Method for synergistically preparing water treatment agent from waste acid and agent thereof

Abstract

The invention provides a method for synergistically preparing a water treatment agent from waste acid and an agent thereof.The method for synergistically preparing the water treatment agent from the waste acid comprises the following steps that after the waste acid and iron powder are mixed and react, filtering is conducted, and a ferrous sulfate solution is obtained; mixing the ferrous sulfate solution with activated carbon to obtain activated carbon loaded with ferrous sulfate; and uniformly mixing the ferrous sulfate-loaded activated carbon with the modified titanium dioxide and the modified bentonite to obtain the adsorbent. According to the method for synergistically preparing the water treatment agent from the waste acid, the waste acid is utilized, so that the recycling rate of the waste acid is increased, and efficient treatment of industrial printing and dyeing wastewater is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, in particular to a method for co-preparing water treatment agents from waste acid and the agents thereof. Background Art

[0002] Industrial waste acid is a type of pollutant generated during the production process of non-ferrous metal smelting. It has high acidity and complex components. In addition to containing high-concentration sulfuric acid, it also contains various heavy metal ions such as nickel, cadmium, and lead, making it difficult to be resourcefully utilized. In the prior art, ferrous sulfate can be prepared by the reaction of waste acid with iron and used as a coagulant for wastewater treatment. However, the resulting product usually has unstable flocculation effects and it is difficult to fully exert the application value of iron ions.

[0003] Industrial printing and dyeing wastewater has the characteristics of containing refractory organic substances, high chroma, poor biodegradability, and complex components. When treated by traditional methods such as activated carbon adsorption, although it has good effects on removing the chroma in the wastewater and reducing the COD value of the wastewater, the cost of activated carbon is relatively high, and its adsorption effect on dyes with strong hydrophilicity and small molecules is not ideal.

[0004] In view of this, there is an urgent need to propose a water treatment agent at present to achieve efficient treatment of industrial printing and dyeing wastewater and good removal effects on dyes with strong hydrophilicity and small molecules. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for co-preparing water treatment agents from waste acid and the agents thereof to solve the problem that the existing water treatment agents have poor removal effects on dyes with strong hydrophilicity and small molecules in industrial printing and dyeing wastewater.

[0006] The present invention provides the following technical solutions: A method for co-preparing water treatment agents from waste acid, comprising the following steps: (1) Mix waste acid with iron powder, after reaction, filter to obtain a ferrous sulfate solution; (2) Mix the ferrous sulfate solution in step (1) with activated carbon to obtain activated carbon loaded with ferrous sulfate; (3) Mix the activated carbon loaded with ferrous sulfate in step (2) with modified titanium dioxide and modified bentonite evenly to obtain the product; Wherein, the modified titanium dioxide is obtained by the following method: Add γ-aminopropyltriethoxysilane to titanium dioxide to obtain amino-functionalized titanium dioxide; Mix the amino-functionalized titanium dioxide with 3,6-thioanthracenediamine, sebac diamine, and hexamethylene diisocyanate, and obtain modified titanium dioxide after reaction; The modified bentonite is obtained by the following method: Mix sodium-based bentonite and allyl triethyl ammonium bromide evenly, react to obtain intercalated bentonite, and then add pentene sulfonamide and initiator thereto, and react to obtain modified bentonite.

[0007] Preferably, in step (2), the ferrous sulfate solution and the activated carbon are mixed in a weight ratio of (5-10):100; Optionally, in the ferrous sulfate solution, the concentration of ferrous sulfate is 0.1-1 mol / L.

[0008] Preferably, in step (3), the titanium dioxide is iron-doped titanium dioxide, which is obtained by the following method: Mix the titanium dioxide precursor solution and the acid solution of iron ions, react and then calcine to obtain iron-doped titanium dioxide; Optionally, the titanium dioxide precursor solution is a mixture of tetrabutyl titanate and ethanol in a volume ratio of (1-3):10; or, the titanium dioxide precursor solution is a mixture of isopropyl titanate and ethanol in a volume ratio of (1-3):10; Optionally, the acid solution of iron ions is a nitric acid solution of ferric chloride, with a pH value of 1-3 and a concentration of iron ions of 50-80 mmol / L; Optionally, the volume ratio of the titanium dioxide precursor solution to the acid solution of iron ions is (15-35):1.

[0009] Preferably, in step (3), the titanium dioxide is iron-doped titanium dioxide, which is obtained by the following method: Drop the titanium dioxide precursor solution into the acid solution of iron ions, stir and react at 25-45 °C for 2-8 h, then raise the temperature to 120-160 °C and react for 10-20 h, and calcine at 400-600 °C for 2-4 h to obtain iron-doped titanium dioxide.

[0010] Preferably, the modified titanium dioxide is specifically obtained by the following method: Disperse the titanium dioxide in toluene, add γ-aminopropyltriethoxysilane, react at 50-60 °C for 6-10 h, filter, wash and dry to obtain amino-functionalized titanium dioxide; Disperse the amino-functionalized titanium dioxide, 3,6-thioanthracenediamine and sebac diamine in N,N-dimethylformamide, stir and dropwise add hexamethylene diisocyanate thereto, react at 60-80 °C for 6-12 h, and obtain modified titanium dioxide after the reaction.

[0011] Preferably, the weight ratio of the titanium dioxide, γ-aminopropyltriethoxysilane and toluene is 1:(0.6-0.8):(30-50); Optionally, the weight ratio of the aminated titanium dioxide, 3,6-thioanthracenediamine, decanediamine, and hexamethylene diisocyanate is 1:(0.8 - 1.5):(0.01 - 0.05):(1.0 - 1.2); Optionally, the concentration of the aminated titanium dioxide in the N,N-dimethylformamide is 1.5 - 3.0 wt%.

[0012] Preferably, β-cyclodextrin is also dispersed in the N,N-dimethylformamide; the weight ratio of the β-cyclodextrin to the aminated titanium dioxide is (0.01 - 0.05):1.

