CN1480043A

CN1480043A - Compound bactericide for treating water and its preparing method

Info

Publication number: CN1480043A
Application number: CNA021296294A
Authority: CN
Inventors: 张天德; 张怡
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-09-05
Filing date: 2002-09-05
Publication date: 2004-03-10

Abstract

A composite bactericide for treating water is prepared from chlorine, sodium chloride, sulfuric acid and lime. Its advantages are high effect, broad spectrum and low poison.

Description

Compound bactericide for water treatment and preparation method thereof

Technical Field

The invention relates to a compound bactericide for water treatment and a preparation method thereof.

Background

At present, the treatment of drinking water, industrial circulating water, oilfield flooding, hospital and factory sewage in China mostly adopts chlorine and hypochlorite bactericides, and although the cost is not high, the efficiency is low. Since harmful substances such as chloroform may be generated, there is a risk of carcinogenesis, and the method is restricted by regulations. The use of chlorine and hypochlorite based disinfectants for drinking water is banned in the unitedstates. When the bactericide is used for a long time, the bacteria can generate drug resistance, the sterilizing effect is reduced, and the bactericide should be replaced at regular intervals.

In the seventies of the twentieth century, the Americans produce stable chlorine dioxide and use the chlorine dioxide for sterilizing water, and good effects are achieved. Chlorine dioxide has been recognized as a new generation fourth generation sterilant with high efficiency, low toxicity, high speed and broad spectrum until now. However, chlorine dioxide is unstable and unsafe and is preferably produced on site and used on site. At present, the chlorine dioxide produced in China is not well solved for technical reasons and stability problems, but is produced by introducing technology and equipment, so that the investment is large and the cost is high. The excellent bactericide is not well popularized and applied in China.

Large scale production of chlorine dioxide is typically accomplished by reacting alkali metal chlorate with a reducing agent at less than one atmosphere of pressure. As described in european patent 445495, us patent 5091166. In small scale applications, such as water treatment, chlorine dioxide is typically produced by reacting sodium chlorite with an acid. The Chinese patent CN1194234A is suitable for small-scale production, but still takes sodium chlorate as a main raw material. Sodium chlorate and sodium chlorite are dangerous chemicals, are not suitable for long-distance transportation and are not easy to obtain on site.

Disclosure of Invention

The present invention adopts the common and easily available chemical raw materials of chlorine, salt, sulfuric acid and lime, etc. to produce chlorine dioxide compound bactericide by using basic chemical method, and can be directly used for watertreatment. The invention also includes: the produced chlorine dioxide compound bactericide is prepared by adding a high-efficiency activating agent, a stabilizing agent and a synergist into a chlorine dioxide aqueous solution, such as: compound bactericide of peroxydicarboxylic acid, percarbamide, etc.

Detailed Description

The invention is realized by the following steps:

1. preparation of calcium chlorate

Chlorine gas with the concentration of about 50 percent is introduced into lime milk with the concentration of 100-150 g/L to realize the following reaction:

the operation pressure is 300-400 Pa, the operation temperature is 55-75 ℃, and the preferable temperature is 65-75 ℃; the chlorination time is 1-2 hours, preferably 1.5 hours. The generated solution contains 80 g/l of calcium chlorate and CaCl₂200 g/l, Ca (ClO)₂And Cl₂Each 1 g/l.

2. Preparation of chlorine dioxide from calcium chlorate, salt and sulfuric acid

The reaction raw materials are calcium chlorate, salt and sulfuric acid. By using HCl generated in the reaction as a reducing agent to react with chloric acid to generate ClO₂The overall reaction is expressed as:

the reaction adopts three reactors connected in series, and the proportion of calcium chlorate and sodium chloride is as follows:

0.5: 1.05-1: 1.05 (molar ratio), preferably 0.5: 1.05, and adding 98% sulfuric acid to react. The concentration of calcium chlorate in the reactor is controlled to be 80 g/L, 30 g/L and 2 g/L in turn; the concentration of sulfuric acid in the reactor is controlled to be 10-11N, 9-10N and 8-9N in sequence; the reaction temperature is controlled at 35 ℃, 45 ℃ and about 55 ℃ in sequence. Air is sucked in through the bottom of the reactor to drive out the generated ClO₂And Cl₂Gas is fed into ClO₂And the absorption tower absorbs the water. Most of ClO₂And a small portion of Cl₂Dissolving in water to obtain chlorine dioxide water solution. Undissolved Cl₂Into the next Cl₂And an absorption tower for absorbing calcium chlorate by lime cream. The dilute acid can be recycled after the sulfate in the waste liquid is recovered.

3. Compounding

According to different requirements, adding a certain amount of high-efficiency activating agent, stabilizing agent and synergist into the chlorine dioxide aqueous solution, such as: peroxydicarboxylic acids, percarbamides, and the like.

Example 1:

Ca(ClO₃)₂the concentration is 20 g/L, the NaCl concentration is 5 g/L, the sulfuric acid concentration is 9N, and the reaction temperature is 30-40 ℃. An aqueous solution of chlorine dioxide of 8 g/l was obtained.

Example 2:

Ca(ClO₃)₂the concentration is 2 g/L, the NaCl concentration is 2 g/L, the sulfuric acid concentration is 9.5N, and the reaction temperature is 40-45 ℃.5 g/l of chlorine dioxide aqueous solution can be prepared.

Claims

1. A compound bactericide for water treatment and a preparation method thereof are characterized in that: the chlorine dioxide compound bactericide is prepared by adopting common and easily available chemical raw materials such as chlorine, sodium chloride, sulfuric acid, lime and the like by a basic chemical method and is directly used for water treatment. The method comprises the following steps:

a) preparing calcium chlorate;

b) preparing chlorine dioxide from calcium chlorate, salt and sulfuric acid;

c) and (4) compounding.

2. The method of claim 1, wherein the raw materials are chlorine, sodium chloride, sulfuric acid, lime and other commonly used and easily available chemical raw materials, and the basic chemical method is adopted to realize the upgrading from chlorine and hypochlorite bactericides to broad-spectrum, efficient and low-toxicity chlorine dioxide bactericides.

3. The process according to claim 1, wherein the calcium chloride is prepared in a concentration of 100 to 150 g/l, preferably 120 g/l. The concentration of the chlorine gas is 10-50%, preferably 50%. The operating pressure is 300-400 Pa. The operation temperature is 55-75 ℃, preferably 65-75 ℃. The chlorination time is 1-2 hours, preferably 1.5 hours.

4. The process of claim 1, wherein the chlorine dioxide is prepared from calcium chlorate, common salt and sulfuric acid, and the preferable ratio of calcium chlorate to sodium chloride is 0.5: 1.05 (molar ratio). The reaction uses three reactors in series, and the preferred reaction conditions are: the concentration of calcium chlorate is controlled to be 80 g/L, 30 g/L and 2 g/L in turn; the concentration of the sulfuric acid is controlled to be 10-11N, 9-10N and 8-9N in sequence; the reaction temperature was controlled at 35 deg.C, 45 deg.C, and 55 deg.C in this order.

5. The method of claim 1, wherein the compounding comprises adding a certain amount of high-efficiency activator, stabilizer and synergist into the chlorine dioxide aqueous solution according to different requirements: peroxydicarboxylic acids, percarbamides, and the like.