A treatment method for wastewater containing antimony ion

Abstract

The present invention relates to a treatment method for removing antimony ions from wastewater, wherein antimony ions can be removed with high efficiency through an adsorption process using polyferric sulfate and a coagulation and sedimentation process using a polymer coagulant and fine sand, and the turbidity of the treated wastewater can also be significantly reduced.

Description

Technology Field

[0001] The present invention relates to a method for minimizing the concentration of antimony ions in wastewater by a treatment process that removes antimony ions from wastewater containing antimony ions with high efficiency. Background Technology

[0002] Since antimony is widely used as a raw material for electronic components or as a flame retardant, wastewater from manufacturing plants for electronic components or flame retardants may contain high concentrations of antimony. If such wastewater containing high concentrations of antimony is discharged directly into rivers or the like, it may cause environmental pollution problems. Therefore, various methods to remove antimony from wastewater containing antimony have been attempted in the past and are exemplified in Patent Document 1 and Patent Document 2. Prior art literature

[0003] JP 3621340 B2JP 4061512 B2 The problem to be solved

[0004] The present invention aims to provide a treatment method capable of removing antimony ions from wastewater with high efficiency, effectively removing other competing ions other than antimony, and further significantly reducing the turbidity of the treated wastewater. means of solving the problem

[0005] The present invention is,

[0006] A method for treating wastewater containing antimony (Sb) ions,

[0007] a) a step of forming a PFS-Sb adsorbent by adding polymeric ferric sulfate (PFS), which is an adsorbent, to wastewater containing antimony ions to coagulate the antimony ions in the wastewater with the polymeric ferric sulfate; and

[0008] b) a step of separating the PFS-Sb adsorbent by sedimentation through coagulation and sedimentation by adding a polymer flocculant and microsand to wastewater containing the PFS-Sb adsorbent formed above;

[0009] Provides a method including

[0010] In a method according to one embodiment of the present invention, the concentration of antimony ions in the wastewater containing antimony ions to be treated may be 0.3 to 30 mg / L.

[0011] In addition, in the method according to one embodiment of the present invention, the adsorption process of step a) may be carried out in an acidic environment with a pH of 3 to 6.

[0012] In addition, in the method according to one embodiment of the present invention, the adsorption process of step a) may be carried out at 40°C or higher.

[0013] In addition, in the method according to one embodiment of the present invention, the amount of ferric polysulfate added in step a) may be 300 to 2000 ppm with respect to wastewater.

[0014] In addition, in the method according to one embodiment of the present invention, the adsorption reaction time of step a) may be 5 minutes or more.

[0015] In addition, in the method according to one embodiment of the present invention, the amount of polymer coagulant added in step b) may be 2 to 50 ppm with respect to wastewater.

[0016] In addition, in the method according to one embodiment of the present invention, the coagulation and precipitation reaction of step b) may be carried out in an environment with a pH of 6 or higher.

[0017] In addition, in the method according to one embodiment of the present invention, the coagulation and precipitation reaction of step b) may be carried out at less than 45°C.

[0018] In addition, the method according to one embodiment of the present invention may further include a step of dewatering the coagulated sludge of the PFS-Sb adsorbate separated by sedimentation in step b) to reduce the moisture content to 85% or less.

[0019] In addition, in the method according to one embodiment of the present invention, the wastewater containing antimony ions to be treated may additionally contain at least one competing ion selected from sodium (Na) ions, calcium (Ca) ions, potassium (K) ions, magnesium (Mg) ions and vanadium (V) ions.

[0020] In addition, in the method according to one embodiment of the present invention, the concentration of the competing ion in the wastewater treated by steps a) and b) may be 0.1 mg / L or less. Effects of the invention

[0021] The wastewater treatment method of the present invention can remove antimony ions from wastewater with high efficiency, significantly improve the overall treatment speed, and furthermore, significantly reduce the turbidity of the treated wastewater. In addition, even if the wastewater contains other competing ions such as vanadium ions in addition to antimony ions, other competing ions other than antimony ions can also be effectively removed. Specific details for implementing the invention

[0022] The present invention will be described in more detail below. Unless otherwise defined, technical and scientific terms used herein have the meanings commonly understood by those skilled in the art to which this invention pertains. Furthermore, descriptions of known functions and configurations that could unnecessarily obscure the essence of the invention are omitted in the following description.

