A combined photocatalytic determination system for chemical oxygen demand with a highly oxidative reagent.
This study focuses on the proposal and validation of a combined photocatalytic (PC) system and a three-parameterized procedure for the determination of chemical oxygen demand (COD; PcCOD(combined)), with a highly oxidative reagent utilized as a photoelectron scavenger and signal indicator. The PcCOD(combined) was the functional combination of photon-efficient thin-layer photocatalytic oxidation, conventional bulk-phase photocatalytic oxidation and photocarrier-efficient high-activity photocatalytic reduction in one single photodigestion system, and consequently, this system possessed high photon-utilization efficiency, automatic stirring function and satisfactory determination characteristics. In comparison with the conventional one-parameterized procedure, the three-parameterized procedure introduces the blank and total photocatalytic reduction responses as two of the three significant analytical parameters. Under the optimized pH value of 3.0-4.5 and a rotating rate of 40 rpm, the representative KMnO(4) species was used for the PcCOD(combined) system as the combined high-activity oxidant, and a narrow and reliable analytical linear range of 0-260 mg L(-1) was achieved during the 10 min duration of the determinations. No observable interference of Cl(-) was found at concentration of the ion up to 2000 mg L(-1). A real sample analysis indicated that the measured values for the PcCOD(combined) were all within a relative deviation below 5% of COD(Cr) of the standard method, which further validates the practical feasibility of the proposed PcCOD(combined) system.
Key Laboratory of Pollution Processes and Environmental Criteria of Ministry of Education, College of Environmental Science and Engineering, Nankai University, Tianjin 300071, PR China.
Aiyong
A
Zhang
Minghua
M
Zhou
Qixing
Q
Zhou
D057919:Biological Oxygen Demand Analysis / Q000379:methods*; D002384:Catalysis; D004784:Environmental Monitoring; D006863:Hydrogen-Ion Concentration; D010084:Oxidation-Reduction; D010100:Oxygen / Q000032:analysis*; D010545:Peroxides / Q000737:chemistry*; D017785:Photons
D010545:Peroxides; C097259:potassium manganese peroxide; D010100:Oxygen