CN-118908236-B - Method for preparing activated zeolite without harmful heavy metal

CN118908236BCN 118908236 BCN118908236 BCN 118908236BCN-118908236-B

Abstract

The invention discloses a method for preparing harmless heavy metal activated zeolite, which comprises the following specific operation steps of S1, selecting alkali modified and dredged natural zeolite, preparing a solution with the natural zeolite, wherein the solid content of the prepared solution is 1-50%, regulating the pH value of the solution system to be 12.5-13.5 by using alkali, and stirring. S2, stirring the solution, adding phosphoric acid to maintain the pH value of the solution to be 5.0-8.5 for reaction, repeatedly cleaning the solution after the reaction until the pH value of the cleaning solution is neutral, and separating the modified natural zeolite from the solution. S3, preparing the modified natural zeolite into a solution, wherein the solid content of the modified natural zeolite in the solution is 1% -50%, dissolving ferrous salt in hydrochloric acid to prepare the solution, adding hydroxylamine hydrochloride, and mixing the modified natural zeolite solution with the ferrous salt, the hydrochloric acid and the hydroxylamine hydrochloride solution. According to the invention, the alkali solution is adopted to modify the natural zeolite, so that the alkali solution not only effectively dredges the pore channels of the natural zeolite and improves the specific surface area of the natural zeolite, but also obviously reduces the aluminum dissolution of the natural zeolite in a gastric acid simulating solution system.

Inventors

LI JIAJUN
ZHANG PING
ZHANG YING
ZHANG XUELING
ZENG XUELIANG

Assignees

杭州南峰药业有限公司

Dates

Publication Date: 20260508
Application Date: 20240429
Priority Date: 20240220

Claims (7)

1. A method for preparing harmless heavy metal activated zeolite is characterized by comprising the following specific operation steps: S1, selecting alkali modified and dredged natural zeolite, preparing a solution with the natural zeolite, wherein the solid content of the prepared solution is 1-50%, regulating the pH value of the solution system to be 12.5-13.5 by using alkali, and stirring; s2, stirring the solution, adding phosphoric acid to maintain the pH value of the solution to be 5.0-8.5 for reaction, repeatedly cleaning the solution until the pH value of the cleaning solution is neutral after the reaction, separating the modified natural zeolite from the solution, and adding an oxidant into the solution collected after the separation; S3, preparing a solution by using the obtained modified natural zeolite, wherein the solid content of the modified natural zeolite in the solution is 1% -50%, dissolving ferrous salt in hydrochloric acid to prepare the solution, adding hydroxylamine hydrochloride, mixing the modified natural zeolite solution with the ferrous salt, the hydrochloric acid and the hydroxylamine hydrochloride solution, and regulating the pH value of the solution to 2.5-4 by using acetic acid for reacting for a period of time; s4, adding a complexing agent into the mixed solution obtained in the step S3, regulating the pH value of the solution to be between 1.0 and 4.0 by using acetic acid, stirring and reacting for a period of time, separating the modified natural zeolite from the solution, and repeatedly cleaning until the pH value of the cleaning solution is neutral and separating again; S5, after the modified natural zeolite in the step S4 is separated from the solution, mixing and stirring the obtained solution with the solution added with the oxidant in the step S2 for reaction, and adding alkali liquor to separate harmful heavy metal precipitate from the solution; S6, preparing the modified heavy metal-free natural zeolite into a solution, wherein the solid content is 1-50%, adding calcium ions, iron ions and zinc ions to modify the heavy metal-free natural zeolite, finally separating the modified natural zeolite from the solution, repeatedly cleaning until the pH value of the cleaning solution is neutral, separating again, drying the obtained modified heavy metal-free natural zeolite at 110 ℃, and activating and modifying at 350-550 ℃ to obtain the activated heavy metal-free natural zeolite.
2. A process for producing a heavy metal-free activated zeolite according to claim 1, wherein the alkali used in step S1 is sodium hydroxide, potassium hydroxide or ammonia.
3. The method for producing a heavy metal-free activated zeolite according to claim 1, wherein the separation in the steps S2 and S4 is a filtration separation by standing natural precipitation for 6 to 24 hours or a filtration separation by centrifugation.
4. The method for producing a harmless heavy metal-activated zeolite according to claim 3, wherein the oxidizing agent in the step S5 is one or more of hydrogen peroxide, sodium percarbonate, ozone, sodium hypochlorite and potassium nitrate.
5. The method for producing activated zeolite by heavy metal ion-free reaction according to claim 4, wherein the molar mass ratio of ferrous ions to hydroxylamine hydrochloride in the step S3 is 10:1 to 100:1, and the mass ratio of modified natural zeolite to ferrous ions in the mixture of modified natural zeolite solution, ferrous salt and hydroxylamine hydrochloride is 5:1 to 100:1.
6. The method for producing a heavy metal activated zeolite according to claim 4, wherein the complexing agent in S4 is a chelating agent, and the mass ratio of the modified natural zeolite to the chelating agent is 10:1-200:1.
7. A method of making a non-hazardous heavy metal activated zeolite according to claim 6 wherein said chelating agent comprises citric acid, ethylenediamine tetraacetic acid, disodium ethylenediamine tetraacetic acid, diethylenetriamine pentaacetic acid and diethylenetriacetic acid, organic acids and phytic acid.

