KR950008879B1 - Waste water clarification method using colloid particles - Google Patents

Abstract

The method for separating and purifying a polluted component i.e. heavy metal ion, coloring matter, organism, etc. in the waste wate by adsorption, occlusion and coprecipitation, is characterized by(a) mixing Na2SO4, Na2SO3, K2SO4, K2SO3, (NH4)2SO4 and/or (NH4)2SO3 with the waste water, and adding CaCl2, Ca(OH)2, Ca(NO3)2, BaCl2, Ba(OH)2, Ba(NO3)2, PbCl2, Pb2(OH)2 and/or Pb(NO3)2 to the mixture to generate and grow a colloid particle of the suspension, or (b) mixing Ca(OH)2 or Ba(OH)2 with the waste water, and adding a carbon dioxide(CO2) gas to the mixture to generate and grow the colloid particle.

Description

Wastewater Purification Method Using Colloidal Particles in Wastewater

The present invention relates to a method for purifying wastewater that effectively adsorbs, occludes and co-separates contaminants in wastewater such as heavy metal ions, pigments, and organic matters by using strong adsorption powers generated and produced during colloidal particles in wastewater. will be.

The environmental pollution caused by urban sewage and industrial wastewater caused by the recent expansion of the population and industrial development has a serious impact on the natural world, and the issue of the deportation of pollution for survival has emerged as an important task for mankind. Therefore, various methods have been proposed for the purification of domestic sewage and factory wastewater.

Representatively, biological treatment methods, electrochemical treatment methods or chemical treatment methods are known as purification methods for industrial wastewater.

A. Biological Treatment

As urban sewage is mainly a domestic wastewater, the contents of pollution are mainly organic matter and almost all are constant, and thus, an active sludge method using various decay bacteria is adopted. Among industrial wastewater, wastewater from factories that deal mainly with animals and plants such as food factories and paper mills is purified in the same way as domestic sewage.

Here, the amount of discharged to urban sewage or factory wastewater is enormous, and the decomposition rate of organic matter by bacteria is very slow. Therefore, the aeration tank, aeration facility, terminal settler, sludge conveying facility, waste sludge treatment facility, etc. are required for the purification process. It is true. Therefore, further improvements such as facility costs, operating costs, and treatment efficiency are desired.

B. Electrochemical Methods

Heavy metal ions in wastewater can be separated experimentally through electrode reactions, but they are not applicable to enormous amounts of wastewater due to low yield of ions, low concentration of heavy metal ions in wastewater, and high power consumption. Became known.

C. Physicochemical Treatment

Factory wastewater differs depending on the industries such as machinery, metals, plating, textiles, dyeing, ceramics, mining, leather, and chemical industries. As it contains special contaminants such as organic matter, it cannot be purified only by strains like urban sewage, but various physicochemical treatment methods are required according to the contents of pollution.

The chemical treatment method has the limitation that the use of expensive chemicals or materials should be avoided from an economic point of view, the reaction should be carried out in a dilute solution, and the reaction temperature should be at room temperature. Therefore, oxidizing agents, acid alkalis for pH adjustment, adsorbents, flocculants, ion exchange resins and the like are currently used.

For example, Cl ₂ gas can be used for sterilization, discoloration, and deodorization as an oxidizing agent. However, since zeolite and activated carbon are adsorbents, zeolite and activated carbon are heavy metal ions because of its high toxicity and difficulty in handling. It is used for adsorption removal of dyes, organic matters, etc., but the pH of 7 shows only 70 to 80% of adsorption rate with only one column of zeolite or activated carbon. Acidic clay and diatomaceous earth are effective in the presence of oil as contaminants, but they have a relatively low absorption rate, are not easily regenerated, and are difficult to economically treat wastewater. In addition, kaoline or briquettes are effective against wastewater contaminated with heavy metal ions such as Hg ⁺⁺ and Cd ⁺⁺ , but their adsorption rate is low and their purification and regeneration processes are difficult.

