KR20190096029A - The treatment reagent of heavy metal waste water having the active ingredient of the sulfide and silicic acid and method thereof - Google Patents

Abstract

The present invention relates to a heavy metal treatment agent having sulfides and silicates as active ingredients and a heavy metal treatment method. More particularly, the present invention relates to a heavy metal treatment agent having sulfides and silicates as active ingredients for maximizing the treatment efficiency of heavy metals contaminated in the wastewater, and the heavy metal treatment method. To this end, in order to treat the wastewater contaminated with heavy metal, a heavy metal treatment agent comprising sulfides and silicates as active ingredients is disclosed.

Description

The treatment reagent of heavy metal waste water having the active ingredient of the sulfide and silicic acid and method

The present invention relates to a heavy metal treatment agent and a method for treating sulfide and silicate as an active ingredient, and more particularly, to a heavy metal treatment agent and treatment method using sulfide and silicate as an active ingredient to maximize the treatment efficiency of heavy metal contaminated in wastewater. It is about.

Recently, industrial wastewater and household sewage caused by the change of industrial structure and population density have caused serious problems. In particular, industrial wastewater discharged from industrial complex contains a considerable amount of heavy metals, and these wastewater flows into groundwater or surface water. It becomes the cause of water pollution.

There are many reasons for the pollution of the environment, but pollution by heavy metals has caused many problems so far. Among the various pollutants, especially heavy metals are not excreted very well and have long-term side effects due to biological accumulation, and heavy metals released into the environment are circulated through the biosphere without decomposing or self-cleaning, and through the food chain process. This is because it can cause a fatal effect on the human body by moving rapidly to a person and causing an acute or chronic disorder in the body. Therefore, the best efforts should be made not to include heavy metals that are fatal to humans in water, and if heavy metals are contaminated, high efficiency heavy metal treatment agents are needed to reliably remove heavy metals to protect the aquatic ecosystem.

Existing treatment methods mainly used to remove these heavy metal ions include evaporation method, reverse osmosis membrane method, liquid membrane method, oxidation / reduction method, activated carbon adsorption, ion exchange resin method, and chemical flocculation precipitation method. Is possible and used to some extent industrially, but it is economically and technically limited. The evaporation method is expensive in energy and has a problem of increasing concentration of nonvolatile materials. The technology using thin films such as reverse osmosis membrane and electrodialysis is too expensive to install and operate, is not selective to metal ions, fouling and membrane destruction. There is a problem. The ion exchange resin method is relatively clean and has the advantage of selectively removing contaminated heavy metal ions at low concentrations, but it is difficult to adsorb and remove heavy metal ions in complex or high concentrations, and the ion exchange resin is composed of polymers. As a result, a large amount of waste treatment costs are required when disposing of the final ion exchange capacity, and since the ion exchange resin itself is generally expensive, it has a problem in that economical efficiency as a treatment agent for treating a large amount of heavy metal is greatly reduced. The chemical flocculation precipitation method is to precipitate heavy metals by hydroxides or emulsions, and it is suitable to be applied in the case of high concentrations of heavy metals in the waste water, and it is easy to install and has a relatively low maintenance cost. However, there is a problem in that the heavy metal removal rate is low and a large amount of chemical coagulant is used to deal with a large amount of sediment sludge generated.

Accordingly, many studies have been conducted to develop a heavy metal treatment agent that minimizes environmental pollution and has high economic efficiency, and prevents the removed heavy metals from eluting under adverse conditions in water. In Korean Patent Laid-Open Publication No. 10-0848620B1, 70 wt% of sodium sesquicarbonate, 5 wt% of ethylenediaminetetraac etic acid (EDTA), 5 wt% of sodium metabisulphite, and 20 wt% of water are mixed. The heavy metal treatment agent and the manufacturing method which consists of the process of making a slurry and drying at 60-65 degreeC for 2 hours are proposed. The present invention is made of a material of sodium sesquicarbonate (Systematic name trisodium hydrogendicarbonate, Na ₃ H (CO ₃ ) ₂ , EDTA, Sodium metabisulfite (Na ₂ S ₂ O ₅ ), whereas in the present invention sulfide and silicate ( Silicic acid alkali salt or silicate is an active ingredient, and there is a difference that can comprehensively remove heavy metals of wastewater composed of high and low concentrations.

