JPS61149290A - Method for treatment of phenol-containing waste water - Google Patents

Abstract

PURPOSE:To obtain the titled method excellent in practicality, by mounting a process for performing the electrolytic oxidation of phenol-containing waste water, to which nickel salt and sodium chloride were added, in a pH range of 6.5-7.5. CONSTITUTION:In the treatment of phenol-containing waste water, nickel (II) salt and sodium chloride are added to phenol-containing waste water to adjust the pH thereof to 6.5-7.5. Nickel oxide and sodium hypochlorite formed by anodic oxidation reaction due to electrolytic oxidation are reacted and phenol- containing waste water is rapidly subjected to oxidation treatment by the formed NiO2 and nascent oxygen O.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for treating phenol-containing waste water and water discharged from drug manufacturing factories, synthetic resin factories, steel factories, etc.

(Prior art and its problems) Conventionally, as a method for treating phenol-containing wastewater discharged from drug manufacturing factories, synthetic resin factories, steel factories, etc.
The activated sludge method, the activated carbon adsorption method, the ion exchange resin method, etc. are known, and the activated sludge method is relatively often adopted industrially. However, the activated fouling method requires a large investment in equipment and has the disadvantage that it is difficult to perform stable treatment unless the concentration of phenol in the waste water, the temperature of the waste water, etc. are strictly controlled. Furthermore, methods for adsorbing and removing phenol contained in wastewater using activated carbon and ion exchange resins are also commonly used, but these methods have drawbacks such as high regeneration costs.

(Objective of the Invention) An object of the present invention is to provide a highly practical method for treating phenol-containing wastewater that solves the above-mentioned problems.

(Structure of the Invention) The present invention provides a process for electrolytically oxidizing phenol-containing wastewater by adding nickel salt and sodium chloride to the phenol-containing wastewater in a pH range of 6.5 to 7.5. This is a processing method.

(Detailed explanation of the structure) The present invention, for example, in treating wastewater containing phenol, first adds nickel (1) salt and sodium chloride to the wastewater, and then nickel oxide and the following are produced by an anodic oxidation reaction. This method uses the following reaction caused by sodium chlorite to treat phenol-containing wastewater.

NizOs+NacA! 0-+2Ni02+NaCA
' (1)2Niot+NacJO-)Nixo
The tetravalent nickel oxide N1ot produced by the reaction of s+Nacl+20(11,(2)) and the nascent oxygen O tend to be very active, and synenol-containing wastewater is rapidly oxidized.

Furthermore, in this case, the tetravalent nickel oxide and sodium hypochlorite can be regenerated through anodic oxidation after the reaction and can be repeatedly reacted with the phenol-containing wastewater.

Also, the pH suitable for all reactions including (1) and (2)
The pH range is from 6.5 to 7.5, and when the pH is lower than 6.5, it becomes difficult to generate nickel oxide and sodium hypochlorite by anodic oxidation, and J) H is 7.5.
, 5, the reaction rates of (1) and (2) become extremely slow.

Furthermore, the treatment of phenol-containing wastewater in the present invention is preferable (for example, the phenol concentration is 110,001).
When adding nickel (f) salt and sodium chloride to a product adjusted to p, the amount of nickel (f) salt to be added may be about 11,000 Pp in terms of nickel concentration relative to the phenol concentration.

Further, the amount of sodium chloride added may be about 2000 ppm in terms of sodium chloride concentration relative to phenol-concentrated KK.

In this way, phenol-containing wastewater to which nickel (1) salt and sodium chloride have been added is electrolytically oxidized, but in this case it is preferable to make the anode potential as high as possible without causing oxygen generation. It is preferable to use an electrode with a high resistance, such as a lead dioxide electrode.

The method of the present invention is advantageously applied to the treatment of synenol-containing wastewater, which is different from the conventionally widely used activated sludge method, activated carbon adsorption method, ion exchange resin method, etc., and can significantly reduce the phenol component in the wastewater. I can do it.

Next, the present invention will be explained in more detail with reference to examples.

(Example) A 500 ml beaker equipped with one anode, one cathode, and one stirring bar was used as an electrolytic cell.

In this case, the distance between the anode and cathode was set to a total of 10 cylinders.

Stainless steel was used for the anode and lead peroxide cathode.

Next, using a phenol aqueous solution of 11,000 Pp as a model wastewater, add nickel sulfate (nickel concentration: 11,000 p1) and sodium chloride (concentration: 2,000 pI) to this aqueous solution, and then adjust the pH to 7 with sodium hydroxide. Adjust to .0 and stir 4
Electrolytic treatment was performed at a current density of A/di'. The results are processed in Example 1. It is shown in Figure 1.

(Comparative Example) Next, Processing Examples 2 to 5 were conducted for comparison with Processing Example 1. The results are Processing Example 2, Processing Example 3, Processing Example 4,
Processing example 5 is shown in FIG.

In this case, in Treatment Example 2, add to'ooppm of nickel sulfate (1) to a phenol aqueous solution of 100ppm and add sodium chloride in an amount to give a sodium chloride concentration of 2000ppm, adjust the pH to 50 with sodium hydroxide, and stir. In the second treatment example 3, in which electrolytic treatment was performed at a current density of 4 A/dm' from
The sodium chloride concentration is 2000
Add the amount to give pI)m and further adjust the pH with sodium hydroxide.
was adjusted to 9.0 and electrolytic treatment was performed at a current density of 4 A/d- while stirring.

In treatment example 4, too ppm of an aqueous phenol solution of sodium dichloride was added in an amount to give a sodium chloride concentration of 2000 pI)m, and the pH was adjusted to 7.0 with sodium hydroxide. After stirring, the mixture was heated at a current density of 4 A/d77f'. Electrolytic treatment (without adding nickel sulfate) was performed.

In treatment example 5, nickel sulfate was added to a 11,000 ppm phenol aqueous solution in an amount to give a nickel concentration of xoooppm, and further hydroxylated. O
After adjusting K and stirring, electrolytic treatment was carried out at a current density of 4 A/d- (without adding sodium chloride).

As is clear from FIG. 1, in Treatment Example 2, the treatment rate was 22% at 90.5 hours from the start of the electrolytic treatment, and the treatment rate was 80 cm at 3 hours. Further, in Treatment Example 3, the treatment rate was 18% in 0.5 hours from the start of electrolytic treatment, and 60% in 3 hours. Furthermore, in treatment example 4.5, the treatment rate of 5096 was 90% in 3 hours at 0.5 hours from the start of the electrolytic treatment.

On the other hand, when the treatment method of the present invention was used, a treatment rate of 100 g was obtained in 90.5 hours from the start of the electrolytic treatment. The great effects of the present invention could be obtained in both cases of 7 enol aqueous solution L of pf)m and phenol aqueous solution of 100 ppm.

(Effects of the Invention) As described above, by treating phenol-containing wastewater with the treatment method of the present invention, it is possible to treat the phenol-containing wastewater in a short time and at a high treatment rate.

In addition, since the optimum J)H for electrolytic treatment is in the range of 6.5 to 7.5, only a small amount of neutralizing agent is needed for post-treatment, and there are fewer operational risks and corrosion problems of treatment equipment. It has great industrial advantages.

Further, the method of the present invention has the advantage that it is not affected by the seasons, and there is no need for regeneration work, etc., and maintenance is extremely easy.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the relationship between phenol treatment rate and treatment time.

Claims (1)

[Claims] A method for treating phenol-containing wastewater, comprising the step of adding nickel (II) salt and sodium chloride to the phenol-containing wastewater and electrolytically oxidizing the mixture to a pH in the range of 6.5 to 7.5.