CN108079937B

CN108079937B - Adsorbent based on waste coal gangue and preparation method and application thereof

Info

Publication number: CN108079937B
Application number: CN201810075110.2A
Authority: CN
Inventors: 包红旭; 张欣; 张�浩; 杨华; 苏弘治; 张馨月; 吕志忠; 李良玉; 黄颖芝; 刘唯玉; 杨雨萌; 陈阳
Original assignee: Liaoning University
Current assignee: Liaoning University
Priority date: 2018-01-26
Filing date: 2018-01-26
Publication date: 2020-07-14
Anticipated expiration: 2038-01-26
Also published as: CN108079937A

Abstract

The invention relates to an adsorbent based on waste coal gangue and a preparation method and application thereof, belonging to the field of resource utilization of solid waste. The method comprises the steps of drying and crushing coal gangue discharged in the coal mining process and the coal washing process, mixing the dried and crushed coal gangue with potassium carbonate in a mass ratio of 5:1, adding water, drying, calcining at 600 ℃ for 40min, heating to 850 ℃, and calcining for 50min to obtain the Zn-containing coal gangue treated based on the waste coal gangue²⁺A novel adsorbent for waste water. The invention applies the waste coal gangue to the Zn containing heavy metal²⁺In the treatment of the wastewater, the preparation is simple and convenient, the cost is low, and the removal efficiency can reach about 92 percent.

Description

Adsorbent based on waste coal gangue and preparation method and application thereof

Technical Field

The invention relates to a method for efficiently removing Zn in industrial wastewater based on waste coal gangue²⁺Belonging to the field of solid waste resource utilization.

Background

With the progress of the modernization level of industrial production in China, a large amount of domestic wastewater and industrial wastewater is increased, and heavy metal pollution is getting more and more serious. Due to their non-biodegradable nature, metal ions accumulate continuously, increasing in number along the food chain. Therefore, the toxic and side effects of the traditional Chinese medicine are more obvious in high-nutrition animals, and can cause nervous dysfunction, bone softening, stomach function failure and animal poisoning. How to remove heavy metals in wastewater efficiently is an urgent task at present.

The coal gangue is solid waste generated in the production and processing processes of coal, the annual emission amount is about 10 percent of the annual coal yield, 30 hundred million tons of coal are accumulated and stored at present, the occupied area is about 1.2 million hectares, and the coal gangue is one of the industrial solid waste with the largest emission amount in China at present. China's coal system still discharges nearly 1 million tons of coal gangue every year now. Along with the development of national economy, the total quantity of coal demand is continuously increased, the production quantity of coal gangue is also greatly increased, and the environmental pollution of the coal gangue becomes one of the most prominent environmental problems in the coal industry of China. The coal gangue is a natural resource for development and utilization, and the coal gangue must be fully recycled by means of technological progress, so that waste is changed into valuable, and the harm of the coal gangue to the environment is reduced.

The coal gangue is called low-grade humic acid, and the humic acid contains functional groups and bridge bonds and has excellent adsorption, exchange and complexation properties. The coal gangue has good adsorbability on pollutants in water, soil and atmosphere and good application prospect, and the research on the coal gangue as an adsorbent in the treatment of heavy metal wastewater is not deeply carried out at present, is in a test stage and is not mature, and a plurality of modification methods are complex. Therefore, an adsorbent with simple preparation process and low cost is researched.

Disclosure of Invention

One of the purposes of the invention is to provide a novel adsorbent prepared by fully utilizing waste coal gangue, aiming at the problem of low removal rate of heavy metal ions in the traditional sewage treatment, and by virtue of excellent adsorption, exchange and complexation properties of rich functional groups and bridge bonds in the coal gangue, the novel adsorbent can be used for treating Zn in industrial wastewater²⁺The adsorption is carried out, and other components (such as organic matters and inorganic salts) contained in the wastewater can react with the coal gangue, so that the removal rate of pollutants in the sewage is improved, and the industrial application prospect is good.

The invention also aims to provide a preparation method of the adsorbent based on the waste coal gangue.