Korean Patent Laid-Open Publication No. 10-2005-0054135A discloses a water treatment agent containing a porous alkaline hematite material produced as a byproduct in the process of producing alumina from bauxite, which is environmentally friendly to remove heavy metals from acid mine wastewater as well as red tide bioremediation. And pH neutralization. The present invention uses a porous alkaline hematite material produced as a by-product in the process of manufacturing alumina, while the present invention contains a high concentration in the removal of heavy metals by using a heavy metal treatment agent composed of sulfides and silicates There is a difference from the cited invention as it consists of a heavy metal agent (Agent) that can simultaneously remove heavy metals or heavy metals contained in trace concentrations.

In Korean Unexamined Patent Publication No. 10-2001-0007770A, one genus GLOEPHYLLUON SP. Candida sp. (2 kinds of Candida sp., Bacillus sp), 3 kinds.Leuconostoc MESENTROIDES SUBPCREMORIS) (16 types) FUNGI (2 types) Other two kinds of microorganisms and heavy concentrations of wastewater containing heavy metals prepared by mixing aconic acid which neutralizes nickel, mercury, lead, cadmium, uranium, etc. This invention is inoculated with 10 ml of E. coli (KCCM-10167) in 2 kg of fecal soil excreted by earthworms, and acorn fruit powder (aconic acid) in 2 kg of fecal soil inoculated with E. coli. ) 1 kg of evenly mixed and mixed with 1 kg of acorn fruit powder (aconic acid) mixed with 2 kg of earthworm fecal soil, while a high concentration wastewater treatment agent is composed of insoluble preparations in water, while the present invention is Soluble in Heavy metals contained in the waste water by using a heavy metal treatment agent composed of a sulfide and a silicate together with the sulfides to form an insoluble precipitate of the heavy metal sulfide by sulfides, and a very small amount of heavy metals remaining in the water by hydroxy-heavy metal silicate Insoluble precipitates of (Hydroxy-heavy metal silicate) are produced, and insoluble precipitates produced by the heavy metal treatment agent of the present invention containing sulfides and silicates as active ingredients are separated by a flocculation process to increase the concentration of heavy metals contaminated in water. Regardless of its concentration, it is possible to maximize the treatment efficiency of heavy metals regardless of its concentration, and to remove the heavy metals in the treated water to a level where there is no presence (about 0.1 ppm or less).

Korean Patent Laid-Open Publication No. 10-1999-0080537A is an industrial wastewater treatment agent having an excellent ability to remove heavy metals and harmful components, comprising 25 to 50% chitosan and 50 to 75% rare earth compounds. All harmful components such as oxygen demand, suspended solids, and turbidity can be treated and existing wastewater treatment facilities can be used as it is, reducing costs. Chitosan, which is a component of the present invention, is a natural polymer and needs to be dissolved under acidic conditions in order to be used as a wastewater treatment agent. In case of water treatment according to the amount, the rare earth compound should be relatively supplied. Therefore, the supply of expensive rare earth compound cannot provide economic feasibility. In the present invention, the present invention is composed of chitosan and rare earth compounds. Consisting of a heavy metal treatment agent with a persilicate as an active ingredient, there is a difference from the cited invention as the treatment efficiency can be maximized regardless of the concentration of heavy metal at a low price.

In Korean Patent Laid-Open No. 10-1997-0069115A, 20 to 80 g of monoethanol amine (NH ₂ CH ₂ CH ₂ OH) is mixed and stirred with 10 to 40 g of water (H ₂ O) to obtain a first mixture solution, and to the first mixture solution. 20-60 g of tannins are added, followed by agitation to obtain a second mixture, and 30-120 g of 25-86% sulfuric acid (H ₂ SO ₄ ) is added to the second mixture to stir to obtain a third mixture. 10-80 g of formalin (HCHO) was slowly added to the third mixture, followed by stirring to obtain a fourth mixture. Then, 10-100 g of water (H ₂ O) was poured into the fourth mixture to obtain a fifth mixture, and the fifth mixture was mixed. 1 to 300 g of ferric sulfate (FeSO ₄ ) and ferric chloride (FeCl ₃ ) were added and stirred to obtain a sixth mixture, and the content of aluminum hydroxide (Al ₂ O ₃ ) was 4 to 15%. A method for producing a flocculant for water purification treatment, which is prepared by rapidly stirring the water treatment agent (generally used wastewater treatment agent) in 50 to 3,000 g, is proposed. The. The present invention is composed of a coagulant for wastewater purification treatment by a process including monoethanol amine, tannin, sulfuric acid, formalin, sulfuric acid and ferric chloride, and aluminum hydroxide, and the manufacturing process is very complicated and harmful to the water environment. Since formalin is contained, it is not only able to provide a function as a flocculant for wastewater purification but also differs from the present invention having sulfide and silicate as active ingredients.

