Method for efficiently removing heavy metals in grease by using ion exchange resin

Abstract

The invention belongs to the field of heavy metal pollution comprehensive treatment and food safety, and particularly relates to a method for efficiently removing heavy metal in grease, and extremely high remaining amount is kept. According to the method, the saturated solution containing dipotassium phosphate is used for pretreating the ion exchange resin, so that the capacity of the ion exchange resin for subsequently removing heavy metals in the grease is improved, meanwhile, the grease has extremely high remaining capacity, and the grease loss is reduced. According to the method for efficiently removing the iron ions in the grease, the removal effect of the heavy metal iron in the grease is mainly researched, and the result of the embodiment shows that after the grease is treated by the method for efficiently removing the iron ions in the grease, the content of the iron ions in the grease is lower than 15 ppm, the grease remaining amount can reach 98% or above, and the iron removal effect is remarkable. The method is expected to be used for removing other heavy metals in the grease, so that effective recycling of the waste grease is realized, and meanwhile, the method is simple to operate, low in site equipment investment, expected to be used for large-scale industrial production and wide in application prospect.

Description

Technical Field

[0001] The present invention belongs to the field of comprehensive treatment of heavy metal pollution and food safety, and particularly relates to a method for efficiently removing heavy metals from oils and fats by utilizing ion exchange resins. Background Art

[0002] In recent years, as people's living standards and consumption levels continue to improve, the amount of waste oil generated in my country's catering industry has also increased year by year. However, my country lacks specialized waste oil recycling agencies. A large amount of waste oil is taken away by unqualified individuals and eventually discarded or flows into the hands of farmers. Some oil is discharged into the sewer. These treatment methods will cause the toxic substances in the waste oil to slowly accumulate in livestock and the environment, eventually affecting people's health.

[0003] However, after being processed, waste oil and grease can not only reduce pollution to the environment, but also be reused to reduce people's energy consumption. The recycling and utilization of waste oil and grease mainly include feed processing, conversion into biodiesel, conversion into agricultural fertilizers, and production of detergents. In order to achieve the recycling and utilization of waste oil and grease, toxic substances in the waste oil and grease must be removed. One of the most harmful toxic substances in waste oil and grease is heavy metals. If the heavy metal content in the human body accumulates to a certain level, it will cause heavy metal poisoning, which has a serious impact on the human digestive system, circulatory system, nervous system, respiratory system, etc. At present, the technologies or methods for removing toxic substances, especially heavy metals, from waste oil and grease mainly include KTI technology, biological treatment method, advanced oxidation method, membrane separation method, adsorption method and electrochemical method. Among them, adsorption method is an effective and economical method. According to existing research and application examples, the adsorption method has significant advantages in treating heavy metals in waste grease. Factors affecting the adsorption effect include temperature, amount of adsorbent, adsorption time, initial concentration of heavy metal ions and pH value of the solution. The adsorption method can enrich and extract the target metal elements. At the same time, the adsorption method has broad application prospects in removing heavy metals from waste grease due to its simple operation, low cost, high efficiency and reusability.

[0004] In order to reduce the impact of waste oil on the environment and human health and realize the comprehensive utilization of energy, it is particularly important to find more effective oil treatment methods. The adsorption method has great advantages in oil treatment due to its low treatment cost. Summary of the Invention

[0005] The purpose of the present invention is to effectively reduce the heavy metal content in oils and fats to an extremely low level to meet food safety and environmental protection requirements. The method of the present invention can reuse waste oils and fats, thereby reducing pollution and improving energy utilization, and has certain guiding significance for industrial production.

