RU2712682C2 - Vegetable based sorbent production method - Google Patents

Abstract

FIELD: chemistry.SUBSTANCE: invention relates to production of a sorbent based on a vegetable base, which can be used for cleaning aqueous solutions. Wheat offal is used as initial vegetal raw material. Offal, which is a waste of agricultural production, is washed and hydrated with water in two steps, dried in two steps: at temperature of 60 °C and at temperature of 100–105 °C to constant weight is milled to obtain 0.2–2 mm fraction.EFFECT: invention enables extraction of heavy metal ions and organic contaminants at temperature of 25–35 °C.1 cl, 4 ex

Description

The invention relates to a technology for the production of plant-based sorbents that can be used to purify pollutants from aqueous solutions.

Sorption purification is one of the effective ways to remove contaminants from water and aqueous solutions. This is one of the main ways to improve the environmental situation in the national economy.

The processing of agricultural waste is an urgent task, which allows to reduce the harm caused by waste, the environment and expand the range of nutrients. A method for producing a phytosorbent (plant-based sorbent), for example, based on wood sawdust by treating them with chemical agent 1 (2-hydroxy-ethyl) -4,5,6,7 tetrahydroindole in an acetone solution at a ratio of 1: 0.01 and aging is described within 12 hours. Sorption capacity under static conditions for metals was 0.7-1.4 mg / g [1]. The disadvantage of this method is the relative complexity of the technology, low sorption capacity.

A method has been patented for the production of phytosorbent, in which oil cake is used as the initial plant material — waste from the process of pumpkin seed processing [2]. After drying, pumpkin seeds were cold pressed to produce edible vegetable oil. In the form of waste cake is formed, containing mainly not less than 4.5 wt. % nitrogen according to Kjeldahl and 10-15 wt. % fiber.

To obtain a sorbent, crushed cake was washed with water at a ratio of 1: 5-10 to an unpainted wash liquid, dried at a temperature of 100-105 ° C to constant weight, crushed, dispersed, 0.2-2 mm fractions were taken, and a powdery sorbent was obtained - the finished product with a specific bulk density of 0.25-0.35 g / cm ³ containing at least 4.5% Kjeldahl nitrogen and at least 4% fiber. The prepared sorbent was subjected to a test to purify aqueous solutions of heavy metals — from copper and cadmium with a static sorption capacity of 3.5 mg / g and from methylene blue 0.6 mg / g.

For testing in a beaker, 0.5 g of a sorbent and 20 ml of an aqueous solution containing, for example, 100 mg / l of copper (II) in the form of sulfate were mixed in a mass ratio of 1:40; they were kept at room temperature for 4 hours; 5.0 mg / l copper ion. Sorption capacity was 3.5 mg / g. When using a solution of 15 mg / l of dye, 2 mg / l of methylene blue was found, sorption capacity of 0.6 mg / g.

The disadvantages of the method: the complexity of the technology, the limited resource of raw materials.

A known method of producing a sorbent on a plant-based meal - waste processing seeds of melons, for example, watermelon for vegetable oil [3, prototype].

Cake was washed with water after crushing at a weight ratio of cake: water of 1:40, dried to constant weight at a temperature of 100-105 ° C, crushed, dispersed, and a 0.2-2 mm fraction was selected. The obtained sorbent in the form of a powder contained fiber and a protein-carbohydrate complex, characterized by a Kjeldahl nitrogen content of at least 0.5 wt. % The processing technology of the cake and the tests were the same as described previously. The sorbent made it possible to clean aqueous solutions of heavy metals, for example, copper and zinc with a sorption capacity of 2-4 mg / g.

The disadvantages of the method are the limited possibilities for the purification of aqueous solutions relative to organic impurities and the resource of sorbents.

The technical task is the expansion of sorption capabilities, including organic pollution, resource and assortment of sorbents.

The problem is solved in such a way that bran, waste from the processing of grain crops into flour, for example, wheat bran, which are produced in large quantities in mill production, is used as the source of plant materials. On a large scale, bran is also used as feed and feed additives in animal husbandry and poultry farming.

In addition, wheat, rye bran and others are used after additional processing in the food industry as additives rich in fiber and proteins, as well as macro- and microelements [4].

To obtain the sorbent, wheat bran was used as raw material, sold in the shop “Medical nature” in Volgograd. Packing of IP KFH Belyaevsky A.S. pos. Novy Rogachik, Volgograd region. Bran is packed in a plastic sealed bag weighing 300 g in the form of gray particles of 1-2 mm in size with a bulk mass of 0.36 g / cm ³ .

