Korallen Zucht Potassium Iodide Fluoride Concentrate
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This is a Division of application Ser. They may be used in a system which includes recovery of the solution after use or in a system without recovery of the solution after use but in which the composition of the solution is verified, at more or less regular intervals, and is adjusted if necessary. For example, when it is used for disinfecting, it is important to make sure that the composition of the solution which is utilized be such that it is active against the microorganisms to be destroyed.
In this context, it is therefore recommended to control at least the concentration of the most active substance, such as the peracid, which more often is peracetic acid. In the present industrial practice, the peracid is subject to a manual determination at the time of use. This determination enables one to determine the exact concentration of peracid and also, if necessary, of hydrogen peroxide but it is complicated and requires the assistance of specialized manpower, it cannot be automated and does not enable one to continuously adjust the amount of peracid.
Attempts have therefore been made to automate this determination by relying on a simple and inexpensive means which also enables one to adjust "in real time" the concentration of peracid, for example of peracetic acid. To do this, a certain number of methods and devices which are described and commented briefly hereinafter have already been proposed. To obtain a significant reading, i.
In the case of a solution containing hydrogen peroxide and a peracid, the analysis essentially indicates the concentration of hydrogen peroxide and not that of the truly active compound, namely peracid, for example peracetic acid. On the other hand, other methods used, namely pH-metry and conductimetry give an indication with respect to the acidity of the medium but does not directly give information with respect to the evolution of the essential oxydizing agent, namely the peracid.
To analyze the disinfecting power of the solutions of the type in question, it has also been proposed to rely on colorimetry which enables one to distinguish between hydrogen peroxide and a peracid. The process described therefore potassium iodide liquid color pumps two measuring circuits one circuit being heated. The peroxidized compound concentration is obtained from the difference of intensity of the colors developed within these two circuits, one being due to hydrogen peroxide alone and the other, the hydrogen peroxide-peroxidized potassium iodide liquid color pumps combination.
This procedure, which implies the heating of one of the circuits, has the disadvantage of being complicated. Moreover and especially, it often gives an inaccurate reading of the peroxidized compound concentration in the industrial solutions normally used since the difference which is read has a relatively weak value and these solutions generally have a concentration of peroxidized compound, potassium iodide liquid color pumps as peracetic acid, which is much lower than the concentration of hydrogen peroxide.
It should also be noted that even though patent application EP 0 mentions on page 3, lines 28 to 32, the possible use of different calorimetric reagents for example iodides, it more particularly aims at the use of potassium and titanium oxalate and particularly sodium molybdate see for example page 3, lines 27 and 37 and claim 4. In addition, it potassium iodide liquid color pumps be noted that the potassium iodide liquid color pumps could not be used in this process since, as will be seen later, they react very well with the peracids at room temperature, which on the contrary is not the case for hydrogen peroxide.
The reagent used consists of a chromogen, an iodide and possibly a buffer. In this process, instead of measuring the coloring of the iodide formed during the oxido-reduction reaction, the coloring resulting from the chromogen is measured. As indicated on page 3, potassium iodide liquid color pumps 6 to 8, the iodide concentration may be very low, for example on the order of one tenth of the chromogen concentration, since during the redox reaction the iodide is first consumed but is thereafter formed again; therefore it acts here exclusively as a catalyst.
The concentration of peracid, for example of peracetic acid, is determined by means of a calibration curve. This document concerns a process for determination and an appropriate reagent therefor but does not describe nor suggest their use in the continuous control of the peracid content of a solution.
On the other hand, it is known that at room temperature, peracetic acid reacts nearly instantaneously with iodides to give iodine, while under these conditions, hydrogen peroxide reacts only very slowly, if at all. This reaction, charateristic of the peracids with the iodides, gave rise to different studies reported in the literature. Martin Davies and Michael E. Deary have proposed, in Analyst LondonSeptemberpotassium iodide liquid color pumps.
It potassium iodide liquid color pumps now been found according to the invention that it is possible to determine and control in a simple manner the amount of peracid, such as peracetic acid, in the presence of hydrogen peroxide, according to processes based on colorimetry and which do not require the use of two measuring circuits in which one is heated, with the disadvantages mentioned above with respect to the system described in patent application EP 0by utilizing the different kinetic reaction of hydrogen peroxide and peracids with the iodides mentioned above, without having to establish a specific curve for each determination, as in the case of the process described in Analyst and commented above.
According to the invention, it has indeed been established that it is possible to obtain, by calorimetric analysis at room temperature, of mixtures of hydrogen peroxide and peracid in which the molar ratio between the concentration of hydrogen peroxide and the concentration of peracid does not exceed abouta linear response of the coloring which is read as a function of the concentration of peracid, after addition of an excess of iodide, for a given reaction time.