[0023] The present invention is,

[0024] A method for treating wastewater containing antimony (Sb) ions,

[0025] a) a step of forming a PFS-Sb adsorbent by adding polymeric ferric sulfate (PFS), which is an adsorbent, to wastewater containing antimony ions to coagulate the antimony ions in the wastewater with the polymeric ferric sulfate; and

[0026] b) a step of separating the PFS-Sb adsorbent by sedimentation through coagulation and sedimentation by adding a polymer flocculant and microsand to wastewater containing the PFS-Sb adsorbent formed above;

[0027] Provides a method including

[0028] In a method according to one embodiment of the present invention, antimony exists as a hydroxide through a hydration reaction in wastewater, and accordingly, antimony ions in wastewater are Sb 3 + , Sb 5 + or a mixed form thereof, but is not limited thereto.

[0029] In a method according to one embodiment of the present invention, the concentration of antimony ions in wastewater containing antimony ions to be treated may preferably be 0.3 to 30 mg / L, 0.3 to 10 mg / L, 0.5 to 10 mg / L, or 0.5 to 1.5 mg / L. Accordingly, the method according to one embodiment of the present invention can improve the antimony removal rate in wastewater by the above-mentioned preferred antimony ion concentration range. Furthermore, even within the above-mentioned preferred antimony ion concentration range, the antimony removal rate may be further improved as the antimony ion concentration increases.

[0030] In a method according to one embodiment of the present invention, when adding polymeric ferric sulfate (PFS), which is an adsorbent, to wastewater containing antimony ions in step a), the polymeric ferric sulfate may preferably be added to the wastewater in an aqueous solution state. Since the aqueous solution of polymeric ferric sulfate has a pH of 2 or less, it may affect the pH of the wastewater to be treated.

[0031] In a method according to one embodiment of the present invention, the adsorption process by the adsorbent in step a) can preferably be carried out in an acidic environment of pH 3 to 6, pH 3 to 5, or pH 4 to 5. By applying the preferred pH range, the adsorption between polyferric sulfate and antimony ions is efficiently achieved, thereby ultimately improving the antimony removal rate. Specifically, considering the original pH of the wastewater to be treated, the amount of aqueous solution of polyferric sulfate added can be set to form the preferred pH range. In addition, to form the preferred pH range, a pH regulator such as sulfuric acid, hydrochloric acid, sodium hydroxide, calcium hydroxide, or ammonium hydroxide may be appropriately added as needed after adding polyferric sulfate.

[0032] In a method according to one embodiment of the present invention, the adsorption process of step a) can preferably be carried out at 40°C or higher, 60°C or higher, 40°C to 90°C, 50°C to 80°C, or 60°C to 70°C. Accordingly, the method according to one embodiment of the present invention can efficiently improve the antimony removal rate in wastewater by applying the above preferred adsorption temperature range. Furthermore, even within the above preferred adsorption temperature range, the antimony removal rate can be further improved as the adsorption temperature increases. In particular, when the concentration of antimony ions in the wastewater containing antimony ions to be treated is low, ranging from 0.3 to 30 mg / L, the antimony removal rate can be significantly improved by setting the adsorption temperature to 60°C or higher. Furthermore, as the adsorption temperature increases, the activity of antimony ions attempting to be adsorbed onto polyferric sulfate increases, and the particle size of the PFS-Sb adsorbate can also be reversibly increased.

[0033] In a method according to one embodiment of the present invention, the amount of ferric polysulfate added in step a) may preferably be 300 to 2000 ppm, 300 to 1000 ppm, 400 to 800 ppm, or 500 to 700 ppm with respect to wastewater. Accordingly, the method according to one embodiment of the present invention can improve the antimony removal rate while maintaining the iron concentration in the wastewater appropriately by the above preferred range of added amount. Furthermore, even within the above preferred range of added amount, as the amount added increases, the adsorption of antimony ions and ferric polysulfate increases, thereby further improving the antimony removal rate.

