Как использовать а растворенный кислород и рН метр для очистки сточных вод
Как a pH Метр Работает
The pH of any solution can be expressed in terms of hydrogen ion концентрация. Должное к the ионизация эффект из вода сама, every liter of pure вода содержит 10-7 граммы [H плюс ] at 22 градус C, and the atomic вес и атомный валентность из водород are оба 1, so each liter of pure вода содержит 10-7 грамм эквиваленты of [H plus ] ], потому что [H плюс ] in pure вода is произведено десоциация из вода молекулы сами, that is:
H2O=H plus plus OH-
Чистый вода есть нейтральный, that is, the concentrations of the two ions are equal, [H plus ]=[OH-], the product of which is a constant temperature constant, called ion product K вода.
K water=[H plus ][OH-]=10-7*10-7=10-14
The above formula is applicable to any acid-base solution, that is, any aqueous solution, in which [H plus ][OH-] product is equal to 10-14}. для пример, in some водный раствор [H plus ]=10-3, then [OH-] must be 10-11, so for any kind of aqueous solution, as long as [H plus ] is known, then [OH-] is easy to get, usually The pH is defined by the negative value of the common logarithm of the hydrogen ion concentration, expressed as: pH{{7% 7d}lg[H plus ],
So the pH of a neutral solution is equal to 7. If there is an excess of hydrogen ions, the pH value is less than 7, and the solution is acidic; else, the solution is alkaline if there is an excess of hydroxide ions.
The pH value depends on the amount of dissolved substances, so the pH value can sensitively The change of water quality. The change of pH value has a great impact on the reproduction and survival of organisms, and also seriously влияет the biochemical function of activated sludge, which effects the treatment effect. The pH value of shoage is generally control between 6.5 and 7.
The pH value is usually measured by the potentiometric method. A constant potential reference electrode and a measuring electrode are commonly used to form a primary battery. The electromotive force of the primary battery depends on the concentration of hydrogen ions and also depends on the pH of the solution. Type sinker pH meter. The measuring electrode of the instrument adopts a special glass electrode sensitive to pH, which has the characteristics of high measurement accuracy and good anti-interference. When it is immersed in the solution to be tested, the hydrogen ions in the solution to be tested are balanced with the hydrogen ions in the hydration layer on the surface of the electrode bulb, and at the same time, the solution inside and outside the glass bulb and the hydration layer on the inner wall of the electrode bulb generate a potential difference, and the glass electrode The interior is filled with a buffer solution with a fixed pH value, and the lead-out electrode is immersed in the internal solution to form a half-cell, and the half-cell formed by immersing the calomel electrode in a saturated potassium chloride solution is simultaneously introduced into the converter for measurement. Different pH values correspond to different potentials, which are converted into standard 4-20mA output through the transmitter.
Как Растворенный Кислород Анализаторы Работа
The oxygen content in water can fully show the degree of self-purification of water. For biological treatment plants using activated sludge, it is very important to know the oxygen content of the aeration tank. The increase of dissolved oxygen in sewage will promote biological activities other than anaerobic microorganisms, thus removing volatile substances and substances that are prone to natural oxidation ions to purify the sewage.
Там есть три основные методы для определения кислород содержание: автоматический колориметрический анализ анализ и химический анализ измерение, парамагнитный метод измерение, и электрохимический метод измерение. The количество of dissolved кислород in вода is is generally измерено by electrochemical method.
Кислород банка растворение в воде , и растворимость зависит от температура , общее давление вода поверхность , частично давление и соли растворенные в воде The The The Greater the ability of water to dissolve oxygen. The Relationship is determined by Henry's law and Dalton's law. Henry's law that the the sollubility of a gas is directal proportional to its partial давление.
The oxygen measurement sensor consists of a cathode (commonly made of gold and platinum), a current-carrying counter electrode (silver), and a current-free reference electrode (silver). The electrodes are immersed in electrolytes such as KCl and KOH, and the sensor is covered by a diaphragm. The coating separates the electrodes and electrolyte from the liquid to be measured, and only dissolved gas can penetrate the coating, thus protecting the sensor, preventing the electrolyte from escaping, and preventing the intrusion of foreign substances to cause pollution and poisoning.
A поляризация напряжение is прикладной между счетчик электрод и the катод. Если the измерение cell is погруженный в вода с растворенный кислород, кислород кислород диффузный через диафрагма и кислород молекулы присутствие на катод (избыток электроны) восстановление к гидроксид ионы [OH-]. The электрохимический эквивалент из серебро хлорид is осажденный on счетчик электрод (электрон дефицит). For each oxygen molecule, the cathode emits 4 electrons, and the counter electrode accepts electrons to form a to form a to: 4Ag plus 4Cl-=4AgCl plus 4e-.
Особенности of pH Meter
The glass on the pH electrode will gradually age over time, the gradient (the change in the electrode output potential caused by a unit pH change) will deteriorate, and it will take a long time to reach a stable potential. The service life of general electrodes can reach two years. In addition, temperature also has a great influence on aging. The aging degree of storage at 100 degree for several weeks is equivalent to the aging degree of storage at room temperature for one year.
The dissolved oxygen meter has the характеристики of easy installation, long calibration period (3~4 months), insensitivity to other substances, etc., and can monitor the use of the electrolyte in the membrane and probe. Generally, the electrolyte and membrane should be replaced every one to three years. .