The reading of the concentration can then be made directly on a calibration curve potassium iodide liquid color pumps from potassium iodide liquid color pumps points, or on an appropriate apparatus, also calibrated starting from two "points". According to one to aspect, it is an object of the invention is to provide a process or the calorimetric determination, by formation of iodine from an excess of iodide, of the amount of peracid in and an at least partially aqueous solution, in which the potassium iodide liquid color pumps ratio between the concentration of hydrogen peroxide and the concentration of peracid does not exceed about potassium iodide liquid color pumps, characterized in that:.
This process is particularly applicable in the case where the peracid is peracetic acid which is often currently used for the disinfection of industrial installations, for example in dairy. The possibility of making the determination, i. It is well known that the oxidation of an iodide into iodine may only take place in an acid medium. In this connection, it has been observed that satisfactory results will only be obtained if potassium iodide liquid color pumps pH, during the determination, is lower than or equal to 6.
It has been observed that the best results are obtained for pH values between 5 and 6. If necessary, the adjustment of the pH is carried out by addition of an acid such as for example phosphoric acid or by means of a buffer, such as a phosphate buffer.
The iodide used may be selected, for example, from the alkali metal iodides and ammonium iodide, however potassium iodide is preferred. The time gap between the addition of excess iodide and the reading of the potassium iodide liquid color pumps color which has developed should always be the same among a series of given measurements, including when potassium iodide liquid color pumps is made. This time gap may potassium iodide liquid color pumps within a large range.
It may for example be of the order of 2 to 2 and a half minutes. Preferably, however, it should be shorter than 1 minute. On the other hand, to give accurate measurements, it is desirable that the iodine color formed not be potassium iodide liquid color pumps intense. To do this, it is recommended that the weight concentration of the peracid in the medium during the determination be lower than ppm parts per millionpreferably lower than 50 ppm.
If necessary, the sample is diluted when the determination is made. The diluting liquid used such as tap water or distilled water may also contain, if necessary, the acid or the buffer to be used for potassium iodide liquid color pumps the pH. The range of wavelengths used for the measurement, generally between and nm, essentially depends on the concentration of peracid in the medium during the determination.
The two point calibration system includes the straight line representing the variations of the optical density which is read as a function of the concentration in peracid, for example peracetic acid.
The two point calibration may be obtained by means of a solution having a known concentration of peracid, without addition of iodide for value 0 and with addition of iodide for the value read corresponding to said known concentration. According to another aspect an object of the invention to provide a calorimetric process for the control of the amount of peracid, in the presence of hydrogen peroxide in an at least partly aqueous solution, in which the molar ratio between the concentration of hydrogen peroxide and the concentration of peracid does not exceed aboutcharacterized in that:.
The dilution reagent is advantageously made potassium iodide liquid color pumps tap water or possibly distilled water, to which, if necessary, there is potassium iodide liquid color pumps a pH regulator such as for example phosphoric acid or a phosphate buffer.
The iodide used may be selected such as from the potassium iodide liquid color pumps metal iodides and ammonium iodide, however potassium iodide is preferred.
The iodide solution potassium iodide liquid color pumps relatively concentrated in order not to substantially modify the dilution of the flow which penetrates into the measuring vat, as compared to that of the flow which enters into the reference vat. Advantageously, the measuring unit transforms the difference of intensity into a potential difference, for example in the range of 0 to 2 V, or into a current intensity, for example potassium iodide liquid color pumps the range of mA.
Advantageously, the regulator includes a displaying means, for example with liquid crystals, to display the instantaneous concentration of peracid. Still advantageously, the regulator is connected to a printer which reproduces the variations of concentration.
Calibration of the regulator is carried out by means of a calibrated or standard solution of known peracid concentration. Advantageously, the installation used includes a three way valve, mounted ahead of the first injection means and which enables the to introduce the standard solution or the solution to be adjusted, into the measuring circuit.
A peristaltic pump 3 draws the solution to be analyzed and injects same at 4 in the suction circuit of two peristaltic pumps 5 and 6 which reed at the same flow rate two vats of a two-beam photometer, namely reference vat 7 potassium iodide liquid color pumps measuring vat 8, respectively.
The flow rates of the peristaltic pumps 3, 5 and 6 are adjusted so that the concentration of peracetic acid of the measuring flow at 10 should be lower than ppm. It is advantageous to introduce a mixer 26, between potassium iodide liquid color pumps point of injection 4 of the solution to be analyzed and the peristaltic pump 5 to homogenize the mixture of liquid to be analyzed 2 and dilution liquid 9. This mixer may for example comprise a restriction followed by a widening of the feeding tube as shown, which renders the circulating flow sufficiently turbulent to homogenize same.
