Sorption material for wastewater treatment from synthetic surfactants and method for its preparation

Abstract

FIELD: wastewater treatment.SUBSTANCE: sorption material for purifying wastewater from synthetic surfactants (SAS), containing CaCO3 (49%), other substances (Mg(OH)2, Ca(OH)2, SiO2, Al(OH)3) (21%) and technical paraffin (30%), and a method for its preparation, including mixing pre-dried at a temperature of 105 °C up to 3% moisture content of water treatment sludge from thermal power plants, the composition of which is represented by: CaCO3 – 70-75%, other substances (Mg(OH)2, Ca(OH)2, SiO2, Al(OH)3) – 25-30%, heated to 60 °C by technical paraffin, introduced in an amount of 30% by weight, until a lumpy mass is obtained, which is then evenly distributed on a horizontal plate with a thickness of no more than 5 mm, and then pressed through a forming die with a cell size of 1 mm.EFFECT: development of a sorption material for wastewater treatment to reduce energy costs for modifying the original material of production waste.2 cl, 2 dwg

Description

[0001] The invention relates to the purification of wastewater from synthetic surfactants (SAAS) and can be used in wastewater treatment plants of industrial and municipal enterprises.

[0002] The prototype is a method for sorption purification of wastewater from surfactants using sugar industry waste - saturate sludge containing about 75% CaCO3 and organic matter, based on preliminary thermal modification of the sludge at a temperature of 600°C-900°C. (Sorption extraction of sodium lauryl sulfate from aqueous media using sugar industry waste / Zh.A. Sapronova, R.O. Fetisov, S.V. Sverguzova, I.G. Shaikhiev / / Bulletin of KSTU. 2014. Vol. 17, No. 3. - P.163).

[0003] The main disadvantage of the known material is that the proposed approach to modifying production waste is characterized by high energy costs associated with processing the sediment in a kiln at high temperatures (600°C-900°C).

[0004] The task that the proposed invention is aimed at solving is to eliminate the indicated disadvantage of the prototype.

[0005] The technical result is a reduction in energy costs for the modification of the original material of production waste.

[0006] The technical result is achieved in that the sorption material for purifying wastewater from synthetic surfactants contains, according to the present invention, CaCO3, other substances, technical paraffin in the following ratio of components, wt. %:

[0007]

[0008] The method for preparing a sorption material involves mixing sludge from water treatment at thermal power plants, pre-dried at a temperature of 105° to 3% moisture content, with technical paraffin heated to 60°C, introduced in an amount of 30% by weight, until a lumpy mass is obtained, which is then evenly distributed on a horizontal plate with a thickness of no more than 5 mm, and then pressed through a forming die with a cell size of 1 mm.

[0009] The authors proposed a composition of a sorption material designed for the purification of wastewater from anionic surfactants during mixing in a constant volume under static conditions, developed on the basis of production waste - sludge from water treatment plants of thermal power plants.

[0010] The sorption material is the sludge from water treatment at thermal power plants, the composition of which is represented by CaCO3 - 70-75%, other substances (Mg (OH) 2, Ca (OH) 2, SiO2, Al (OH) 3) - 25-30%, pre-dried at a temperature of 105 ° to 3% humidity, which is mixed with technical paraffin heated to 60 ° C, introduced in an amount of 30% by weight, until a lumpy mass is obtained, which is then uniformly distributed on a horizontal plate with a thickness of no more than 5 mm, and then pressed through a forming die with a mesh size of 1 mm. As a result, granules of regular shape with a diameter of 1-1.5 mm are obtained. The resulting brown granules have hydrophobic properties, the adsorption capacity of the developed granules is 22.1 mg / dm 3 .

[0011] A sorption material based on paraffin-modified thermal power plant water treatment sludge is loaded into a mixer equipped with an agitator for wastewater treatment under constant volume and static conditions. Adsorption is 80-90% complete within the first 40-50 minutes. Adsorption takes 60 minutes to reach full saturation.

[0012] To regenerate the material, desorption of the contaminant is performed using steam at a temperature of 100°C and a velocity of 0.1 m / s. The processing time was 30 minutes. The granules retain their shape, are not abraded, and are not crushed. The sorption capacity of the granules decreases by no more than 3% after one regeneration.

