CN-122010055-A - Method for preparing calcium peroxide by using oyster shells and application thereof

Abstract

The invention discloses a method for preparing calcium peroxide by utilizing oyster shells and application thereof, and belongs to the technical field of oyster shell recycling. The method comprises the steps of 1) cleaning oyster shells, sun-drying and grinding the oyster shells into powder, 2) dissolving the oyster shell powder by hydrochloric acid, adjusting the pH value of a reaction solution to be alkaline by sodium hydroxide, then adding ammonia water and slowly dripping H 2 O 2 , 3) filtering after dripping, and drying a solid product to obtain CaO 2 . Compared with CaO 2 and commercial CaO 2 prepared by the traditional preparation method using calcium chloride as a substrate, the method for preparing CaO 2 has a longer H 2 O 2 release period, the purity of CaO 2 prepared by the method is higher and can reach more than 80%, the purity of commercial CaO 2 is 65-75%, and the specific surface area of CaO 2 prepared by the method is far lower than that of commercial CaO 2 . In addition, the invention adopts cheap and easily available initial raw materials, the synthesis process is environment-friendly, the operation is simple and convenient, the product purity is high, the process is stable, and the method is suitable for industrial production.

Inventors

• LIU XIAOTIAN
• LIAO YONGKAI
• CAO HONGJIAN
• CAI CHAO

Assignees

• 中国科学院城市环境研究所

Dates

Publication Date

20260512

Application Date

20260120

Claims (9)

1. 1. A method for preparing calcium peroxide by using oyster shells, which is characterized by comprising the following steps: 1) Washing oyster shells, sun-drying, crushing, and sieving to obtain oyster shell powder with the particle size of 50-150 mu m; 2) Placing the oyster shell powder prepared in the step 1) into a beaker, slowly adding hydrochloric acid solution, and continuously stirring until no bubbles exist, so as to prepare acidolysis solution; 3) Adjusting the pH value of the acidolysis solution prepared in the step 2) to be alkaline by using a sodium hydroxide solution, and filtering to remove solid impurities to obtain filtrate; 4) Adding 30mL of ammonia water into the filtrate prepared in the step 3) at room temperature, stirring and mixing uniformly, slowly dropwise adding 30mL of hydrogen peroxide solution, continuously stirring, immediately filtering after dropwise adding, completing solid-liquid separation, and drying and grinding a solid product to obtain calcium peroxide; In the step 3), the concentration of the sodium hydroxide is 1.0mol/L; In the step 4), the concentration of the ammonia water is 25% -28%, and the concentration of the hydrogen peroxide is 15% -30%; In the step 4), the drying temperature is 80-100 ℃.
2. 2. The method for preparing calcium peroxide by using oyster shell according to claim 1, wherein the concentration of the hydrochloric acid solution is 3-5 mol/L.
3. 3. The method for preparing calcium peroxide by utilizing oyster shell according to claim 1, wherein the solid-to-liquid ratio of oyster shell powder to hydrochloric acid solution is 1:4-10 g/mL.
4. 4. The method for preparing calcium peroxide by using oyster shell according to claim 1, wherein the alkaline pH value is 11-12.
5. 5. A calcium peroxide prepared by the method of claim 1.
6. 6. Use of the calcium peroxide of claim 5 in the field of environmental protection, wherein the calcium peroxide of claim 5 and the citric acid-Fe 2+ are used to construct a Fenton-like system to generate hydroxyl radicals for degrading organic pollutants in soil and water.
7. 7. The use according to claim 6, wherein the organic contaminant in the use is phenanthrene.
8. 8. The use according to claim 6, wherein the molar ratio of calcium peroxide, citric acid and Fe 2+ is 2:1:1.
9. 9. The use according to claim 6, wherein Fe 2+ is ferrous sulfate or ferrous chloride.

Description

Method for preparing calcium peroxide by using oyster shells and application thereof Technical Field The invention belongs to the technical field of environmental protection, and particularly relates to a method for preparing calcium peroxide by using oyster shells and application thereof. Background Oyster is the first big shellfish in the world and is also the most important marine economic shellfish in China. At present, oyster meat is mainly utilized in oyster production and processing, but the inedible part oyster shells accounting for more than 60% of the mass of the inedible part oyster shells are not effectively utilized, and most oyster shells are discarded as solid garbage and are accumulated on the beach and other places. However, the residual meat and juice in the waste oyster shells and the like can be spoiled, and the mosquitoes and flies can be bred to generate toxic substances and harmful gases, so that the land and marine environment are directly or indirectly seriously polluted. Therefore, development of oyster shell high-value utilization technology, improvement of resource utilization efficiency and additional value, reduction of environmental pollution, and the like have become key problems to be solved in the fields of environmental protection and resource recycling. Oyster shell is composed of inorganic matter, protein and polysaccharide, and has a highly ordered multiple microlayer structure. The main inorganic substance in the oyster shell is calcium carbonate (CaCO 3) which accounts for more than 90% of the oyster shell by mass. In recent years, oyster shells are widely studied to prepare calcium-based environmental functional materials by using the oyster shells as raw materials because of the abundant calcium elements, and the oyster shells are applied to the fields of water quality purification, soil improvement and the like. Calcium peroxide (CaO 2) is white or yellow crystal powder, is odorless and tasteless, is nontoxic and harmless, and has wide application in various fields. CaO 2 has good application prospect in environmental pollution restoration due to the characteristics of controllable O 2 and H 2O2 release capability, thermal stability, no pollution of reaction products and the like. Furthermore, the reaction of CaO 2 with H 2 O directly releases H 2O2 and is considered solid H 2O2. Recent researches show that compared with the traditional hydrogen peroxide, caO 2 serving as a source of H 2O2 and Fe 2+ can continuously generate free radicals with strong oxidability, so that the degradation efficiency of organic pollutants is remarkably improved, and the method becomes a research hot spot in the field of environmental pollution restoration. Currently, three general methods for synthesizing calcium peroxide include a calcium salt method, a calcium oxide method and a calcium hydroxide method. The principle is that calcium sources (calcium chloride, calcium oxide, calcium hydroxide and the like) are reacted with H 2O2 to prepare CaO 2. However, nCaO 2 prepared by the existing method at home and abroad has the characteristics of small particle size, large specific surface area and the like, so that the reaction rate of CaO 2 and H 2 O is high, the slow release of H 2O2 is difficult to last, and the stable and long-term repairing effect is difficult to obtain in the practical environmental pollution repairing engineering. Therefore, how to use oyster shells as a calcium source to prepare CaO 2 with long-acting H 2O2 relieving performance, improve the added value and protect the environment is a technical problem which needs to be solved by the technicians in the field. Disclosure of Invention The invention aims to provide a method for preparing calcium peroxide by utilizing oyster shells and application thereof. In order to achieve the above object, the technical scheme of the present invention is as follows: A method for preparing calcium peroxide by using oyster shells comprises the following steps in sequence: 1) Washing oyster shells, sun-drying, crushing, and sieving to obtain oyster shell powder with the particle size of 50-150 mu m; 2) Placing the oyster shell powder prepared in the step 1) into a beaker, slowly adding hydrochloric acid solution, and continuously stirring until no bubbles exist, so as to prepare acidolysis solution; 3) Adjusting the pH value of the acidolysis solution prepared in the step 2) to be alkaline by using a sodium hydroxide solution, and filtering to remove solid impurities to obtain filtrate; 4) And 3) adding 30mL of ammonia water into the filtrate obtained in the step 3) at room temperature, stirring and mixing uniformly, slowly dropwise adding 30mL of hydrogen peroxide solution, continuously stirring, immediately filtering after the dropwise adding is finished, completing solid-liquid separation, and drying and grinding a solid product to obtain the calcium peroxide. Preferably, in the step 2), the concentration of the hydrochloric acid