The invention also aims to provide an adsorbent based on waste coal gangue for adsorbing Zn in industrial wastewater²⁺The use of (1).

The technical scheme adopted by the invention is as follows: an adsorbent based on waste coal gangue is prepared from coal gangue powder and potassium carbonate.

Preferably, the waste coal gangue powder-potassium carbonate ratio of the adsorbent based on waste coal gangue is 5:1 by mass ratio.

In the adsorbent based on the waste coal gangue, the coal gangue powder contains 53-60% of SiO by weight percentage₂，20～25％Al₂O₃，4～8％CaO，2～5％MgO，5～10％Fe₂O₃。

A preparation method of an adsorbent based on waste coal gangue comprises the following steps:

1) washing the coal gangue with distilled water for 2-3 times, removing impurities, putting the coal gangue into an oven, baking the coal gangue for 24 hours at 55 ℃, crushing the coal gangue, and sieving the crushed coal gangue with a 200-mesh sieve, wherein undersize products are coal gangue powder.

2) Adding a proper amount of water into coal gangue powder and potassium carbonate, uniformly mixing, and baking for 24 hours at 55 ℃.

3) And (4) putting the dried mixture into a muffle furnace for calcining to obtain the adsorbent.

Preferably, in the above preparation method of the adsorbent based on waste coal gangue, step 3), the dried mixture is placed in a muffle furnace, and is calcined for 40min at 600 ℃, and then is calcined for 50min at 850 ℃ to obtain the adsorbent.

The adsorbent based on waste coal gangue is used for removing Zn in industrial wastewater²⁺The use of (1). The method comprises the following steps: and (3) adjusting the pH value of the industrial wastewater to be 7-8, uniformly adding the adsorbent into the industrial wastewater according to the proportion of 2-2.5 kg per cubic meter, and stirring for reaction for 1.5-2 h.

The invention has the beneficial effects that:

1) the raw materials are wide in source and low in cost;

2) the raw materials used in the invention are solid wastes in coal mining industry, belong to resource recycling and are harmless to the environment.

3) The gangue adsorbent of the invention has simple preparation and obvious effect, and can treat Zn in industrial wastewater²⁺The removal rate of the catalyst is as high as about 92 percent, and the catalyst has good industrial prospect.

Drawings

FIG. 1 shows the addition of the adsorbent of the present invention in combination with Zn²⁺Adsorption rate is shown in the figure.

FIG. 2 shows the pH value of wastewater and Zn²⁺Adsorption rate is shown in the figure.

FIG. 3 is a graph showing the relationship between the stirring reaction time and the adsorption rate of heavy metal ions.

Detailed Description

The invention is further illustrated by the following specific examples, but is not limited thereto. Because the quality of the sewage and the adopted treatment process are different in various places, the pretreatment parameters can be correspondingly changed, and therefore, the key parameters in the invention can be properly adjusted on the premise of not departing from the essence of the invention and the scope of the appended claims.

Example 1

Coal gangue extracted from a coal mining area of Berkeley is taken, and the chemical components of the coal gangue are shown in Table 1. Washing with distilled water for 2-3 times, removing impurities, putting into an oven, and baking at 55 ℃ for 24h to dry. Crushing in a grinder, sieving with a 200-mesh sieve, and taking undersize products to obtain coal gangue powder for later use.

According to the mass ratio of 5:1, coal gangue powder and potassium carbonate solid are taken, a proper amount of water is added, the mixture is uniformly mixed, and the mixture is baked for 24 hours at the temperature of 55 ℃ to be dried; and putting the dried mixture into a muffle furnace, calcining for 40min at 600 ℃, heating to 850 ℃, and calcining for 50min to obtain the target product, namely the adsorbent based on the waste coal gangue.

TABLE 1

Composition (I)	SiO₂	Al₂O₃	CaO	MgO	Fe₂O₃	Na₂O+K₂O	Loss on ignition
								Ratio (%)	55	21	6	3	7	1.5	6.5

Example 2

(I) source of wastewater

The sewage comes from industrial production wastewater containing heavy metal ions in the zinc plant of the cucurbit island, the pH is 6.57, and Zn²⁺The concentration of (A) was 136.11 mg/L.

