A solid cleaning agent

Abstract

The invention discloses a solid cleaning agent, which belongs to the technical field of cleaning agents; the solid cleaning agent includes the following components by mass: 1 5 parts of bio-enzyme preparations, 3 10 parts of surfactants, 50 75 parts of chelating agents, 1 5 parts of cleaning aids and 20 30 parts of inorganic compounds; the surfactant includes an anionic surfactant and a nonionic surfactant; the anionic surfactant is sodium α-olefin sulfonate or amidocarboxylic acid sodium salt, and the amidocarboxylic acid sodium salt has a benzene ring and an amide group; the nonionic surfactant is coconut oil fatty acid diethanolamide. The invention discloses a solid cleaning agent with good cleaning performance, which can not only clean organic pollutants inside membrane separation elements, but also has a high removal efficiency for composite pollutants formed by the combination of calcium ions and aluminum ions with organic matter.

Description

Technical Field

[0001] The present invention relates to the technical field of cleaning agents, in particular to a solid cleaning agent. Background Art

[0002] With industrial development and the increasing demand for water resources, membrane separation elements such as ultrafiltration, reverse osmosis, and nanofiltration membranes are widely used for water purification. However, after a period of use, various contaminants gradually accumulate within membrane separation elements. The accumulation of these contaminants not only affects the membrane's permeability but also significantly reduces system efficiency. To address this issue, the system periodically flushes the membrane with water to remove some of the contaminants from the membrane surface. However, water flushing alone often fails to completely remove contaminants from within the membrane, leading to a continuous decline in performance. Therefore, it is crucial to use specialized cleaning agents to effectively remove contaminants adhering to the membrane's interior and restore membrane cleaning efficiency. Commonly used cleaning agents on the market are generally compounded liquid cleaning agents. The use of these liquid cleaning agents increases storage and transportation costs, and solid cleaning agents are relatively rare on the market. Therefore, the development of a solid cleaning agent has practical significance and market prospects. Summary of the Invention

[0003] The object of the present invention is to provide a solid cleaning agent to improve the removal efficiency of organic pollutants on contaminated membrane separation elements and composite pollutants formed by the combination of calcium ions and aluminum ions with organic matter.

[0004] The technical solutions adopted by the present invention to achieve the above-mentioned purpose are:

[0005] A solid cleaning agent comprises the following components in parts by mass: 1-5 parts of a biological enzyme preparation, 3-10 parts of a surfactant, 50-75 parts of a chelating agent, 1-5 parts of a cleaning aid, and 20-30 parts of an inorganic compound; the surfactant comprises an anionic surfactant and a nonionic surfactant; the anionic surfactant is sodium α-olefin sulfonate or sodium amidocarboxylate, wherein the sodium amidocarboxylate has a benzene ring and an amide group; and the nonionic surfactant is coconut oil fatty acid diethanolamide.

[0006] The solid cleaning agent of the present invention has excellent cleaning performance and can effectively remove organic pollutants inside the membrane separation element, as well as complex pollutants formed by the combination of calcium ions and aluminum ions with organic matter, thereby restoring the normal separation performance of the membrane separation element; the solid cleaning agent uses sodium salt of amide carboxylic acid instead of sodium α-olefin sulfonate as an anionic surfactant, and the sodium salt of amide carboxylic acid has a benzene ring and an amide group, and can form micelles in the solution, so that the solubilized substance is dissolved inside the micelles, which helps to indirectly improve the solubility of organic pollutants inside the membrane separation element, as well as complex pollutants formed by the combination of calcium ions and aluminum ions with organic matter, thereby achieving effective removal of these pollutants.

[0007] Preferably, the mass ratio of the anionic surfactant to the nonionic surfactant is 1:0.1-0.5.