[0006] In order to achieve the above objectives, the following technical solutions are proposed:

[0007] The present invention provides a method for efficiently removing heavy metals from oils and fats, comprising the following steps:

[0008] (1) Soak the ion exchange resin in deionized water for 24 h, and then dry it in an oven at 70°C;

[0009] (2) Take 1 g of the dried resin in step 1 and soak it in 10 mL of saturated potassium hydrogen phosphate solution for 30 min;

[0010] (3) Wash the resin soaked in step 2 with deionized water for 3-5 times, and dry the washed ion exchange resin in a 70°C oven for no more than 6 hours;

[0011] (4) 100 g of oil and grease were mixed with ion exchange resin in a ratio of ion exchange resin to oil = 1:100, and stirred in a magnetic stirrer for 40 min. The temperature of the magnetic stirrer was 50° C. and the stirring rate was not more than 400 rpm, preferably 200 rpm.

[0012] The beneficial effects of the present invention are:

[0013] (1) This method is highly efficient and can effectively reduce the heavy metal content in oils and fats to an extremely low level, meeting the requirements of food safety and environmental protection.

[0014] (2) This method has good selectivity for target metals while maintaining the quality and inventory of the original oil.

[0015] (3) This method is simple to operate, requires low investment in site equipment, and is expected to be put into large-scale production.

[0016] (4) Use saturated solution of dipotassium hydrogen phosphate to reduce wastewater treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a diagram illustrating the principle of removing iron ions from oils and fats;

[0018] Figure 2 The comparison of the removal effect of iron ions from oils and fats by different ion exchange resin pretreatment methods;

[0019] Figure 3 The figure compares the iron removal effects of different ion exchange resin treatment methods when the ratio of ion exchange resin to oil is 1:100. DETAILED DESCRIPTION

[0020] In order to further illustrate the present invention, the technical solutions provided by the present invention are described in detail below in conjunction with specific embodiments. The described embodiments are only some embodiments of the present invention and not all embodiments. It should be understood that the following specific implementation methods are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0021] Example 1

[0022] (1) Soak the ion exchange resin in deionized water for 24 h, and then dry it in an oven at 70°C;

[0023] (2) Take 1 g of the resin dried in step 1 and soak it in 50 mL of 1% potassium hydrogen phosphate solution for 30 min;

[0024] (3) Wash the resin soaked in step 2 with deionized water 3-5 times, and dry the washed ion exchange resin in an oven at 70°C;

[0025] (4) 100 g of oil and grease were mixed with ion exchange resin in a ratio of ion exchange resin to oil = 1:100, and stirred in a magnetic stirrer for 40 min at a temperature of 50 °C and a stirring rate of 200 rpm.

[0026] Take the grease after 0.1g processing and clear up, in the grease that has cleared up, add the water of 50mL, then add 4mL1+1 hydrochloric acid and 1mL hydroxylamine hydrochloride solution, low fire boils to about remaining 30mL, move in the 50mL colorimetric tube after being cooled to room temperature, then in water sample and standard series colorimetric tube, respectively add 2mL o-phenanthroline solution, add 10mL ammonium acetate buffer solution again after mixing, respectively add pure water to 50mL scale, mix, place 10-15min, then utilize UV-1300 ultraviolet spectrophotometer to measure iron ion content in water, measuring principle is under the condition of pH=3-9, and low iron ion can generate stable orange-red complex with o-phenanthroline, has maximum light absorption at wavelength 510nm place. When o-phenanthroline is excessive, controlling solution pH is 2.9-3.5, can make color development be accelerated. Water sample is earlier through adding acid and boiling the insoluble compound of dissolving iron, eliminates the interference of cyanide, nitrite, polyphosphate simultaneously. Adding hydroxylamine hydrochloride can reduce high iron to low iron and eliminate the interference of oxidants. According to the above method, the iron ion content in 0.1g of oil is measured to be 2.45ug.

[0027] Example 2

[0028] (1) Soak the ion exchange resin in deionized water for 24 h, and then dry it in an oven at 70°C;

[0029] (2) Take 1 g of the resin dried in step 1 and soak it in 50 mL of 5% potassium hydrogen phosphate solution for 30 min;

[0030] (3) Wash the resin soaked in step 2 with deionized water 3-5 times, and dry the washed ion exchange resin in an oven at 70°C;

[0031] (4) 100 g of oil and grease were mixed with ion exchange resin in a ratio of ion exchange resin to oil = 1:100, and stirred in a magnetic stirrer for 40 min at a temperature of 50 °C and a stirring rate of 200 rpm.