[0013] Preferably, the modified bentonite is obtained by the following method: mixing sodium-based bentonite, allyl triethyl ammonium bromide, and water uniformly, stirring and reacting at 40 - 60 °C for 2 - 6 h to obtain intercalated bentonite, then adding pentene sulfonamide and an initiator thereto, and stirring and reacting at 50 - 70 °C for 2 - 3 h to obtain the modified bentonite after the reaction; Optionally, the weight ratio of the sodium-based bentonite, allyl triethyl ammonium bromide, water, pentene sulfonamide, and initiator is 100:(5 - 10):(300 - 500):(2 - 8):(0.5 - 1.5); Optionally, the initiator is azobisisobutyronitrile.

[0014] Optionally, the modified bentonite is obtained by the following method: mixing sodium-based bentonite, allyl triethyl ammonium bromide, and water uniformly, stirring and reacting at 40 - 60 °C for 2 - 6 h to obtain intercalated bentonite, then adding pentene sulfonamide, 4-(vinyloxy)benzenesulfonamide, and an initiator thereto, and stirring and reacting at 50 - 70 °C for 2 - 3 h to obtain the modified bentonite after the reaction; The weight ratio of the 4-(vinyloxy)benzenesulfonamide to the pentene sulfonamide is 1:(30 - 50).

[0015] Preferably, in step (3), the weight ratio of the activated carbon loaded with ferrous sulfate, the modified titanium dioxide, and the modified bentonite is 1:(2 - 8):(10 - 30).

[0016] The present invention provides a water treatment agent obtained by the method of co-preparing the water treatment agent with the waste acid described above.

[0017] The above scheme of the present invention has at least the following beneficial effects: (1)The method for co-preparing water treatment agents from waste acid according to the present invention comprises the following steps: mixing waste acid with iron powder, filtering after reaction to obtain a ferrous sulfate solution; mixing the ferrous sulfate solution with activated carbon to obtain activated carbon loaded with ferrous sulfate; and uniformly mixing the activated carbon loaded with ferrous sulfate with modified titanium dioxide and modified bentonite to obtain the product. The method for co-preparing water treatment agents from waste acid according to the present invention improves the resource utilization rate of waste acid by utilizing waste acid, and realizes the efficient treatment of industrial printing and dyeing wastewater. Through the mutual cooperation of activated carbon loaded with ferrous sulfate, modified titanium dioxide and modified bentonite, the present invention realizes the efficient treatment of industrial printing and dyeing wastewater by utilizing the synergistic effects of physical adsorption, inorganic coagulation, organic flocculation and catalytic oxidation, and achieves good removal effects on dyes with strong hydrophilicity and small molecules.

[0018] For the activated carbon loaded with ferrous sulfate according to the present invention, ferrous sulfate serves as an inorganic coagulant and activated carbon serves as an adsorbent, which can remove pollutants such as dye molecules and heavy metal ions in industrial printing and dyeing wastewater. Loading ferrous sulfate on activated carbon can achieve the slow release of ferrous sulfate, realize long-term and stable treatment during continuous treatment, greatly improve the utilization rate of the agent, and have strong adaptability in the case of large water quality fluctuations, preventing the exceeding standard of Fe 2+ / Fe 3+ in the effluent and reducing the risk of secondary pollution.

[0019] The modified titanium dioxide according to the present invention is obtained by the following method: adding γ-aminopropyltriethoxysilane to titanium dioxide to obtain amino-functionalized titanium dioxide; mixing the amino-functionalized titanium dioxide with 3,6-thioxanthene diamine, sebacic diamine and hexamethylene diisocyanate, and obtaining modified titanium dioxide after reaction. The modified titanium dioxide first grafts amino groups on the surface of the titanium dioxide through γ-aminopropyltriethoxysilane, and then the isocyanate in hexamethylene diisocyanate reacts with the amino groups through interfacial polymerization to form urea bonds, and cross-linking occurs between the amino groups grafted on the titanium dioxide, the amino groups of 3,6-thioxanthene diamine and the amino groups of sebacic diamine to form a polymer network and anchor it on the surface of the titanium dioxide.

[0020] The porous structure of the polymer network of the modified titanium dioxide can physically adsorb pollutants in printing and dyeing wastewater. The titanium dioxide can play a role in photocatalysis to degrade organic pollutants. The thioanthracene ring anchored on the surface of titanium dioxide, as a π-π conjugate structure, can adsorb aromatic rings and other structures of dye molecules in printing and dyeing wastewater under the action of π-π stacking. At the same time, its conjugate structure can provide strong electron-withdrawing ability and electron delocalization characteristics, which can promote the separation of photo-generated electron-hole pairs, expand the photocatalytic response range of titanium dioxide, and improve the photocatalytic degradation efficiency of titanium dioxide for organic pollutants. In addition, the sulfur atom of the thioanthracene ring contains two pairs of lone pairs of electrons and has a low electronegativity, which is easy to participate in free radical reactions, can attack the chromophore of the dye, break it down into small molecules, and the rigid conjugate structure of the thioanthracene ring makes it not easily decomposed when participating in free radical reactions, realizing more continuous and stable high-efficiency decolorization.

[0021] The modified titanium dioxide is rich in urea bonds, which connect the dispersed functional groups through strong covalent bonds and introduce flexible chain segments through sebac diamine, forming a rigid-flexible alternating network structure, enabling the chain segments to adapt to the spatial configuration of dye molecules through bending and stretching. This not only facilitates the action of the thioanthracene ring but also enables the urea groups to adsorb and enrich dye particles through hydrogen bonding, thereby forming microfloc aggregates, which are then connected into large flocs through bridging action to accelerate sedimentation. In particular, small molecule dyes with good hydrophilicity are small in size and strong in polarity, and are easily dissociated into ionic states in water and are not easily removed. The urea group has strong hydrogen bonding, and the amino group of the urea group can be used as a hydrogen bond donor, and the carbonyl group can be used as a hydrogen bond acceptor, which can produce multi-site hydrogen bonding with small molecule dyes with good hydrophilicity, improving the adsorption selectivity for them.