[0008] Preferably, in the preparation of the amidocarboxylic acid sodium salt, octadecylamine, methyl 4-vinylbenzoate and 1,4-cyclohexanediyl chloride are reacted in the presence of an acid binding agent, and then saponified with sodium hydroxide to obtain the amidocarboxylic acid sodium salt; the acid binding agent is triethylamine.

[0009] More preferably, the molar ratio of octadecylamine to methyl 4-vinylbenzoate is 1:1-2, and the molar ratio of octadecylamine to 1,4-cyclohexanediyl chloride is 1:0.2-1.

[0010] Preferably, the preparation of the sodium salt of amidocarboxylic acid is specifically as follows:

[0011] Methanol is added to octadecylamine, and methyl 4-vinylbenzoate is added dropwise. The mixture is stirred at room temperature for 12-36 hours, and the mixture is rotary evaporated. Triethylamine and 1,4-cyclohexanediyl chloride are added, and the mixture is stirred at 30-50°C for 6-18 hours. After the reaction solution is cooled, it is washed with deionized water, rotary evaporated, and sodium hydroxide solution is added. The mixture is then washed with detergent and dried to obtain a sodium salt of an amidocarboxylic acid.

[0012] More preferably, the usage ratio of octadecylamine and methanol is 1 mol:300-500 mL.

[0013] More preferably, the molar ratio of octadecylamine to methyl 4-vinylbenzoate is 1:1-2.

[0014] More preferably, the usage ratio of octadecylamine and triethylamine is 1 mol:1-2 mL.

[0015] More preferably, the molar ratio of octadecylamine to 1,4-cyclohexanediyl chloride is 1:0.2-1.

[0016] More preferably, the usage ratio of octadecylamine and sodium hydroxide is 1 mol:50-150 mL, and the concentration of sodium hydroxide is 0.2-1 mol / L.

[0017] More preferably, the detergent comprises ethanol and cyclohexane, and the volume ratio of ethanol to cyclohexane is 1:5-15.

[0018] Preferably, the bioenzyme preparation includes alkaline protease, lipase and α-amylase, the mass ratio of alkaline protease to lipase is 1:1-2, and the mass ratio of alkaline protease to α-amylase is 1:1-2.

[0019] Preferably, the chelating agent includes tetrasodium EDTA, sodium tripolyphosphate and sodium citrate, the mass ratio of tetrasodium EDTA to sodium tripolyphosphate is 1:1-2, and the mass ratio of tetrasodium EDTA to sodium citrate is 1:0.2-1.

[0020] Preferably, the cleaning aid is sodium polymethacrylate, which has sodium carboxylate groups.

[0021] Preferably, the cleaning aid is modified sodium polymethacrylate having a benzene ring. The present invention uses modified sodium polymethacrylate as a cleaning aid in a solid cleaning agent, further enhancing the cleaning performance of the solid cleaning agent and improving the removal efficiency of organic contaminants within contaminated membrane separation elements, as well as complex contaminants formed by the combination of calcium ions and aluminum ions with organic matter.

[0022] More preferably, the preparation of modified sodium polymethacrylate is specifically as follows:

[0023] Mix methacrylic acid and 4-vinylbenzoic acid, add toluene, stir evenly, introduce nitrogen for 20-60 minutes, add azobisisobutyronitrile, stir and react at 60-100°C for 2-6 hours, slowly add sodium hydroxide solution dropwise, cool the reaction solution to room temperature, wash with acetone 2-5 times, vacuum filter, and vacuum dry at 55-75°C for 6-18 hours to obtain modified sodium polymethacrylate.

[0024] More preferably, the mass ratio of methacrylic acid to 4-vinylbenzoic acid is 1:2-5.

[0025] More preferably, the usage ratio of methacrylic acid to toluene is 1 g:10-30 mL.

[0026] More preferably, the mass ratio of methacrylic acid to azobisisobutyronitrile is 1:0.02-0.1.

[0027] More preferably, the usage ratio of methacrylic acid to sodium hydroxide is 1 g:10-30 mL, and the concentration of sodium hydroxide is 0.2-1 mol / L.