Korean Patent Laid-Open Publication No. 10-1997-0042306A proposes a composition of a heavy metal treatment agent comprising sodium dimethylthiocarbamate, sodium sulfide, calcium hydroxide and water. The present invention is composed of a heavy metal treatment agent consisting of sodium sulfide may be considered similar to the invention of the present application. However, in the case of mixing sodium sulfide and calcium hydroxide, which are the constituents of the present invention, in water to prepare the heavy metal treating agent of the present invention, the insoluble calcium sulfide (CaS) and hydroxide immediately before the heavy metals are treated, as shown in Scheme 1. The formation of sodium (NaOH) has already lost the ability to remove heavy metals by sodium sulfide, which makes it incapable of treating heavy metals in the wastewater, as well as the already produced calcium sulfide (CaS) before water treatment to remove heavy metals. It is decomposed to form a mixture of calcium hydroxide (Ca (OH) ₂ ), calcium hydrogen sulfide (Ca (SH) ₂ ) and calcium hydrogen sulfide (Ca (SH) (OH)) to remove the heavy metals contained in the wastewater. On the other hand, in the case of the present invention, since the alkali sulfide and silicate dissolved in water are mixed together, the heavy metal before water treatment Not cause performance degradation for Li, the above-referenced invention and a difference according to the high level and constituted by any structure capable of removing heavy metals by standing comprehensive without being affected in the heavy metal content of the lower concentration contained in the waste water.

Ca (OH) ₂ + Na ₂ S → CaS + 2NaOH] --------------------- Scheme 1

CaS + H ₂ O → Ca (SH) (OH) ---------------------------- Scheme 2

Referring to the above-mentioned cited invention, the treatment of high concentrations of heavy metals contained in the wastewater up to the concentration of tens of ppm by the chemical treatment method using a single sulfide or hydroxide was possible without water treatment, but the water treatment was less than the emission standard prescribed by the Ministry of Environment. It is not yet possible to completely treat heavy metals by chemical treatment methods to low concentrations of 0.2 ppm or less or 0.1 ppm) or to trace levels below the detection limit of the inductively coupled plasma atomic emission spectrometer (ICP-AES). There are many difficulties until.

Republic of Korea Patent Publication No. 10-0848620B1 Republic of Korea Patent Publication No. 10-2005-0054135A Republic of Korea Patent Publication No. 10-2001-0007770A Republic of Korea Patent Publication No. 10-1999-0080537A Republic of Korea Patent Publication No. 10-1997-0069115A Republic of Korea Patent Publication No. 10-1997-0042306A Republic of Korea Patent Publication No. 10-0427911B1 Republic of Korea Patent Publication No. 10-1336824B1 Korean Patent Publication No. 1996-0003920B1 Japanese Patent Publication No. 1994-54542B2

Accordingly, the present invention has been made to solve the problems described above, and provides a new heavy metal treatment agent which can replace the conventional heavy metal treatment method by simple sulfide sulfide or hydroxide (Hydroxide) as in the present invention. It is an object of the present invention to provide an invention capable of comprehensively removing high concentration heavy metals and low concentration heavy metals regardless of the concentration of heavy metals contained in waste water when using heavy metal treatment agents containing sulfides and silicates as active ingredients.

However, the objects of the present invention are not limited to the above-mentioned objects, and other objects not mentioned will be clearly understood by those skilled in the art from the following description.

The above object of the present invention can be achieved by providing a heavy metal treatment agent, comprising a sulfide and a silicate as an active ingredient in a heavy metal treatment agent for treating wastewater contaminated with heavy metals.

In addition, sulfides treat heavy metals at a first concentration (high concentration of at least 1 ppm or more), and silicates treat low concentrations of heavy metals of at least 1 ppm or less at a second concentration at a concentration relatively low compared to heavy metals of the first concentration.