[0022] The modified bentonite described in the present invention is obtained by the following method: Sodium bentonite is mixed evenly with allyl triethyl ammonium bromide, and the intercalated bentonite is obtained by reaction. Then, pentene sulfonamide and an initiator are added thereto, and the modified bentonite is obtained after reaction. The main component of sodium bentonite is layered silicate, and sodium ions are in the interlayer. After adding allyl triethyl ammonium bromide, the quaternary ammonium salt exchanges with sodium ions, and allyl triethyl ammonium bromide is inserted into the interlayer through electrostatic action, increasing the interlayer spacing. Then, through the reaction of pentene sulfonamide and allyl triethyl ammonium bromide, sulfonamide groups are introduced into the interlayer of the modified bentonite.

[0023] Sodium-based bentonite has a low adsorption capacity and good hydrophilicity, and it is easy to form a colloidal suspension in water that is difficult to settle or flocculate. The modified bentonite increases the adsorption sites through intercalation treatment, which can greatly improve its adsorption capacity. More importantly, after modification, the hydrophobic carbon chain formed by allyl triethyl ammonium bromide and pentene sulfonamide makes the bentonite form a hydrophobic interface, and the sulfonamide group has a good adsorption effect on phenolic organic compounds, carboxylic acid organic compounds, etc., which can greatly improve the treatment efficiency. By replacing activated carbon with the modified bentonite, the dosage of activated carbon can be greatly reduced and the cost can be reduced.

[0024] (2) In the method for co-preparing water treatment agents from waste acid in the present invention, when the modified titanium dioxide is prepared, β-cyclodextrin is also added. β-cyclodextrin is cyclic and has the characteristics of hydrophilic on the outside and hydrophobic in the inner cavity. When dispersing the amino-functionalized titanium dioxide, 3,6-thioanthracenediamine, and decanediamine in N,N-dimethylformamide, adding the β-cyclodextrin can regulate the orderly arrangement of the three. After reacting with hexamethylene diisocyanate, the microstructure of the product can be optimized, and the treatment effect of the obtained water treatment agent can be improved. Detailed implementation manners

[0025] In the embodiments of the present invention, those not specified in specific conditions are carried out according to conventional conditions or conditions recommended by the manufacturer. For reagents or instruments whose manufacturers are not specified, they are all conventional products that can be obtained through commercial purchase. Raw materials from different manufacturers and models do not affect the implementation of the technical solution of the present invention and the realization of the technical effect.

[0026] In the following examples, the 3,6-thioanthracenediamine has the following structural formula:

[0027] The decanediamine has the following structural formula:

[0028] The 4-(vinyloxy)benzenesulfonamide has the following structural formula:

[0029] The CAS number of the pentene sulfonamide is 245368-50-7, and it has the following structural formula:

[0030] The CAS number of the allyl triethyl ammonium bromide is 29443-23-0.

[0031] The above raw materials are commercially available products and can be obtained by purchase.

[0032] Example 1

[0033] The method for co-preparing water treatment agents from waste acid in this embodiment includes the following steps: (1) Mix the waste acid with iron powder, filter after the reaction to obtain a ferrous sulfate solution; It should be noted that the theoretical molar ratio of sulfuric acid in the waste acid to the iron powder is 1:1. The input amount of iron powder can be determined according to the sulfuric acid content in the waste acid, as long as the sulfuric acid can be completely or basically consumed.

[0034] (2) Mix the ferrous sulfate solution in step (1) with activated carbon to obtain activated carbon loaded with ferrous sulfate; Among them, the ferrous sulfate solution and the activated carbon are mixed in a weight ratio of 5:100; in the ferrous sulfate solution, the concentration of ferrous sulfate is 0.5 mol / L.

[0035] (3) Mix the activated carbon loaded with ferrous sulfate in step (2) with modified titanium dioxide and modified bentonite evenly according to a weight ratio of 1:2:20 to obtain the product.

[0036] In this embodiment, the modified titanium dioxide is obtained through the following method: Disperse titanium dioxide in toluene, add γ-aminopropyltriethoxysilane, react at 50 °C for 8 h, filter, wash, and dry to obtain amino-functionalized titanium dioxide; Disperse the amino-functionalized titanium dioxide, 3,6-thioanthracenediamine, and decanediamine in N,N-dimethylformamide, stir and dropwise add hexamethylene diisocyanate thereto, react at 60 °C for 8 h, and obtain modified titanium dioxide after the reaction.

[0037] Among them, the weight ratio of titanium dioxide, γ-aminopropyltriethoxysilane, and toluene is 1:0.6:40; the weight ratio of amino-functionalized titanium dioxide, 3,6-thioanthracenediamine, decanediamine, and hexamethylene diisocyanate is 1:1.2:0.03:1.0; the concentration of amino-functionalized titanium dioxide in the N,N-dimethylformamide is 2.4 wt%.

[0038] In this embodiment, the modified bentonite is obtained through the following method: Mix sodium-based bentonite, allyl triethyl ammonium bromide, and water evenly, stir and react at 40 °C for 6 h to obtain intercalated bentonite, then add pentene sulfonamide and initiator thereto, stir and react at 50 °C for 3 h, and obtain modified bentonite after the reaction; Among them, the weight ratio of sodium-based bentonite, allyl triethyl ammonium bromide, water, pentene sulfonamide, and initiator is 100:5:400:2:1.0; the initiator is azobisisobutyronitrile.

[0039] Example 2

[0040] The method for co-preparing water treatment agents from waste acid in this embodiment includes the following steps: (1) Mix waste acid with iron powder, filter after reaction to obtain a ferrous sulfate solution; (2) Mix the ferrous sulfate solution in step (1) with activated carbon to obtain activated carbon loaded with ferrous sulfate; Among them, the ferrous sulfate solution and activated carbon are mixed in a weight ratio of 10:100; in the ferrous sulfate solution, the concentration of ferrous sulfate is 1 mol / L.

[0041] (3) Mix the activated carbon loaded with ferrous sulfate in step (2) with modified titanium dioxide and modified bentonite evenly in a weight ratio of 1:5:30 to obtain the product.

