CN1067511A - Reagent for quick measurement of water hardness - Google Patents

Abstract

A kind of reagent for quick measurement of water hardness is specially adapted to the mensuration of boiler feed water hardness, and it is to contain EDTANa ₂Aqueous solution in, add an amount of acid chromium blue k, absolute ethyl alcohol, NH ₄OH and NH ₄The formulated pH of Cl is the determination of aqueous solution reagent of 9.9-11.5.Use mensuration reagent of the present invention, can easy, promptly measure water hardness, and overcome the defective that prior art exists, has cost low (have only original 1/10), low in the pollution of the environment, instrument, equipment and technician are required advantages such as low, be fit to very much each enterprises and institutions and use.

Description

Reagent for quick measurement of water hardness

A kind of reagent for quick measurement of water hardness can be qualitative and measure the hardness of water (contain natural water, tap water, and the soft water of all size that is prepared by these water) quantitatively.

Present technique belongs to the water hardness measuring field.

In the prior art, how the mensuration of the water hardness carries out in special laboratory.Be example with the present classic method of using-EDTA compleximetry: need to be equipped with tens of kinds of chemical reagent such as tens of kinds of instruments such as muffle furnace, drying baker, precision balance, water still, exsiccator, buret, measuring cup, crucible and hydrochloric acid, EDTA, zinc paste, ammoniacal liquor, ammonium chloride, ethanol, eriochrome black T.At first, arrive water sample location water sampling then, get back to the laboratory by rules preparation benchmark liquid and titer.Utilize mentioned reagent and instrument that water sample hardness is measured, calculated, draw measurement result.There is following defective in this method in practicality.

1, need the consumption huge fund to purchase a complete set of instrument, equipment and chemical reagent, the cost height;

2, in above-mentioned chemical examination work, the weighing of plurality of reagents, preparation and demarcation, calculating etc., not only operating performance complexity, and also high to the requirement of laboratory personnel's technical merit, add repeatedly weighing, titration, calculating, thereby cumulative errors is big.

3, the poor stability of reagent water solution.As the eriochrome black T instability of indicator, measurement result is had a significant impact especially.

4,, must be heated to 30 ℃～40 ℃, otherwise the result is higher to water at low temperature.

Defective at prior art exists the object of the present invention is to provide a kind of reagent for quick measurement of water hardness.Change original numerous and diverse mensuration formality.Do not need any instrument, equipment, test tube only, a drop bottle (or buret) just can determine water hardness accurately, simply, fast.

Principle of the present invention is as follows: at NH ₄OH-NH ₄Under the CI condition, EDTANa ₂Be combined into the very strong blue reagent of stability with acid chrome blue K.Meet Ca in the detected water sample ²⁺, Mg ²⁺When existing, Ca ²⁺, Mg ²⁺Elder generation and EDTANa ₂Complexing, unnecessary Ca ²⁺, Mg ²⁺Generate red complex compound with the acid chrome blue K complexing again.When terminal point, be purple (red+indigo plant).Then according to the volume (ml number) of getting detected water sample and consume reagent volume, calculate the hardness of water sample.

Chemical formula: Na ₂Y+H ₂In → Na ₂Y-H ₂The In(blueness)

Na ₂Y+Ca ²⁺(Mg ²⁺The Y(of) → Ca(Mg) is colourless)

H ₂In+Ca ²⁺(Mg ²⁺The In(of) → Ca(Mg) redness)

(Na wherein ₂Y represents EDTANa ₂H ₂In represents acid chrome blue K)

According to above-mentioned principle, the inventor adopts the very strong NH of surge capability, screening ability ₄OH, NH ₄CI makes reagent, adds EDTANa ₂Make indicator with the acid chrome blue K that reaction sensitivity is high.Rationally be mixed with blue reagent for quick measurement of water hardness.Have good diffusivity and stability, after special processing, the term of validity can reach more than 3 years again.

Reagent for quick measurement of water hardness of the present invention is to contain EDTANa ₂Aqueous solution in, add an amount of acid chrome blue K complexometric indicator, absolute ethyl alcohol, NH ₄OH and NH ₄CI is made into pH value and is 9.9～11.5 determination of aqueous solution reagent, and in measuring reagent, the component concentration of above-mentioned each material is (percentage by weight):

EDTANa ₂0.002～21.6%

Acid chrome blue K 0.01～1.0%

Absolute ethyl alcohol (95%) 6～24%

NH ₄OH 0.5～50%

NH ₄CI 0.05～20%

Distilled water 9～90%

The aqueous solution fast measuring reagent of foregoing invention is applicable to the hardness measurement of the various water (unboiled water, soft water and boiler standard water) of hardness below 10mg-N/l.Concrete assay method is as follows:

1, at first in test tube, splashes into 1 reagent;

2, slowly add detected water sample, till presenting purple.