[0034] In a method according to one embodiment of the present invention, the adsorption reaction time of step a) may preferably be 5 minutes or more, and more preferably 10 minutes or more or 15 minutes or more. Antimony ions in wastewater require a reaction time to sufficiently come into contact with ferric polysulfate, and the reaction time required to sufficiently achieve an antimony removal rate can be secured by the preferred adsorption reaction time. In particular, when the concentration of antimony ions in the wastewater containing antimony ions to be treated is low, ranging from 0.3 to 30 mg / L, the antimony removal rate can be significantly improved by making the adsorption reaction time 10 minutes or more.

[0035] In a method according to one embodiment of the present invention, during the adsorption reaction of step a), antimony ions can be solidified by bonding to ferric polysulfate through chemical bonding and / or electrostatic attraction.

[0036] In the method according to one embodiment of the present invention, the reactor for the adsorption reaction in step a) is not limited to a specific reactor type, and various reactors such as a continuous stirred tank reactor (CSTR), a batch reactor, a continuous plug flow reactor (PFR), or a fixed bed reactor may be used.

[0037] In a method according to one embodiment of the present invention, during the adsorption reaction of step a), the stirring speed of the reactor may preferably be 40 to 100 rpm, 50 to 90 rpm, or 70 to 90 rpm.

[0038] The PFS-Sb adsorbent obtained by step a) of the present invention is not dissolved in wastewater, but its settling ability may be low. Therefore, in order to increase the settling efficiency of the PFS-Sb adsorbent and improve the separation efficiency from wastewater, the settling performance of the PFS-Sb adsorbent can be improved by additionally adding a polymer flocculant and microsand to the wastewater as in step b).

[0039] In step b) of the present invention, a polymer coagulant and fine sand are added to wastewater containing the PFS-Sb adsorbent from step a), thereby separating the PFS-Sb adsorbent by sedimentation through coagulation and sedimentation. At this time, as the PFS-Sb adsorbent reacts with the polymer coagulant and fine sand, a coagulated sludge of the PFS-Sb adsorbent is formed, and the coagulated sludge corresponds to an aggregate of PFS-Sb-coagulant-fine sand.

[0040] In a method according to one embodiment of the present invention, the amount of polymer coagulant added in step b) may preferably be 2 to 50 ppm, 10 to 30 ppm, or 10 to 20 ppm with respect to wastewater. At this time, if the amount of polymer coagulant added is less than 2 ppm with respect to wastewater, sufficient coagulation efficiency of the PFS-Sb adsorbent may not be achieved. Furthermore, if the amount of polymer coagulant added exceeds 50 ppm with respect to wastewater, physical properties such as viscosity and surface tension of the wastewater may change, and the sedimentation efficiency of the PFS-Sb adsorbent may actually decrease. Therefore, by the above-mentioned preferred amount of polymer coagulant, an optimal amount for effective coagulation and sedimentation of the PFS-Sb adsorbent can be established.

[0041] In the method according to one embodiment of the present invention, the polymer coagulant in step b) may be a nonionic, cationic, or anionic type that is generally used in the art, and the type thereof is not particularly limited. For example, commercially available polymer coagulant N3977 (Nalco: specific gravity (@ 25℃) 1.03~1.07, viscosity 400~1200 cP, pH 8.1, boiling point 98℃, freezing point -20℃) may be used.

[0042] In a method according to one embodiment of the present invention, the size of the polymer coagulant in step b) may preferably be 0.5 to 20 mm or 1 to 10 mm. At this time, if the size of the polymer coagulant is smaller than 0.5 mm, the sedimentation efficiency due to the coagulation of the PFS-Sb adsorbate may be reduced.

[0043] In a method according to one embodiment of the present invention, the fine sand in step b) may be small sand grains, with an average particle size preferably of 100 to 140 μm and a density preferably of 1.28 to 1.36 g / ml. By using both a polymer coagulant and fine sand in the coagulation and sedimentation of PFS-Sb adsorbents, the method of the present invention can significantly improve the coagulation efficiency and sedimentation speed of PFS-Sb adsorbents compared to the case where only a polymer coagulant is used alone, and can also significantly reduce the turbidity of the treated wastewater.

