CN100504360C - A method for measuring chemical oxygen demand based on photocatalytic chemiluminescence and its detection device - Google Patents

Abstract

This invention relates to a method for detecting needing volume of chemical oxygen in solution with optical catalyzed chemical luminescence and a detector, which utilizes ultraviolet light emitted by an UV-lamp to catalyze and degradate organic pollutants in water, the product of which generates strong chemical luminescence with luminal of a luminous reagent and the luminous strength forms a linear relation with organics concentration in the sample and the theoretical chemical oxygen-needed volume value so as to realize the test. The detector is composed of a creepage pump for transporting water samples and luminous reagents, an optical catalyst reaction apparatus made up of a closed quartz tube with a UV-lamp in it and an optical catalyst reaction tube winded on the outer wall of the quartz tube and an UV-lamp condensation water circulation flow channel, a chemical luminous flow cell, a photoelectric detect device for testing luminous signals and a data process system connected with the detector.

Description

A kind of method and detection means thereof based on photocatalysis chemical luminescent detecting chemical oxygen demand (COD)

Technical field the invention belongs to chemical and environmental science, particularly a kind of method and detection means thereof of measuring chemical oxygen demand of water body based on the photocatalysis chemiluminescence principle.

Background technology chemical oxygen demand (COD) (Chemical Oxygen Demand, be called for short COD) is one of important indicator of estimating water pollution, is the project of conventional determining during water quality monitoring is analyzed.And still there are many drawbacks in the method for conventional determining COD at present: long as analysis time, and (the Ag of consume expensive ₂SO ₄), poisonous (HgSO ₄) reagent, require high to operator's experimental skill.Therefore set up a kind of simply, the COD assay method is significant fast.In recent years, the method for photocatalysis to degrade organic matter has caused people's very big concern.Analytical work persons have begun photocatalysis is incorporated into analysis field.Recently, Australia analytical work person has proposed a kind of COD assay method of ultraviolet catalytic electrochemical principle, but the influence of this method exists factors such as electrode is polluted easily, poor reproducibility is difficult to have actual application value.The core technology of patent of the present invention is that the ultraviolet light that utilizes uviol lamp to launch carries out photocatalysis treatment to the organic contaminant in the water body, solution after photo-irradiation treatment mixes the generation chemiluminescence with the luminescence reagent luminol, this chemiluminescence intensity becomes certain linear relationship with solution C OD, utilizes this principle can realize detection to water body COD.This method is a kind of new method of simple, quick, sensitive mensuration chemical oxygen demand (COD).Literature search finds, utilizes the water sample after the photocatalysis treatment to realize the assay method of the chemical oxygen demand (COD) in the water body is not appeared in the newspapers as yet with this principle of luminol reaction generation chemiluminescence.

Summary of the invention the purpose of this invention is to provide a kind of method and detection means thereof based on photocatalysis chemical luminescent detecting chemical oxygen demand (COD).It is characterized in that: the detection means of described photocatalysis chemical luminescent detecting water body COD, it constitutes the airtight quartz ampoule of transmission water sample and the peristaltic pump of luminescence reagent, built-in uviol lamp and is wound in light-catalyzed reaction device, chemiluminescence flow cell, the photoelectricity testing part that detects luminous signal and the data handling system that links to each other with photoelectricity testing part that light-catalyzed reaction pipeline and uviol lamp condensate water circulation stream three on this quartz ampoule outer wall are constituted; The method of described mensuration water sample COD is to utilize ultraviolet light that the organism in the water sample is had photocatalytic Degradation, the free radical that produces or other reactive intermediate and luminescence reagent luminol (Luminol) can produce this characteristic of strong chemiluminescence, and the COD of water sample is measured.