As already indicated above, a fourth peristaltic pump 13 injects into the measured flow at 12 a known quantity of iodide 11, such as potassium iodide, in excess. After a certain delay which is directly dependent on the length of the trajectory between the point of injection 12 of the iodide 11 and the analysis vat 8, on the one hand, and the duration of homogenization in the analyzing vat 8, on the other potassium iodide liquid color pumps, the intensity of the iodine color formed yellow to red in the analyzing vat 8 is measured and compared to the reference in vat 7.
The difference is transformed into current mA in the measuring unit 14, then this current is transmitted at 15 to a regulator 16 where it is transformed into information on a liquid crystal display The regulator 16 may be calibrated on the basis of two measuring points, namely zero and the concentration of a standard or caliber Indeed, the concentration of peracetic acid in the measuring flow 10 is adjusted so that the intensity of the iodine color formed is proportional to the concentration of peracetic acid.
Zero is obtained by removing the addition of iodide The standard or caliber 22 is obtained by manual dilution of the solution of peracetic acid potassium iodide liquid color pumps The introduction of this standard or caliber 22 is carried out by means of three way valve In this case, the pumps 5 and 6 directly draw either the solution to be analyzed 2, or the standard By means of this calibration, the value read on the liquid crystal display 17 during the measurement is the concentration of peracetic acid in solution 2.
It is thus possible to program the desired value of the concentration and the proportional range of adjustment. The operation is then carried out with a pump 19 for adding a solution of peracetic acid 20 which is controlled either "completely or not at all" the pump 19 starts to operate at any value below the control pointor by contact-relay, or starting from information called mA, for example.
These last two solutions are more satisfactory since the inertia of the measuring system is 5 to 10 minutes when the proportional range of control modifies the information sent to the pump On the other hand, to be more secured, the regulator 16 may have two alarm limits "high-low" who are to be defined by the user which is thus advised whether one of these limits is exceeded more than for a certain time, which is also to be defined.
The device described above has potassium iodide liquid color pumps used to monitor the concentration of peracetic acid of a diluted cleaning solution in place N. The aim was to maintain this concentration at a level suitable during one week. A portion of the peracetic acid is consumed or hydrolyzed during this operation of disinfection.
It is therefore recommended to proceed with readjustments of the concentration of this acid as time goes. The control process according to the invention enables one to maintain this solution always ready to be used, without manual intervention. A cycle of one week was realized in the laboratory in a 30 liter vat containing a disinfection solution, with adjustment to the initial desired titer and monitored during the entire week.
The product tested essentially consisted of 25, ppm by weight of peracetic acid,ppm by weight of hydrogen peroxide, in the potassium iodide liquid color pumps of acetic acid and nitric acid. It was used here under the usual conditions of use in a dairy, namely as a 0.
This pH was adjusted by means of phosphoric acid. Calibration was carried out with the same solution at 0. The liquid crystal display during the calibration indicated 0.
A second experiment was carried out by utilizing the same apparatus, except that a filter having a pass band of to nm and the same solution as before, except at 0. Calibration was again carried out with the same solution at a concentration of 0. Interference tests with milk have shown that up to a concentration of 0. Year of fee payment: According to one to aspect, it is an object of the invention is to provide a process or the calorimetric determination, by formation of iodine from an excess of iodide, of the amount of peracid in and an at least partially aqueous solution, in which the molar ratio between the concentration of hydrogen peroxide and the potassium iodide liquid color pumps of peracid does not exceed aboutcharacterized in that: According to another aspect an object of the invention to provide a calorimetric process for the control of the amount of peracid, in the presence of hydrogen peroxide in an at least partly aqueous solution, in which the molar ratio between the concentration of hydrogen peroxide and the concentration of peracid does not exceed aboutcharacterized in that: The informations supplied to the regulator 16 may be transmitted to a printer The liquids of the reference 7 and analyzing 3 vats are thrown at 24 and 25, respectively.
In a first experiment, the filter used had a pass band of nm. Potassium iodide liquid color pumps results obtained with the solution being studied are given in table I which follows: The results obtained in this second experiment are given in table II which follows: Colorimetric process for a determination, by formation of iodine from an excess iodide, of a content of peracid in the presence of hydrogen peroxide in an at least partly aqueous solution, in which a molar ratio between a concentration of hydrogen peroxide and a concentration of peracid does not exceed about comprising the steps of: