Measurement of Ph in polluted water
Measurement of Ph in polluted water
Food factories require that the pH value of wastewater discharged be between 6.5 and 8.5. In the production process of fruit and vegetable sweat drink factories, carbonated beverage factories, dairy factories, breweries, etc., it is common to use large unrecognized to clean containers and equipment. In addition, it will use hydrochloric acid, nitric acid and other acidic cleaning agents. Therefore, not only the pH value of the raw water should be measured, but also the pH value of the wastewater should be measured to determine whether the wastewater needs to be neutralized.
Operation method
Measurement of Ph in polluted water
Principle
1. PH test paper is suitable for water samples with high chromaticity and buffering effect. 2. PH potentiometer is often called acidimeter, which uses saturated mercuric electrode as reference electrode and off-duty electrode as indicator electrode to form a battery, and the potential difference changes to 59.1mV for each change of one pH unit in the solution at 25℃, 101.3kpa (=1atm). pH value of the solution can be read directly by acidimeter. The use of acidimeter can refer to the instrument manual.
Materials and Instruments
PH test paper Standard PH Buffer Move 1.PH test paper method Caveat Wastewater samples must be analyzed as soon as possible, preferably in the field, before the determination of pH value, do not open the wastewater sample bottle.Do not use the off-duty electrode in the solution containing oil or grease, the oil or grease in the sample can be removed by layering with a separatory funnel. If the electrode is stained with an oil film, it can be cleaned with ethanol or acetone, and then washed thoroughly with water.After the measurement, the off-duty electrode should be immersed in water for storage, and the saturated calomel electrode should be covered with a rubber cap or rubber stopper after use, and attention should be paid to replenish the saturated potassium chloride solution in time. For more product details, please visit Aladdin Scientific website.
pH Potentiometer
In order to roughly know the pH of the water sample, can be used PH paper method. Determination of the water sample point in the test paper to make its color, compared with the standard color plate, you can get the pH value, this method is simple, but the determination of error is large, is not applicable to the chromaticity is very high and buffer effect of water samples.
2. pH potentiometer method
(2) Instrument
Acid meter or ion activity meter are available
(3) Reagent: standard PH buffer
(4) Experimental steps
Turn on the power switch and preheat for a certain period of time according to the requirements for the use of the acidimeter.
Comparison of instrument scale with pH standard solution, off-duty electrode should be pre-soaked in water for more than a day and night, before correction, rinse the two electrodes with water, filter about dry, the off-duty electrode off-duty bubbles immersed in the PH standard solution dug with the measured solution (note that saturated ganoderma electrode to have crystallized potassium chloride, and at the same time, must be removed from ganoderma electrode under the rubber sleeve and the upper part of the rubber stopper), careful shaking of the solution for 1 min, and the pH value of the calibration solution. Adjust the instrument pointer so that it is located in the pH value of the correction solution, note that the standard solution and the temperature of the water sample to be measured must be the same as the room temperature.
Determination of pH value of water samples: When determining, first wash the electrode with water samples 3-5 times, and then insert the electrode into the 50ml water samples placed indoors for more than half an hour, gently shake the water samples to make it uniform, and repeatedly read the pH value until the count is stable.