Method for preparing catalyst from rubber sludge and application

Abstract

The invention discloses a method for preparing a catalyst from rubber sludge, which specifically comprises the following steps: crushing and sieving dried rubber sludge, mixing with KOH, activating for 1 hour at 850-950 DEG C in a nitrogen atmosphere, putting an activated product into boiling water, stirring for 0.5-1 hour, carrying out solid-liquid separation, washing and drying the solid, carrying out acid pickling on the dried product by using a hydrochloric acid solution, and carrying out solid-liquid separation to obtain the catalyst. Washing, drying and grinding the solid to obtain a catalyst; the catalyst prepared by the method has the advantages of multiple reaction active sites, good catalytic performance, high specific surface area, stable structure and the like, can be used for activating persulfate to degrade antibiotics, and has good application value and application prospect; meanwhile, the preparation method disclosed by the invention also has the advantages of simple process, convenience in operation, easiness in obtaining raw materials, low cost and easiness in realizing industrial production, and has a relatively great application prospect in the field of environmental catalysis.

Description

Technical Field

[0001] The invention belongs to the technical field of material preparation and environmental catalysis, and particularly relates to a method for preparing a catalyst by utilizing rubber sludge and application of the catalyst in treating antibiotic wastewater. Background Art

[0002] Advanced oxidation processes (AOPs) based on persulfate (PMS) have attracted increasing attention in the field of organic matter degradation due to their high redox potential and long half-life. Their high degradation efficiency can be attributed to the generation of a large number of active species in the system, such as ·OH, SO4· - 、O2· - and 1 O2, etc. SO4 - (OPR: 2.5-3.1eV) has higher oxidation capacity, higher oxidation selectivity and wider pH range compared with ·OH (ORP: 1.8-2.7eV), which has attracted extensive attention from researchers. Fe is the second most abundant metal element in nature, and has the characteristics of low toxicity, natural friendliness, storability and easy availability. 2+ / Fe 3+ The method of activating PMS to produce activity by electron circulation has been widely used in the degradation of refractory organic pollutants in wastewater. However, during the catalytic degradation process, Fe is easy to aggregate due to its high surface free energy, resulting in low metal atom utilization and few catalytic active sites. In recent years, carbon-based materials rich in defects and heteroatoms have a large number of bond structures and coordination, which can strongly anchor metal atoms and effectively solve the problem that metal atoms are easy to aggregate due to high surface free energy. They have been widely studied. Phosphorus (P) is a non-metallic element with a large atomic size and high electron donating ability. The presence of P atoms can reconstruct the electronic structure, accelerate the transmission speed of electrons, and is conducive to accelerating the catalytic process of magnetic catalysts. Therefore, the design of defect-rich carbon-based materials anchoring Fe-based catalysts using P with high electron donating ability has good development prospects in oxygen reduction reactions. Industrial solid waste contains rich organic and inorganic active components, some of which can serve as adsorption centers or catalytic activity, so that solid waste shows good catalytic activity.

[0003] The planting and processing industries of natural rubber have been fully developed in Yunnan. Despite this, the phosphorus content in natural rubber processing wastewater (10 million tons / year) generally exceeds the standard, which will not only have a significant impact on the ecological environment, but will also seriously restrict the sustainable development of the natural rubber industry. After adsorption, flocculation and sedimentation of natural rubber processing wastewater, organic pollutants and phosphorus-containing waste adsorbents in the rubber wastewater are discharged in the form of sludge, which will still pollute the environment if not properly handled. At present, the main method of managing rubber sludge is incineration, which occupies a large amount of land and causes environmental pollution, resulting in a low overall utilization rate of rubber sludge.

[0004] At present, there is no report on using rubber sludge to prepare catalysts and use them to treat wastewater containing organic matter. Summary of the invention