In addition, the sulfide includes 90 to 95% by weight, silicate includes 5 to 10% by weight. Preferably, the inclusion rate of the silicate is contained in a ratio of 2 to 10% relative to the sulfide.

In addition, heavy metals of the first concentration react with sulfides to form insoluble precipitates of the metal sulfides, and heavy metals of the second concentration that are not treated with sulfides react with silicates to form insoluble precipitates of hydroxy-heavy metal silicates.

The sulfide is selected from at least one of sodium hydrogen sulfide (NaHS), potassium hydrogen sulfide (KHS), lithium sulfide (LiHS), sodium sulfide (Na2S), potassium sulfide (K2S), and lithium sulfide (Li2S).

In addition, the sulfide is dissolved in the waste water at a concentration of 3.5% by weight to 50% by weight, or dissolved at a concentration of 5.0% by weight to 40% by weight, or dissolved in any one of 12% by weight to 28% by weight. It is preferable.

In addition, the silicate is KS standard liquid sodium silicate (1 type Na2O: 17-18%, SiO2: 36-38%), two types of liquid sodium silicate (Na2O: 14-15%, SiO2: 34-36%), liquid 3 types of sodium silicate (Na2O: 9.0-10%, SiO2: 28-30%), 4 types of liquid sodium silicate (Na2O: 6.0-7.0%, SiO2: 23-25%), powdered sodium silicate, potassium silicate, and silicic acid At least one of lithium.

In addition, the silicate is dissolved in the waste water at a concentration of 0.1 to 2.5% by weight, or dissolved at a concentration of 0.5 to 2.0% by weight, or at a concentration of 0.75 to 1.5% by weight.

On the other hand, an object of the present invention is to add a sulfide and silicate to the wastewater containing heavy metals to produce insoluble precipitates of metal sulfides and hydroxy-heavy metal silicates, the first of adjusting the pH of the wastewater according to the addition of sulfides and silicates The second pH control step, the inorganic coagulant input step of adding a positively charged inorganic coagulant to agglomerate insoluble precipitates of metal sulfides and hydroxy-heavy metal silicates having anionic charges, the second to adjust the pH of the waste water according to the inorganic coagulant input It can be achieved by providing a method for treating a heavy metal, characterized in that it comprises a step of adjusting the pH, the step of adding a polymer flocculant to form flocculated insoluble precipitate into a floc, and a solid-liquid separation step of removing the floc.

The heavy metal is at least one selected from nickel, cadmium, lead, mercury, arsenic, and copper.

Meanwhile, the heavy metal treatment agent composed of sulfide and silicate (Silicate or Silicic acid alkali metal salt) which can be dissolved in water according to the present invention reacts with heavy metals in water, and heavy metal sulfide and hydroxy-heavy metal silicates (Hydroxy Insoluble precipitates of -heavy metal silicate are produced, and the treatment efficiency of heavy metals contained in the waste water can be maximized by the water treatment method that aggregates and separates the precipitated insoluble substances.

In the case of the conventional heavy metal treatment agent using a single sulfide or hydroxide, even if the water treatment is performed completely because of high solubility in water, it is likely that a large amount of heavy metals are eluted in the treated water or completely contaminated wastewater containing a very small amount of heavy metals According to the present invention as described above, it is possible to remove heavy metals regardless of the low or high concentration of heavy metals contaminated in water, as well as the cost of starting materials for preparing them is significantly lower. Since it is excellent in price competitiveness to cope with the method of sulfide or hydroxide alone, the cost of water treatment is low, and heavy metals precipitated by reacting with the heavy metal treatment agent of the present invention containing sulfides and silicates as active ingredients may be Prevents environmental pollution after heavy metal treatment due to no elution In addition, the heavy metal treatment agent of the present application reacts with high concentrations of heavy metals contaminated in water to form sulfides and insoluble precipitates of heavy metals, and the heavy metals present in trace amounts react with silicates to form hydroxy-heavy metal silicates (Hydroxy-heavy). It is configured to generate insoluble precipitates of metal silicate, which is effective to completely remove high and low concentrations of heavy metals contained in wastewater.

Hereinafter, with reference to the drawings will be described a preferred embodiment of the present invention. In addition, one Example described below does not unduly limit the content of this invention described in the Claim, and the whole structure demonstrated by this Embodiment is not necessarily required as a solution of this invention. In addition, the matters obvious to those skilled in the art and the art may be omitted, and the description of the omitted elements (methods) and functions may be sufficiently referred to without departing from the spirit of the present invention.

