Fabrication of ferrous tungstate with enhanced sonocatalytic performance for meloxicam removal

The composites ferrous tungstate (FeWO 4 ) were fabricated as the sonocatalyst for degradation of meloxicam (MEL) in water. The composites are prepared carefully via hydrothermal reaction of sodium tungstate dehydrate and ferrous ammonium sulfate hexahydrate. The morphology of FeWO 4 were controlled successfully, by adjusting the acidity of the reaction solution (pH = 5, 6, 7, 8, 9). Multiple characterization results revealed that the obtained FeWO 4 shared the similar nano-microspheres structure, but with different BET surface area and energy gap. The sonocatalytic experiments showed that FeWO 4 nanomaterials with various synthetic pH values had different sonocatalytic performance on degradation of meloxicam (MEL), and FeWO 4 synthesized at pH 6 reaches maximum of 73.5% on degradation of MEL. This phenomenon was not only due to the moderate BET surface area (31.18 m 2 /g), moderate pore size distribution (10–30 nm) and moderate energy gap (1.73 eV) of FeWO 4 nano-microspheres, ·OH and holes also played a key role in the removal of MEL. The obtained catalyst was proved to be stable enough after four cycles. Our study demonstrates a novel finding, not reported previously, that FeWO 4 could be utilized as a promising sonocatalyst to degrade MEL by ultrasound-driven.