Preparation and application of solid titanium-iron flocculant for treating emulsion wastewater without breaking emulsion
The solid titanium-iron flocculant prepared by the sol-gel method solves the problems of low efficiency and environmental unfriendliness of traditional flocculants in treating emulsion wastewater, and achieves efficient and economical emulsion wastewater treatment, which is suitable for various water environments.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHANXI UNIV
- Filing Date
- 2025-01-06
- Publication Date
- 2026-06-12
AI Technical Summary
Existing technologies struggle to efficiently treat emulsion wastewater without demulsification. Traditional flocculants are ineffective at removing emulsion droplets and organic pollutants from emulsion wastewater and also present problems such as high cost and biotoxicity.
Solid titanium-iron flocculants were prepared using the sol-gel method. A covalently bonded hybrid flocculant was formed by the cross-linking reaction of organic titanate esters and iron salts in a protic solvent. This flocculant was used for the treatment of emulsion wastewater without demulsification.
It achieves efficient coagulation removal of emulsion droplets and organic pollutants in emulsion wastewater without demulsification, reduces costs, improves the charge neutralization capacity of flocculants, adapts to a wide range of pH changes, and is environmentally friendly.
Smart Images
Figure CN119774731B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the technical field of flocculants for water treatment, specifically relating to the preparation and application of a solid titanium-iron flocculant for treating emulsion wastewater without demulsification. Background Technology
[0002] With the increase in global population and economic development, water pollution and water scarcity have become increasingly prominent problems, posing a serious threat to the sustainable development of society as a whole. It is widely believed worldwide that wastewater resource utilization is the most effective way to address this challenge, as it not only provides high-quality reclaimed water but also allows for resource / energy recovery. However, due to the complex and varied composition of wastewater from different sources, it often contains small amounts of difficult-to-treat components that are difficult to completely remove using existing treatment technologies, or whose treatment processes are lengthy and costly, hindering sustainable development. Emulsion wastewater is a typical example of difficult-to-treat wastewater, and it exists in large quantities in my country.
[0003] In emulsion-related wastewater, oil pollutants generally exist in the form of stable oil-in-water droplets (<20 mm), characterized by high surfactant content, multi-component coexistence, strong system stability, and high oil content. Because surfactants act as emulsifiers, a robust interfacial film protective layer is formed around the droplets, with hydrophilic groups pointing towards water and hydrophobic groups towards oil. This film, by reducing interfacial energy (interfacial tension) and zeta potential, protects the emulsion, allowing it to remain stable in water for a long time, making it difficult to remove effectively using traditional physical and biological water treatment methods. Therefore, demulsification has long been the core of emulsion wastewater treatment technology. This involves adding demulsifiers or using physical methods (changing temperature, high-voltage electric fields, ultrasound, membrane filtration, etc.) to destabilize the existing droplets in the wastewater. Then, physical, chemical, and biological methods are used to achieve oil-water separation and the removal of surfactants and other organic pollutants, as well as various additives. This usually requires a combination of several methods. In existing research, demulsification is considered the most difficult step in emulsion wastewater treatment, severely restricting the clean and efficient treatment of emulsion wastewater. Therefore, developing new methods for the simple and efficient treatment of emulsion wastewater without the need for demulsification has broad application prospects.
[0004] Flocculation, as an indispensable water treatment technology, has attracted much attention due to its maturity, economy, practicality, relative efficiency, and ease of construction and upgrading. The structure and performance of flocculants play a crucial role in the wastewater treatment effect during the flocculation process. Currently, wastewater treatment mainly uses two categories of flocculants: inorganic flocculants (including aluminum and iron salts) and organic synthetic flocculants (such as polyacrylamide and polyacrylamide and their derivatives). Inorganic flocculants are inexpensive, but also have drawbacks such as high dosage, pH sensitivity, and the toxicity of residual metal ions (such as Al ions). Organic synthetic polymeric flocculants, most commonly PAM and its derivatives, have relatively low dosage requirements, their ability to remove emulsions needs improvement, and they are also more expensive and may have some biological toxicity. Flocculants destabilize colloidal particulate pollutants in water and cause them to coagulate (or flocculate) into large aggregates (flocculates) through charge neutralization, adsorption bridging, and trapping, achieving sedimentation separation. However, traditional flocculants are difficult to remove emulsion droplets from emulsion wastewater without breaking the emulsion, and they also cannot remove dissolved organic pollutants from the water. Summary of the Invention
[0005] To address the problems existing in the prior art, this invention utilizes a special sol-gel method to dissolve organic titanate in a protic solvent and an alcohol-water solution of iron salt to undergo a cross-linking reaction and form a sol. This sol further coagulates to form a gel, which is then aged and dried to obtain a solid titanium-iron flocculant. This flocculant can achieve non-demulsifying coagulation treatment of emulsion wastewater.
[0006] The technical solution of the present invention is as follows:
[0007] A method for preparing a solid titanium-iron flocculant for treating emulsion wastewater without demulsification includes the following steps:
[0008] Step 1: Dissolve the stabilizer in a protic solvent, then add an organotitanate ester to obtain solution A;
[0009] Step 2: Dissolve the inorganic iron salt in a low-carbon fatty alcohol or a low-carbon fatty alcohol / water mixture, adjust the pH, and obtain solution B;
[0010] Step 3: Add solution B to solution A and stir until homogeneous to form a sol;
[0011] Step 4: Aging and drying the above sol to obtain the solid titanium-iron flocculant.
[0012] Further, in step 1, the stabilizer is one of acetic acid, acetylacetone, and ethyl acetoacetate; the protic solvent is one of methanol, ethanol, isopropanol, tert-butanol, and ethylene glycol monomethyl ether; and the organic titanate is one of tetrabutyl titanate, tetraisopropyl titanate, tetrapropyl titanate, and tetraethyl titanate.
[0013] Furthermore, in step 1, the molar ratio of the stabilizer to the organic titanate is 1:1 to 30.
[0014] Furthermore, in step 1, the volume ratio of the stabilizer to the proton solvent is 1:10 to 200.
[0015] Furthermore, in step 2, the inorganic iron salt is one of FeCl2, FeCl3, Fe(NO3)2, Fe(NO3)3, FeSO4, and Fe2(SO4)3; and the low-carbon fatty alcohol is one of methanol, ethanol, isopropanol, and tert-butanol.
[0016] Furthermore, in step 2, the molar ratio of iron salt to organic titanate is 1:0.5-5, and the pH is 1.0-6.0.
[0017] Furthermore, the sol aging time in step 4 is 8 to 48 hours.
[0018] A solid titanium-iron flocculant prepared by the preparation method described above is an organic-inorganic hybrid flocculant formed by Fe atoms uniformly embedded in the Ti-OR structural framework and covalently bonded.
[0019] An application of a solid titanium-iron flocculant as described above for treating emulsion wastewater without demulsification.
[0020] Furthermore, the emulsion wastewater includes mine water containing emulsion, food processing wastewater, cutting fluid wastewater, oilfield wastewater, wastewater from daily chemical production enterprises, and domestic sewage containing oil-water mixed emulsions.
[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0022] (1) This invention uses a special sol-gel method to prepare a solid titanium-iron hybrid flocculant through aging and drying; (2) The flocculant of this invention hybridizes organic titanate and iron atoms through covalent bonds, and the organic component of the organic titanate and the inorganic component iron salt are linked by Fe-O-Ti hydrolysis and condensation; (3) The titanium and iron metal ions in the flocculant molecules of this invention are more evenly distributed, and the combination of titanium salt and iron salt can better adapt to the pH value in the water environment, and has a wider range of applications; (4) The solid form of the flocculant product of this invention overcomes the transportation and storage stability problems of traditional liquid flocculants and reduces transportation costs. (5) The flocculant of the present invention has better charge neutralization, adsorption bridging and netting sweeping capabilities. The high valence of titanium and iron greatly improves the charge neutralization ability of the flocculant and promotes the coagulation and removal of emulsions with negative surface charge in water. The covalently hybridized organic functional groups ensure that emulsion wastewater can be treated by coagulation without demulsification and can efficiently remove water turbidity and pollutants such as organic matter, nitrogen and phosphorus. (6) Since titanium and iron are not harmful to the biosphere, and titanium is also a biocompatible element, the flocculant of the present invention will not affect human health and the surrounding ecological environment, which is conducive to the resource utilization of emulsion wastewater after treatment. Attached Figure Description
[0023] Figure 1 Infrared spectrum of the flocculant obtained in Preparation Example 1.
[0024] Figure 2 The graph shows the change in pollutant removal rate of simulated wastewater treated with the flocculant obtained in Example 1 as a function of dosage.
[0025] Figure 3 The graph shows the change in pollutant removal rate of commercially available PAC (polyaluminum chloride) in simulated wastewater treatment with the dosage.
[0026] Figure 4 Microscopic images of flocs in simulated wastewater treated with the flocculant obtained in Example 1. Detailed Implementation
[0027] The present invention will be further illustrated below with specific embodiments and application examples, but the scope of protection of the present invention is not limited thereto.
[0028] Unless otherwise specified, all reagents used in the following examples are commercially available products and have been used directly without purification before use.
[0029] Preparation Example 1
[0030] A method for preparing a solid titanium-iron flocculant for treating emulsion wastewater without demulsification includes the following steps:
[0031] (a) Take 0.1 mol of glacial acetic acid and dissolve it in 100 mL of anhydrous ethanol under stirring at 300 rpm (the volume ratio of glacial acetic acid to anhydrous ethanol is about 7 / 100). Continue stirring for 10 min, then slowly add 0.1 mol of tetraisopropyl titanate solution dropwise under stirring and continue stirring for 30 min to obtain a homogeneous mixed solution A.
[0032] (b) Dissolve 0.1 mol Fe(NO3)3 in 25 mL of deionized water and 25 mL of anhydrous ethanol, stir at 300 rpm for 30 min, adjust the pH to 2 with glacial acetic acid, and continue stirring for 30 min to obtain mixed solution B.
[0033] (c) At room temperature, with stirring at 300 rpm, slowly add mixed solution B to mixed solution A at a rate of 0.2 ml / min, and continue stirring at 300 rpm for 60 min to obtain a homogeneous sol.
[0034] (d) Place the sol obtained in step (c) in a glass container, age it for 8 hours, and then vacuum dry it at 45°C to constant weight to obtain the solid titanium-iron flocculant.
[0035] The infrared spectrum of solid titanium-iron flocculant is as follows: Figure 1 As shown, 3300cm -1 The broadband amplitude originates from the stretching vibrations of the -OH groups in the solid titanium-iron composite flocculant. 668cm -1 Corresponding to the bending vibration of Fe-OH, 790 cm -1 The peak at 1179 cm⁻¹ can be attributed to the stretching vibration of the Ti-O-Ti bond. -1 This is attributed to the vibrations of the Fe-O-Fe wave. Wavenumber: 1620 cm⁻¹ -1 The vicinity corresponds to the -OH bending vibration, 1347 cm. -1 This is caused by the symmetric and asymmetric stretching vibrations of the Fe-O-Fe and Ti-O-Fe groups.
[0036] Preparation Example 2
[0037] A method for preparing a solid titanium-iron flocculant for treating emulsion wastewater without demulsification includes the following steps:
[0038] (a) Take 0.05 mol of acetylacetone and dissolve it in 200 mL of isopropanol under stirring at 100 rpm (the volume ratio of acetylacetone to isopropanol is about 5.1 / 200). Continue stirring for 10 min, then slowly add 1 mol of tetrabutyl titanate solution dropwise under stirring and continue stirring for 30 min to obtain a homogeneous mixed solution A.
[0039] (b) Dissolve 0.2 mol Fe2(SO4)3 in 30 mL of deionized water and 20 mL of isopropanol, stir at 300 rpm for 30 min, adjust the pH to 4 with glacial acetic acid, and continue stirring for 30 min to obtain mixed solution B.
[0040] (c) At room temperature, with stirring at 300 rpm, slowly add mixed solution B to mixed solution A at a rate of 0.2 ml / min, and continue stirring at 100 rpm for 120 min to obtain a homogeneous sol.
[0041] (d) Place the sol obtained in step (c) in a glass container, age it for 16 hours, and then vacuum dry it at 60°C to constant weight to obtain the solid titanium-iron flocculant.
[0042] Preparation Example 3
[0043] A method for preparing a solid titanium-iron flocculant for treating emulsion wastewater without demulsification includes the following steps:
[0044] (a) Take 0.01 mol of ethyl acetoacetate and dissolve it in 200 mL of methanol under stirring at 300 rpm (the volume ratio of ethyl acetoacetate to methanol is approximately 1.26 / 200). Continue stirring for 10 min, then slowly add 0.3 mol of tetraethyl titanate solution dropwise under stirring and continue stirring for 30 min to obtain a homogeneous mixed solution A.
[0045] (b) Dissolve 0.1 mol FeCl3 in 10 mL of deionized water and 30 mL of methanol, stir at 300 rpm for 30 min, adjust the pH to 6 with glacial acetic acid, and continue stirring for 30 min to obtain mixed solution B.
[0046] (c) At room temperature, with stirring at 300 rpm, slowly add mixed solution B to mixed solution A at a rate of 0.2 ml / min, and continue stirring at 300 rpm for 60 min to obtain a homogeneous sol.
[0047] (d) Place the sol obtained in step (c) in a glass container, age it for 48 hours, and then vacuum dry it at 45°C to constant weight, which is the solid titanium-iron flocculant.
[0048] Preparation Example 4
[0049] A method for preparing a solid titanium-iron flocculant for treating emulsion wastewater without demulsification includes the following steps:
[0050] (a) Take 0.1 mol of acetylacetone and dissolve it in 200 mL of ethylene glycol monomethyl ether under stirring at 300 rpm (the volume ratio of acetylacetone to ethylene glycol monomethyl ether is approximately 10.2 / 200). Continue stirring for 10 min, then slowly add 1 mol of tetraisopropyl titanate solution dropwise under stirring and continue stirring for 30 min to obtain a homogeneous mixed solution A.
[0051] (b) Dissolve 2 mol Fe(NO3)2 in 5 mL deionized water + 35 mL anhydrous ethanol, stir at 300 rpm for 30 min, adjust the pH to 1 with glacial acetic acid, and continue stirring for 30 min to obtain mixed solution B.
[0052] (c) At room temperature, with stirring at 300 rpm, slowly add mixed solution B to mixed solution A at a rate of 0.2 ml / min, and continue stirring at 300 rpm for 60 min to obtain a homogeneous sol.
[0053] (d) Place the sol obtained in step (c) in a glass container, age it for 16 hours, and then vacuum dry it at 45°C to constant weight to obtain the solid titanium-iron flocculant.
[0054] Preparation Example 5
[0055] A method for preparing a solid titanium-iron flocculant for treating emulsion wastewater without demulsification includes the following steps:
[0056] (a) Take 0.2 mol of glacial acetic acid and dissolve it in 300 mL of tert-butanol under stirring at 300 rpm (the volume ratio of glacial acetic acid to anhydrous ethanol is about 14 / 300). Continue stirring for 10 min. Slowly add 0.4 mol of tetraethyl titanate solution under stirring. Continue stirring for 30 min to obtain a homogeneous mixed solution A.
[0057] (b) Dissolve 0.2 mol FeSO4 in 10 mL of deionized water and 30 mL of tert-butanol, stir at 300 rpm for 30 min, adjust the pH to 2 with glacial acetic acid, and continue stirring for 30 min to obtain mixed solution B.
[0058] (c) At room temperature, with stirring at 300 rpm, slowly add mixed solution B to mixed solution A at a rate of 0.2 ml / min, and continue stirring at 300 rpm for 60 min to obtain a homogeneous sol. (d) Place the sol obtained in step (c) in a glass container, age for 24 h, and then vacuum dry at 45 °C to constant weight to obtain the solid titanium-iron flocculant.
[0059] Preparation Example 6
[0060] A method for preparing a solid titanium-iron flocculant for treating emulsion wastewater without demulsification includes the following steps:
[0061] (a) Take 0.2 mol of acetylacetone and dissolve it in 200 mL of anhydrous ethanol under stirring at 300 rpm (the volume ratio of acetylacetone to anhydrous ethanol is approximately 20.2 / 200). Continue stirring for 10 min, then slowly add 0.5 mol of tetrabutyl titanate solution dropwise under stirring and continue stirring for 30 min to obtain a homogeneous mixed solution A.
[0062] (b) Dissolve 0.1 mol FeCl2 in 10 mL of deionized water and 25 mL of anhydrous ethanol, stir at 300 rpm for 30 min, adjust the pH to 1 with glacial acetic acid, and continue stirring for 30 min to obtain mixed solution B.
[0063] (c) At room temperature, with stirring at 300 rpm, slowly add mixed solution B to mixed solution A at a rate of 0.2 ml / min, and continue stirring at 300 rpm for 60 min to obtain a homogeneous sol.
[0064] (d) Place the sol obtained in step (c) in a glass container, age it for 48 hours, and then vacuum dry it at 45°C to constant weight, which is the solid titanium-iron flocculant.
[0065] Application Example 1
[0066] The solid titanium-iron flocculant obtained in Example 1 was applied to the coagulation treatment of simulated wastewater containing emulsion-kaolin-phosphorus-nitrogen. The treatment results are as follows: Figure 2 As shown in the figure, it can be found that at the optimized dosage of 100 mg / L, the removal rates of COD, ammonia nitrogen, nitrate nitrogen, total phosphorus, turbidity, and emulsion can reach 51.3%, 24.6%, 35.9%, 90%, 93%, and 59.6%, respectively. In the comparative experiment, the flocculation treatment results of commercially available PAC (polyaluminum chloride) on the same simulated emulsion are as follows... Figure 3 As shown, under the optimized dosage of 2.25 times (225 mg / L) of the solid titanium-iron flocculant of the present invention, the COD 16.5%, ammonia nitrogen 8.4%, nitrate nitrogen 12.6%, total phosphorus 84%, turbidity 88%, and emulsion 10.8% are all lower than the treatment results of the solid titanium-iron flocculant of the present invention, and the removal rates of COD and emulsion are much lower.