As the flocculant, aluminum sulfate, ferric salt, chitosan, sawdust, bark, ferritte may be used. Aluminum sulfate (Al ₂ (SO ₄ ) ₃ 18H ₂ O) is known to be suitable for the coagulation and sedimentation and purification of suspended solids in raw water of muddy water during the production of municipal water. Dyeing wastewater can also be used to remove COD from dyes, but the effect depends on the type of dye. For example, 35% in basic dyes and 92% in sulfur dyes have been shown to be able to coagulate.

In addition, ferric salt (FeCl ₃ 6H ₂ O) acts almost the same as aluminum sulfate, but it appears that it can not be used to avoid iron ions.

In addition, the use of cation exchange resins for waste water allows the exchange of all cations as well as the cations of heavy metals, which can be temporarily and almost completely removed. However, when regenerating ion exchange resin saturated with cations, the pollutant cations are mixed again in the wastewater, so it is not meaningful to use them for wastewater treatment except for special laboratory purpose.

As described above, various methods of purifying domestic sewage and factory wastewater are known. Currently, zeolite or activated carbon is rarely used as an adsorbent when purifying plant wastewater, and aluminum sulfate or iron chloride is used. The addition of hydrated aluminum sulfate or ferric salt to the wastewater results in partial hydrolysis.

Al ₂ (SO ₄ ) ₃ + 6H ₂ O 2Al (OH) ₃ + 3H ₂ SO ₄

FeCl ₃ + 3H ₂ O Fe (OH) ₃ + 3 HCl

At this time, the produced aluminum hydroxide or iron tetrahydride may be involved in the adsorption by generating colloidal particles, but in general, the degree of hydrolysis in neutral conditions is less than 2%, and in the acidic wastewater solution, the hydrolysis is greatly suppressed. The effect was extremely small, and only A ⁺⁺⁺ ions or Fe ⁺⁺⁺ ions with large ionic values were found to be involved in the aggregation effect of colloidal particles.

Hydrolysis of the aluminum sulfate or ferric salt is promoted in the weakly basic wastewater, but colloidal adsorption cannot be performed because the colloidal particles of the produced aluminum hydroxide or iron hydroxide dissolve as complex ions.

Al (CH) ₃ + OH ^- Al (OH) ^- ₄

Fe (CH) ₃ + OH ^- Fe (OH) ^- ₄

In addition, Al and Fe have both properties, so in a highly basic solution, aluminum hydroxide and iron hydroxide act as an acid and neutralize to form salts. Therefore, the adsorption force and cohesion force are lost.

Al (OH) ₃ H ₃ AlO ₃ HAlO ₂ + H ₂ O

Fe (OH) ₃ H ₃ HFeO ₃ HFeO ₂ + H ₂ O

That is, aluminum sulfate or ferric salt has a slight adsorption force in the neutral region of the water and acts as a flocculant.

The present inventors have studied to improve the problems of the conventional wastewater purification treatments, as a result, can supplement the anion solution in the weak acid general factory wastewater in which heavy metal ions, pigments, and organics coexist, and can produce a colloid of suspension. When the additive is added, the fine colloidal particles produced in the early stage have a strong physicochemically strong adsorbing power compared to the adsorbability of ordinary colloids. Therefore, unlike the case of adding colloidal substances or adsorbents alone, the heavy metal ions and pigments in the wastewater The present invention was found to be able to effectively separate organic matters by adsorption, occlusion, and coprecipitation.

Accordingly, the present invention utilizes or supplements a component in wastewater to purify wastewater, and adds a suspension substance to produce colloidal particles to grow and generate strong colloidal particles. The present invention relates to a method for separating and purifying contaminants in adsorption, storage, and coprecipitation.

In the present invention, the selection of a drug and a method of using the same may exemplify the following four aspects.