(II) adding amount of adsorbent for removing metal ions Zn²⁺Influence of (2)

The method comprises the following steps: 100ml of sewage was taken, 0.05g, 0.10g, 0.15g, 0.20g, 0.25g, 0.30g of the waste coal gangue-based adsorbent prepared in example 1 was added, respectively, reacted for 2 hours, and then Zn in the solution was measured²⁺The content of (a). The results are shown in FIG. 1.

As can be seen from the test results in FIG. 1, as the amount of the added adsorbent increases, it is added to Zn²⁺The adsorption rate of (A) is increased. Zn is added when the addition amount of the waste coal gangue-based adsorbent is 0.20g²⁺Better adsorption effect.

(III) removing metal ions Zn by pH pair of wastewater²⁺Influence of (2)

The method comprises the following steps: taking 100ml of sewage, respectively using dilute HCl and NaOH to adjust the pH values to 6, 7, 8, 9 and 10, adding 0.20g of the waste coal gangue-based adsorbent prepared in example 1, reacting for 2 hours, and then measuring Zn in the solution²⁺The content of (a). The results are shown in FIG. 2.

As can be seen from the results in FIG. 2, as the pH of the wastewater increases, the adsorbent based on the waste coal gangue is responsible for Zn²⁺The adsorption rate of (A) is increased. Has better adsorption effect in the range of pH 7-8 and can adsorb Zn²⁺The adsorption rate can reach 90.0-92.0%.

(IV) adsorption time for removing metal ions Zn²⁺Influence of (2)

The method comprises the following steps: taking 100ml of sewage, adjusting the pH value to 7, adding 0.20g of the adsorbent based on the waste coal gangue prepared in the example 1, reacting for 0.5h, 1.0h, 1.5h, 2.0h and 2.5h, and then measuring Zn in the solution²⁺The content of (a). The results are shown in FIG. 3.

As can be seen from the test results in FIG. 3, the adsorbent based on waste coal refuse is responsible for Zn with the increase of the adsorption time²The adsorption rate of (A) is increased. When the adsorption is carried out for 1.5 to 2.0 hours, Zn is treated²The adsorption rate of (b) was 92.1% of the maximum adsorption rate.

Through the screening of conditions, the optimal process conditions are as follows: adjusting the pH value of the industrial wastewater to be 7-8, uniformly adding an adsorbent into the industrial wastewater according to the proportion of 2-2.5 kg per cubic meter, stirring and reacting for 1.5-2 h, and allowing the gangue adsorbent to react with Zn²The adsorption rate of (b) was 92.1% of the maximum adsorption rate.

Claims

1. Adsorbent based on waste coal gangue for removing Zn in industrial wastewater²⁺The method is characterized by comprising the following steps: adjusting the pH of industrial wastewater to = 7-8, wherein Zn is contained in the industrial wastewater²⁺The preparation method of the adsorbent based on the waste coal gangue comprises the following steps of washing the coal gangue with distilled water for 2-3 times, removing impurities, putting the coal gangue into an oven, baking the coal gangue for 24 hours at 55 ℃, crushing the coal gangue, sieving the crushed coal gangue with a 200-mesh sieve, taking undersize as coal gangue powder, taking the coal gangue powder and potassium carbonate, adding appropriate amount of water, uniformly mixing the coal gangue powder and the potassium carbonate, baking the mixture for 24 hours at 55 ℃, putting the dried mixture into a muffle furnace, calcining the mixture for 40 minutes at 600 ℃, and then calcining the mixture for 50 minutes at 850 ℃ to obtain the adsorbent, wherein the coal gangue powder and the potassium carbonate are added according to the proportion of 100ml of industrial wastewater and 0.20g of the adsorbent based on the waste coal gangue, and the mass ratio is = 5: 1.

2. The method according to claim 1, wherein the gangue powder contains 53-60% SiO by weight₂，20～25% Al₂O₃，4～8%CaO，2～5%MgO，5～10%Fe₂O₃。