[0042] In this embodiment, the modified titanium dioxide is obtained by the following method: Disperse titanium dioxide in toluene, add γ-aminopropyltriethoxysilane, react at 60 °C for 10 h, filter, wash and dry to obtain amino-functionalized titanium dioxide; Disperse the amino-functionalized titanium dioxide, 3,6-thioanthracenediamine and decanediamine in N,N-dimethylformamide, stir and dropwise add hexamethylene diisocyanate thereto, react at 80 °C for 12 h, and obtain modified titanium dioxide after the reaction.

[0043] Among them, the weight ratio of titanium dioxide, γ-aminopropyltriethoxysilane and toluene is 1:0.7:50; the weight ratio of amino-functionalized titanium dioxide, 3,6-thioanthracenediamine, decanediamine and hexamethylene diisocyanate is 1:0.8:0.05:1.2; the concentration of amino-functionalized titanium dioxide in the N,N-dimethylformamide is 3.0 wt%.

[0044] In this embodiment, the modified bentonite is obtained by the following method: Mix sodium-based bentonite, allyl triethyl ammonium bromide and water evenly, stir and react at 60 °C for 4 h to obtain intercalated bentonite, then add pentene sulfonamide and initiator thereto, stir and react at 70 °C for 3 h, and obtain modified bentonite after the reaction; Among them, the weight ratio of sodium-based bentonite, allyl triethyl ammonium bromide, water, pentene sulfonamide and initiator is 100:10:500:8:1.5; the initiator is azobisisobutyronitrile.

[0045] Example 3

[0046] The method for co-preparing water treatment agents from waste acid in this embodiment includes the following steps: (1) Mix waste acid with iron powder, filter after reaction to obtain a ferrous sulfate solution; (2) Mix the ferrous sulfate solution in step (1) with activated carbon to obtain activated carbon loaded with ferrous sulfate; Among them, the ferrous sulfate solution and the activated carbon are mixed in a weight ratio of 8:100; in the ferrous sulfate solution, the concentration of ferrous sulfate is 0.1 mol / L.

[0047] (3) Mix the activated carbon loaded with ferrous sulfate in step (2) with modified titanium dioxide and modified bentonite evenly in a weight ratio of 1:8:10 to obtain the product.

[0048] In this embodiment, the modified titanium dioxide is obtained by the following method: Disperse titanium dioxide in toluene, add γ-aminopropyltriethoxysilane, react at 55 °C for 6 h, filter, wash, and dry to obtain amino-functionalized titanium dioxide; Disperse the amino-functionalized titanium dioxide, 3,6-thioanthracenediamine, and decanediamine in N,N-dimethylformamide, stir and dropwise add hexamethylene diisocyanate thereto, react at 70 °C for 6 h, and obtain modified titanium dioxide after the reaction.

[0049] Among them, the weight ratio of the titanium dioxide, γ-aminopropyltriethoxysilane, and toluene is 1:0.8:30; the weight ratio of the amino-functionalized titanium dioxide, 3,6-thioanthracenediamine, decanediamine, and hexamethylene diisocyanate is 1:1.5:0.01:1.1; the concentration of the amino-functionalized titanium dioxide in the N,N-dimethylformamide is 1.5 wt%.

[0050] In this embodiment, the modified bentonite is obtained by the following method: Mix sodium-based bentonite, allyl triethyl ammonium bromide, and water evenly, stir and react at 50 °C for 2 h to obtain intercalated bentonite, and then add pentene sulfonamide and an initiator thereto, stir and react at 60 °C for 2 h to obtain modified bentonite after the reaction; Among them, the weight ratio of the sodium-based bentonite, allyl triethyl ammonium bromide, water, pentene sulfonamide, and initiator is 100:8:300:5:0.5; the initiator is azobisisobutyronitrile.

[0051] Example 4

[0052] The method for co-preparing water treatment agents from waste acid in this embodiment includes the following steps: (1) Mix waste acid with iron powder, filter after the reaction to obtain a ferrous sulfate solution; (2) Mix the ferrous sulfate solution in step (1) with activated carbon to obtain activated carbon loaded with ferrous sulfate; Among them, the ferrous sulfate solution and activated carbon are mixed in a weight ratio of 8:100; in the ferrous sulfate solution, the concentration of ferrous sulfate is 0.8 mol / L.

[0053] (3) Mix the activated carbon loaded with ferrous sulfate in step (2) with modified titanium dioxide and modified bentonite evenly in a weight ratio of 1:6:18 to obtain the product.

[0054] In this embodiment, the modified titanium dioxide is obtained by the following method: Disperse titanium dioxide in toluene, add γ-aminopropyltriethoxysilane, react at 50 °C for 10 h, filter, wash, and dry to obtain amino-functionalized titanium dioxide; Disperse the amino-functionalized titanium dioxide, 3,6-thioanthracenediamine, and decanediamine in N,N-dimethylformamide, stir and dropwise add hexamethylene diisocyanate thereto, react at 70 °C for 10 h, and obtain modified titanium dioxide after the reaction.

[0055] Among them, the weight ratio of the titanium dioxide, γ-aminopropyltriethoxysilane, and toluene is 1:0.7:50; the weight ratio of the amino-functionalized titanium dioxide, 3,6-thioanthracenediamine, decanediamine, and hexamethylene diisocyanate is 1:1.2:0.04:1.0; the concentration of the amino-functionalized titanium dioxide in the N,N-dimethylformamide is 1.8 wt%.

[0056] In this embodiment, the modified bentonite is obtained by the following method: Mix sodium-based bentonite, allyl triethylammonium bromide, and water evenly, stir and react at 50 °C for 5 h to obtain intercalated bentonite, and then add pentene sulfonamide and initiator thereto, stir and react at 50 °C for 3 h to obtain modified bentonite after the reaction; Among them, the weight ratio of the sodium-based bentonite, allyl triethylammonium bromide, water, pentene sulfonamide, and initiator is 100:8:500:3:0.8; the initiator is azobisisobutyronitrile.

[0057] Example 5

[0058] The method for co-preparing water treatment agents from waste acid in this embodiment is the same as that in Example 4, except that: the titanium dioxide is replaced with iron-doped titanium dioxide.