Description

Method for preparing activated zeolite without harmful heavy metal Technical Field The invention relates to the technical field of zeolite treatment methods, in particular to a method for manufacturing harmless heavy metal activated zeolite. Background According to incomplete statistics, natural zeolite deposits in nearly 400 places in China have been found, the total reserve is about 30 parts per million (UBt), the natural zeolite is various, more than 80 different types of zeolite exist in nature, the different types of zeolite have different characteristics and applications, the natural zeolite is acid-resistant and alkali-resistant, has excellent stability, ion exchange, hemostasis performance and harmful substance adsorption performance, and the natural zeolite is widely applied to the fields of sewage treatment, soil improvement, air purification, ion exchange materials, catalysts, animal feeds, cosmetics, medical appliances and the like. The zeolite is used as feed additive, and can improve activity of partial enzyme in animal body, improve oxidation resistance, reduce harmful substances such as aflatoxin and heavy metal, reduce nitrate burden, reduce ammonia in feces, and be beneficial to colon microbiota and epithelial cells. In addition, the zeolite also has a nutritive value, and the addition of 5% of zeolite powder in the feed can accelerate the growth of livestock, strengthen the body, fresh meat and high laying rate. The zeolite is acid-resistant and alkali-resistant, has excellent stability, ion exchange and hemostatic properties and the function of adsorbing harmful substances, and is added into the gastrointestinal tract of animals when the feed is fed, harmful heavy metals such as lead, mercury, cadmium, radioactive elements such as cesium, radium and strontium can be captured and fixed in zeolite pore structures by the zeolite and discharged along with excrement, and the harmful heavy metals in the gastrointestinal tract of the animals can be removed when the zeolite is added into the feed, so that the animals are healthier. However, zeolite is not modified, aluminum dissolution under gastric acid condition is present to increase animal aluminum intake to produce adverse effect, and excellent ion exchange performance of zeolite can even adsorb beneficial elements (such as calcium, iron and zinc) in animal body to excrete them out of human body, so that daily intake of beneficial elements required by animal is insufficient to affect animal health. At present, only the determination value of arsenic in zeolite is specified in the feed sanitation standard in China, other harmful heavy metals are not specified in the determination value, and the zeolite as a feed additive has the harmful heavy metals (lead, mercury, cadmium and the like) which are not specified in the determination value, so that other harmful heavy metals in the feed are possibly higher, and the quality of the feed is possibly influenced. In addition, zeolite is added as a raw material in cosmetics, can effectively adsorb many harmful substances in human skin, and has excellent skin cleaning effect and is widely used. According to the requirements of the national safety technical Specification of cosmetics, the relevant limit standards of harmful heavy metals in cosmetics are lead less than or equal to 10mg/kg, mercury less than or equal to 1mg/kg, arsenic less than or equal to 2mg/kg and cadmium less than or equal to 5mg/kg. However, zeolite is used as a raw material of cosmetics, harmful heavy metals (lead, arsenic, mercury and cadmium) are not specified to be determined, and if the content of the harmful heavy metals is high, the quality of the cosmetics is affected. Along with the improvement of the living standard of people, the zeolite is used as a feed additive and a raw material of cosmetics, and the content limit of harmful substances can gradually increase the requirements. Therefore, the technology for removing harmful heavy metals in zeolite has great social value. Many studies in the early days were based on the treatment (adsorption) of heavy metal contaminated sewage or soil using zeolite, and there are some documents reporting the removal of heavy metal contaminated soil by leaching method using complexing agent or chelating agent, and a few documents reporting the removal of arsenic from wastewater using modified zeolite. No literature reports a method for thoroughly removing harmful heavy metals such as lead, arsenic, mercury and cadmium in natural zeolite, and a method for solving the problem that aluminum in zeolite dissolves out under the condition of gastric acid and inhibiting or reducing the absorption of beneficial elements (such as calcium, iron and zinc) from being excreted outside the body. The zeolite is aluminosilicate, the natural zeolite has complex components, and a great deal of researches show that the content of harmful heavy metals such as lead, arsenic, mercury and cadmium is high, and t