[0032] Weigh 0.1g of treated grease for digestion, add 50mL of water to the digested grease, then add 4mL of 1+1 hydrochloric acid and 1mL of hydroxylamine hydrochloride solution, boil on low heat until about 30mL remains, cool to room temperature and transfer to a 50mL colorimetric tube, then add 2mL of o-phenanthroline solution to the water sample and the standard series colorimetric tubes, mix well, add 10mL of ammonium acetate buffer solution, add pure water to each to the 50mL scale, mix well, and let it stand for 10-15min. Then, use a UV-1300 ultraviolet spectrophotometer to measure the iron ion content in the water. According to the above method, the iron ion content in 0.1g of grease is 1.48ug.

[0033] Example 3

[0034] (1) Soak the ion exchange resin in deionized water for 24 h and then dry it in an oven at 60°C;

[0035] (2) Take 1 g of the dried resin in step 1 and soak it in 10 mL of saturated potassium hydrogen phosphate solution for 30 min;

[0036] (3) Wash the resin soaked in step 2 with deionized water 3-5 times, and dry the washed ion exchange resin in an oven at 60°C;

[0037] (4) 100 g of oil and grease were mixed with ion exchange resin in a ratio of ion exchange resin to oil = 1:100, and stirred in a magnetic stirrer for 40 min at a temperature of 50 °C and a stirring rate of 200 rpm.

[0038] Weigh 0.1g of treated grease for digestion, add 50mL of water to the digested grease, then add 4mL of 1+1 hydrochloric acid and 1mL of hydroxylamine hydrochloride solution, boil on low heat until about 30mL remains, cool to room temperature and transfer to a 50mL colorimetric tube, then add 2mL of o-phenanthroline solution to the water sample and the standard series colorimetric tubes, mix well, add 10mL of ammonium acetate buffer solution, add pure water to each to the 50mL scale, mix well, let it stand for 10-15min, and then use a UV-1300 ultraviolet spectrophotometer to measure the iron ion content in the water. According to the above method, the iron ion content in 0.1g of grease is 1.52ug.

[0039] Example 4

[0040] (1) Soak the ion exchange resin in deionized water for 24 h, and then dry it in an oven at 70°C;

[0041] (2) Take 1 g of the dried resin in step 1 and soak it in 10 mL of saturated potassium hydrogen phosphate solution for 30 min;

[0042] (3) Wash the resin soaked in step 2 with deionized water 3-5 times, and dry the washed ion exchange resin in an oven at 70°C;

[0043] (4) 100 g of oil and grease were mixed with ion exchange resin in a ratio of ion exchange resin to oil = 1:100, and stirred in a magnetic stirrer for 40 min at a temperature of 50 °C and a stirring rate of 200 rpm.

[0044] Weigh 0.1g of treated grease for digestion, add 50mL of water to the digested grease, then add 4mL of 1+1 hydrochloric acid and 1mL of hydroxylamine hydrochloride solution, boil on low heat until about 30mL remains, cool to room temperature and transfer to a 50mL colorimetric tube, then add 2mL of o-phenanthroline solution to the water sample and the standard series colorimetric tubes, mix well, add 10mL of ammonium acetate buffer solution, add pure water to each to the 50mL scale, mix well, and let it stand for 10-15min. Then, use a UV-1300 ultraviolet spectrophotometer to measure the iron ion content in the water. According to the above method, the iron ion content in 0.1g of grease is 1.48ug.

[0045] Example 5

[0046] (1) Soak the ion exchange resin in deionized water for 24 h and then dry it in an oven at 80°C;

[0047] (2) Take 1 g of the dried resin in step 1 and soak it in 10 mL of saturated potassium hydrogen phosphate solution for 30 min;

[0048] (3) Wash the resin soaked in step 2 with deionized water 3-5 times, and dry the washed ion exchange resin in an oven at 80°C;

[0049] (4) 100 g of oil and grease were mixed with ion exchange resin in a ratio of ion exchange resin to oil = 1:100, and stirred in a magnetic stirrer for 40 min at a temperature of 50 °C and a stirring rate of 200 rpm.