[0059] In this embodiment, the iron-doped titanium dioxide is obtained by the following method: Drop the titanium dioxide precursor solution into the acid solution of iron ions, stir and react at 25 °C for 2 h, then raise the temperature to 140 °C and react for 10 h, and calcine at 400 °C for 3 h to obtain iron-doped titanium dioxide.

[0060] Among them, the titanium dioxide precursor solution is prepared by mixing isopropyl titanate and ethanol in a volume ratio of 1:10. The acidic solution of iron ions is a nitric acid solution of ferric chloride, with a pH value of 1 and an iron ion concentration of 80 mmol / L; the volume ratio of the titanium dioxide precursor solution to the acidic solution of iron ions is 15:1.

[0061] Example 6

[0062] The method for co-preparing water treatment agents with waste acid in this example is the same as that in Example 4, except that: the titanium dioxide is replaced with iron-doped titanium dioxide.

[0063] In this example, the iron-doped titanium dioxide is obtained by the following method: The titanium dioxide precursor solution is dropped into the acidic solution of iron ions, stirred and reacted at 45 °C for 8 h, then heated to 160 °C and reacted for 20 h, and calcined at 600 °C for 2 h to obtain iron-doped titanium dioxide.

[0064] Among them, the titanium dioxide precursor solution is prepared by mixing tetrabutyl titanate and ethanol in a volume ratio of 2:10. The acidic solution of iron ions is a nitric acid solution of ferric chloride, with a pH value of 3 and an iron ion concentration of 50 mmol / L; the volume ratio of the titanium dioxide precursor solution to the acidic solution of iron ions is 35:1.

[0065] Example 7

[0066] The method for co-preparing water treatment agents with waste acid in this example is the same as that in Example 4, except that: the titanium dioxide is replaced with iron-doped titanium dioxide.

[0067] In this example, the iron-doped titanium dioxide is obtained by the following method: The titanium dioxide precursor solution is dropped into the acidic solution of iron ions, stirred and reacted at 30 °C for 5 h, then heated to 120 °C and reacted for 12 h, and calcined at 550 °C for 4 h to obtain iron-doped titanium dioxide.

[0068] Among them, the titanium dioxide precursor solution is prepared by mixing tetrabutyl titanate and ethanol in a volume ratio of 3:10. The acidic solution of iron ions is a nitric acid solution of ferric chloride, with a pH value of 2 and an iron ion concentration of 65 mmol / L; the volume ratio of the titanium dioxide precursor solution to the acidic solution of iron ions is 26:1.

[0069] Example 8 The method for co-preparing water treatment agents from waste acid in this example is the same as that in Example 7, except that in the preparation process of the modified titanium dioxide, β-cyclodextrin is also dispersed in the N,N-dimethylformamide; the weight ratio of the β-cyclodextrin to the amino-functionalized titanium dioxide is 0.01:1.

[0070] In this example, the modified titanium dioxide is obtained by the following method: Disperse titanium dioxide in toluene, add γ-aminopropyltriethoxysilane, react at 50 °C for 10 h, filter, wash, and dry to obtain amino-functionalized titanium dioxide; Disperse the amino-functionalized titanium dioxide, 3,6-thioanthracenediamine, decanediamine, and β-cyclodextrin in N,N-dimethylformamide, stir and dropwise add hexamethylene diisocyanate thereto, react at 70 °C for 10 h, filter after the reaction, wash with water, and dry to obtain modified titanium dioxide.

[0071] Example 9 The method for co-preparing water treatment agents from waste acid in this example is the same as that in Example 7, except that in the preparation process of the modified titanium dioxide, β-cyclodextrin is also dispersed in the N,N-dimethylformamide; the weight ratio of the β-cyclodextrin to the amino-functionalized titanium dioxide is 0.05:1.

[0072] In this example, the modified titanium dioxide is obtained by the following method: Disperse titanium dioxide in toluene, add γ-aminopropyltriethoxysilane, react at 50 °C for 10 h, filter, wash, and dry to obtain amino-functionalized titanium dioxide; Disperse the amino-functionalized titanium dioxide, 3,6-thioanthracenediamine, decanediamine, and β-cyclodextrin in N,N-dimethylformamide, stir and dropwise add hexamethylene diisocyanate thereto, react at 70 °C for 10 h, filter after the reaction, wash with water, and dry to obtain modified titanium dioxide.

[0073] Example 10 The method for co-preparing water treatment agents from waste acid in this example is the same as that in Example 7, except that in the preparation process of the modified titanium dioxide, β-cyclodextrin is also dispersed in the N,N-dimethylformamide; the weight ratio of the β-cyclodextrin to the amino-functionalized titanium dioxide is 0.03:1.

[0074] In this example, the modified titanium dioxide is obtained by the following method: Disperse titanium dioxide in toluene, add γ-aminopropyltriethoxysilane, react at 50 °C for 10 h, filter, wash, and dry to obtain amino-functionalized titanium dioxide; Disperse the amidated titanium dioxide, 3,6-thioanthracenediamine, decanediamine, and β-cyclodextrin in N,N-dimethylformamide, stir and dropwise add hexamethylene diisocyanate thereto, react at 70 °C for 10 h, filter after the reaction, wash with water, and dry to obtain modified titanium dioxide.

[0075] Example 11

[0076] The method for co-preparing a water treatment agent with waste acid in this example is the same as that in Example 10, except that: during the preparation process of the modified bentonite, 4-(vinyloxy)benzenesulfonamide is further added. The weight ratio of the 4-(vinyloxy)benzenesulfonamide to the pentene sulfonamide is 1:30.

[0077] In this example, the modified bentonite is obtained by the following method: Mix sodium-based bentonite, allyl triethylammonium bromide, and water evenly, stir and react at 40 °C for 4 h to obtain intercalated bentonite, and then add pentene sulfonamide, 4-(vinyloxy)benzenesulfonamide, and an initiator thereto, stir and react at 50 °C for 2 h, and obtain modified bentonite after the reaction.