Heavy metal treatment agent using the sulfide and silicate according to the present invention as an active ingredient, regardless of the high or low concentration of heavy metals contained in the waste water can be high removal rate of heavy metals and maximize the water treatment efficiency. In addition, insoluble precipitates of heavy metal sulfides and hydroxy-heavy metal silicates produced by the reaction of sulfides and silicates with heavy metals have excellent binding strength with heavy metals to prevent heavy metals from eluting back into water. The contaminated wastewater can be removed to a concentration below the detection limit (preferably approximately 1 ppm or less).

Heavy metal treatment agent (pharmaceutical) according to the present invention is composed of dissolving 3.5 to 50% by weight of sulfide and 0.1 to 2.5% by weight of silicate in water (or wastewater). Thus, wt% other than sulfides and silicates can be considered as wastewater containing heavy metals. However, it is preferable that the heavy metal treatment agent containing sulfides and silicates as an active ingredient contains more proportions of sulfides for treating heavy metals at higher concentrations than silicates for treating heavy metals at low concentrations. As an example, the content of sulfide may be included in approximately 90 to 95%, and the content of silicate may be included in approximately 5 to 10%. Preferably, the content of the silica trichloride is contained in a ratio of about 2 to 10% relative to the content of sulfide. However, the above-mentioned content of sulfide and silicate may be changed as necessary, and additional other components may be added according to the type of wastewater.

Sulfide is a medicine to provide for water treatment when the concentration of heavy metals in water is high (approximately 1 ppm or more of heavy metals). Sodium sulfide (NaHS), potassium hydrogen sulfide (KHS), and lithium sulfide (LiHS) ), One or more sulfides selected from sodium sulfide (Na ₂ S), potassium sulfide (K ₂ S), and lithium sulfide (Li ₂ S) may be selected. The sulfide concentration may vary depending on the type of wastewater containing heavy metals, but is preferably dissolved in a concentration of 3.5% by weight to 50% by weight, more preferably in a concentration of 5.0% by weight to 40% by weight. Preference is given to dissolving most preferably at a concentration of 12% to 28% by weight.

When the amount of sulfide is dissolved at a concentration of 50% by weight, when the temperature of the waste water is low, the solubility is lowered, which may give visual discomfort as precipitated in water, and the efficacy of the heavy metal treatment agent may be slightly lower than other contents. In addition, when the amount of sulfide is dissolved at a concentration of 3.5% by weight or less, it may provide an advantage of sufficiently preventing the formation of sulfide precipitates at low temperatures, but the heavy metal concentration in the wastewater or the amount of wastewater to be treated is huge. In order to produce insoluble precipitates of metal sulfide by reacting stoichiometrically with heavy metals contained in waste water, it is necessary to increase logistics costs, storage and management problems due to the relatively high amount of heavy metal treatment agent. It is preferred that the above 12 wt% to 28 wt% sulfide is dissolved in water. In order to secure a competitiveness for water treatment, it is preferable to use sodium hydrogen sulfide or sodium sulfide which is inexpensive in sulfides.

On the other hand, the silicate can be measured by mobilizing analytical equipment by generating an insoluble precipitate of hydroxy-heavy metal silicate in the trace amount of heavy metal ions dissolved in the waste water (approximately when the concentration of heavy metal is less than 1ppm) Its purpose is to treat heavy metals up to an unattainable concentration (approximately 0.02 ppm). Silicate consists of KS standard liquid sodium silicate (Na ₂ O: 17-18%, SiO 2: 36-38%), liquid sodium silicate (Na ₂ O: 14-15%, SiO 2: 34-36%) , 3 kinds of liquid sodium silicate (Na ₂ O: 9.0-10%, SiO 2: 28-30%), 4 kinds of liquid sodium silicate (Na ₂ O: 6.0-7.0%, SiO 2: 23-25%), powdered sodium silicate At least one silicate selected from potassium silicate and lithium silicate is selected. The silicate is preferably dissolved in waste water at 0.1 to 2.5% by weight, more preferably at 0.5 to 2.0% by weight, most preferably at 0.75 to 1.5% by weight? .