[0005] The present invention provides a method for preparing a catalyst by utilizing rubber sludge and the use of the catalyst in treating wastewater with organic pollutants. The catalyst prepared by the present invention has the advantages of high specific surface area, multiple reaction active sites, good catalytic performance, high metal atom utilization rate, stable structure, etc. Meanwhile, the preparation method of the present invention has simple process, convenient operation, easy-to-obtain raw materials, low cost, easy to realize industrial production, and has great application prospects in the field of environmental catalysis.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions: 1. Dry the rubber sludge at a constant temperature of 55-65℃ for 36-48h, ball mill for 2-3h, and then pass through a 180-mesh sieve to obtain rubber sludge powder (RS); 2. Grind and mix rubber sludge powder and KOH in a mortar, with the mass ratio of rubber sludge to KOH being 1:0.8-1.2, pour the mixture into a crucible, place the crucible in a tube furnace in a nitrogen atmosphere, calcine at 850-950°C for 1 hour, place the calcined product in boiling water and stir for 0.5-1 hour, separate the solid and liquid, and wash and dry the solid; The washing is carried out with water or anhydrous ethanol, and the number of washing times is 3 to 5 times; 3. Evenly mix the hydrochloric acid solution and the dried product of step 2, stir the mixture for 25-35 minutes, separate the reaction product into solid and liquid, wash, dry and grind the solid to obtain the catalyst, wherein the pH of the hydrochloric acid solution is 4.5-5.5, and the mass volume ratio of the dried product to the hydrochloric acid solution is 1:18-20 (g:mL).

[0007] The washing is carried out with water or anhydrous ethanol, and the number of washing times is 3 to 5 times; 4. Use catalysts to degrade antibiotics in water bodies. Specifically, the catalyst is mixed with antibiotic wastewater, stirred, and persulfate is added to perform a catalytic degradation reaction to complete the degradation of antibiotics in the water body.

[0008] The mass volume ratio of the catalyst to the antibiotic (tetracycline hydrochloride) wastewater is 10mg-40mg:40mL; the concentration of persulfate in the reaction system is 0.2mmol / L-3mmol / L; the persulfate is potassium peroxymonosulfate; and the concentration of tetracycline hydrochloride is 10mg / L-40mg / L.

[0009] Compared with the prior art, the present invention has the following advantages: (1) The present invention uses industrial rubber sludge as raw material, specifically regulates the defect density in the carbon-based catalyst, and adopts a KOH pyrolysis-assisted synthesis strategy to prepare a catalyst with the advantages of high specific surface area, multiple reaction active sites, high metal atom utilization, stable structure, and rich intrinsic defects. The preparation method is simple to operate, has a high yield, can significantly increase the specific surface area of ​​the catalyst, improve the catalytic efficiency of the catalyst, and promote the generation of lattice defects. At the same time, the preparation method of the present invention also has the advantages of simple process, convenient operation, easy availability of raw materials, low cost, easy to realize industrial production, and has great application prospects, especially in the field of environmental catalysis. (2) The present invention adopts simple calcination and utilizes phosphorus in rubber sludge to design a carbon-based single-atom Fe catalyst rich in defect sites, which can adjust the surface electronic configuration, have good electron storage and transmission capabilities, promote Fe circulation, thereby promoting PMS activity and improving the catalytic efficiency of the catalyst; (3) The catalyst prepared by the present invention can be mixed with tetracycline hydrochloride wastewater to achieve effective degradation of organic pollutants under constant temperature oscillation conditions, which has the advantages of simple process, convenient operation, low cost, high treatment efficiency, and good degradation effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is the XRD pattern of rubber sludge RS; Figure 2 is the XRD pattern of the catalyst RSFP of Example 1; Figure 3 is the SEM image of rubber sludge RS; Figure 4 is the SEM image of catalyst RSFP; Figure 5 It is a time-degradation efficiency diagram when the catalyst degrades tetracycline hydrochloride solution under oscillation conditions in Example 1 and Comparative Examples 1-2; Figure 6 It is a fitting diagram of the degradation rate constant when the catalyst in Example 1 and Comparative Examples 1-2 degrades tetracycline hydrochloride under oscillating conditions. DETAILED DESCRIPTION

