, FeШGluSiW 1.0 g/L, H2O2 20 mmol/L, and pH = 6.5, 4-CP was completely decomposed in 40 min in the dark and in 15 min under irradiation. When the reaction time was prolonged to 2 h, the corresponding total organic carbon removals under dark and irradiated conditions were ca. 27% and 72%, respectively. The high catalytic activity of FeIIIGluSiW is resulted from hydrogen bonding of H2O2 on the FeIIIGluSiW surface. The enhanced degradation of 4-CP under irradiation arises from simultaneous oxidation of 4-CP through Fenton-like and photocatalytic processes respectively catalyzed by ferric iron and the SiW12O404- hetropolyanion in FeШGluSiW.
