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Essential information for sludge treatment and disposal technicians IC anaerobic reactor construction drawing Activated Carbon Adsorption Handbook PDF Environmental Science and Engineering Dictionary Industrial waste gas purification and utilization Urban Wastewater Treatment Plant Design and Calculation (Second Edition) The latest atmospheric environmental protection standards (all) Oilfield wastewater treatment status and development trend Announcement of the list of national urban sewage treatment facilities (2014) Process design of indigo dyed yarn wastewater treatment Environmental Green Certificates Compilation Determination of COD by atmospheric pressure microwave digestion Practical electronic manual for environmental workers (latest) National General Ventilation Pipe Calculation Table I want to send you some information on environmental protection design and hope to be useful to everyone. Essential information for sludge treatment and disposal technicians IC anaerobic reactor construction drawing Activated Carbon Adsorption Handbook PDF Environmental Science and Engineering Dictionary Industrial waste gas purification and utilization Back to list Views: 1597|Reply: 9 [Sewage] Total trihalomethane detection method in water [Copy Link] Tvevnxkkw 372 Post 1062 integral 284 gold Diamond membership: Send a message Elevator direct to the landlord Published on 2012-12-21 12:50:01 | View the author|only big picture First, the method summary The water sample containing volatile trihalomethane is sampled in a sealed bottle and stored at a low temperature, and then taken out with a needle to be infused into a blow trap device for concentration. The concentrated sample is separated and measured by introducing a carrier gas into a gas chromatograph, and the concentration of total trihalomethane in the water sample is detected by an Electrolytic Conductivity Detector (ELCD; or Hall Detector, referred to as HD). . Second, the scope of application The method is applicable to tap water, mineral water, drinking water, river water, reservoir water, lake water and groundwater, such as Chloro-form, Bromodichloromethane, Dibromochloromethane and Analysis of four trihalomethanes such as Bromo-form. The detection limits of reagents for chloroform, monobromodichloromethane, dibromochloromethane and tribromomethane were 0.061 μg/L, 0.048 μg/L, 0.13 μg/L and 0.27 μg/L, respectively. Third, interference (1) The main interference in the analysis process comes from the volatile organic compounds contained in the reagent water. The reagent water shall be heated while passing through the nitrogen gas flowing through the organic matter column to remove the interference in the water. The treated reagent water shall be stored in a glass bottle and sealed to avoid contamination. (2) The interference may also come from the purge gas, or the memory effect remaining from the previous analysis of the high concentration sample, or the organic matter in the chamber is adsorbed on the trapping column of the blow trapping device. interference. Therefore, each time you turn on the machine, you must first ventilate, clean the trapping column and pipeline at high temperature, and then carry out the experiment after the instrument blank test. Fourth, the equipment (1) Blowing and catching equipment (the capture and desorption modes of the blow trap system are shown in Figure 1 and Figure 2) 1. Capturing column: Column with adsorbent TENAX GC, 12〞 × 1/8〠or other columns of equivalent nature. 2. Suggested conditions for capturing concentration: Standby temp.: 35°C Dry purge time: 11min Purge flow rate: 40mL/min Desorb time : 4min Desorb temp.: 180 °C Baking purification temperature (Bake temp.) : 200 ° C Bake time: 10min (2) Gas chromatograph 1. A gas chromatograph with an electrolytic conductivity sensing detector and a temperature control program. 2. An integrator, recorder or computer for chromatography. 3. Chromatography and recommended operating conditions: DB-5MS, 30m × 0.53mm, 1.5μm (thickness) or equivalent. Chromatography initial temperature: 30 ° C Chromatography initial temperature retention time: 6min Chromatography temperature rise rate: 8 ° C / min End temperature of the chromatography: 150 ° C Chromatography end temperature retention time: 2min Carrier gas (HE) flow rate: 12mL/min Supplemental gas (HE) flow rate: 30mL/min 4. Recommended operating conditions for electrolytically conductive proximity detectors: Reaction tank: nickel 1/16" (outer diameter), 0.02" (inside diameter) Reaction temperature: 900 ° C Reaction base temperature: 200 ° C Electrolyte: n-propanol Electrolyte flow rate: 0.05 mL/min Reaction gas (H_2) flow rate: 100mL/min (3) Pure water manufacturing equipment: Equipment capable of producing pure water resistance greater than 17 MΩ - cm at 25 °C. (4) Analytical balance: It can be scaled to 0.1mg. (5) Heating plate: Those with stirring function. (6) Sample injection system: Automatic or manual, the injected sample volume is 5mL. (7) Refrigerator (or cabinet): It can be kept at 4 °C. (8) Glass containers and sample containers (Note 1): 1. Quantitative bottle: Borax glass, 10 mL, with glass cover. 2. Vial (with Teflon gasket rotating cover): borosilicate glass, 40 mL. (9) Water and gas removal devices. Five, reagents (1) Solvent: Methanol, analytical reagent grade, purity above 99.9 %; n-propanol, analytical reagent grade, purity over 99.9%. (2) Standard products (Note 2, Note 3): 1. Trichloromethane, analytical reagent grade, purity above 99.9 %. 