When the silicate is dissolved in less than 0.1% by weight of heavy metals treated with sulfides when added to the reaction tank with a heavy metal treatment agent, the low content of silicon does not provide sufficient reactivity with the heavy metals present. Therefore, heavy metal ions dissolved in water do not produce insoluble precipitates of hydroxy-heavy metal silicate, and thus there is a problem that it is not possible to sufficiently process the trace amount of heavy metals. When the silicate is dissolved in more than 2.5% by weight, the heavy metal ions dissolved in the water have the advantage of sufficiently insoluble precipitate of hydroxy-heavy metal silicate, but the ratio of sulfides in the water Since this relatively low limit is limited in treating wastewater containing a large amount of heavy metals in water, silicates are dissolved at a concentration of 0.75 to 1.5% by weight.

When the heavy metal treatment agent containing the above-mentioned sulfides and silicates as active ingredients is supplied to water containing heavy metals, heavy metals in high concentration react with sulfides to form insoluble precipitates of metal sulfides. The heavy metals of silica are insoluble precipitates of hydroxy-heavy metal silicate by silicates, which are present as suspended matter in water.

On the other hand, the suspended solids produced by the heavy metal treatment agent containing the sulfide and silicate as an active ingredient is as follows. A first pH adjustment step is performed to control the pH of the wastewater raised by alkali-containing sulfides and silicates to a range of 6.5-7.6. The first pH control step and the second pH control step to be described later use low-cost sulfuric acid (H ₂ SO ₄ ), hydrochloric acid (HCl), sodium hydroxide (NaOH) with low economic burden without providing a secondary source of pollution. It is desirable to adjust. High concentrations of sulfuric acid (H ₂ SO ₄ ), hydrochloric acid (HCl) and sodium hydroxide (NaOH) can cause significant damage, such as inadvertent human breathing or burns, so dilute to approximately 1/5 or more. It is preferable to use.

Next, an inorganic coagulant input step is carried out to introduce a positively charged inorganic coagulant to agglomerate insoluble precipitates (floating materials) of metal sulfides and hydroxy-heavy metal silicates having anionic charges generated by sulfides and silicates. Inorganic coagulants include polyaluminum chloride (PAC), aluminum sulfate (Al ₂ (SO ₄ ) _{3 18} H ₂ O), ferrous sulfate (FeSO ₄ · 7H ₂ O), sulfuric acid Ferric Sulfate (Fe ₂ (SO ₄ ) ₃ ), Ferric Sulfate (Ferric Chloride: FeCl ₃ ), Calcium Hydroxide (Ca (OH) ₂ ), Calcium Oxide (CaO), Aluminum At least one inorganic coagulant to be selected from sodium aluminate (Na ₂ Al ₂ O ₂ ) is selected, and it is preferable to supply so that a concentration of 0.5 to 25 ppm is maintained.

Next, a second pH adjustment step is performed to adjust the pH lowered by the acidic inorganic coagulant to the range of 6.5 ~ 7.6. The description of the above-described primary pH adjustment step used in the secondary pH adjustment step will be replaced.

Next, the flocculant of finely aggregated insoluble precipitate is formed to form a huge floc, and a polymer coagulant input step for smooth solid-liquid separation is performed. Acrylamide is used as the polymer coagulant, and may vary depending on the shape or concentration of the produced suspended solids, but it is preferable to supply it in a concentration range of 0.1 to 10 ppm, and in order to further promote the formation of flocs, agar, starch, gelatin (Gelatin It is preferable that an organic flocculent aid including) is further supplied.

A process including a solid-liquid separation step for removing floc formed in water can be completely processed to the level of detection limit of heavy metals contained in the water. The solid-liquid separation step is a method of filtration, centrifugation. The solid solution can be separated by the method selected from the method and the filter press method, and it can be changed depending on the amount of treated water or the structure of the wastewater treatment plant. When the amount of wastewater is small, the method of filtration or centrifugation is advantageous. When the amount of waste water is large, solid-liquid separation using a filter press is advantageous.

