Heating and ultraviolet irradiation: Gas pressure meter-based analytical system for on-site and rapid monitoring of permanganate index (CODMn).

• Organic pollutants were oxidized into gases by acidic KMnO 4. • Gas pressure meter was served as a portable detector. • Heating and ultraviolet irradiation were used for assisting catalytic gas generation. • A portable analytical system was fabricated for COD Mn on-site and rapid analysis. Permanganate index (COD Mn) is one of the important indicators of surface water quality measurement. Herein, a portable analytical system was developed for on-site and rapid analysis of COD Mn , organic substances in water were oxidized and transformed into gases, so that COD Mn concentration was converted into a change of gas pressure signal, the pressure signal change was further detected by a gas pressure meter. Heating method and ultraviolet (UV) irradiation method were used as assisting technologies for oxidization of organic substances by acidic KMnO 4 , a linear range of 2–150 mg l -1 and a detectable limit of 2 mg l -1 were obtained. Those methods were further applied to the detection of COD Mn in various water samples (lake waters and domestic sewage) and certified reference water samples (BWZ 6974–2016C and BWZ 7617–2016), with recoveries of 89–111 %. Among them, a portable analytical system based on UV irradiation gas pressure meter was further established and used for the analysis of COD Mn in field. It is a promising analytical system/device for COD Mn monitoring in field, offering advantages of low-cost, easy-operation, portability and rapidness. [Display omitted] [ABSTRACT FROM AUTHOR]