阅读说明：本技术 一种CSW/nZVI复合活化剂及其应用 (CSW/nZVI composite activator and application thereof ) 是由 韩毅 孙慧群 徐志兵 韦启信 陈琪 嵇然 雷雳 黄书敏 于 2019-10-29 设计创作，主要内容包括：本发明公开了一种CSW/nZVI复合活化剂及其应用,该复合活化剂由以下方法制备而成：1、在氮气保护下,将FeSO<Sub>4</Sub>·7H<Sub>2</Sub>O溶解于去离子和无水乙醇的混合溶剂中,得到溶液A；2、在氮气保护下,将硫酸钙晶须加入溶液A中,搅拌混合均匀并静置,得到溶液B；3、在氮气保护下,边搅拌边将NaBH<Sub>4</Sub>溶液滴加入溶液B,滴加完成后,停止搅拌并静置30-40min,将所得的混合液过滤,将滤饼洗涤并干燥,得到所述的CSW/nZVI复合活化剂。该活化剂提高了纳米零价铁的活化性能,解决了Fe<Sup>0</Sup>在水中团聚问题的同时,大大提高了纳米零价铁的反应速率,而且,硫酸钙晶须可以有效改善污泥微观结构,促进污泥深度脱水,因此,将该活化剂用于对污泥脱水处理中,能增强污泥脱水效果,而且不产生二次污染。(The invention discloses a CSW/nZVI composite activator and application thereof, wherein the composite activator is prepared by the following method: 1. under the protection of nitrogen, FeSO 4 ·7H 2 Dissolving O in a mixed solvent of deionized water and absolute ethyl alcohol to obtain a solution A; 2. adding the calcium sulfate whiskers into the solution A under the protection of nitrogen, stirring and mixing uniformly, and standing to obtain a solution B; 3. under the protection of nitrogen, stirring and adding NaBH 4 And dropwise adding the solution B into the solution, stopping stirring after dropwise adding, standing for 30-40min, filtering the obtained mixed solution, washing and drying the filter cake to obtain the CSW/nZVI composite activator. The activating agent improves the activation performance of the nano zero-valent iron and solves the problem of Fe 0 The reaction rate of the nano zero-valent iron is greatly improved while the problem of agglomeration in water is solved, and the calcium sulfate whisker can effectively improve the microstructure of sludge and promote deep dehydration of the sludge, so that the activating agent can be used for sludge dehydration treatment to enhance the sludge dehydration effect without generating secondary pollution.)

1. A CSW/nZVI composite activator is characterized by being prepared by the following method:

1.1 under the protection of nitrogen, FeSO₄·7H₂Dissolving O in a mixed solvent of deionized water and absolute ethyl alcohol to obtain a solution A;

1.2, adding the calcium sulfate whiskers into the solution A under the protection of nitrogen, stirring and mixing uniformly, and standing to obtain a solution B;

1.3 under the protection of nitrogen, stirring and adding NaBH₄And dropwise adding the solution B into the solution, stopping stirring after dropwise adding, standing for 20-60min, filtering the obtained mixed solution, washing and drying the filter cake to obtain the CSW/nZVI composite activator.

2. The CSW/nZVI composite activator of claim 1, wherein: the particle size of the calcium sulfate whisker is 100-150 mu m, and the length-diameter ratio is 60-120.

3. The CSW/nZVI composite activator of claim 1, wherein: the FeSO₄·7H₂The mol ratio of O to calcium sulfate crystal whisker is 0.1-0.5:1, NaBH₄With FeSO₄·7H₂The molar ratio of O is 2-4: 1.

4. The CSW/nZVI composite activator of claim 1, wherein: the volume ratio of the absolute ethyl alcohol to the deionized water is 1: 3.

5. The CSW/nZVI composite activator of claim 1, wherein: in the step 1.2, after the calcium sulfate whisker is added, the stirring time is 30-50min, and the standing time is 30-50 min.

6. The use of the CSW/nZVI composite activator in the deep dehydration of sludge according to claim 1.

7. The application of the CSW/nZVI compound activator in claim 6, wherein the method for deep dewatering the sludge by using the CSW/nZVI compound activator comprises the following steps:

firstly adding persulfate into the sludge, wherein the adding amount of the persulfate is 0.6-1.2mg/g of sludge dry basis, uniformly stirring, then adding the CSW/nZVI composite activator, wherein the adding amount of the CSW/nZVI composite activator is 1.2-4mg/g of sludge dry basis, uniformly stirring, and finally mechanically dewatering.

8. Use of a CSW/nZVI composite activator according to claim 7, wherein: the persulfate is potassium persulfate or sodium persulfate.

9. Use of a CSW/nZVI composite activator according to claim 7, characterized in that the stirring method is: rapidly stirring at 370rpm/min for 3-8min at 310-.

Technical Field

The invention belongs to the technical field of deep dehydration treatment of domestic sludge, and particularly relates to a CSW/nZVI composite activator and application thereof, which is a technology for conditioning sludge by activating persulfate through a nano zero-valent iron composite activator.

Background

The sludge is produced along with the sewage treatment process, along with the deepening of the attention degree of China on the sewage treatment, the popularization of the construction of urban sewage treatment plants and the continuous improvement of treatment process technology, the sewage treatment efficiency is greatly improved, and the yield of the sludge is also rapidly increased. Therefore, the improvement of the dehydration performance of the sludge and the obvious reduction of the water content of the sludge are the premise of realizing sludge reduction, harmlessness and recycling, and have important research significance and social value.

The composition of the sludge is complex, and the factors influencing the sludge dehydration are more. In order to solve the problem of difficulty in sludge dewatering, in recent years, researchers at home and abroad have carried out a lot of research, and the main improvement methods comprise a hydrothermal method, a microwave method, a biological method, nano-particle adding, an advanced oxidation method and the like. The traditional advanced oxidation technology comprises a Fenton/Fenton-like oxidation method, an ultraviolet light catalytic oxidation method and an ozone oxidation method, and due to the fact that the traditional advanced oxidation technology has strict reaction conditions and high running cost, researchers have turned their eyes to the persulfate advanced oxidation technology in recent years.

The nano zero-valent iron has a good effect of removing various pollutants, and is widely researched and applied to polluted water bodies, soil and bottom mud. The preparation of the nano zero-valent iron, the application in the pollution treatment aspect, the action mechanism and the like are summarized in more detail by the predecessors, and the problems of the nano zero-valent iron in the application are mentioned, but few people concentrate on the arrangement. After preliminary experiments and literature reference, the use of Fe is found⁰Can reduce excessive Fe²⁺The sulfate radical is consumed, other anions are prevented from being introduced, the effect on organic matters is more targeted, and secondary pollution is not caused. However, Fe⁰Slow dissolution rate in water, and restriction of Fe²⁺Producing a rate, thereby affecting the wholeBulk reaction process, which also restricts S₂O₈ ^2-/Fe⁰The system is applied to the improvement of sludge dewatering performance in a large scale. Therefore, how to increase Fe⁰Dissolution rate, acceleration of Fe²⁺Is generated by effecting S₂O₈ ^2-/Fe⁰The key of the efficient conditioning of the sludge dewatering performance of the oxidation system is.

Calcium Sulfate Whisker (CSW) is a short fiber-shaped crystal grown in a single crystal form, and has the characteristics of high mechanical strength, good compatibility, loose structure, small density, large specific surface area and the like, if Fe is added⁰Loaded on the surface of the calcium sulfate whisker and beneficial to improving Fe⁰The dispersion degree in water increases the contact area of the reaction and avoids agglomeration. And no report is found on the research of loading zero-valent iron on the calcium sulfate whisker and conditioning the sludge dewatering performance.

Disclosure of Invention

Based on the prior art, the invention provides a CSW/nZVI composite activator and application thereof, the activator is prepared by calcium sulfate whisker loaded nano zero-valent iron, the activation performance of the nano zero-valent iron is improved, and Fe is solved⁰The reaction rate of the nano zero-valent iron is greatly improved while the problem of agglomeration in water is solved, and the calcium sulfate whisker can effectively improve the microstructure of sludge and promote deep dehydration of the sludge, so that the activating agent can be used for sludge dehydration treatment to enhance the sludge dehydration effect without generating secondary pollution.

The technical scheme adopted for realizing the above purpose of the invention is as follows:

a CSW/nZVI composite activator is prepared by the following steps:

1. under the protection of nitrogen, FeSO₄·7H₂Dissolving O in a mixed solvent of deionized water and absolute ethyl alcohol to obtain a solution A;

2. adding the calcium sulfate whiskers into the solution A under the protection of nitrogen, stirring and mixing uniformly, and standing to obtain a solution B;

3. under the protection of nitrogen, stirring and adding NaBH₄Dropwise adding the solution B into the solution, stopping stirring and standing the solution after the dropwise addition is finishedAnd (3) filtering the obtained mixed solution for 20-60min, and washing and drying a filter cake to obtain the CSW/nZVI composite activator.

Furthermore, the particle size of the calcium sulfate whisker is 100-150 μm, and the length-diameter ratio is 60-120.

Further, the FeSO₄·7H₂The mol ratio of O to calcium sulfate crystal whisker is 0.1-0.5:1, NaBH₄With FeSO₄·7H₂The molar ratio of O is 2-4: 1.

Further, the volume ratio of the absolute ethyl alcohol to the deionized water is 1: 3.

Further, in the step 2, after the calcium sulfate whisker is added, the stirring time is 30-50min, and the standing time is 30-50 min.

An application of a CSW/nZVI composite activator in deep dehydration of sludge.

Further, the method for deeply dehydrating the sludge by using the CSW/nZVI composite activator comprises the following steps:

firstly adding persulfate into the sludge, wherein the adding amount of the persulfate is 0.6-1.2mg/g of sludge dry basis, uniformly stirring, then adding the CSW/nZVI composite activator, wherein the adding amount of the CSW/nZVI composite activator is 1.2-4mg/g of sludge dry basis, uniformly stirring, and finally mechanically dewatering.

Further, the persulfate is potassium persulfate or sodium persulfate.

Further, the stirring method comprises the following steps: rapidly stirring at 370rpm/min for 3-8min at 310-.

Compared with the prior art, the invention has the beneficial effects and advantages that:

1. the calcium sulfate whisker used in the invention is an inorganic material, has stable property, is environment-friendly and has no secondary pollution. Has larger specific surface area and mechanical strength, and can provide a tiny water outlet channel in the sludge mechanical filter pressing process.

2. The CSW/nZVI composite activator prepared by the invention has stable property and excellent performance, and compared with single nZVI composite activator, the persulfate activation efficiency is obviously increased.

3. The CSW/nZVI composite activator and persulfate prepared by the method do not cause pH reduction of filtrate and secondary pollution in the process of conditioning sludge dehydration, and the conditioning effect is multiplied compared with that of single nZVI.

4. The CSW/nZVI composite activator prepared by the invention is used for dehydrating sludge, is an in-situ treatment process, avoids the cost of sludge transportation, does not need to add other reagents, is suitable for the process conditions of the existing urban sewage treatment plant, and does not need to add other process facilities.

Drawings

FIG. 1 is a scanning electron microscope photograph of the CSW/nZVI composite activator prepared in example 1.

Fig. 2 is an X-ray diffraction pattern of the CSW/nZVI composite activator prepared in example 1 and example 2.

Detailed Description

The present invention will be described in detail with reference to specific examples.