[0044] In a method according to one embodiment of the present invention, the amount of fine sand added in step b) may preferably be 400 to 8000 ppm, 1000 to 6000 ppm, or 2000 to 4000 ppm with respect to wastewater.

[0045] In a method according to one embodiment of the present invention, the flocculation and precipitation reaction of step b) can preferably be carried out in an environment of pH 6 or higher, pH 6 to 10, or pH 6 to 8. At this time, if the flocculation and precipitation reaction of step b) is carried out in an environment of pH 6 or lower, the flocculation of the PFS-Sb adsorbate may not occur efficiently. Therefore, to form the preferred pH range, a pH regulator such as sodium hydroxide, calcium hydroxide, or ammonium hydroxide may be appropriately added.

[0046] In a method according to one embodiment of the present invention, the aggregation and precipitation reaction of step b) may preferably be carried out at less than 45°C, 42°C or lower, or between 35°C and 42°C. At this time, if the aggregation and precipitation reaction of step b) is carried out at 45°C or higher, the aggregation of the PFS-Sb adsorbate may not occur efficiently.

[0047] In a method according to one embodiment of the present invention, during the coagulation and sedimentation reaction of step b), the stirring speed of the reactor may preferably be 20 to 80 rpm, 30 to 70 rpm, or 40 to 60 rpm.

[0048] In a method according to one embodiment of the present invention, step b) may be carried out sequentially within the same reactor after step a). Alternatively, after step a) is carried out, the reactant of step a) may be transferred to another reactor, and step b) may be carried out within the other reactor. In particular, when steps a) and b) are carried out within different reactors, the stirring speed of the reactor for step b) may preferably be lower than the stirring speed of the reactor for step a).

[0049] In a method according to one embodiment of the present invention, only fine sand is separated from the aggregated sludge of the PFS-Sb adsorbent (aggregate of PFS-Sb-coagulant-fine sand) separated by sedimentation in step b), using a separation device such as a hydrocyclone, and the separated fine sand can be reused in step b). Subsequently, the aggregate of the PFS-Sb-coagulant can be dewatered using a solid-liquid separation device to preferably reduce the moisture content to 85% or less or 75% or less.

[0050] A method according to one embodiment of the present invention may further include a step of dewatering the flocculated sludge of the PFS-Sb adsorbate separated by sedimentation in step b) to reduce the moisture content to 85% or less. More specifically, the flocculated sludge of the PFS-Sb adsorbate settled in step b) may be separated from the bottom of the reactor and subsequently transferred to a solid-liquid separation device for dewatering. The solid-liquid separation device is not limited to a specific form and various devices such as a filter press, vacuum filter, belt press, screw press, centrifugal dewatering machine, decanter, or multi-disc type dewatering machine may be used; however, the use of a filter press or decanter is preferred from the perspective of reducing the moisture content. By dewatering the flocculated sludge of the PFS-Sb adsorbate with the solid-liquid separation device, the moisture content may preferably be reduced to 85% or less or 75% or less.

[0051] In a method according to one embodiment of the present invention, the wastewater containing antimony ions to be treated may additionally contain at least one competing ion selected from sodium (Na) ions, calcium (Ca) ions, potassium (K) ions, magnesium (Mg) ions, and vanadium (V) ions, and the competing ion may preferably be a vanadium ion. In practice, the wastewater containing antimony ions may also contain other metal ions other than antimony, and if other metal ions are highly toxic like vanadium ions, they also need to be removed. Not only antimony ions but also the competing ions may be adsorbed onto ferric polysulfate, and in particular, vanadium ions may undergo preferential adsorption over antimony ions to form a PFS-V adsorbent. Subsequently, as the PFS-V adsorbent reacts with a polymer coagulant and fine sand, it may form a coagulated sludge of the PFS-V adsorbent, and the coagulated sludge corresponds to an aggregate of PFS-V-coagulant-fine sand.