[0050] Weigh 0.1g of treated grease for digestion, add 50mL of water to the digested grease, then add 4mL of 1+1 hydrochloric acid and 1mL of hydroxylamine hydrochloride solution, boil on low heat until about 30mL remains, cool to room temperature and transfer to a 50mL colorimetric tube, then add 2mL of o-phenanthroline solution to the water sample and the standard series colorimetric tubes, mix well, add 10mL of ammonium acetate buffer solution, add pure water to each to the 50mL scale, mix well, let it stand for 10-15min, and then use a UV-1300 ultraviolet spectrophotometer to measure the iron ion content in the water. According to the above method, the iron ion content in 0.1g of grease is 1.54ug.

[0051] Comparative Example 1

[0052] Weigh 0.1g of untreated grease for digestion, add 50mL of water to the digested grease, then add 4mL of 1+1 hydrochloric acid and 1mL of hydroxylamine hydrochloride solution, boil on low heat until about 30mL remains, cool to room temperature and transfer to a 50mL colorimetric tube, then add 2mL of o-phenanthroline solution to the water sample and the standard series colorimetric tubes, mix well, then add 10mL of ammonium acetate buffer solution, add pure water to each to the 50mL scale, mix well, and let it stand for 10-15min. Then, use a UV-1300 ultraviolet spectrophotometer to measure the iron ion content in the water. According to the above method, the iron ion content in 0.1g of grease is 21.65ug.

[0053] Comparative Example 2

[0054] (1) Soak the ion exchange resin in deionized water for 24 h, and then dry it in an oven at 70°C;

[0055] (2) 1 g of the dried resin from step 1 was soaked in 50 mL of 1% ammonium dihydrogen phosphate solution for 30 min;

[0056] (3) Wash the resin soaked in step 2 with deionized water 3-5 times, and dry the washed ion exchange resin in an oven at 70°C;

[0057] (4) 100 g of oil and grease were mixed with ion exchange resin in a ratio of ion exchange resin to oil = 1:100, and stirred in a magnetic stirrer for 40 min at a temperature of 50 °C and a stirring rate of 200 rpm.

[0058] Weigh 0.1g of treated grease for digestion, add 50mL of water to the digested grease, then add 4mL of 1+1 hydrochloric acid and 1mL of hydroxylamine hydrochloride solution, boil on low heat until about 30mL remains, cool to room temperature and transfer to a 50mL colorimetric tube, then add 2mL of o-phenanthroline solution to the water sample and the standard series colorimetric tubes, mix well, add 10mL of ammonium acetate buffer solution, add pure water to each to the 50mL scale, mix well, and let it stand for 10-15min, then use a UV-1300 ultraviolet spectrophotometer to measure the iron ion content in the water. According to the above method, the iron ion content in 0.1g of grease is 11.44ug.

[0059] Comparative Example 3

[0060] (1) Soak the ion exchange resin in deionized water for 24 h, and then dry it in an oven at 70°C;

[0061] (2) 1 g of the dried resin from step 1 was soaked in 50 mL of 5% ammonium dihydrogen phosphate solution for 30 min;

[0062] (3) Wash the resin soaked in step 2 with deionized water 3-5 times, and dry the washed ion exchange resin in an oven at 70°C;

[0063] (4) 100 g of oil and grease were mixed with ion exchange resin in a ratio of ion exchange resin to oil = 1:100, and stirred in a magnetic stirrer for 40 min at a temperature of 50 °C and a stirring rate of 200 rpm.

