Cutting fluid sterilization method based on electrolyzed brine and application of cutting fluid sterilization method

Abstract

The invention relates to the technical field of cutting fluid sterilization, in particular to a cutting fluid sterilization method based on electrolyzed brine, which comprises the following steps: S1, measuring a bacterium-containing cutting fluid sample; s2, weighing a certain amount of analytically pure sodium chloride, adding the analytically pure sodium chloride into the bacterium-containing cutting fluid sample, and stirring until the sodium chloride is completely dissolved to form an electrolyte; s3, a graphite electrode is inserted into the electrolyte obtained in the S2, direct current is applied for electrolysis to form sodium hypochlorite, a pH meter is used for measuring the pH value change of the solution in real time in the electrolysis process, the electrolysis time is recorded, and after electrolysis is completed, a power source is turned off, and the graphite electrode is taken out; s4, carrying out bacterial detection on the electrolyzed solution through a contact culture method; sodium hypochlorite generated through electrolysis can be used for rapid sterilization, and corrosion and degradation of the cutting fluid are inhibited; only electric energy and low-cost sodium chloride are consumed, chemical bactericides are not needed, the cost is remarkably reduced, harmful residues are avoided, health hazards are avoided, and a solution is provided for cutting fluid management in the metal processing industry.

Description

TECHNICAL FIELD

[0001] The application relates to a cutting fluid sterilization technology field, in particular to a cutting fluid sterilization method based on electrolytic brine and application thereof. BACKGROUND

[0002] In the field of mechanical manufacturing, the performance stability of cutting fluid as a key process medium directly affects the machining precision and production efficiency. However, the cutting fluid in the centralized liquid supply system faces serious microbial contamination problems, especially during holidays, the oil substances such as hydraulic oil and guide rail oil introduced by equipment maintenance are mixed into the liquid supply pool, the frequency of circulation is reduced, and the supplement of new liquid is delayed, which provides a nutrient base for bacterial reproduction, leading to the density of bacteria rising to more than 10 6 CFU / mL, causing the cutting fluid to deteriorate, the pH to abnormally rise, and the antirust / lubricating performance to deteriorate.

[0003] The traditional solution to bacterial contamination of cutting fluid mainly relies on chemical sterilizing agents (such as isothiazolinone, formaldehyde releasing agent, and phenolic compound). Although such sterilizing agents can inhibit bacterial growth in the short term, there are significant drawbacks in long-term and large-scale use: on the one hand, chemical agents can stimulate the skin and respiratory tract of workers, causing occupational health problems such as allergy and respiratory inflammation; on the other hand, the sterilizing agents on the market are generally expensive, and continuous high-frequency use will significantly increase the operation and maintenance cost of enterprises, and increase the economic burden. At the same time, chemical residues may also cause the composition of cutting fluid to be complex and changeable, affecting its subsequent treatment and recycling, which is contrary to the concept of green manufacturing.

[0004] Therefore, there is an urgent need for an efficient, economical and harmless sterilization technology to eliminate chemical residues and achieve long-term bacteriostasis, so as to ensure the performance stability of cutting fluid and reduce the comprehensive maintenance cost. SUMMARY

[0005] The purpose of the present application is to provide a cutting fluid sterilization method based on electrolytic brine and application thereof, which solves the problem that the traditional solution to bacterial contamination of cutting fluid mainly relies on chemical sterilizing agents, which is effective in the short term but has significant drawbacks in long-term use: stimulating workers to cause health problems, high cost increasing the burden of enterprises, and chemical residues affecting the subsequent treatment of cutting fluid, which is contrary to the concept of green manufacturing.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical scheme: a cutting fluid sterilization method based on electrolytic brine, comprising the following steps: Step S1: measuring a bacterial cutting fluid sample; Step S2: weighing a certain amount of analytical pure sodium chloride and adding it to the bacterial cutting fluid sample, and stirring until the sodium chloride is completely dissolved to form an electrolyte; Step S3: inserting the graphite electrode into the electrolyte obtained in S2, controlling the electrode spacing to be 2-3 cm, and applying direct current electrolysis to form sodium hypochlorite, and setting the current density to be 10-100 mA / cm 2 During the electrolysis process, the pH meter is used to measure the real-time pH value change of the solution and record the electrolysis time, and after the electrolysis is completed, the power is turned off and the graphite electrode is taken out; Step S4: detecting the bacteria in the electrolyzed solution by contact culture method.