In the above-mentioned first pH adjustment step, sulfides and high concentrations of wastewater react with each other to form precipitates of metal sulfides, and at the same time, alkali silicates are proposed to completely remove unreacted low concentrations of heavy metals. It is possible to neutralize up to the area. Alkali silicates (e.g. sodium silicate, Na ₂ SiO ₃ ) feed with hydrochloric acid (HCl) or sulfuric acid (H ₂ SO ₄ ) to reach the 6.5-7.6 range, producing insoluble precipitates of hydroxy-heavy metal silicates. Silicic acid (Si (OH) ₄ ) and by-products of sodium sulfate or sodium chloride are produced. Therefore, in order to treat the heavy metal contaminated in water to a very small amount, the pH of the silicate contained in the drug of the heavy metal treatment agent should be adjusted to the above suggested range.

<Example 1>

In a 200 ml beaker, 100 g of sodium sulfide-9 hydrate (Na ₂ S9H ₂ O) and 7 g of three types of liquid sodium silicate were measured, and 150 ml of distilled water was supplied and stirred to completely dissolve sodium sulfide-9 hydrate. The solution mixed with sodium silicate and dissolved sodium sulfide was transferred to a 200ml volumetric flask, and a heavy metal treatment drug was prepared in which sulfide and silicate coexisted by filling with distilled water and shaking up to the graduation line. In order to confirm the efficiency of the prepared heavy metal treatment agent, 1,000 ppm of heavy metal stock solutions of arsenic (As), mercury (Hg), Pb (lead), nickel (Ni), and cadmium (Cd) were accurately placed in a 500 ml volumetric flask. After supplying 10 ml each, distilled water was filled to the grid line and shaken to prepare a mixed solution in which arsenic, mercury, lead, nickel, and cadmium were diluted to 20 ppm concentration. About 500 ml of the 20 ppm concentration of the heavy metal mixed solution prepared in a 1-liter beaker was collected, followed by slowly dropping 5 ml of the heavy metal treatment agent prepared above while stirring to insoluble precipitate of metal sulfide and hydroxy-heavy metal silicate ( Suspended solids) and neutralized pH. Dilute aluminum sulfate (Al ₂ (SO ₄ ) ₃ · 16-18H ₂ O) of Samjeon Pure Chemical Co., Ltd. to easily separate insoluble precipitates (floating materials) of metal sulfide suspended from water and hydroxy-heavy metal silicates. While stirring, the inorganic coagulant of aluminum (Al) was supplied to the solution containing the suspended solids at a concentration of about 20 ppm, and then neutralized again. The polymer coagulant of the diluted polyacrylamide was immediately dissolved in water at a concentration of about 2.5 ppm. A large floc was generated and settled so that the suspended solids of the insoluble precipitates of the metal sulfide and the hydroxy-heavy metal silicates were precipitated to facilitate the solid-liquid separation of the suspended solids. After the solid-liquid separated supernatant was filtered, the efficiency of heavy metal removal by the heavy metal treatment agent was determined using a Thermo Scientific iCAP 7400 duo Inductively Coupled Plasma-Atomic Emission Spectrometer (ICP-AES).

<Example 2>

To manufacture a heavy metal treatment agent, 20 ml of a heavy metal treatment agent made by supplying 7.0 g of sodium hydrogen sulfide (NaHS) of Samjeon Pure Chemical and 0.2 g of liquid potassium silicate of Schemtech Co., Ltd. as a sulfide in a 200 ml beaker was supplied to a mixed solution of heavy metals. The same procedure as in Example 1 was conducted except for the one.

Comparative Example 1

The same procedure as in Example 1 was carried out except that 100 g of sodium sulfide-9 hydrate was prepared without dissolving sodium silicate in a 200 ml beaker to prepare a heavy metal treatment agent.

Comparative Example 2

The same procedure as in Example 2 was carried out except that potassium silicate was not supplied to the 200 ml beaker and 7.0 g of sodium hydrogen sulfide alone was supplied.

The results for Example 1, Example 2, Comparative Example 1, and Comparative Example 2 described above are shown in Table 1 below.

division heavy metal As (ppm) Hg (ppm) Pb (ppm Cu (ppm) Ni (ppm) Cd (ppm) Example 1 N.D. N.D. N.D. N.D. N.D. N.D. Example 2 N.D. N.D. N.D. N.D. N.D. N.D. Comparative Example 1 1.25 0.48 0.16 0.88 1.34 0.42 Comparative Example 2 1.06 0.44 0.19 0.85 1.18 0.44 N.D. stands for Non-detectable and the detection limit is 0.05 ppm.