[0028] Preferably, the inorganic compound includes sodium hydroxide and sodium sulfate, and the mass ratio of sodium hydroxide to sodium sulfate is 1:0.2-1.

[0029] The present invention also discloses a method for preparing a solid cleaning agent, comprising the steps of mixing 1-5 parts of a biological enzyme preparation, 50-75 parts of a chelating agent, 1-5 parts of a cleaning aid and 20-30 parts of an inorganic compound, crushing and screening the mixture, adding 3-10 parts of a surfactant, drying the mixture, and screening the mixture to obtain a solid cleaning agent; the solid cleaning agent is in the form of particles with a diameter of 1.5-3.5 mm.

[0030] Preferably, a method for preparing a solid cleaning agent comprises:

[0031] 1-5 parts of a biological enzyme preparation, 50-75 parts of a chelating agent, 1-5 parts of a cleaning aid and 20-30 parts of an inorganic compound are weighed, crushed and sieved with a grinder, and evenly mixed to form a powdery mixture. The mixture is transported to a disc granulator or a drum granulator, 3-10 parts of a surfactant is sprayed onto the surface of the mixture by high-pressure spraying, and rolling granulation is performed. The granules are then transported to a drying drum for drying, and sieved to obtain particles with a diameter of 1.5-3.5 mm to obtain a solid cleaning agent.

[0032] More preferably, the biological enzyme preparation includes alkaline protease, lipase and α-amylase.

[0033] More preferably, the mass ratio of alkaline protease to lipase is 1:1-2.

[0034] More preferably, the mass ratio of alkaline protease to α-amylase is 1:1-2.

[0035] More preferably, the chelating agents include tetrasodium EDTA, sodium tripolyphosphate, and sodium citrate.

[0036] More preferably, the mass ratio of tetrasodium EDTA to sodium tripolyphosphate is 1:1-2.

[0037] More preferably, the mass ratio of tetrasodium EDTA to sodium citrate is 1:0.2-1.

[0038] More preferably, the cleaning aid is sodium polymethacrylate or modified sodium polymethacrylate.

[0039] More preferably, the inorganic compound includes sodium hydroxide and sodium sulfate.

[0040] More preferably, the mass ratio of sodium hydroxide to sodium sulfate is 1:0.2-1.

[0041] More preferably, the surfactant includes anionic surfactants and nonionic surfactants.

[0042] More preferably, the anionic surfactant is sodium α-olefin sulfonate or sodium amidocarboxylate.

[0043] More preferably, the nonionic surfactant is coconut oil fatty acid diethanolamide.

[0044] More preferably, the mass ratio of the anionic surfactant to the nonionic surfactant is 1:0.1-0.5.

[0045] The invention also discloses the use of the solid cleaning agent in cleaning the filter membrane separation element.

[0046] The present invention utilizes amidocarboxylic acid sodium salt and modified sodium polymethacrylate to prepare a solid cleaning agent, thereby achieving the following beneficial effects: the solid cleaning agent has excellent removal efficiency for organic pollutants within membrane separation elements, as well as for complex pollutants formed by the combination of calcium ions and aluminum ions with organic matter. The solid cleaning agent has a calcium ion removal efficiency of 90-99% and an aluminum ion removal efficiency of 83-98%. Therefore, the present invention provides a solid cleaning agent with high removal efficiency for organic pollutants and complex pollutants formed by the combination of calcium ions and aluminum ions with organic matter. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 This is the infrared spectrum of the amidocarboxylic acid sodium salt obtained in Example 4 of the present invention. DETAILED DESCRIPTION

[0048] The present invention will be further described in detail below in conjunction with specific embodiments. The examples provided are only for illustrating the present invention and are not intended to limit the scope of the present invention. The examples provided below can serve as a guide for further improvements by those skilled in the art and are not intended to limit the present invention in any way.