[0011] The content of the present invention is further explained by the following examples, but these examples do not limit the protection scope of the present invention. The methods in the embodiments are conventional methods unless otherwise specified, and the reagents used are conventional reagents sold on the market unless otherwise specified; The rubber sludge in the embodiment comes from Xishuangbanna Jingyang Co., Ltd. of Yunnan Natural Rubber Industry Group; Example 1: Preparation of a catalyst with high efficiency persulfate activation using rubber sludge 1. Dry the rubber sludge at 60℃ for 36-48h, ball mill for 2-3h and pass through 180 mesh sieve to obtain rubber sludge powder. The XRD pattern of the sieved rubber sludge is shown in Figure 1 From the figure, it can be seen that the physical phase shows amorphous. The SEM picture of the sieved rubber sludge is shown in Figure 3 , it can be seen from the figure that it is a solid block; 2. Put 3g of rubber sludge powder and 3g of KOH into a mortar and grind for 0.5h to obtain a uniform mixed powder, put it into a corundum crucible, place it in a tube furnace under nitrogen protection, heat it to 900℃ at a heating rate of 5℃ / min, and keep it at 900℃ for 1h. After natural cooling, take it out, stir it with boiling water for 1h, filter, wash the solid with water for 5 times, and dry it at 60℃ overnight to obtain a precursor. Mix the precursor with a hydrochloric acid solution with a pH of 4.95 (1:20), stir for 0.5-1h, filter, wash the solid with water for 5 times, and dry it at 60℃ for 5h to obtain the catalyst RSFP. The XRD pattern of the catalyst RSFP is shown in Figure 2 From the figure, it can be seen that the catalyst phase is amorphous. The SEM image of the catalyst RSFP is shown in Figure 4 , it can be seen from the figure that the catalyst is a fluffy block structure.

[0012] Comparative Example 1: Preparation of calcined rubber sludge catalyst 3 g of rubber sludge was put into a crucible, placed in a tubular furnace, heated to 900 °C at a heating rate of 5 °C / min, and kept at 900 °C for 1 h. After natural cooling, it was taken out to obtain a black powder sample, which was calcined rubber sludge and named RSFP-1.

[0013] Comparative Example 2: Preparation of rubber sludge without hydrochloric acid pickling Take 3g of rubber sludge and 3g of KOH and put them into a mortar and grind them for 0.5h to obtain a uniform mixed powder. Put it into a corundum crucible and place it in a tubular furnace under nitrogen protection. Heat it to 900℃ at a heating rate of 5℃ / min and keep it at 900℃ for 1h. After natural cooling, take it out, put it into boiling water and stir it for 0.5-1h, filter it, wash the solid with water 5 times, and dry it at 60℃ overnight to obtain catalyst RSFP-2.

[0014] Example 2: Application of the catalysts in Example 1 and Comparative Examples 1-2 in treating antibiotic wastewater The catalyst RSFP of Example 1, the catalyst RSFP-1 of Comparative Example 1, and the catalyst RSFP-2 of Comparative Example 2 were weighed, 30 mg each, and placed in 40 mL of a 20 mg / L tetracycline hydrochloride solution, respectively. They were first adsorbed for 30 min, and then 6.1 mg of potassium hydrogen sulfate was added to the tetracycline hydrochloride solution to carry out a catalytic degradation reaction. During the persulfate activation reaction, 3 mL of the tetracycline hydrochloride solution was taken at 5 min, 10 min, 15 min, and 20 min, respectively. The absorbance value of tetracycline hydrochloride in the solution was measured by a spectrophotometer, and the degradation efficiency of the tetracycline hydrochloride solution of different catalysts under different time conditions was calculated.

[0015] Results Figure 5 ,It can be seen from the figure that the RSFP catalyst of Example 1 exhibits the best catalytic activity, and its degradation rate reaches 100%, indicating that RSFP has the ability to efficiently activate PMS and produce a large amount of active oxygen.

[0016] The degradation rate constant fitting results are shown in Figure 6 ,It can be seen from the figure that the rate of catalyst RSFP is dozens of times that of other catalysts, indicating that the catalytic performance of catalyst RSFP is excellent.

[0017] The above embodiments are only preferred implementations of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A method for preparing a catalyst from rubber sludge, characterized in that: The dried rubber sludge is crushed and sieved, mixed with KOH, activated in a nitrogen atmosphere at 850-950°C for 1 hour, and the activated product is placed in boiling water and stirred for 0.5-1 hour, the solid-liquid separation is performed, the solid is washed and dried, the dried product is acid-washed with a hydrochloric acid solution, the solid-liquid separation is performed, the solid is washed, dried, and ground to obtain a catalyst.

2. The method for preparing a catalyst from rubber sludge according to claim 1, characterized in that: The mass ratio of rubber sludge to KOH is 1:0.8-1.2, and the pH of the hydrochloric acid solution is 4.5-5.

5.

3. A catalyst obtained by the method for preparing a catalyst from rubber sludge according to any one of claims 1 to 2.

4. Use of the catalyst according to claim 3 in treating tetracycline hydrochloride wastewater.

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