[0078] Example 12 The method for co-preparing a water treatment agent with waste acid in this example is the same as that in Example 10, except that: during the preparation process of the modified bentonite, 4-(vinyloxy)benzenesulfonamide is further added. The weight ratio of the 4-(vinyloxy)benzenesulfonamide to the pentene sulfonamide is 1:50.

[0079] In this example, the modified bentonite is obtained by the following method: Mix sodium-based bentonite, allyl triethylammonium bromide, and water evenly, stir and react at 60 °C for 2 h to obtain intercalated bentonite, and then add pentene sulfonamide, 4-(vinyloxy)benzenesulfonamide, and an initiator thereto, stir and react at 70 °C for 3 h, and obtain modified bentonite after the reaction.

[0080] Example 13 The method for co-preparing a water treatment agent with waste acid in this example is the same as that in Example 10, except that: during the preparation process of the modified bentonite, 4-(vinyloxy)benzenesulfonamide is further added. The weight ratio of the 4-(vinyloxy)benzenesulfonamide to the pentene sulfonamide is 1:40.

[0081] In this example, the modified bentonite is obtained by the following method: Sodium-based bentonite, allyl triethyl ammonium bromide, and water were mixed evenly and stirred at 50 °C for 6 h to obtain intercalated bentonite. Then, pentene sulfonamide, 4-(vinyloxy)benzenesulfonamide, and an initiator were added thereto, and the mixture was stirred at 60 °C for 2 h to obtain modified bentonite after the reaction.

[0082] Comparative Example 1

[0083] The method for co-preparing a water treatment agent from contaminated acid in this comparative example was the same as that in Example 4, except that: step (3) was not included, and the activated carbon loaded with ferrous sulfate obtained in step (2) was used as the product.

[0084] Comparative Example 2 The method for co-preparing a water treatment agent from contaminated acid in this comparative example was the same as that in Example 4, except that: in step (3), the modified titanium dioxide was not included.

[0085] Comparative Example 3 The method for co-preparing a water treatment agent from contaminated acid in this comparative example was the same as that in Example 4, except that: in step (3), the modified bentonite was not included.

[0086] Comparative Example 4 The method for co-preparing a water treatment agent from contaminated acid in this comparative example was the same as that in Example 4, except that: in step (3), the modified titanium dioxide was replaced with titanium dioxide.

[0087] Comparative Example 5 The method for co-preparing a water treatment agent from contaminated acid in this comparative example was the same as that in Example 4, except that: in step (3), the modified bentonite was replaced with sodium-based bentonite.

[0088] Comparative Example 6 The method for co-preparing a water treatment agent from contaminated acid in this comparative example was the same as that in Example 4, except that: in step (3), the preparation method of the modified titanium dioxide was different. Without amino-functionalization treatment, the polymerization reaction was directly carried out using titanium dioxide.

[0089] In this comparative example, the modified titanium dioxide was specifically obtained by the following method: Titanium dioxide, 3,6-thioanthracenediamine, and sebac diamine were dispersed in N,N-dimethylformamide, and hexamethylene diisocyanate was added dropwise thereto with stirring. The reaction was carried out at 70 °C for 10 h to obtain modified titanium dioxide after the reaction.

[0090] Comparative Example 7 The method for co-preparing a water treatment agent from contaminated acid in this comparative example was the same as that in Example 4, except that: in step (3), the preparation method of the modified titanium dioxide was different. The 3,6-thioanthracenediamine was not added for the polymerization reaction.

[0091] The modified titanium dioxide is specifically obtained by the following method: Disperse titanium dioxide in toluene, add γ-aminopropyltriethoxysilane, react at 50 °C for 10 h, filter, wash, and dry to obtain aminated titanium dioxide; Disperse the aminated titanium dioxide and sebac diamine in N,N-dimethylformamide, stir and dropwise add hexamethylene diisocyanate thereto, react at 70 °C for 10 h, and obtain modified titanium dioxide after the reaction.

[0092] Comparative Example 8

[0093] The method for co-preparing a water treatment agent with contaminated acid in this comparative example is the same as that in Example 4, except that: in step (3), the preparation method of the modified titanium dioxide is different, and the 3,6-thioanthracenediamine is replaced with 2,6-diaminoanthracene.

[0094] The 2,6-diaminoanthracene has the structure shown below:

[0095] Comparative Example 9

[0096] The method for co-preparing a water treatment agent with contaminated acid in this comparative example is the same as that in Example 4, except that: in step (3), the preparation method of the modified titanium dioxide is different, and sebac diamine is not added for the polymerization reaction.

[0097] The modified titanium dioxide is specifically obtained by the following method: Disperse titanium dioxide in toluene, add γ-aminopropyltriethoxysilane, react at 50 °C for 10 h, filter, wash, and dry to obtain aminated titanium dioxide; Disperse the aminated titanium dioxide and 3,6-thioanthracenediamine in N,N-dimethylformamide, stir and dropwise add hexamethylene diisocyanate thereto, react at 70 °C for 10 h, and obtain modified titanium dioxide after the reaction.

[0098] Comparative Example 10 The method for co-preparing a water treatment agent with contaminated acid in this comparative example is the same as that in Example 4, except that: in step (3), the preparation method of the modified bentonite is different, and it is not subjected to intercalation treatment.

[0099] The modified bentonite is specifically obtained by the following method: Mix sodium bentonite and water evenly, stir and react at 50 °C for 5 h, then add pentene sulfonamide and an initiator thereto, stir and react at 50 °C for 3 h, and obtain modified bentonite after the reaction.

[0100] Comparative Example 11

[0101] The method for co-preparing water treatment agents from contaminated acid in this comparative example is the same as that in Example 4, except that: in step (3), the preparation method of the modified bentonite is different. It is intercalated bentonite and does not react with pentene sulfonamide.

[0102] The modified bentonite is specifically obtained by the following method: Mix sodium-based bentonite, allyl triethyl ammonium bromide, and water evenly, and stir and react at 50 °C for 5 h to obtain intercalated bentonite.