[0007] Further, the initial bacterial density of the bacterial-containing cutting fluid sample is ≥10 5 CFU / mL.

[0008] Further, in step S3, the electrolysis time is set to 8-15 minutes.

[0009] Further, in step S3, the electrolysis voltage is set to 10-15V.

[0010] Further, in step S2, the amount of analytical grade sodium chloride added is 0.2-0.4wt% of the mass of the cutting fluid.

[0011] Further, the contact culture method includes: contacting the cutting fluid with the colony slide for 5-10 seconds after electrolysis; and the culture conditions are 25-30℃ and 24-48 hours.

[0012] An application of a cutting fluid sterilization method based on electrolytic brine, which adopts the above-mentioned method to sterilize the cutting fluid to reduce the bacterial content in the cutting fluid.

[0013] Compared with the prior art, the beneficial effects of the present application are as follows: The present application can deal with severe pollution with an initial bacterial density of ≥10 5 CFU / mL by precisely controlling the electrolysis time, voltage and sodium chloride addition amount, generating sodium hypochlorite by electrolytic brine, rapidly killing bacteria in the cutting fluid by its strong oxidizing property, effectively inhibiting the corruption and performance degradation of the cutting fluid due to bacterial growth; and only consuming electrical energy and cheap analytical grade sodium chloride, without the need for complex chemical sterilizing agents, greatly reducing the cost; at the same time, abandoning traditional chemical sterilizing agents, there is no harmful residue, avoiding health hazards such as worker allergy, green and environmentally friendly, suitable for cutting fluid maintenance in multiple industries, with outstanding advantages in ensuring cutting fluid performance, cost reduction and efficiency improvement, and occupational health and environmental protection, providing a solution for cutting fluid management in the metal processing industry. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is a schematic diagram of bacterial density under different electrolysis times of the present application; Figure 2 is a schematic diagram of bacterial density under different electrolysis voltages of the present application; Figure 3 A schematic diagram of the bacterial density of different sodium chloride content of the present application; Figure 4 A device for preparing sodium hypochlorite from electrolytic brine and a reaction principle diagram of the present application; Figure 5 A comprehensive schematic diagram of the mechanism of action and electrode reaction of the present application. DETAILED DESCRIPTION

[0015] Please refer to Figures 1-5 A cutting fluid sterilization method based on electrolytic brine, comprising the following steps: Step S1: Measure the bacterial cutting fluid sample; the initial bacterial density of the bacterial cutting fluid sample is ≥10 5 CFU / mL; Step S2: Weigh a certain amount of analytical grade sodium chloride and add it to the bacterial cutting fluid sample, and stir until the sodium chloride is completely dissolved to form an electrolyte; Step S3: Insert the graphite electrode into the electrolyte obtained in S2, control the electrode spacing to be 2-3 cm, and apply direct current electrolysis to form sodium hypochlorite, set the current density to be 10-100 mA / cm 2 , use a pH meter to measure the pH value change of the solution in real time during electrolysis and record the electrolysis time, after electrolysis is completed, turn off the power and take out the graphite electrode; the electrolysis time is set to 8-15 minutes; the electrolysis voltage is set to 10-15V; the addition amount of analytical grade sodium chloride is 0.2-0.4wt% of the mass of the cutting fluid; Step S4: Detect the bacteria in the electrolyzed solution by contact culture method; the contact culture method includes: the bacterial colony slide cutting fluid after electrolysis is contacted for 5-10 seconds; the culture conditions are 25-30℃, 24-48 hours.