[0049] The experimental methods in the following examples are conventional methods unless otherwise specified. The materials and reagents used in the following examples are commercially available unless otherwise specified.

[0050] Example 1:

[0051] S1. Preparation of solid cleaning agent, comprising:

[0052] The solid cleaning agent comprises the following raw materials in parts by weight: 0.5 parts of alkaline protease, 0.5 parts of lipase, 0.5 parts of α-amylase, 5 parts of sodium α-olefin sulfonate, 1 part of coconut oil fatty acid diethanolamide, 25 parts of tetrasodium ethylenediaminetetraacetic acid, 30 parts of sodium tripolyphosphate, 10 parts of sodium citrate, 2 parts of sodium polymethacrylate, 15.5 parts of sodium hydroxide and 10 parts of sodium sulfate. Alkaline protease, lipase, α-amylase, tetrasodium ethylenediaminetetraacetic acid, sodium tripolyphosphate, sodium citrate, sodium polymethacrylate, sodium hydroxide and sodium sulfate are weighed according to the proportion, crushed and sieved with a grinder, and uniformly mixed to form a powdery mixture. The mixture is transported to a disc granulator or a drum granulator, and sodium α-olefin sulfonate and coconut oil fatty acid diethanolamide are sprayed onto the surface of the mixture by high-pressure spraying to perform rolling granulation. The granules are then transported to a drying drum for drying, and sieved to screen particles with a diameter of 2.5 mm to obtain a solid cleaning agent.

[0053] Example 2:

[0054] S1. Preparation of sodium salt of amidocarboxylic acid, comprising:

[0055] Methanol was added to octadecylamine, followed by the dropwise addition of methyl 4-vinylbenzoate. The mixture was stirred at room temperature for 24 hours, followed by rotary evaporation. Triethylamine and 1,4-cyclohexanediyl chloride were then added, and the mixture was stirred at 40°C for 12 hours. After cooling, the reaction solution was washed with deionized water, rotary evaporation was performed, sodium hydroxide solution was added, and the mixture was washed with a detergent and dried to obtain the amidocarboxylic acid sodium salt. The molar ratio of octadecylamine to methanol was 1 mol:400 mL; the molar ratio of octadecylamine to methyl 4-vinylbenzoate was 1:1.5; the molar ratio of octadecylamine to triethylamine was 1 mol:1.5 mL; the molar ratio of octadecylamine to 1,4-cyclohexanediyl chloride was 1:0.4; the molar ratio of octadecylamine to sodium hydroxide was 1 mol:100 mL, and the concentration of sodium hydroxide was 1 mol / L. The detergents included ethanol and cyclohexane, with the volume ratio of ethanol to cyclohexane being 1:9.

[0056] S2. Preparation of a solid detergent: except that sodium α-olefin sulfonate is substituted for the amidocarboxylic acid sodium salt prepared in step S1 of this embodiment, other conditions are the same as those in Example 1.

[0057] Example 3:

[0058] In the preparation of the solid detergent, the other conditions were the same as those in Example 2, except that the amount of amidocarboxylic acid sodium salt was changed to 3 parts by mass.

[0059] Example 4:

[0060] S1. Preparation of amidocarboxylic acid sodium salt is the same as in Example 2.

[0061] S2. Preparation of modified sodium polymethacrylate, comprising:

[0062] Methacrylic acid and 4-vinylbenzoic acid were mixed, toluene was added, and the mixture was stirred evenly. Nitrogen was introduced for 30 minutes, followed by the addition of azobisisobutyronitrile. The mixture was stirred at 80°C for 4 hours, and sodium hydroxide solution was slowly added dropwise. The reaction solution was cooled to room temperature, washed three times with acetone, vacuum filtered, and dried at 60°C for 12 hours to obtain modified sodium polymethacrylate. The mass ratio of methacrylic acid to 4-vinylbenzoic acid was 1:3; the amount ratio of methacrylic acid to toluene was 1g:20mL; the mass ratio of methacrylic acid to azobisisobutyronitrile was 1:0.1; the amount ratio of methacrylic acid to sodium hydroxide was 1g:20mL, and the concentration of sodium hydroxide was 1 mol / L.