The chemical composition of wheat bran (on average), wt. %:

humidity 14.7

ash content in terms of dry matter 5.0

mass fraction of crude protein 15.0

mass fraction of crude fiber 8.4

mass fraction of crude fat 3.7

Wheat bran in order to obtain a sorbent was treated with water in a mass ratio of 1: 3-5 for 30 minutes to remove impurities and hydrate the components, the aqueous layer was separated. The washed bran was dried in an oven with a fan in a glass beaker for 1 hour at a temperature of 60 ° C, then at a temperature of 100-105 ° C to constant weight, crushed, 0.2-2 mm fractions were taken. The finished sorbent contained nitrogen at least 2.5% with a bulk density of 0.25-0.30 g / cm ³ . The yield of dry bran is 80%. Next, tests were carried out for sorption ability. To ensure good results (in particular the separation of solids from liquid), the sorption process was carried out at a temperature of 25-35 ° C. A portion of bran in a glass beaker was mixed with a solution of copper and cadmium ions at a concentration of 100 mg / l, kept for 4.5 hours. Then the aqueous layer was separated and the residual content of copper and cadmium ions was determined in it. Additionally, sorption of the dye, methylene blue, was carried out in a solution with a concentration of 15 mg / L. After sorption, the color intensity was visually evaluated in a test tube and the result was calculated.

Example 1. Preparation of the sorbent.

20 g of wheat bran (initial sample) was loaded into a glass beaker, 100 ml of distilled water (1: 5 ratio) was added, and it was kept for 30 min at room temperature with stirring. The aqueous upper layer was separated, then another 2 times 70 ml of water was added, held for 30 minutes, the aqueous layer was again separated. The wet cake was dried in an oven with a fan 4 hours to constant weight. Yield 16 g (80%). The Kjeldahl nitrogen content is 2.5%. The bulk density of 0.3 g / cm ³ , 8% fiber.

Example 2. Test for the sorption ability of copper ions.

A portion of dry bran 0.5 g in a glass beaker was mixed with 20 ml of a solution of copper (II) ions (ratio 1:40) with a concentration of 100 mg / l in a water bath with a temperature of 25-35 ° C for 4.5 hours. 38 mg / L of copper was detected in the aqueous layer. Sorption capacity under static conditions 2.5 mg / g, the degree of extraction of 62%.

Example 3. The test for sorption ability with a solution of cadmium ions.

The sorption process was carried out as in example 2. The cadmium content in the aqueous layer was 35 mg / L. Sorption capacity of 2.6 mg / g, the degree of extraction of 65%.

Example 4. Test for sorption ability of the dye methylene blue.

As in example 2, 0.5 g of sorbent and 20 ml of dye with a concentration of 15 mg / L were mixed in a glass. Weathered 2 hours. The residual dye concentration in the aqueous layer is 5 mg / g. Sorption capacity of 0.4 mg / g, the degree of extraction of 67%.

Thus, the proposed method allows to obtain a sorbent for cleaning solutions from mineral and organic contaminants - from copper and cadmium with a degree of extraction of 62-65% and methylene blue - 67%, to expand the resource and assortment of sorbents, to utilize production waste.

The list of sources of information taken into account during the examination.

1. A.S. USSR No. 1498551, 1987, IPC B01J 20/22.

2. Pat. RF №2253510, 2004, IPC B01J 20/22.

3. Pat. RF №2212931, 2002, IPC B01J 20/22.

4. Wheat bran. TU 9196-004-09645951-2012. Manufactured by: Everest LLC, Russia, St. Petersburg, 196608, ul. Motorists, 6.

Claims (1)

A method of obtaining a plant-based sorbent for extraction of copper, cadmium and organic molecules from solutions, which consists in the fact that wheat bran, which is a waste of agricultural production, is treated with distilled water, taken from the calculation of the mass ratio of water: bran equal to 5: 1, the processing is carried out with stirring for 30 minutes, then the aqueous layer is separated, water is added to the bran in two stages in equal portions with the total amount of water at the mentioned stages corresponding to the mass the water: bran ratio of 7: 1 is held for 30 minutes, the aqueous layer is separated, the wet cake is dried first at 60 ° C, then at 100-105 ° C, crushed and a 0.2-2 mm bulk fraction is collected a density of 0.3 g / cm ³ .