As shown in Comparative Examples 1 and 2 of Table 1 above, when heavy metal water treatment using a heavy metal treatment agent composed of a single sulfide does not exhibit the ability of treating a small amount of heavy metal in which sulfide is present at a low concentration, most heavy metals are traced. It was confirmed that it was detected.

On the other hand, as shown in Examples 1 and 2, in the case of the heavy metal treatment agent composed of sulfide and silicate, it is possible to clearly remove the heavy metals in the water to the level that cannot be detected by the inductively coupled plasma atomic emission spectrometer (ICP-AES). As a result, it was confirmed that the problem of heavy metal treatment using a sulfide alone can be largely solved.

In the following description of the present invention, those skilled in the art and those skilled in the art may omit descriptions, and descriptions of such omitted components (methods) and functions may be sufficiently referred to without departing from the technical spirit of the present invention. Could be.

Description of the configuration and functions of the above-described parts have been described separately from each other for convenience of description, and any configuration and function may be implemented by being integrated into other components, or may be further subdivided as necessary.

As mentioned above, although demonstrated with reference to one Embodiment of this invention, this invention is not limited to this, A various deformation | transformation and an application are possible. That is, those skilled in the art will readily appreciate that many modifications are possible without departing from the spirit of the invention. In addition, when it is determined that the detailed description of the known function and its configuration or the coupling relationship for each configuration of the present invention may unnecessarily obscure the subject matter of the present invention, it should be noted that the detailed description is omitted. something to do.

Claims (9)

A heavy metal treatment agent for treating wastewater contaminated with heavy metals,
Heavy metal treatment agent comprising a sulfide and silicate as an active ingredient.
The method of claim 1,
The sulfide treats a heavy metal of a first concentration, and the silicate treats a heavy metal of a second concentration of a relatively small concentration compared to the heavy metal of the first concentration.
The method of claim 2,
The sulfide is 90 to 95% by weight, the silicate is heavy metal treatment, characterized in that it comprises 5 to 10% by weight.
The method of claim 2,
The heavy metal of the first concentration reacts with the sulfide to form an insoluble precipitate of the metal sulfide,
The heavy metal of the second concentration that is not treated with the sulfide reacts with the silicate to produce an insoluble precipitate of hydroxy-heavy metal silicate.
The method of claim 2,
The sulfide is at least one of sodium hydrogen sulfide (NaHS), potassium hydrogen sulfide (KHS), lithium sulfide (LiHS), sodium sulfide (Na ₂ S), potassium sulfide (K ₂ S), and lithium sulfide (Li ₂ S). Heavy metal treatment agent, characterized in that selected.
The method of claim 5,
The sulfide is,
Dissolved in the waste water at a concentration of 3.5% by weight to 50% by weight, or dissolved in a concentration of 5.0% by weight to 40% by weight, or dissolved in a concentration of any one of 12% by weight to 28% by weight. Heavy metal treatment agents.
The method of claim 2,
The silicate is liquid sodium silicate of KS standard (Na ₂ O: 17-18%, SiO ₂ : 36-38%), liquid sodium silicate 2 (Na ₂ O: 14-15%, SiO ₂ : 34 ~ 36%), 3 types of liquid sodium silicate (Na ₂ O: 9.0-10%, SiO ₂ : 28-30%), 4 types of liquid sodium silicate (Na ₂ O: 6.0-7.0%, SiO ₂ : 23-25% ), Powdered sodium silicate, potassium silicate, and lithium silicate at least one selected from heavy metals treatment agent.
The method of claim 7, wherein
The silicate is,
The heavy metal treatment agent is dissolved in the waste water at a concentration of 0.1 to 2.5% by weight, or dissolved at a concentration of 0.5 to 2.0% by weight, or dissolved at a concentration of 0.75 to 1.5% by weight.
Adding sulfides and silicates to the wastewater containing heavy metals to produce insoluble precipitates of metal sulfides and hydroxy-heavy metal silicates,
First pH control step of adjusting the pH of the waste water according to the addition of the sulfide and silicate,
An inorganic coagulant input step of introducing a positively charged inorganic coagulant to agglomerate the insoluble precipitates of the metal sulfide and hydroxy-heavy metal silicate having an anion charge,
A second pH adjusting step of adjusting the pH of the wastewater according to the inorganic coagulant input;
A polymer coagulant input step for forming flocculated insoluble precipitate into flocs, and
And a solid-liquid separation step of removing the floc.