[0063] S3. Preparation of a solid detergent. Except that sodium α-olefin sulfonate is substituted for sodium amidocarboxylate prepared in step S1 of this embodiment, and sodium polymethacrylate is substituted for modified sodium polymethacrylate prepared in step S2 of this embodiment, other conditions are the same as those in Example 1.

[0064] Example 5:

[0065] In the preparation of the solid detergent, except that the amount of modified sodium polymethacrylate used was changed to 1 part by mass, other conditions were the same as those in Example 4.

[0066] Comparative Example 1:

[0067] S1. Preparation of modified sodium polymethacrylate, same as Example 4.

[0068] S2. Preparation of a solid cleaning agent: except that sodium polymethacrylate is substituted for the modified sodium polymethacrylate prepared in step S1 of this comparative example, other conditions are the same as those in Example 1.

[0069] Experimental example

[0070] 1. Material characterization

[0071] The infrared spectrum of the amidocarboxylic acid sodium salt prepared in Example 4 was measured by Fourier transform infrared spectrometer using KBr pellet method at wave number 400-4000 cm -1 Measurement within the range, resolution 0.06cm -1 , scanned 32 times.

[0072] Figure 1 The infrared spectrum of the amidocarboxylic acid sodium salt prepared in Example 4 of the present invention is shown at 2920 cm -1 、2850cm -1 The absorption peaks of saturated alkanes -CH3 and -CH2 appear near 1660 cm -1 There is a C=O absorption peak near 1650cm -1 and 1490cm-1 The absorption peak of benzene ring appears near 1565cm -1 The absorption peak of -COONa group appears near 1360cm -1 An absorption peak of CN appears nearby.

[0073] 2. Determination of membrane separation element flux after cleaning

[0074] The solid cleaning agents obtained in Examples 1-5 and Comparative Example 1 were added to pure water having a total dissolved solid content of less than 100 mg / L at 25°C to a final concentration of 2%, and the pH was adjusted to 12. A pre-contaminated membrane separation element was selected and installed in a membrane cleaning device. The solid cleaning agents obtained in Examples 1-5 of the present invention and Comparative Example 1 were respectively delivered into the membrane using a cleaning pump. The membrane was circulated or soaked for 12 hours to ensure that the solid cleaning agents obtained in Examples 1-5 of the present invention and Comparative Example 1 were fully in contact with the membrane separation element for cleaning. The flux of the membrane separation element after cleaning (m 3 / m 2 / d), membrane separation element flux = fluid volume m 3 / (membrane effective area m 2 × time d), the measurement results are shown in Table 1.

[0075] Table 1 Flux of membrane separation element after cleaning (m 3 / m 2 / d)

[0076]

[0077] As shown in Table 1, the higher post-cleaning flux of the membrane separation element in Examples 2-3 compared to Example 1 is due to the use of sodium α-olefin sulfonate as the anionic surfactant in Example 1, while Examples 2-3 replaced sodium α-olefin sulfonate with sodium amidocarboxylate in the preparation of the solid cleaning agent. The higher post-cleaning flux of the membrane separation element in Example 2 is due to the reduced amount of sodium amidocarboxylate used in Example 3. This demonstrates that using sodium amidocarboxylate as the anionic surfactant in preparing the solid cleaning agent effectively improves the cleaning performance of the solid cleaning agent, thereby increasing the post-cleaning flux of the membrane separation element.