The first embodiment comprises at least one agent selected from the group consisting of Na ₂ SO ₄ , Na ₂ SO ₃ , K ₂ SO ₄ , K ₂ SO ₃ , (NH ₄ ) SO ₄ or (NH ₄ ) ₂ SO ₃ in the wastewater. 1 material is mixed and then CaCl ₂ , Ca (OH) ₂ , Ca (NO ₃ ) ₂ , BaCl ₂ , Ba (OH) ₂ , Ba (NO ₃ ) ₂ , PbCl ₂ , Pb ₂ (OH) ₂ or By adding one or more second substances selected from the group consisting of Pb (NO ₃ ) ₂ to produce suspended colloidal particles, they adsorb, occlude, and separate contaminants in the wastewater such as heavy metal ions, pigments, and organics. I can cleanse it.

In the second embodiment, Na ₂ CO ₃ , NaHCO ₃ , K ₂ CO ₃ , KHCO ₃ , (NH ₄ ) ₂ CO _3, or NH ₄ HCO ₃ is added by mixing one or more first substances selected from the group consisting of Next, CaCl ₂ , Ca (OH) ₂ , Ca (NO ₃ ) ₂ , BaCl ₂ , Ba (OH) ₂ , Ba (NO ₃ ) ₂ , SrCl ₂ , Sr (OH) ₂ , Sr (NO ₃ ) ₂ , By adding one or more second substances selected from the group consisting of MgCl ₂ , Mg (OH) ₂ or Mg (NO ₃ ) ₂ to form and grow suspended colloidal particles, they can be used in wastewater such as heavy metal ions, pigments and organics Contaminants can be separated and purified by adsorption, occlusion and coprecipitation.

In a third embodiment, a waste water is mixed with Na ₂ C ₂ O ₄ , K ₂ C ₂ O _4, or (NH ₄ ) ₂ C ₂ O ₄ , containing one or more first substances selected therefrom, and then mixed with CaCl ₂ , Caustic colloidal particles are formed by adding one or two or more second substances selected from the group consisting of Ca (OH) ₂ , Ca (NO ₃ ) ₂ , BaCl ₂ , Ba (OH) ₂ or Ba (NO ₃ ) ₂ . By growing, contaminants in wastewater such as heavy metal ions, dyes and organics can be separated and purified by adsorption, occlusion and coprecipitation.

In the fourth embodiment, Ca (OH) ₂ or Ba (OH) ₂ is added to the waste water, mixed, and CO ₂ gas is added to grow colloidal particles to adsorb contaminants in the waste water such as heavy metal ions, pigments, and organic matter. Can be separated and purified by occlusion, co-precipitation.

In the embodiment of the present invention, while adjusting the pH of the wastewater in accordance with the contamination of the wastewater, take a minimum amount of one or two or more first substances according to any one of the first to fourth embodiments, and put into a quantitative wastewater stock solution and mix well uniformly. . To this, one or two or more second substances capable of producing suspension colloids are taken and slowly added while mixing well made of concentrated aqueous solution. At this time, the first material and the second material may be used interchangeably.

^{Other, Cd ++, Pb ++, Cr} +++, Cu ++, Hg ++, heavy metal ions and Al ^+++, Mg ^++, Be ⁺⁺ ions such as Fe ⁺⁺⁺ are alkali solution It was found that the purification of the suspension by sedimentation was more effective because the suspension and the adsorption of lime oil were well adsorbed by making the suspension of hydroxide in.

The present invention will be described below with reference to Examples, but the scope of the present invention is not limited to these Examples.

Example 1

The wastewater test solution was made as follows.

① 0.102g of pigment methylene blue cow was taken and dissolved in 100ml, and 5ml of the solution was taken again and put into 1000ml of volumetric flack.

② 0.675 g of CdSO ₄ was dissolved in 100 ml, and the solution was again taken and placed in a 1000 ml volumetric flask.

③ 1.860 g of Na salt (Na ₂ EDTA 2H ₂ O) of EDTA (ethylene diamine tetra acetic acid) was dissolved in 500 ml (0.01 M), and the solution was taken again in 10 ml and placed in a 1000 ml volumetric flask.