When water sample reddens during in the 1ml left and right sides, illustrate that hardness is bigger, add a reagent again, see reaction, add reagent again if take on a red color; If being blueness adds water sample again, so continuous adjusting reagent drips the ml number of number and water sample, is terminal point until presenting purple.Drip number (or ml number) and water sample ml number according to reagent then, calculate detected water sample hardness by following formula.

Detected water sample hardness (mg-N/l)=(splash into the normal concentration of reagent * splash into the volume (ml) * 1000 of reagent)/(volume of detected water sample (ml))=(splash into the normal concentration of reagent * splash into the volume (ml) of reagent)/(cumulative volume of test tube solution (ml)-splash into the volume (ml) of reagent) * 1000

Use reagent for quick measurement of water hardness of the present invention; not only can overcome the defective that prior art exists to greatest extent; have cost low (have only original cost 1/10), easy to carry, easy to use; reaction velocity is fast; advantages such as the result is accurate, and do not need instrument, equipment, to the technician require low; and can reduce the discharging of a large amount of chemical substances, play effect to environmental protection.

Reagent for quick measurement of water hardness of the present invention can be regulated the accuracy of agent prescription and container according to the measurement range of concrete hardness and the requirement of accuracy of measurement, produces the needs that reagents series satisfies various uses.

For example: domestic the most frequently used low-pressure boiler water, stipulate in the national standard that give total hardness of water≤0.03mg-N/l, it is 10 that the inventor has prepared PH

EDTANa ₂0.036%

Acid chrome blue K 0.06%

NH ₄OH 10.84%

NH ₄CI 1.45%

Absolute ethyl alcohol 12.05%

Distilled water 75.56%

The inventor is referred to as the reagent for quick measurement of water hardness of " two titration ".

During mensuration, only need water sampling 5ml in test tube, splash into after two reagent shake, observe color,, illustrate that this water hardness≤0.03mg-N/l meets state-set standard, can use if be blueness or purple; If take on a red color, illustrate that this water hardness＞0.03mg-N/l is not inconsistent national standard, bans use of.

" two titration " reagent is one embodiment of the present of invention, the inventor for easy, measure water sample hardness rapidly, accurately, in " two titration " reagent, established vigilant dripping according to the demineralizer working curve again, be that water sampling 5ml adds a reagent, if be blue explanation water sample hardness＜0.015mg-N/l, demineralizer is working properly; If be purple or the red explanation water hardness 〉=0.015mg-N/l, the demineralizer water outlet near losing efficacy or losing efficacy, should arouse attention.Drip second this moment again, as be blue, and then the water hardness is between 0.015mg-N/l and 0.003mg-N/l, near losing efficacy; As be red, water lost efficacy, needed to handle again.

Reagent for quick measurement of water hardness of the present invention can also be determined proportioning according to different needs.Once measure water hardness accurately, satisfy the needs of measuring.

Claims (2)

1, a kind of reagent for quick measurement of water hardness is specially adapted to the mensuration of boiler feed water hardness, it is characterized in that, is containing EDTANa ₂Aqueous solution in, add an amount of acid chrome blue K complexometric indicator, absolute ethyl alcohol, NH ₄OH and NH ₄It is 9.9～11.5 determination of aqueous solution reagent that CI is made into pH value, in measuring reagent, and the component concentration of above-mentioned each material (percentage by weight):

EDTANa ₂0.002～21.6%

The blue K 0.01～1.0% of acid network

Absolute ethyl alcohol (95%) 6～24%

NH ₄OH 0.5～50%

NH ₄Cl 0.05～20%

Distilled water 9～90%.

2, reagent for quick measurement of water hardness as claimed in claim 1 is characterized in that, when pH value was 10, the prescription of reagent was as follows:

EDTANa ₂0.036%

Acid chrome blue K 0.06%

NH ₄OH 10.84%

NH ₄CI 1.45%

Absolute ethyl alcohol 12.05%

Distilled water 75.56%