Its testing process is: at first open uviol lamp and condensation cycle water in the light-catalyzed reaction device, water sample solution is transferred in the photo catalysis reactor by the flow velocity of peristaltic pump with 0.1-1.5mL/min, and in photo catalysis reactor, stop 0-3min, the luminescence reagent luminol solution is by the flow velocity input of another peristaltic pump with 0.1-1.5mL/min, with mix through the water sample solution after the ultraviolet light illumination after enter into flow cell, produce chemiluminescence, the optical signals photoelectric detector detects, and is delivered to data handling system.Get redistilled water and do blank assay according to above-mentioned testing process.Light signal and the light signal difference of blank sample and the concentration and all linear variation of theoretical COD value of analyzed solution that water sample produces.

Described light-catalyzed reaction device constitutes: the center is a uviol lamp, uviol lamp is positioned in the airtight quartz glass tube, the peripheral light-catalyzed reaction pipeline that twines quartzy material (or transparent teflon material) of this airtight quartz ampoule is positioned over airtight quartz ampoule and the peripheral reaction pipeline that twines thereof in the glass container of cooling circulating water then.

The invention has the beneficial effects as follows and to realize the chemical oxygen demand (COD) in the water body (COD) fast detecting.Its principal feature is exactly can be to the various organic contaminant catalytic degradations in the water body, its catalytic degradation product oxidation luminol and produce chemiluminescence, and luminous intensity is directly proportional with the theoretical COD value of organic contaminant to be measured.Based on this principle, can realize the mensuration of chemical oxygen demand (COD) in the water body.The advantage of this invention mainly contains: analysis speed is fast, the detection sensitivity height, and operation only needs a kind of reagent of luminol (Luminol) easily, is a kind of analytical approach of green.

Description of drawings Fig. 1 is based on photocatalysis chemiluminescence COD detector arrangement schematic diagram

Fig. 2 is a light-catalyzed reaction device structural drawing

Embodiment the present invention is a kind of method and detecting device thereof that utilizes the ultraviolet catalytic effect to measure water sample chemical oxygen demand (COD) (COD).The formation of this ultraviolet catalytic detecting device is: uviol lamp 14 is positioned in the airtight quartz glass tube 16, peripheral quartzy material (or teflon material) the light-catalyzed reaction pipeline 15 that twines of this quartz glass tube, be positioned over then in the glass container 17 that is full of condensation cycle water, condensation cycle water enters from glass container inlet 9, gets rid of from exporting 7 then; Analyzed water sample 11 is input in the light-catalyzed reaction pipeline 15 through peristaltic pump 10, then from exporting 13 outputs; Luminescence reagent luminol (Luminol) 1 mixes with the water sample solution through light-catalyzed reaction of outlet 13 outputs through peristaltic pump 2 inputs, and the pond 3 that circulates then produces chemiluminescence signal, discharges through waste liquid mouth 4 then; The optical signals photoelectric detector detects 6, is delivered to data handling system 5, and through calculation process, light signal is linear change with the variation of the theoretical COD value of solution concentration and solution.The method of described mensuration water sample chemical oxygen demand (COD) (COD) is: catalytic degradation reaction can take place in the organism in the solution under the UV-irradiation effect, chemiluminescence reaction further takes place with luminescence reagent luminol (Luminol) in free radical or ion that this reaction produces under alkali condition, luminous intensity is directly proportional with the theoretical COD value of organic contaminant to be measured, utilize this characteristic, set up fast measuring water sample chemical oxygen demand (COD) (COD).

Its testing process is: open condensation recirculated water, condensate water 9 enters condensed water container 17 from entering the mouth, discharge through exporting 7 then, open the uviol lamp power supply 12 in the light-catalyzed reaction device, water sample solution 11 is transferred in the light-catalyzed reaction pipeline 15 by the flow velocity of peristaltic pump 10 with 0.1-1.5mL/min, and at this stop 0-3min, by outlet 13 outputs, concentration is 1.0 * 10 then ^-6-1.0 * 10 ^-33mol/L luminescence reagent luminol solution 1 is by the flow velocity input of another peristaltic pump 2 with 0.1-1.5mL/min, with through after the three-way pipe place is mixed, being entered into flow cell 3 by water sample solution behind the ultraviolet lighting, produce chemiluminescence, optical signals photoelectric detector 6 detects, and is delivered to data handling system 5.Get redistilled water and do blank assay according to above-mentioned testing process.Light signal and the light signal difference of blank sample and the concentration and all linear variation of theoretical COD value of analyzed solution that water sample produces.