④ The flasks filled in ①, ②, ③ were filled with d-water to the mark (漂 船).

Waste water test solution prepared as above 1 10 ml of 0.01 M Na ₂ SO ₄ solution was added to the solution, mixed well to make a uniform solution, and again, 10 ml of 0.1 M BaCl ₂ solution was added to the mixture with a stirrer, and slowly added thereto. The measurement results are shown in Table 1 below.

TABLE 1

Note 1: The amount of EDRA remaining in the supernatant is quantified according to the EDTA titration method. It was converted into the PPM value. At this time, a standard solution of 0.01M Mg ⁺⁺ ion and BTindicator were used.

Note (2): The maximum absorption wavelength (λ max ≒ 450 nm) of the dilute methylene blue solution was determined, and a methylene blue solution was prepared at this wavelength for absorption analysis.

Note (3): Determination of Cd ⁺⁺ is determined by the absorbance method using Dithizon as a color developing reagent. It was converted into the PPM value in (λmax = 530 nm).

Example 2

Instead of 0.1M solution of BaCl ₂ After the experiment, as shown in 0.1M Pb (NO ₃₎ in Example 1 except that the _second solution is shown in Table 2 below.

TABLE 2

Example 3

Wastewater Test Solution 1 Neutralize with 0.1M Na ₂ CO ₃ solution, add 10 ml again, mix well, and slowly add 10 ml of 0.1MCaCl ₂ with a stirrer. After standing for 10 minutes, the result of measuring the residual amount of contaminants in the supernatant is shown in Table 3 below.

TABLE 3

Example 4

Wastewater Test Solution 1 Make 10M of 3M lime oil, mix well and let stand for 10 minutes. Take only this supernatant, add Ca (OH) ₂ and the equivalent Na ₂ CO ₃ solution in the supernatant, and then rest for 10 minutes. The supernatant is neutralized to pH 7 with HCl solution and the contaminants in the solution are measured.

TABLE 4

Example 5

Wastewater Test Solution 1 10 ml of 0.1 M Na ₂ C ₂ O ₄ solution was added to the mixture, and the mixture was added well while 10 ml of 0.1 M BaCl ₂ was mixed well. After adding the solution for 10 minutes, the supernatant was taken and the contaminant in the test solution was measured.

TABLE 5

Example 6

Wastewater Test Solution 1 Add 10 ml of 3M lime oil to the mixture, mix well, and let stand for 10 minutes. Take only this supernatant, add Ca (OH) ₂ and the equivalent Na ₂ C ₂ O ₄ solution in the supernatant, and then rest for 10 minutes. This supernatant is neutralized to pH 7 with HCl solution, and the results of measuring the contaminants in the solution are shown in Table 6 below.

TABLE 6

Example 7

Wastewater Test Solution 1 Add 10 ml of 3M lime oil to the mixture, mix well, and let stand for 10 minutes. Take only this supernatant and let the supernatant reach a pH of 7 via CO ₂ gas. At this time, when the pH becomes more acidic than 7, the produced CaCO ₃ is dissolved again, thereby reducing the purification effect through adsorption. When the pH is about 7, the contaminant in the supernatant is measured.

TABLE 7

Example 8

Wastewater Test Solution 1 10 ml of 0.1M Ba (OH) ₂ is added to the mixture, and the mixture is left to stand for 10 minutes. Only the supernatant is taken through CO ₂ gas. When the solution reaches pH 7, stop the passage of gas and let stand for 10 minutes to measure the contaminants in the supernatant is shown in Table 8.

TABLE 8

Claims (1)

In the wastewater purification method in which heavy metals, pigments and other organic substances are dissolved, lime oil or heavy soil water (Ba (OH ₂ )) is added to the wastewater to precipitate heavy metal components as hydroxides, and CO ₂ gas is then added to the supernatant. Purification method characterized in that the adsorption of the primary and secondary in the process of almost completely precipitate the dissolved Ca ⁺⁺ or Ba ⁺⁺ added to this.