[0064] Weigh 0.1g of treated grease for digestion, add 50mL of water to the digested grease, then add 4mL of 1+1 hydrochloric acid and 1mL of hydroxylamine hydrochloride solution, boil on low heat until about 30mL remains, cool to room temperature and transfer to a 50mL colorimetric tube, then add 2mL of o-phenanthroline solution to the water sample and the standard series colorimetric tubes, mix well, add 10mL of ammonium acetate buffer solution, add pure water to each to the 50mL scale, mix well, let it stand for 10-15min, and then use a UV-1300 ultraviolet spectrophotometer to measure the iron ion content in the water. According to the above method, the iron ion content in 0.1g of grease is 10.58ug.

[0065] Comparative Example 4

[0066] (1) Soak the ion exchange resin in deionized water for 24 h, and then dry it in an oven at 70°C;

[0067] (2) Take 1 g of the dried resin in step 1 and soak it in 10 mL of saturated ammonium dihydrogen phosphate solution for 30 min;

[0068] (3) Wash the resin soaked in step 2 with deionized water 3-5 times, and dry the washed ion exchange resin in an oven at 70°C;

[0069] (4) 100 g of oil and grease were mixed with ion exchange resin in a ratio of ion exchange resin to oil = 1:100, and stirred in a magnetic stirrer for 40 min at a temperature of 50 °C and a stirring rate of 200 rpm.

[0070] Weigh 0.1g of treated grease for digestion, add 50mL of water to the digested grease, then add 4mL of 1+1 hydrochloric acid and 1mL of hydroxylamine hydrochloride solution, boil on low heat until about 30mL remains, cool to room temperature and transfer to a 50mL colorimetric tube, then add 2mL of o-phenanthroline solution to the water sample and the standard series colorimetric tubes, mix well, add 10mL of ammonium acetate buffer solution, add pure water to each to the 50mL scale, mix well, let it stand for 10-15min, and then use a UV-1300 ultraviolet spectrophotometer to measure the iron ion content in the water. According to the above method, the iron ion content in 0.1g of grease is 10.62ug.

[0071] Comparative Example 5

[0072] (1) Soak the ion exchange resin in deionized water for 24 h, and then dry it in an oven at 70°C;

[0073] (2) 1 g of the dried resin from step 1 was soaked in 50 mL of 1% trisodium phosphate solution for 30 min;

[0074] (3) Wash the resin soaked in step 2 with deionized water 3-5 times, and dry the washed ion exchange resin in an oven at 70°C;

[0075] (4) 100 g of oil and grease were mixed with ion exchange resin in a ratio of ion exchange resin to oil = 1:100, and stirred in a magnetic stirrer for 40 min at a temperature of 50 °C and a stirring rate of 200 rpm.

[0076] Weigh 0.1g of treated grease for digestion, add 50mL of water to the digested grease, then add 4mL of 1+1 hydrochloric acid and 1mL of hydroxylamine hydrochloride solution, boil on low heat until about 30mL remains, cool to room temperature and transfer to a 50mL colorimetric tube, then add 2mL of o-phenanthroline solution to the water sample and the standard series colorimetric tubes, mix well, add 10mL of ammonium acetate buffer solution, add pure water to each to the 50mL scale, mix well, and let it stand for 10-15min, then use a UV-1300 ultraviolet spectrophotometer to measure the iron ion content in the water. According to the above method, the iron ion content in 0.1g of grease is 9.75ug.

[0077] Comparative Example 6

[0078] (1) Soak the ion exchange resin in deionized water for 24 h, and then dry it in an oven at 70°C;

[0079] (2) Take 1g of the resin dried in step 1 and soak it in 50mL of 5% trisodium phosphate solution for 30 minutes.

[0080] (3) Wash the resin soaked in step 2 with deionized water 3-5 times, and dry the washed ion exchange resin in an oven at 70°C;

[0081] (4) 100 g of oil and grease were mixed with ion exchange resin in a ratio of ion exchange resin to oil = 1:100, and stirred in a magnetic stirrer for 40 min at a temperature of 50 °C and a stirring rate of 200 rpm.