[0013] Thus, the technical result is achieved by replacing the waste from the sugar industry - saturating sludge with water treatment sludge, formed into granules with a paraffin binder in the amount of 30% (by weight) without additional heating in a kiln to a temperature of 600-900 ° C, which eliminates energy costs for high-temperature processing and minimizes the negative impact on the atmosphere due to the absence of the formation of polluted gas environments formed during the firing of the material

[0014] The invention is illustrated in Figure 1, which shows an adsorption isotherm of sodium lauryl sulfate on the resulting sorption material under static conditions. As can be seen from Figure 1, the resulting isotherm belongs to Type I according to the BET classification, indicating monomolecular adsorption. This type of isotherm is also characteristic of microporous materials. The sorption capacity of the resulting material for the synthetic surfactant (sodium lauryl sulfate) is 22.1 mg / g.

[0015] Water treatment sludge from thermal power plants is a product of liming and coagulation of natural water in a clarifier.

[0016] Chemical composition of water treatment sludge:

[0017] CaCO3+ MgO + Mg(OH)2+ Fe(OH)3+ SiO2+ Al(OH)3

[0018] The sludge was analyzed by gas chromatography-mass spectroscopy with electron ionization on a DFS mass spectrometer manufactured by Thermo Fisher Sci. Co., which revealed a typical set of functional groups of humic substances: OH, NH, CH3, CH2, aromatic C=C bonds, C-O carboxyl and OH alcohol groups up to 12% by weight of the total mass of the sample.

[0019] Paraffin is a mixture of aliphatic saturated hydrocarbons with a composition of C 18 H 38 to C 35 N 72 Insoluble in water, it imparts hydrophobic properties to water treatment sludge.

[0020] The binder paraffin was preheated to 60°C. A plastic mass was then prepared by gradually increasing the binder amount by 30% (by weight) until a lumpy mass was obtained. The mass was then evenly distributed on a horizontal plate no more than 5 mm thick and passed through a sieve with a 1 mm mesh size. The resulting granules were of regular shape and 1-1.5 mm in diameter.

[0021] Experimental studies were conducted to determine the sorption capacity of paraffin-modified water treatment sludge for surfactants. Laboratory studies were conducted using model surfactant solutions prepared using sodium lauryl sulfate, the most common anionic surfactant. The initial concentration of the model LSS solution was 45 mg / dm3. 3 .

[0022] Paraffin-modified sludge is a non-polar adsorption material, which is a significant advantage for surfactant adsorption from polar liquids (water). According to Rehbinder's law, surfactant adsorption reduces the polarity difference at the phase boundary. Paraffin modification imparts hydrophobicity to the sludge. Therefore, only the pollutant (LSS) is adsorbed from the polar solvent (water).

[0023] Paraffin was added to the sludge in amounts ranging from 15 to 50% (wt.). As can be seen from the table (Fig. 2), the most effective binder addition is 30%. At a minimum value of 15% (wt.), the material's pores are not uniformly filled, and insufficient surface hydrophobicity is observed. At a maximum value of 50%, the sorption capacity decreases, caused by the pores on the sludge surface being filled with paraffin, which becomes blocked by the binder and inaccessible to the penetration of synthetic surfactant molecules.

[0024] Thus, the use of the proposed invention, in comparison with the prototype, will reduce energy costs for high-temperature roasting and minimize the anthropogenic impact of polluted gas environments on the natural environment, while maintaining the efficiency of wastewater treatment from synthetic surfactants.

[0025] The work was carried out using a grant provided in 2025 by the Science and Technology Fund of the Republic of Tatarstan for the implementation of fundamental and applied scientific work in scientific and educational organizations, enterprises and organizations of the real sector of the economy of the Republic of Tatarstan” (agreement No. 9 dated 1.12.2025).

Claims

1. Sorption material for wastewater treatment from synthetic surfactants, containing CaCO3, other substances (Mg(OH)2, Ca(OH)2, SiO2, Al(OH)3), technical paraffin in the following ratio of components, wt.%: CaCO3 49 49 Other substances (Mg(OH)2, Ca(OH)2, SiO2, Al(OH)3) 21 Technical paraffin 30 2. A method for preparing a sorption material according to paragraph 1, which includes mixing sludge from water treatment of thermal power plants, pre-dried at a temperature of 105°C to 3% moisture content, the composition of which is represented by: CaCO3 - 70-75%, other substances (Mg(OH)2, Ca(OH)2, SiO2, Al(OH)3) - 25-30%, with technical paraffin heated to 60°C, introduced in an amount of 30 wt.%, until a lumpy mass is obtained, which is then uniformly distributed on a horizontal plate with a thickness of no more than 5 mm, and then pressed through a forming die with a cell size of 1 mm.

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