[0052] In a method according to one embodiment of the present invention, the concentration of the competing ion in the wastewater treated by steps a) and b) may preferably be 0.1 mg / L or less. In particular, when the competing ion is a highly toxic vanadium ion, a high removal rate for both antimony ions and vanadium ions can be achieved by using an adsorbent, ferric polysulfate.

[0054] Examples of the present invention are described below. However, the following examples are merely preferred examples of the present invention, and the present invention is not limited to the following examples.

[0055] [Example 1]

[0056] Antimony ion Sb 5 + A simulated wastewater with a concentration of 1.7 mg / L was prepared.

[0057] a) Step

[0058] Polyferric sulfate was added as an adsorbent in an aqueous solution to the prepared simulated wastewater, and the amount of polyferric sulfate added was 600 ppm relative to the wastewater. Accordingly, the pH of the wastewater was adjusted to 4.5, and the reactor was stirred at a stirring speed of 70 rpm for 15 minutes at 60°C to carry out an adsorption reaction between antimony ions and polyferric sulfate, thereby forming a PFS-Sb adsorbent.

[0059] b) Step

[0060] Polymer coagulant N3977 (Nalco: specific gravity (@ 25℃) 1.03–1.07, viscosity 400–1200 cP, pH 8.1, boiling point 98℃, freezing point -20℃) and fine sand (small sand grains: average particle size 120 μm, density 1.32 g / ml) were added to wastewater containing PFS-Sb adsorbates, with the amounts of polymer coagulant and fine sand added being 20 ppm and 2000 ppm, respectively, relative to the wastewater. Subsequently, sodium hydroxide was added to the wastewater to adjust the pH to 7, and the reactor was stirred at a stirring speed of 50 rpm for 5 minutes at 40℃ to carry out the coagulation and sedimentation reactions of the PFS-Sb adsorbates, thereby causing the PFS-Sb adsorbates to settle in the form of coagulated sludge.

[0061] c) Characteristics of treated wastewater

[0062] The coagulated sludge of the settled PFS-Sb adsorbate (aggregation of PFS-Sb-coagulant-fine sand) was separated and removed from the bottom of the reactor, and the concentration of antimony ions remaining in the treated wastewater was analyzed by atomic absorption spectroscopy. As a result of the analysis, the concentration of antimony ions remaining in the wastewater was 0.14 mg / L, so the removal rate of antimony ions from the wastewater was 92%.

[0063] In addition, the turbidity of the treated wastewater was measured using a Hach Lange 2100AN IS laboratory turbidity meter, and a turbidity of 4.6 NTU was confirmed.

[0064] [Example 2]

[0065] a) The procedure was carried out in the same manner as Example 1, except that the adsorption reaction time of step a) was changed to 5 minutes.

[0066] The concentration of antimony ions remaining in the treated wastewater was 0.77 mg / L, so the removal rate of antimony ions from the wastewater was 55%.

[0067] [Example 3]

[0068] a) The procedure was carried out in the same manner as Example 1, except that the adsorption reaction temperature of step a) was changed to 40℃.

[0069] The concentration of antimony ions remaining in the treated wastewater was 0.37 mg / L, so the removal rate of antimony ions from the wastewater was 78%.

[0070] [Example 4]

[0071] Antimony ion Sb 5 + The procedure was carried out in the same manner as Example 1, except that a simulated wastewater with a concentration of 2.0 mg / L was prepared and used.

[0072] Since the concentration of antimony ions remaining in the treated wastewater was 0.1 mg / L, the removal rate of antimony ions from the wastewater was 95%.

[0073] [Example 5]

[0074] Antimony ion Sb 5 + The concentration is 1.7 mg / L and vanadium ion V 5 + A simulated wastewater with a concentration of 3 mg / L was prepared.

[0075] a) Step

[0076] Polyferric sulfate was added as an adsorbent in an aqueous solution to the prepared simulated wastewater, and the amount of polyferric sulfate added was 1200 ppm relative to the wastewater. Accordingly, the pH of the wastewater was adjusted to 4.5, and by stirring the reactor at a stirring speed of 70 rpm for 30 minutes at 60°C, an adsorption reaction between antimony ions and vanadium ions and polyferric sulfate was carried out to form PFS-Sb adsorbates and PFS-V adsorbates.