[0016] The above method can effectively reduce the bacterial content in the cutting fluid.

[0017] Experimental principle The principle of electrolytic brine sterilization technology is to generate sodium hypochlorite (NaClO) by electrolyzing brine (analytical grade sodium chloride), and sodium hypochlorite (NaClO) kills microorganisms by virtue of its strong oxidation effect, the main mechanism of action includes: denaturation of protein in microbial cells, damage to cell membrane leading to leakage of cell contents, damage to DNA and RNA to block genetic information transmission, interference with metabolic pathways to inhibit energy supply, so that microorganisms cannot normal replication, and ultimately lose the ability to survive and reproduce. (As shown in the accompanying drawings Figure 4 and Figure 5 , the reaction equation under electrolysis conditions is as follows: 2NaCl + 2H2O → 2NaOH + Cl2↑ + H2↑ Cl2 + 2NaOH → NaCl + NaClO + H2O Experimental process 1. Sample preparation: Take 500 mL of bacteria-containing cutting fluid (bacterial index is 10 6 CFU / mL, which is severely contaminated); Experimental equipment and auxiliary materials: constant temperature magnetic stirrer, electronic balance, pH meter, constant temperature incubator, adjustable DC power supply, graphite electrode, agar colony counting plate, sterile syringe, rubber bulb dropper, stopwatch; Experimental reagents: 75% disinfectant alcohol (V / V), analytical pure sodium chloride (NaCl).

[0018] 2. Test steps Accurately take 500 mL of bacteria-containing cutting fluid sample (bacterial index is 10 6 CFU / mL) with a sterile syringe; Weigh a certain amount of analytical pure sodium chloride (NaCl) by electronic balance, add it to the above 500 mL bacteria-containing cutting fluid, and fully stir with constant temperature magnetic stirrer until sodium chloride is completely dissolved; Electrolysis treatment: Insert the graphite electrode into the sample solution, connect the adjustable DC voltage regulator and set appropriate voltage and current; turn on the DC power supply for electrolysis treatment and record the electrolysis time; use the pH meter to detect the pH value change of the sample solution during electrolysis and record the data, after electrolysis, turn off the power and take out the graphite electrode.

[0019] Bacteria detection: Unscrew the agar colony counting plate cover, take out the slide (note to avoid touching the culture medium); rinse the slide with the sample to be tested, ensure that both sides of the culture medium are completely wet and contact with the sample for 5-10 seconds, after the excess liquid flows down (the bottom of the slide can be lightly touched with a water-absorbing paper), tighten the slide back into the test tube; fill in the label and paste it on the test tube, place the test tube in a 27-30°C incubator for 24-48 hours, then perform bacterial reading.

[0020] 3. Experimental data analysis 1) Keep the electrolysis voltage and sodium chloride addition amount unchanged: By changing the electrolysis time, it is observed that the bacterial density gradually decreases with the extension of the electrolysis time. The experimental results show that when the electrolysis time reaches 10 minutes, more than 90% of the bacteria can be effectively killed. Further extension of the electrolysis time, the bacterial density basically no longer changes, indicating that at this time a relatively stable sterilization effect state has been reached. This shows that under certain conditions (i.e. fixed electrolysis voltage and sodium chloride concentration), there is an optimal electrolysis time point (10 minutes in this experiment), after which increasing the electrolysis time has limited help to improve the sterilization efficiency. (As shown in the different electrolysis time bacterial density shown in the description Figure 1