Lifting several examples is below again further specified effect of the present invention.

Embodiment one: the analog sample experiment.Choose citric acid, glucose, lactose, malonic acid, oxalic acid, sucrose and this six kinds of organic compounds for detecting sample, the mixed solution of preparing the single solution of above-mentioned organic compound and six kinds of material compositions respectively is as water sample.Open uviol lamp condensation cycle water, condensate water 9 enters condensed water container 17 from entering the mouth, and discharges through exporting 7 then, opens the uviol lamp power supply 12 in the light-catalyzed reaction device, and the power of uviol lamp 14 is 125 watts.Water sample is written in the photocatalytic degradation reaction pipeline 15 by peristaltic pump 2, closes peristaltic pump 2 then, and residence time 3min opens peristaltic pump 2 then.Concentration is 5.0 * 10 ^-5Mol/L luminescence reagent luminol, mixes in flow cell 3 with water sample after the light-catalyzed reaction with the input of flow velocity 1.5mL/min speed through peristaltic pump 11, and the chemiluminescence signal of generation is detected by photoelectric detector 6, analyzes through data handling system 5 then.By the single and hybrid analog-digital simulation water sample that above-mentioned six kinds of organism are prepared, luminous signal value that is obtained in this detecting device and its theoretical COD value are linear, and can well fit.

Embodiment two: the standard model experiment.Six kinds of standard items water samples that determination object provides for national standard material center, its numbering is divided into GBW (E) 080274 CODMn, GBW (E) 080427 CODMn, GBW (E) 080428 CODMn, GBW (E) 080424 CODCr, GBW (E) 080425 CODCr and GBW (E) 080426 CODCr.Wherein GBW (E) 080274 CODMn adopts high purity material glucose and three purified water accurately to prepare for the Clean Operating Lab of (20 ± 2) ℃ in room temperature, this standard substance is mainly used in calibration instrument or carries out the quality control of analytic process and method evaluation etc., remains five kinds and is the simulation natural water-like.The mensuration process is: open uviol lamp condensation cycle water, condensate water 9 enters condensed water container 17 from entering the mouth, and discharges through exporting 7 then, opens the uviol lamp power supply 12 in the light-catalyzed reaction device, and the power of uviol lamp 14 is 125 watts.Water sample is written in the photocatalytic degradation reaction pipeline 15 by peristaltic pump 2, closes peristaltic pump 2 then, and residence time 3min opens peristaltic pump 2 then.Concentration is 5.0 * 10 ^-5Mol/L luminescence reagent luminol, mixes in flow cell 3 with water sample after the light-catalyzed reaction with the input of flow velocity 1.5mL/min speed through peristaltic pump 11, and the chemiluminescence signal of generation is detected by photoelectric detector 6, analyzes through data handling system 5 then.Because first three kind standard all is to demarcate with the standard permanganimetric method, so with GBW (E) 080274 CODMn calibration value preparation series of standards calibration curve, measure simulation natural water-like GBW (E) 080427 CODMn with this method again, GBW (E) 080428 CODMn. measurement result and calibration value are fine to coincide.Measure six kinds of standard water samples with this law, first three is planted the sample determination result and omits height than calibration value, and then three kinds of samples are more lower slightly than calibration value (standard potassium dichromate method).This method oxidability is described than permanganimetric method height, approaching with potassium dichromate method.

