抄録
The total phosphorus measurement in wastewater based on the molybdenum blue absorption spectrophotometry was automated and continued by using “continuous micro flow analysis” technique. A sample, an oxidizing reagent and a coloring reagent are continuously pumped with a peristaltic pump at the flow rates of 200, 100 and 100μ1/min, respectively. The sample is first mixed with the oxidizing reagent and the mixture is introduced into an oxidation reaction tube (0.5mm i.d. and 8m length) in an aluminium block bath heated at 140°C. All phosphorus compounds are converted to phosphate ion during the heating for about 5minutes. A platinum wire with a diameter of 0.2mm is inserted into the reaction tube to serve as a catalyst for the oxidation reaction. The stream from the reacton tube is then mixed with a stream of the coloring reagent. The color intensity of the molybdenum blue formed in the mixed stream introduced into a flow cell of a photometer was measured. The absorbance at 880nm is continuously recorded, thus the total phosphorus in the sample is automatically measured. The method was successfully applied to continuous monitoring of total phosphorus concentration in wastewater from chemical laboratories.