[0077] b) Step

[0078] Polymer coagulant N3977 (Nalco: specific gravity (@ 25℃) 1.03–1.07, viscosity 400–1200 cP, pH 8.1, boiling point 98℃, freezing point -20℃) and fine sand (small sand grains: average particle size 120 μm, density 1.32 g / ml) were added to wastewater containing PFS-Sb adsorbents, with the amounts of polymer coagulant and fine sand added being 40 ppm and 4000 ppm, respectively, relative to the wastewater. Subsequently, sodium hydroxide was added to the wastewater to adjust the pH to 7, and the reactor was stirred at a stirring speed of 50 rpm for 10 minutes at 40℃ to carry out coagulation and sedimentation reactions for the PFS-Sb adsorbents and PFS-V adsorbents, thereby causing the PFS-Sb adsorbents and PFS-V adsorbents to settle in the form of coagulated sludge.

[0079] c) Characteristics of treated wastewater

[0080] The coagulated sludge of the settled PFS-Sb adsorbent (aggregation of PFS-Sb-coagulant-fine sand) and the coagulated sludge of the PFS-V adsorbent (aggregation of PFS-V-coagulant-fine sand) were separated and removed from the bottom of the reactor, and the concentrations of antimony ions and vanadium ions remaining in the treated wastewater were analyzed by atomic absorption spectroscopy. As a result of the analysis, the concentrations of antimony ions and vanadium ions remaining in the wastewater were 0.3 mg / L and 0.1 mg / L or less, respectively, so the removal rates of antimony ions and vanadium ions in the wastewater were 82% and 97% or more, respectively.

[0081] [Comparative Example 1]

[0082] Step a) was carried out in the same manner as in Example 1, and in Step b), a polymer coagulant and fine sand were added to the wastewater containing the PFS-Sb adsorbent in the same manner as in Example 1. Subsequently, the pH of the wastewater was adjusted to 5, and the reactor was stirred at a stirring speed of 50 rpm for 5 minutes at 40°C, but it was observed that the PFS-Sb adsorbent did not coagulate.

[0083] [Comparative Example 2]

[0084] Step a) was carried out in the same manner as in Example 1, and in Step b), a polymer coagulant and fine sand were added to the wastewater containing the PFS-Sb adsorbent in the same manner as in Example 1. Subsequently, the pH of the wastewater was adjusted to 7, and the reactor was stirred at a stirring speed of 50 rpm for 5 minutes at 50°C, but it was observed that the PFS-Sb adsorbent did not coagulate.

[0085] [Comparative Example 3]

[0086] Antimony ion Sb 5 + A simulated wastewater with a concentration of 1.7 mg / L was prepared.

[0087] a) Step

[0088] Polyferric sulfate was added as an adsorbent in an aqueous solution to the prepared simulated wastewater, and the amount of polyferric sulfate added was 600 ppm relative to the wastewater. Accordingly, the pH of the wastewater was adjusted to 4.5, and the reactor was stirred at a stirring speed of 70 rpm for 15 minutes at 60°C to carry out an adsorption reaction between antimony ions and polyferric sulfate, thereby forming a PFS-Sb adsorbent.

[0089] b) Step

[0090] Polymer coagulant N3977 (Nalco: specific gravity (@ 25℃) 1.03~1.07, viscosity 400~1200 cP, pH 8.1, boiling point 98℃, freezing point -20℃) was added to wastewater containing PFS-Sb adsorbates, and the amount of polymer coagulant added was 20 ppm relative to the wastewater. Subsequently, sodium hydroxide was added to the wastewater to adjust the pH of the wastewater to 7, and the reactor was stirred at a stirring speed of 50 rpm for 20 minutes at 40℃ to carry out the coagulation and sedimentation reaction of the PFS-Sb adsorbates, thereby settling the PFS-Sb adsorbates in the form of coagulated sludge.