Embodiment three: environmental water sample is measured.Artificial lake water and certain the chemical plant sewer gathered respectively in Chengdu, the Sichuan Province Nan Heshui of municipal government, each park, city are measured.The mensuration process is: open uviol lamp condensation cycle water, condensate water 9 enters condensed water container 17 from entering the mouth, and discharges through exporting 7 then, opens the uviol lamp power supply 12 in the light-catalyzed reaction device, and the power of uviol lamp 14 is 125 watts.Water sample is written in the photocatalytic degradation reaction pipeline 15 by peristaltic pump 2, closes peristaltic pump 2 then, and residence time 3min opens peristaltic pump 2 then.Concentration is 5.0 * 10 ^-5Mol/L luminescence reagent luminol, mixes in flow cell 3 with water sample after the light-catalyzed reaction with the input of flow velocity 1.5mL/min speed through peristaltic pump 11, and the chemiluminescence signal of generation is detected by photoelectric detector 6, analyzes through data handling system 5 then.Measured value and standard permanganate indices method can finely fit, and the reliability of this method has been described.

Claims (6)

1. A method for measuring chemical oxygen demand based on photocatalytic chemiluminescence, characterized in that: the organic matter in the solution will undergo a catalytic degradation reaction under the action of ultraviolet light irradiation, and the free radicals or ions produced by the reaction will be released under alkaline conditions. Further chemiluminescent reaction with luminescent reagent luminol (Luminol), the luminous intensity is directly proportional to the theoretical COD value of the organic pollutant to be measured, using this characteristic to establish a rapid determination of the chemical oxygen demand (COD) of water samples; its The detection process is: first turn on the ultraviolet lamp in the photocatalytic reaction device and condense the circulating water, the water sample solution is transferred to the photocatalytic reactor by the peristaltic pump at a flow rate of 0.1-1.5mL/min, and stays in the photocatalytic reactor 0-3min, the concentration is 1.0×10 ^-6 -1.0×10 ^-3 mol/L luminescent reagent luminol solution is input by another peristaltic pump at a flow rate of 0.1-1.5mL/min, and the water after ultraviolet light irradiation The sample solution is mixed into the flow cell to generate chemiluminescence, and the light signal is detected by the photodetector and sent to the data processing system. 2. A detection device based on photocatalytic chemiluminescence to measure the chemical oxygen demand of water body, characterized in that: the ultraviolet lamp (14) is placed in a sealed quartz glass tube (16), and the quartz glass tube is surrounded by quartz material or polymer. The photocatalytic reaction pipeline (15) made of tetrafluoroethylene is then placed in a glass container (17) full of condensed circulating water, and the condensed circulating water enters from the glass container inlet (9) and is then discharged from the glass container outlet (7) The analyzed water sample (11) is input into the photocatalytic reaction pipeline (15) through the peristaltic pump (10), and then output from the photocatalytic reaction pipeline outlet (13); the luminescent reagent luminol (1) is passed through the peristaltic pump (2) input, mixed with the photocatalytic reaction water sample solution output from the photocatalytic reaction pipeline outlet (13), then enters the chemiluminescent flow cell (3), generates a chemiluminescent signal, and then passes through the waste liquid port (4) Exhaust; the light signal is detected by the photodetector (6) and sent to the data processing system (5). 3. A method for measuring chemical oxygen demand based on photocatalytic chemiluminescence according to claim 1, characterized in that the photocatalytic chemiluminescence analysis method is used to monitor the chemical oxygen demand of water body on-line. 4. A detection device for measuring chemical oxygen demand based on photocatalytic chemiluminescence according to claim 2, characterized in that: the photocatalytic chemiluminescence detection device consists of an ultraviolet lamp (14), a sealed quartz tube (16), and a photocatalytic chemiluminescence detection device. It consists of a catalytic reaction pipeline (15) and a chemiluminescence flow cell (3). 5. A detection device for measuring chemical oxygen demand based on photocatalytic chemiluminescence according to claim 2, characterized in that the ultraviolet lamp (14) of the photocatalytic chemiluminescence detection device can be any light source. 6. A detection device for measuring chemical oxygen demand based on photocatalytic chemiluminescence according to claim 2, characterized in that the photocatalytic reaction pipeline (15) in the photocatalytic degradation device can be a Light-transmitting quartz or polytetrafluoroethylene material.

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