This paper proposes an optical method which allows determination of the organic compound concentration in water by measurement of the UV (ultraviolet) absorption at a wavelength of 250 nm~300 nm. The UV absorbance was analyzed by means of a multiple linear regression model for estimation of the total organic carbon contents in water, which showed a close correlation with the UV absorbance, demonstrating a high adjusted coefficient of determination, 0.997. The comparison of the TOC (total organic carbon) concentrations for real samples (tab water, sea, and river) calculated from the UV absorbance spectra, and those measured by a conventional TOC analyzer indicates that the higher the TOC value the better the agreement. This UV absorbance method can be easily configured for real-time monitoring water pollution, and built into a compact system applicable to industry areas.

Presently, significant attention has been paid towards the rational synthesis of nanostructured anode and cathode electrode materials for assembling high-performance supercapacitors. Despite significant progress being achieved in designing cathode electrode materials, anode electrode materials with high capacitance are hardly investigated. In the present article, a tungsten oxide (WO₃) thin film is prepared on a flexible stainless steel substrate by a wet chemical method and used as an anode electrode to fabricate a flexible asymmetric supercapacitor (ASC). An electrochemical investigation of the WO₃ thin film shows a maximum specific capacitance of 530 F g⁻¹ at 1 mA cm⁻² in a potential window of 0 to −0.8 V in 1 M Na₂SO₄ electrolyte. In addition, a highly energetic, flexible ASC device is assembled using a WO₃ thin film as an anode, a MnO₂ thin film as a cathode and polymer gel as an electrolyte. The as-assembled MnO₂//WO₃ ASC device exhibited a stable electrochemical potential window of 1.8 V and better cycling stability. What's more, the flexible MnO₂//WO₃ ASC device achieves a high specific capacitance of 115 F g⁻¹ with an acceptable specific energy of 52 W h kg⁻¹ at a current density of 3 mA. Hence, the proposed flexible MnO₂//WO₃ ASC device creates one more option for anode materials to develop flexible energy storage devices.