[0103] Effect experimental example

[0104] To verify the technical effects of the method for co-preparing water treatment agents from contaminated acid described in the present invention, the following tests are carried out: Take the water treatment agents prepared by the method for co-preparing water treatment agents from contaminated acid obtained in Examples 1-13 and Comparative Examples 1-11, and put them into industrial printing and dyeing wastewater at a dosage of 1 g / L. Under visible light radiation conditions (the cut-off wavelength of the filter is λ>420 nm), aerate and stir for 1 h, and measure the CODcr, BOD5, turbidity, and chromaticity in the treated water, and calculate the removal rates of CODcr, BOD5, turbidity, and chromaticity.

[0105] Take methylene blue, acid red G, and sulfur blue CV, and prepare aqueous solutions of 100 mg / L, 10 mg / L, and 60 mg / L respectively as the water samples to be treated. Put the water treatment agents prepared by the method for co-preparing water treatment agents from contaminated acid obtained in Examples 1-13 and Comparative Examples 1-11 into the above water samples to be treated at a dosage of 1 g / L. Under visible light radiation conditions (the cut-off wavelength of the filter is λ>420 nm), aerate and stir for 1 h, and measure the concentrations of each dye molecule in the treated water, and calculate the removal rate.

[0106] After the test, the results are as follows:

[0107] According to the above results, it can be seen that the method for co-preparing water treatment agents from contaminated acid described in the present invention utilizes the synergistic effects of physical adsorption, inorganic coagulation, organic flocculation, and catalytic oxidation to achieve efficient treatment of industrial printing and dyeing wastewater and achieve good removal effects on dyes with strong hydrophilicity and small molecules.

[0108] According to the results of Examples 1-4 and Examples 5-7, when the raw material titanium dioxide of the modified titanium dioxide is replaced with iron-doped titanium dioxide, when the obtained medicament is used to treat industrial printing and dyeing wastewater, the removal rates of CODcr, BOD5, and chromaticity all increase to varying degrees, while the turbidity removal rate slightly decreases or is basically stable, and the removal effects of methylene blue, acid red G, and sulfur blue CV also increase to a certain extent. This is because the introduction of iron into the crystal lattice of iron-doped titanium dioxide improves the photocatalytic activity and is conducive to the decomposition and removal of organic pollutants.

[0109] According to the results of Example 7 and Examples 8-10, β-cyclodextrin, as a template agent added during the preparation of the modified titanium dioxide, can adjust the microstructure of the modified titanium dioxide and affect the distribution of functional groups, etc. Therefore, the removal rates of CODcr, BOD5, turbidity, and chromaticity all increase significantly, especially BOD5 and turbidity, which increase significantly. This is because the distribution of thioanthracene rings and ureido groups not only affects the photocatalytic degradation process but also affects the flocculation effect. The removal rates of methylene blue, acid red G, and sulfur blue CV increase to varying degrees. Among them, the removal effect of acid red G increases significantly, while the removal rates of methylene blue and sulfur blue CV only increase slightly. This may be because acid red G is an anionic dye with good hydrophilicity and a small molecular weight, and the ureido groups and the arrangement of flexible chains of the modified titanium dioxide can be more exposed under the action of β-cyclodextrin, serving as adsorption sites and greatly improving the adsorption selectivity of acid red G. Methylene blue is a cationic dye with good hydrophilicity and a small molecular weight and is relatively less affected. Sulfur blue CV is an anionic dye with poor hydrophilicity and a large molecular weight and mainly relies on the hydrophobic interaction and chemical adsorption with thioanthracene rings and is also relatively less affected.

[0110] According to the results of Example 10 and Examples 11-13, compared with Example 10 in which only pentene sulfonamide is introduced into the modified bentonite, Examples 11-13 in which pentene sulfonamide and 4-(vinyloxy)benzenesulfonamide are introduced can achieve better comprehensive performance. In particular, the removal rate of BOD5 increases significantly, and the removal effect on sulfur blue CV also increases significantly. It can be seen that introducing a small amount of benzene rings between the layers of bentonite can increase the hydrophobic surface of the modified bentonite compared with only introducing sulfonamide, which is beneficial to capturing amphiphilic organic substances, and such substances are an important part of BOD5. For printing and dyeing wastewater with complex components, through the cooperation of modified bentonite, activated carbon loaded with ferrous sulfate, and modified titanium dioxide, better comprehensive treatment effects can be achieved for more pollutants with different properties.

[0111] According to the results of Example 4 and Comparative Example 1, the decrease in the turbidity removal effect and the chromaticity removal effect of the activated carbon loaded with ferrous sulfate is relatively small, and the removal effect of acid red G is significantly reduced. It can be seen that the turbidity removal and decolorization effects of the activated carbon loaded with ferrous sulfate are relatively good, and the removal effect of acid red G is poor.

[0112] According to the results of Example 4, Comparative Examples 2, 4, 6, 7, 8, and 9, the addition of unmodified titanium dioxide (Comparative Example 4) not only fails to improve the performance of the water treatment agent, but also decreases in many indicators compared to the absence of titanium dioxide (Comparative Example 2). This is due to the decrease in the proportion of activated carbon and bentonite in the water treatment agent. Titanium dioxide that has not been treated with amino (Comparative Example 6) is difficult to combine with other polymer monomers, and the effect is also unsatisfactory. The modified titanium dioxide (Comparative Example 7) to which the 3,6-thioanthracene diamine is not added for polymerization reaction, although the turbidity removal effect and the acid red G removal effect are significantly improved, the lack of thioanthracene rings, CODcr, BOD5, and chromaticity removal effects are poor, and the performance of the 3,6-thioanthracene diamine replaced with 2,6-diaminoanthracene (Comparative Example 8) is not much different. It can be seen that the introduction of anthracene rings alone cannot significantly improve the CODcr, BOD5, and chromaticity removal effects. The modified titanium dioxide to which the decanediamine was not added for polymerization (Comparative Example 9), although the thioanthracene ring can improve various properties to a certain extent, has a poor spatial configuration, and the CODcr, BOD5, and chromaticity removal effects are limited, and the flocculation effect is difficult to be effectively exerted, resulting in poor turbidity removal effect.