[0021] 2) In the case of keeping the electrolysis time and the amount of sodium chloride unchanged: By changing the electrolysis voltage, it is observed that the bacterial density decreases with the increase of the voltage. When the electrolysis voltage reaches 12V, most of the bacteria can be killed. Further increase of the voltage, the change of the bacterial density becomes very small, indicating that at this time it has approached the maximum sterilization effect. This shows that under certain conditions (i.e. fixed electrolysis time and sodium chloride concentration), there is an optimal electrolysis voltage (12V in this experiment), after which increasing the voltage has limited help to improve the sterilization efficiency. (As shown in the different electrolysis voltage bacterial density shown in the description Figure 2

[0022] 3) In the case of keeping the electrolysis time and the electrolysis voltage unchanged: By changing the amount of sodium chloride, it is observed that the bacterial density decreases with the increase of the sodium chloride concentration. When the amount of sodium chloride reaches 1.5 grams, more than 90% of the bacteria can be killed. Further increase of the amount of sodium chloride, the bacterial density basically remains unchanged, indicating that at this time a relatively stable sterilization effect has been reached. This shows that under certain conditions (i.e. fixed electrolysis time and electrolysis voltage), there is an optimal amount of sodium chloride (1.5 grams in this experiment), after which increasing the sodium chloride has limited help to improve the sterilization efficiency. (As shown in the different sodium chloride content bacterial density shown in the description Figure 3

[0023] In summary, the electrolytic brine sterilization technology can quickly and effectively kill bacteria in cutting fluid, and only consumes electric energy and sodium chloride, has the characteristics of low cost and simple operation. Compared with the traditional addition of bactericides, this technology is more environmentally friendly and will not produce harmful chemicals, which can avoid the occurrence of mass allergy and other health hazards in workers. The application of electrolytic brine sterilization technology can improve the maintenance level of cutting fluid, and has important practical significance and broad application prospect in the metal processing industry.

[0024] ​​​The above merely preferred embodiments of the present application are not used to limit the present application, any modification, equivalent replacement and improvement etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. An electrolytic brine-based cutting fluid sterilization method characterized by, The method comprises the following steps: Step S1: measuring a bacterial-containing cutting fluid sample; Step S2: weighing a certain amount of analytical pure sodium chloride and adding it into the bacterial-containing cutting fluid sample, and stirring until the sodium chloride is completely dissolved to form an electrolyte; Step S3: insert the graphite electrode into the electrolyte obtained in S2, control the electrode spacing to be 2-3 cm, apply direct current electrolysis to form sodium hypochlorite, set the current density to be 10-100 mA / cm 2 During the electrolysis process, use a pH meter to measure the real-time pH value change of the solution and record the electrolysis time. After the electrolysis is completed, turn off the power and take out the graphite electrode; Step S4: detecting bacteria in the electrolyzed solution by a contact culture method.

2. The electrolytic brine-based cutting fluid sterilization method according to claim 1, characterized by, The initial bacterial density of the bacterial-containing cutting fluid sample is ≥ 10 5 CFU / mL.

3. The method of claim 1, wherein the electrolytic brine is prepared by adding 0.1 to 0.5% of sodium chloride to 100 parts of water. In the step S3, the electrolysis time is set to 8-15 minutes.

4. The method of claim 1, wherein the electrolytic brine is prepared by adding 0.1 to 0.3% of sodium chloride to 100 parts of water. In the step S3, the electrolysis voltage is set to 10-15V.

5. The method of claim 1, wherein the electrolytic brine is prepared by adding 0.1 to 0.5% of sodium chloride to 100 parts of water. In the step S2, the added amount of the analytical pure sodium chloride is 0.2-0.4wt% of the mass of the cutting fluid.

6. The method of sterilizing an electrolytic brine-based cutting fluid of claim 1, wherein, The contact culture method comprises: contacting the colony slide electrolyzed cutting fluid for 5-10 seconds; and the culture condition is 25-30℃, 24-48 hours.

7. Use of a method for sterilizing an electrolytic brine-based cutting fluid, characterized in that, The cutting fluid is subjected to sterilization treatment by the method according to any one of claims 1-6 to reduce the bacterial content in the cutting fluid.

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