[0091] c) Characteristics of treated wastewater

[0092] The coagulated sludge of the settled PFS-Sb adsorbate was separated and removed from the bottom of the reactor, and the concentration of antimony ions remaining in the treated wastewater was analyzed by atomic absorption spectroscopy. As a result of the analysis, the concentration of antimony ions remaining in the wastewater was 0.19 mg / L, so the removal rate of antimony ions from the wastewater was 89%.

[0093] In addition, the turbidity of the treated wastewater was measured using a Hach Lange 2100AN IS laboratory turbidity meter, and a turbidity of 12.5 NTU was confirmed.

[0095] When comparing Example 1 and Example 2, it is confirmed that when the adsorption reaction time in step a) of the treatment method is 10 minutes or more (Example 1), the removal rate of antimony ions in wastewater is significantly improved.

[0096] When comparing Example 1 and Example 3, it is confirmed that when the adsorption reaction temperature in step a) of the treatment method is 60°C or higher (Example 1), the removal rate of antimony ions in wastewater is significantly improved.

[0097] When comparing Example 1 and Example 4, it is confirmed that when the initial concentration of antimony ions in the treatment method is higher (Example 4), the removal rate of antimony ions from wastewater is improved.

[0098] According to Example 5, even if the wastewater to be treated contains vanadium ions as well as antimony ions, vanadium ions other than antimony ions can be effectively removed by the treatment method.

[0099] When comparing Example 1 and Comparative Example 1, the pH of the reaction in step b) of the treatment method was changed to less than 6 (Comparative Example 1), but it was found that the PFS-Sb adsorbent did not aggregate.

[0100] When comparing Example 1 and Comparative Example 2, the temperature of the reaction in step b) of the treatment method was changed to 45°C or higher (Comparative Example 2), but it was found that the PFS-Sb adsorbent did not aggregate.

[0101] When comparing Example 1 and Comparative Example 3, when only a polymer coagulant was added in step b) of the treatment method (Comparative Example 3), the reaction rate of the coagulation and precipitation of the PFS-Sb adsorbent was significantly reduced (the reaction time was significantly increased), and the turbidity of the treated wastewater was also significantly increased.

Claims

Claim 1 A method for treating wastewater containing antimony (Sb) ions, comprising: a) a step of adding polymeric ferric sulfate (PFS), which is an adsorbent, to wastewater containing antimony ions to coagulate the antimony ions in the wastewater with the polymeric ferric sulfate to form a PFS-Sb adsorbent; and b) a step of adding a polymer flocculant and microsand to the wastewater containing the formed PFS-Sb adsorbent to separate the PFS-Sb adsorbent by sedimentation through coagulation and sedimentation. A method comprising: a) wherein the concentration of antimony ions in wastewater containing antimony ions to be treated is 0.3 to 30 mg / L; the adsorption process of step a) is carried out in an acidic environment of pH 3 to 6 and at a temperature of 40°C or higher; the amount of ferric polysulfate added in step a) is 300 to 2000 ppm relative to the wastewater; the adsorption reaction time of step a) is 10 minutes or more; the amount of polymer coagulant added in step b) is 2 to 50 ppm relative to the wastewater; the density of the fine sand in step b) is 1.28 to 1.36 g / ml; the amount of fine sand added in step b) is 400 to 8000 ppm relative to the wastewater; and the coagulation and sedimentation reaction of step b) is carried out in an environment of pH 6 or higher and at a temperature of less than 45°C. Claim 2 delete Claim 3 delete Claim 4 delete Claim 5 delete Claim 6 delete Claim 7 delete Claim 8 delete Claim 9 delete Claim 10 A method according to claim 1, further comprising the step of dewatering the coagulated sludge of the PFS-Sb adsorbate separated by sedimentation in step b) to reduce the moisture content to 85% or less. Claim 11 A method according to claim 1, wherein the wastewater containing antimony ions to be treated further contains at least one competing ion selected from sodium (Na) ions, calcium (Ca) ions, potassium (K) ions, magnesium (Mg) ions and vanadium (V) ions. Claim 12 A method according to claim 11, wherein the concentration of the competing ion in the wastewater treated by steps a) and b) is 0.1 mg / L or less.