[0067] Microscopic images of flocs after treatment with the solid titanium-iron flocculant of the present invention are as follows: Figure 4 As shown, the emulsion aggregates in the form of droplets, indicating that no emulsion breaks during the coagulation process, thus achieving emulsion-free coagulation treatment.
[0068] Application Example 2
[0069] The solid titanium-iron flocculant obtained in Example 2 was applied to the coagulation treatment of mine water containing emulsions, and its effects on turbidity and UV were observed. 254 The removal rates for COD, nitrate nitrogen, ammonia nitrogen, and TP were 99%, 90.3%, 49.3%, 32.2%, 22.9%, and 99%, respectively. The corresponding removal rates for PAC were 88% for turbidity and 99% for UV. 254 The removal rates of COD, COD, nitrate titanium nitrogen, and ammonia nitrogen were 48.9%, 6.8%, 3.6%, 2.4%, and TP 88.1%, respectively. The removal rates of COD, nitrate titanium nitrogen, and ammonia nitrogen were much lower than those of the solid titanium iron flocculant of this invention.
Claims
1. A method for preparing a solid titanium-iron flocculant for treating emulsion wastewater without demulsification, characterized in that: Includes the following steps: Step 1: Dissolve the stabilizer in a protic solvent, then add an organotitanate ester to obtain solution A; Step 2: Dissolve the inorganic iron salt in a low-carbon fatty alcohol or a low-carbon fatty alcohol / water mixture, adjust the pH, and obtain solution B; Step 3: Add solution B to solution A and stir until homogeneous to form a sol; Step 4: Aging and drying the above sol to obtain the solid titanium-iron flocculant; The protic solvent is one of methanol, ethanol, isopropanol, tert-butanol, and ethylene glycol monomethyl ether.
2. The preparation method of a solid titanium-iron flocculant for treating emulsion wastewater without demulsification according to claim 1, characterized in that: In step 1, the stabilizer is one of acetic acid, acetylacetone, or ethyl acetoacetate; the organic titanate is one of tetrabutyl titanate, tetraisopropyl titanate, tetrapropyl titanate, or tetraethyl titanate.
3. The preparation method of a solid titanium-iron flocculant for treating emulsion wastewater without demulsification according to claim 1, characterized in that: In step 1, the molar ratio of stabilizer to organic titanate is 1:1 to 30.
4. The preparation method of a solid titanium-iron flocculant for treating emulsion wastewater without demulsification according to claim 1, characterized in that: In step 1, the volume ratio of stabilizer to proton solvent is 1:10~200.
5. The preparation method of a solid titanium-iron flocculant for treating emulsion wastewater without demulsification according to claim 1, characterized in that: In step 2, the inorganic iron salt is one of FeCl2, FeCl3, Fe(NO3)2, Fe(NO3)3, FeSO4, and Fe2(SO4)3; the low-carbon fatty alcohol is one of methanol, ethanol, propanol, and butanol.
6. The preparation method of a solid titanium-iron flocculant for treating emulsion wastewater without demulsification according to claim 1, characterized in that: In step 2, the molar ratio of iron salt to organic titanate is 1:0.5~5, and the pH is 1.0~6.
0.
7. The preparation method of a solid titanium-iron flocculant for treating emulsion wastewater without demulsification according to claim 1, characterized in that: The sol aging time in step 4 is 8~48 h.
8. A solid titanium-iron flocculant prepared by the preparation method according to any one of claims 1-7, characterized in that: It is an organic-inorganic hybrid flocculant formed by Fe atoms uniformly embedded in the Ti-OR structural framework and covalently bonded.
9. An application of the solid ferrotitanium flocculant according to claim 8, characterized in that: Used for treating emulsion wastewater without breaking the emulsion.
10. The application of the solid ferrotitanium flocculant according to claim 9, characterized in that: The emulsion wastewater includes mine water containing emulsions, food processing wastewater, cutting fluid wastewater, oilfield wastewater, wastewater from daily chemical production enterprises, and domestic sewage containing oil-water mixed emulsions.