[0082] Weigh 0.1g of treated grease for digestion, add 50mL of water to the digested grease, then add 4mL of 1+1 hydrochloric acid and 1mL of hydroxylamine hydrochloride solution, boil on low heat until about 30mL is left, cool to room temperature and transfer to a 50mL colorimetric tube, then add 2mL of o-phenanthroline solution to the water sample and the standard series colorimetric tube respectively, mix well and then add 10mL of ammonium acetate buffer solution, add pure water to each to the 50mL scale, mix well, let it stand for 10-15min, and then use UV-1300 ultraviolet spectrophotometer to measure the iron ion content in the water. According to the above method, the iron ion content in 0.1g of grease is 9.98

[0083] ug.

[0084] Comparative Example 7

[0085] (1) Soak the ion exchange resin in deionized water for 24 h, and then dry it in an oven at 70°C;

[0086] (2) Take 1 g of the dried resin in step 1 and soak it in 10 mL of saturated trisodium phosphate solution for 30 min;

[0087] (3) Wash the resin soaked in step 2 with deionized water 3-5 times, and dry the washed ion exchange resin in an oven at 70°C;

[0088] (4) 100 g of oil and grease were mixed with ion exchange resin in a ratio of ion exchange resin to oil = 1:100, and stirred in a magnetic stirrer for 40 min at a temperature of 50 °C and a stirring rate of 200 rpm.

[0089] Weigh 0.1g of treated grease for digestion, add 50mL of water to the digested grease, then add 4mL of 1+1 hydrochloric acid and 1mL of hydroxylamine hydrochloride solution, boil on low heat until about 30mL remains, cool to room temperature and transfer to a 50mL colorimetric tube, then add 2mL of o-phenanthroline solution to the water sample and the standard series colorimetric tubes, mix well, add 10mL of ammonium acetate buffer solution, add pure water to each to the 50mL scale, mix well, and let it stand for 10-15min. Then, use a UV-1300 ultraviolet spectrophotometer to measure the iron ion content in the water. According to the above method, the iron ion content in 0.1g of grease is 9.92ug.

[0090] Comparative Example 8

[0091] (1) Soak the ion exchange resin in deionized water for 24 h and then dry it in an oven at 70°C;

[0092] (2) 1 g of the dried resin from step 1 was soaked in 50 ml of a 1% sodium tripolyphosphate solution for 30 min;

[0093] (3) Wash the resin soaked in step 2 with deionized water for 3-5 times, and dry the washed ion exchange resin in an oven at 70°C;

[0094] (4) 100 g of oil and ion exchange resin were mixed in a ratio of ion exchange resin to oil = 1:100, and stirred in a magnetic stirrer for 40 min at a temperature of 50 °C and a stirring rate of 200 rpm.

[0095] Weigh 0.1g of treated grease for digestion, add 50mL of water to the digested grease, then add 4mL of 1+1 hydrochloric acid and 1mL of hydroxylamine hydrochloride solution, boil on low heat until about 30mL remains, cool to room temperature and transfer to a 50mL colorimetric tube, then add 2mL of o-phenanthroline solution to the water sample and the standard series colorimetric tubes, mix well, add 10mL of ammonium acetate buffer solution, add pure water to each to the 50mL scale, mix well, let it stand for 10-15min, and then use a UV-1300 ultraviolet spectrophotometer to measure the iron ion content in the water. According to the above method, the iron ion content in 0.1g of grease is 11.62ug.

[0096] Comparative Example 9

[0097] (1) Soak the ion exchange resin in deionized water for 24 h and then dry it in an oven at 70°C;

[0098] (2) 1 g of the dried resin from step 1 was soaked in 50 mL of a 5% sodium tripolyphosphate solution for 30 min;

[0099] (3) Wash the resin soaked in step 2 with deionized water for 3-5 times, and dry the washed ion exchange resin in an oven at 70°C;

[0100] (4) 100 g of oil and ion exchange resin were mixed in a ratio of ion exchange resin to oil = 1:100, and stirred in a magnetic stirrer for 40 min at a temperature of 50 °C and a stirring rate of 200 rpm.