[0113] According to the results of Example 4 and Comparative Examples 3, 5, 10, and 11, it can be seen that without the addition of modified bentonite (Comparative Example 3), the BOD5 removal effect is significantly reduced, and the removal effects of sulfide blue CV and acid red G are not ideal. When unmodified sodium-based bentonite (Comparative Example 5) is added, the turbidity removal effect is significantly deteriorated, and the removal effects of BOD5 and sulfide blue CV also decrease. Bentonite that has not been intercalated (Comparative Example 10) not only fails to improve the removal effect of CODcr and BOD5, but may also introduce organic pollutants from polymer monomers. The bentonite that has only been intercalated (Comparative Example 11) has improved various properties to a certain extent, but the overall performance is still poor.

[0114] It is known from common technical knowledge that the present invention can be implemented by other embodiments that do not deviate from its spirit or essential features. Therefore, the above disclosed embodiments are only illustrative in all respects and are not exclusive. All changes within the scope of the present invention or within the scope equivalent to the present invention are encompassed by the present invention.

Claims

1. A method for co-preparing water treatment agents from waste acid, characterized in that, It includes the following steps: (1) Mix waste acid with iron powder, filter after reaction to obtain ferrous sulfate solution; (2) Mix the ferrous sulfate solution in step (1) with activated carbon to obtain activated carbon loaded with ferrous sulfate; (3) Mix the activated carbon loaded with ferrous sulfate in step (2) with modified titanium dioxide and modified bentonite evenly to obtain the product; Among them, the modified titanium dioxide is obtained by the following method: Add γ-aminopropyltriethoxysilane to titanium dioxide to obtain aminated titanium dioxide; Mix the aminated titanium dioxide with 3,6-thioanthracenediamine, sebac diamine, and hexamethylene diisocyanate, and obtain modified titanium dioxide after reaction; The modified bentonite is obtained by the following method: Mix sodium-based bentonite with allyl triethyl ammonium bromide evenly, react to obtain intercalated bentonite, and then add pentene sulfonamide and initiator to it, and obtain modified bentonite after reaction.

2. The method for co-preparing water treatment agents from waste acid according to claim 1, characterized in that, In step (2), the ferrous sulfate solution and the activated carbon are mixed according to a weight ratio of (5-10):100; Optionally, in the ferrous sulfate solution, the concentration of ferrous sulfate is 0.1-1 mol / L.

3. The method for co-preparing water treatment agents from waste acid according to claim 1, characterized in that, In step (3), the titanium dioxide is iron-doped titanium dioxide, which is obtained by the following method: Mix the titanium dioxide precursor solution with the acid solution of iron ions, react and then calcine to obtain iron-doped titanium dioxide; Optionally, the titanium dioxide precursor solution is formed by mixing tetrabutyl titanate and ethanol according to a volume ratio of (1-3):10; or, the titanium dioxide precursor solution is formed by mixing isopropyl titanate and ethanol according to a volume ratio of (1-3):10; Optionally, the acid solution of iron ions is a nitric acid solution of ferric chloride, with a pH value of 1-3 and a concentration of iron ions of 50-80 mmol / L; Optionally, the volume ratio of the titanium dioxide precursor solution to the acid solution of iron ions is (15-35):

1.

4. The method for co-preparing water treatment agents from waste acid according to claim 1, characterized in that, In step (3), the titanium dioxide is iron-doped titanium dioxide, which is obtained by the following method: Drop the titanium dioxide precursor solution into the acid solution of iron ions, stir and react at 25-45 °C for 2-8 h, then raise the temperature to 120-160 °C and react for 10-20 h, and calcine at 400-600 °C for 2-4 h to obtain iron-doped titanium dioxide.

5. The method for co-preparing water treatment agents from waste acid according to claim 1, characterized in that The modified titanium dioxide is specifically obtained by the following method: Disperse the titanium dioxide in toluene, add γ-aminopropyltriethoxysilane, react at 50-60 °C for 6-10 h, filter, wash, and dry to obtain aminated titanium dioxide; Disperse the aminated titanium dioxide, 3,6-thioanthracenediamine, and sebac diamine in N,N-dimethylformamide, stir and dropwise add hexamethylene diisocyanate to it, and react at 60-80 °C for 6-12 h to obtain modified titanium dioxide after reaction.

6. The method for co-preparing water treatment agents from waste acid according to claim 5, wherein The weight ratio of the titanium dioxide, γ-aminopropyltriethoxysilane, and toluene is 1:(0.6-0.8):(30-50); Optionally, the weight ratio of the aminated titanium dioxide, 3,6-thioanthracenediamine, decanediamine, and hexamethylene diisocyanate is 1:(0.8 - 1.5):(0.01 - 0.05):(1.0 - 1.2); Optionally, the concentration of the aminated titanium dioxide in the N,N-dimethylformamide is 1.5 - 3.0 wt%.

7. The method for co-preparing water treatment agents from waste acid according to claim 6, characterized in that, β-cyclodextrin is also dispersed in the N,N-dimethylformamide; the weight ratio of the β-cyclodextrin to the aminated titanium dioxide is (0.01 - 0.05):

1.

8. The method for co-preparing water treatment agents from waste acid according to claim 1, characterized in that, The modified bentonite is obtained by the following method: mixing sodium bentonite, allyl triethyl ammonium bromide, and water evenly, stirring and reacting at 40 - 60 °C for 2 - 6 h to obtain intercalated bentonite, and then adding pentene sulfonamide and an initiator thereto, stirring and reacting at 50 - 70 °C for 2 - 3 h to obtain the modified bentonite after the reaction; Optionally, the weight ratio of the sodium bentonite, allyl triethyl ammonium bromide, water, pentene sulfonamide, and the initiator is 100:(5 - 10):(300 - 500):(2 - 8):(0.5 - 1.5); Optionally, the initiator is azobisisobutyronitrile.

9. The method for co-preparing water treatment agents from waste acid according to claim 1, characterized in that, In step (3), the weight ratio of the activated carbon loaded with ferrous sulfate, the modified titanium dioxide, and the modified bentonite is 1:(2 - 8):(10 - 30).

10. A water treatment agent is obtained by the method for synergistically preparing a water treatment agent from waste acid according to any one of claims 1 - 9.

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