2. Monobromodichloromethane, analytical grade, purity above 99.9 %. 3. Dibromochloromethane, analytical reagent grade, purity above 99.9 %. 4. Tribromomethane, analytical reagent grade, purity above 99.9 %. (3) Dechlorination agent for sample preservation: Ascorbic acid, analytical reagent grade, purity above 99.7 %. (4) Reagent water: Take 3L of purified deionized water, heat to boiling, keep for 15 minutes, then pass nitrogen gas, heat for 1 hour, then keep the temperature at about 90 °C, pour hot into the Teflon-containing gasket The glass bottle of the rotating cover is sealed and stored. (5) Trihalomethane reserve solution: 1. Take about 9.8 mL of methanol. For 10 mL dosing bottle, let it stand for a few minutes and weigh it. Use a 10 μL injection needle to quickly remove the standard bottle from the sealed bottle and add it to the metering bottle (Note: The standard product does not touch the bottleneck and the liquid level. ), and then weigh. The amount of standard added is known in terms of the difference in weight. Dilute to the mark with methanol, weigh and mix, and record to 0.1mg. 2. Pour the standard solution in the dosing bottle into the bottle and store it in the freezer. 3. The effective shelf life of this stock solution is 4 weeks. (6) Trihalomethane intermediate storage solution Add a suitable amount of pure methanol in a 10 mL dosing bottle, add a proper amount of the stock solution to the dosing needle, add methanol to the mark, mix well, pour into the bottle and seal it, and store it in the freezer. (7) Mixed standard solution Add pure methanol to a 10 mL dosing bottle. Add the appropriate volume of the intermediate stock solution to the dosing bottle from the highest to the lowest boiling point of the compound. Add methanol to the mark, mix well, and pour into the bottle. As for the storage in the freezer. (8) Adsorbent: TENAX GC, 60/80 mesh (9) Helium: Purity of more than 99.999%, content of hydrocarbons Should be less than 0.5 ppm. Sixth, sampling and preservation (1) Sampling 30 mg ascorbic acid must be added to the 40 mL sample bottle. If the water sample is the tap water flowing out of the faucet, let it flow for 5 minutes before taking the water sample. Avoid taking ascorbic acid out of the water sample, and there should be no air bubbles remaining in the sample bottle. After the bottle cap is locked, it should be stored in a dark place at 4 °C. (2) Sample preservation Samples should be protected from high temperature sunlight and must be stored in an environment free of organic solvent gases and at low temperatures. To avoid analysis of the results due to sample changes, the analysis must be completed within 14 days. Seven steps (1) Set the instrument conditions to set the instrument conditions of the gas chromatograph, and then establish the instrument conditions of the blow trapping and concentrating equipment, such as (1) and (2) of the equipment. (2) Preparation of the calibration line In conjunction with sample testing, at least 4 different concentrations of the calibration solution are configured to make a calibration curve. (III) Sample analysis Each time 5 mL of the sample is injected into the air capture system, and then the chromatogram and signal obtained by the gas chromatograph are combined with the check line of the seventh and (b) for detection and analysis. Qualitative analysis The qualitative determination of various trihalomethanes by this method is based on the residence time of each compound. Figure 3 shows the chromatogram obtained by ELCD standard solution. The residence time of each compound may vary slightly depending on the condition of the individual instrument, and the analyst should correct it by using a layer map of the mixed standard solution. If necessary, use chromatographic tubes of different polarities or analyze the analytes by gas chromatography mass spectrometry. 2. Quantitative analysis The amount of various trihalomethanes injected can be obtained from the regression equation of the calibration curve. 3. Recovery rate determination In order to determine the recovery rate of the analyte or the chromatographic retention time in the new process, standard addition must be performed. The 5 mL injection needle was first filled with water to a 5 mL mark, and the mixed standard solution was taken up with a micro syringe to inject the standard from the above 5 mL injection needle. The water sample to which the standard is added is injected into the sample tank for analysis, and the recovery rate is calculated. Eight, processing results The concentration of total trihalomethane in the water sample can be obtained by the following formula: A : The total amount of the four trihalomethanes obtained from the calibration curve ( Gg). V : sample injection volume, 5 mL. Nine, quality control (1) When analyzing any 1 batch of samples, 1 blank test should be performed for every 10 samples, and at least 1 blank test should be performed for each batch when less than 10 samples. Blank test contains instrument blank and reagent blank test. (2) This method shall carry out reagent blanks, instrument blanks and field blank experiments. The blank experiment frequency is 10%. If the matrix is ​​different, the frequency should be increased according to the nature of the matrix. The blank value should not be higher than three times the detection limit of each object to be tested. (3) The total trihalomethane recovery rate should be in the range of 75 - 125%. 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Kyushu space analysis method for detecting trihalomethane in water