[0101] Weigh 0.1g of treated grease for digestion, add 50mL of water to the digested grease, then add 4mL of 1+1 hydrochloric acid and 1mL of hydroxylamine hydrochloride solution, boil on low heat until about 30mL remains, cool to room temperature and transfer to a 50mL colorimetric tube, then add 2mL of o-phenanthroline solution to the water sample and the standard series colorimetric tubes, mix well, add 10mL of ammonium acetate buffer solution, add pure water to each to the 50mL scale, mix well, and let it stand for 10-15min. Then, use a UV-1300 ultraviolet spectrophotometer to measure the iron ion content in the water. According to the above method, the iron ion content in 0.1g of grease is 11.98ug.

[0102] Comparative Example 10

[0103] (1) Soak the ion exchange resin in deionized water for 24 h and then dry it in an oven at 70°C;

[0104] (2) Take 1 g of the resin dried in step 1 and soak it in 10 mL of saturated sodium tripolyphosphate solution for 30 min;

[0105] (3) Wash the resin soaked in step 2 with deionized water for 3-5 times, and dry the washed ion exchange resin in an oven at 70°C;

[0106] (4) 100 g of oil and ion exchange resin were mixed in a ratio of ion exchange resin to oil = 1:100, and stirred in a magnetic stirrer for 40 min at a temperature of 50 °C and a stirring rate of 200 rpm.

[0107] Weigh 0.1g of treated grease for digestion, add 50mL of water to the digested grease, then add 4mL of 1+1 hydrochloric acid and 1mL of hydroxylamine hydrochloride solution, boil on low heat until about 30mL remains, cool to room temperature and transfer to a 50mL colorimetric tube, then add 2mL of o-phenanthroline solution to the water sample and the standard series colorimetric tubes, mix well, add 10mL of ammonium acetate buffer solution, add pure water to each to the 50mL scale, mix well, and let it stand for 10-15min. Then, use a UV-1300 ultraviolet spectrophotometer to measure the iron ion content in the water. According to the above method, the iron ion content in 0.1g of grease is 11.12ug.

[0108] Table 1 shows the iron ion content and the amount of fat obtained after treatment in Examples 1-3 and Comparative Examples 1-10.

[0109]

[0110] The results of the embodiments of the present invention show that after being treated by the method for efficiently removing iron ions from oils and fats of the present invention, the iron ion content in the oils and fats is lower than 15 ppm, the oil retention amount can reach more than 98%, and the iron removal effect is significant.

[0111] In summary, the present invention can effectively reduce the iron ion content in oils and fats, and at the same time, use a saturated solution of dipotassium hydrogen phosphate to treat the ion exchange resin, greatly reducing the amount of wastewater treatment and retaining the original quality and reserves.

Claims

1. A method for efficiently removing heavy metals from oils and fats using ion exchange resins, characterized in that: The following steps are involved: (1) Soak the ion exchange resin in deionized water for 24 hours and then dry it in an oven at 60-80°C; (2) taking 1 g of the dried ion exchange resin and soaking it in a solution containing dipotassium hydrogen phosphate for 30 min; (3) washing the soaked ion exchange resin with deionized water for 3-5 times and drying it in an oven at 60-80° C.; (4) Mix the dried ion exchange resin with the oil and stir.

2. The method according to claim 1, characterized in that In step (1), the drying temperature is 70°C.

3. The method according to claim 1, characterized in that In step (2), the dipotassium hydrogen phosphate solution is 10 mL of a saturated dipotassium hydrogen phosphate solution.

4. The method according to claim 1, characterized in that In step (3), the drying temperature is 70°C.

5. The method according to claim 1, characterized in that In step (4), the ratio of ion exchange resin to oil is 1:

100.

6. The method according to claim 1, characterized in that In step (4), the stirring temperature is 50°C.

7. The method according to claim 1, characterized in that In step (4), the stirring rate is 200 rpm.

8. The method according to claim 1, characterized in that In step (4), the stirring time is 40 min.

9. The method according to claim 4, characterized in that In step (3), the drying time does not exceed 6 hours.

10. The method according to claim 7, characterized in that The stirring rate did not exceed 400 rpm.

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