Рефераты | Рефераты по науке и технике | Смягчение воды методом ионного обмена |
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|
0.1 N. раствору NiSO4 |
Н-форма |
2.15 |
|
|
Nа-форма |
2.34 |
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4. |
Механическая прочность |
99% |
Из данных таблицы 1 видно, что испытуемый катионит обладает достаточно высокими показателями величины обменной емкости по ионам кальция и магния.
В качестве объекта исследования нами была использована артезианская вода Шурчинского района Сурхандарьинской области, которая имеет жесткость 12.2 мг-экв/л. Катионитов испытывали в Н- и Na-формах.
1 гр. катионита заливали 200 мл исследуемой воды. Через 24 часа воду отделяли от катионита и определяли ее жесткость трилонометрическим методом в присутствии индикатора хромоген черный. При этом жесткость воды в Н-форме составила 4.5 мг-экв/л, а в Na-форме 2.2 мг-экв/л.
Кроме этого нами были проведены исследования по умягчению водопроводной воды имеющий жесткость 2.5 мг-экв/л. После контакта в течение 6 часов водопроводной воды с катионитом жесткость ее соответствовала при использовании катионита в:
Н-форме – 0.8 мг-экв/л;
Na-форме – 0.4 мг-экв/л.
Результаты полученных исследований свидетельствует о перспективности работы с испытуемым сульфокатионитом.
INTRODUCTION
RIGIDITY of WATER
Scum and adjournment of salts on home appliances (for example, in teapots), film on tea etc. - all this parameters of rigid water. Use of such water for the economic purposes causes a number of inconveniences. For example, the charge of a soap is increased at washing, slowly boil soft meat and vegetables, service life of home appliances decreases. Interrelation of rigidity of water and education of stones in kidneys now is known.
The rigidity of drinking water under the working standards should be not higher 7 mg-ecv/g, and only in the special cases it is supposed up to 10 mg-ecv/g. For the industrial purposes use of rigid water is inadmissible.
The general rigidity of water is a set of properties caused by the contents in it ions of magnesium and calcium.
Hard water must be soften before use.
The first way – reagent method i.e., addition slaked to exhaust and soda Na2CO3 (a limy way), addition of polyphosphates.
The second way - application of cationits , i.e., synthetic ion-exchange pitches (filtering).
Ion-exchange pitches
These are substances capable to an ionic exchange at contact to solutions of electrolits. Ionic-exchange clearing allows to take and utilize a wide spectrum of polluting substances: heavy metals, chrom, nitrates and nitrites, cyanic connections, radioactive substances, and also умягчает and unironing water. Thus the high degree of clearing (up to a level of maximum concentration limit) is reached. Except for that ionits are used for unsalting waters during water-preparation. Inorganic and organic ionits can be natural (for example: zeolites, cellulose, peat, wood) and synthetic (silica gel and the most important ion-exchange pitches). Depending on a degree dissociation of ion-exchange pitches can be strong and weak. Depending on a sort of ions which are connected to active groups of ionits, distinguish the following its form: for cationits - the hydrogen form (H-form) and the salt form, when active groups are connected to ions of metals (for example, Na-form, NH4-form), for anionits OH-form, Cl-form, etc. Ability of ionits to a full exchange is characterized by exchange capacity which is equal to number of its active groups participating in an exchange. For the quantitative characteristic of ion-exchange properties of ionits usually define their dynamic and sometimes full (general) exchange capacity (static). Main requirements to ionits, used for water treating: high exchange capacity, high speed of an ionic exchange, sufficient stability in relation to acids, alkalis, oxidizers and reducers, insolubility in water, organic solvents and solutions of electrolits and limited swelling capacity. In water-preparation in a conditions of life are frequently used high-acid cationits domestic and import manufacturers mainly for softening and iron removal of waters. An example: the structure of cationits can be expressed formula Na2R, where Na+ - rather mobile cation. If to pass hard water through layers of cationits ions of sodium exchange on ions of calcium and magnesium:
