阅读说明：本技术 基于硼酸化零价铁高效还原去除污染物的方法 (Method for removing pollutants based on efficient reduction of borated zero-valent iron ) 是由 张礼知 胡月 于 2019-07-30 设计创作，主要内容包括：本发明涉及一种基于硼酸化零价铁高效还原去除污染物的方法。将硼酸化零价铁加入到污染物溶液中,进行污染物去除；所述的硼酸化零价铁为零价铁表面的部分羟基基团被-OB(OH)<Sub>2</Sub>基团取代的零价铁。本发明提供的基于硼酸化零价铁高效还原去除污染物的方法对不同重金属离子和有机污染物等都具有较好的还原去除能力。硼酸化改性零价铁球磨法制备硼酸化零价铁的方法简单,易操作。(The invention relates to a method for removing pollutants based on borated zero-valent iron efficient reduction. Adding borated zero-valent iron into a pollutant solution to remove pollutants; the borated zero-valent iron is prepared by reacting-OB (OH) with partial hydroxyl groups on the surface of zero-valent iron 2 Group-substituted zero-valent iron. The method for removing pollutants by efficient reduction based on borated zero-valent iron provided by the invention has better reduction removal capability on different heavy metal ions, organic pollutants and the like. The method for preparing the borated zero-valent iron by the borated modified zero-valent iron ball milling method is simple and easy to operate.)

1. A method for removing pollutants by efficiently reducing borated zero-valent iron is characterized by comprising the following steps: adding borated zero-valent iron into a pollutant solution to remove pollutants; the borated zero-valent iron is prepared by reacting-OB (OH) with partial hydroxyl groups on the surface of zero-valent iron₂Group-substituted zero-valent iron.

2. The method of claim 1, wherein: the borated zero-valent iron is prepared by boric acid and zero-valent iron through a ball milling method; the boric acid added in the ball milling process accounts for 0.05-10.0% of zero-valent iron according to molar ratio.

3. The method of claim 2, wherein: the boric acid added in the ball milling preparation process accounts for 1 to 8 percent of zero-valent iron according to molar ratio.

4. The method of claim 2, wherein: the ball milling time is 2-10 h.

5. The method of claim 2, wherein: the rotation speed is 200 and 800 r/min.

6. The method of claim 1, wherein: the zero-valent iron is micron-sized zero-valent iron.

7. The method of claim 1, wherein: the using amount of the borated zero-valent iron is 1-5 g/L.

8. The method of claim 1, wherein: the concentration of the pollutants is 2-10ppm, the reaction temperature is 0-50 ℃, and the reaction pH is 3-10.

9. The method of claim 1, wherein: such contaminants include, but are not limited to, chromium, nickel, lead, 4-chlorophenol, nitrobenzene; the pollutant removing process adopts a shaking table oscillation mode.

10. Borated zero-valent iron in which the hydroxyl groups on the surface of zero-valent iron are substituted by-OB (OH)₂Group-substituted zero-valent iron.

Technical Field

The invention belongs to the field of environmental chemistry, and particularly relates to control and restoration of heavy metal ions and chlorine (nitro) containing organic matters in a water body, which is suitable for treatment of wastewater in the fields of printing and dyeing, industry and the like.

Background

In recent years, heavy metal ions and chlorine (nitro) containing organic matters are commonly reported to pollute the human body, and the human health is seriously harmed due to the characteristics of easy accumulation, irreversibility, high toxicity, slow metabolism, easy enrichment and the like. The zero-valent iron has low price and is environment-friendly, so that the reduction and fixation of heavy metals and the dechlorination/denitrogenation of chlorine/nitro compounds can be realized, and the method is further widely applied to the treatment of polluted underground water.

However, the surface of the zero-valent iron is easily oxidized, and the surface is covered with a layer of iron oxide, and the iron oxide can block the release of electrons in the zero-valent iron, thereby causing the activity of the zero-valent iron to be reduced. Even if the activity of the zero-valent iron is improved by removing (partially) the shell layer on the surface of the zero-valent iron by adopting acid washing, reducing agent reduction, ultrasonic stripping and other modes, the iron oxide is inevitably formed again in the reaction process, so the activity of the zero-valent iron cannot be improved fundamentally. In addition, the hydroxyl groups on the surface of the oxide layer can affect the adsorption of the pollutants, because the hydroxyl groups have hydrophilicity and can reduce the adsorption capacity of the pollutants.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a method for efficiently removing pollutants based on borated zero-valent iron by changing the surface functional group of the zero-valent iron to improve the activity of removing the pollutants.

The technical scheme adopted by the invention for solving the problems is as follows:

borated zero-valent iron in which the hydroxyl groups on the surface of zero-valent iron are substituted by-OB (OH)₂Group-substituted zero-valent iron.

A borated zero-valent iron is used for removing pollutants by high-efficiency reduction, the borated zero-valent iron is added into an aqueous solution of the pollutants to carry out the activity removal of the pollutants; the borated zero-valent iron is obtained by reacting-OB (OH) with hydroxyl groups on the surface of zero-valent iron₂Group-substituted zero-valent iron.

According to the scheme, the borated zero-valent iron is prepared by boric acid and zero-valent iron through a ball milling method.

According to the scheme, the molar ratio of the boric acid added in the ball milling process is 0.05-10.0 percent of zero-valent iron, and the optimal molar ratio is 1-8 percent.

According to the scheme, the ball milling time is as follows: 2-10h, and the rotation speed is 200-. After ball milling, boric acid and zero-valent iron are washed by alcohol and dried in vacuum.

According to the scheme, the zero-valent iron is micron-sized zero-valent iron.

According to the scheme, the purity of the zero-valent iron reaches 90%, and the purity of the boric acid is above the industrial level.

According to the scheme, the using amount of the borated zero-valent iron is 1-5 g/L.

According to the scheme, the concentration of the pollutants is 2-10ppm, the reaction temperature is 0-50 ℃, and the reaction pH is 3-10.

In the above scheme, the contaminants include, but are not limited to, chromium, nickel, lead, 4-chlorophenol, nitrobenzene, and the like.

According to the scheme, the pollutant removing process adopts a shaking table oscillation mode.

The technical principle of the invention is as follows:

the iron oxide surface on the zero-valent iron surface is covered with a layer of hydroxyl, which is not beneficial to adsorbing and removing pollutants, and the activity of the zero-valent iron is reduced. According to the invention, environment-friendly boric acid is selected as a modifier for the surface of the zero-valent iron, and the borated zero-valent iron is prepared by adopting a simple ball milling method. From the infrared characterization (fig. 1a), the infrared of borated zero valent iron presents new peaks relative to the peak of the boronic acid molecule: 1335, 1000, and 925cm^-1Respectively represent a B-O asymmetric expansion joint, a B-O-H in-plane expansion vibration peak and a B-O vibration peak. And at 1150, 1130cm^-1The peak at (b) is increased, indicating that the coordination environment around the boronic acid is changed, thereby decreasing the symmetry of the boronic acid. Boric acid reacts with hydroxyl groups on the iron surface, loses one molecule of water, and is bonded to the zero-valent iron surface in a three-coordinate form (fig. 1 b). The boration can accelerate the corrosion of the zero-valent iron and promote the outward transfer of electrons of the zero-valent iron (figure 2), thereby promoting the removal of the pollutants.

The invention has the advantages that:

1. the method for preparing the borated zero-valent iron by the borated modified zero-valent iron ball milling method is simple and easy to operate.

2. The zero-valent iron has low price, low boric acid consumption and low cost, and can be widely applied to the treatment of actual pollutants.

3. The borated modified zero-valent iron provided by the invention has better reduction removal capability on different heavy metal ions, organic pollutants and the like.

Drawings

FIG. 1 is an infrared diagram (a) and a mechanism diagram (b) of ball-milling borated zero-valent iron;

FIG. 2 Tafel plot of borated zero valent iron;

FIG. 3 is a graph showing the effects of ball milling for preparing borated zero-valent iron and treating hexavalent chromium in polluted water in example 1;

FIG. 4 is a graph showing the effects of ball milling for preparing borated zero-valent iron and treating nickel in a polluted water body in example 2;

FIG. 5 is a diagram showing the effects of ball milling for preparing borated zero-valent iron and treating lead in polluted water in example 3;

FIG. 6 is a graph showing the effects of ball milling for preparing borated zero-valent iron and treating 4-chlorophenol in polluted water in example 4;

FIG. 7 is a graph showing the effects of ball milling for preparing borated zero-valent iron and treating nitrobenzene in polluted water in example 5.

Detailed Description

The following detailed description of the present invention is provided by way of specific embodiments, which are provided for illustration purposes and are not intended to limit the invention.