[0078] The flux of the membrane separation element after cleaning in Example 4-5 is higher than that in Example 2 and Comparative Example 1. This is because, in the preparation of the solid cleaning agent, Examples 4-5 not only use amidocarboxylic acid sodium salt to replace α-olefin sulfonate sodium as the anionic surfactant, but also use modified sodium polymethacrylate to replace sodium polymethacrylate as the cleaning aid; Example 2 only uses amidocarboxylic acid sodium salt to replace α-olefin sulfonate sodium, and Comparative Example 1 only uses modified sodium polymethacrylate to replace sodium polymethacrylate. The flux of the membrane separation element after cleaning in Example 4 is higher than that in Example 5 because, in the preparation of the solid cleaning agent, Example 5 reduces the amount of modified sodium polymethacrylate used. This shows that in the preparation of the solid cleaning agent using amidocarboxylic acid sodium salt as the anionic surfactant, further using modified sodium polymethacrylate as a cleaning aid can further increase the flux of the membrane separation element after cleaning.

[0079] 3. Determination of pressure difference after cleaning

[0080] The solid cleaning agents obtained in Examples 1-5 and Comparative Example 1 were added to pure water containing less than 100 mg / L of total dissolved solids at 25°C to a final concentration of 2%, and the pH was adjusted to 12. A previously contaminated membrane separation element was selected and installed in a membrane cleaning apparatus. The solid cleaning agents obtained in Examples 1-5 and Comparative Example 1 were respectively delivered into the membrane using a cleaning pump. The membranes were circulated or soaked for 12 hours to ensure that the solid cleaning agents obtained in Examples 1-5 and Comparative Example 1 were in full contact with the membrane separation element for cleaning. The pressure difference (MPa) across the membrane separation element after cleaning was measured. The results are shown in Table 2.

[0081] Table 2 Pressure difference after cleaning (MPa)

[0082]

[0083] As shown in Table 2, the pressure difference across the membrane after cleaning in Examples 2-3 is lower than that in Example 1. This is because, in the preparation of the solid cleaning agent, Example 1 uses sodium α-olefin sulfonate as the anionic surfactant, while Examples 2-3 use sodium amidocarboxylate in place of sodium α-olefin sulfonate. The pressure difference across the membrane after cleaning in Example 2 is lower than that in Example 3 because the amount of sodium amidocarboxylate used in the preparation of the solid cleaning agent in Example 3 is reduced. This demonstrates that using sodium amidocarboxylate as the anionic surfactant in preparing the solid cleaning agent effectively improves the cleaning performance of the solid cleaning agent, thereby reducing the pressure difference across the membrane after cleaning.

[0084] The pressure difference across the membrane after cleaning in Examples 4-5 is lower than that in Example 2 and Comparative Example 1. This is because, in the preparation of the solid cleaning agent, Examples 4-5 not only use sodium amidocarboxylate as an anionic surfactant instead of sodium α-olefin sulfonate, but also use modified sodium polymethacrylate as a cleaning aid instead of sodium polymethacrylate. Example 2 only uses sodium amidocarboxylate as an anionic surfactant instead of sodium α-olefin sulfonate, and Comparative Example 1 only uses modified sodium polymethacrylate as a cleaning aid instead of sodium polymethacrylate. The pressure difference across the membrane after cleaning in Example 4 is lower than that in Example 5 because, in the preparation of the solid cleaning agent, Example 5 reduces the amount of modified sodium polymethacrylate used. This shows that when preparing a solid cleaning agent using sodium amidocarboxylate as an anionic surfactant, further using modified sodium polymethacrylate as a cleaning aid can further reduce the pressure difference across the membrane after cleaning.

[0085] 4. Calcium ion removal efficiency

[0086] When using membrane separation elements for water purification, calcium ions coexisting in the water combine with organic matter to form a composite fouling layer on the membrane surface, affecting the normal operation of the membrane separation element. The solid cleaning agents obtained in Examples 1-5 and Comparative Example 1 were added to pure water with a total dissolved solids content of less than 100 mg / L at 25°C to a final concentration of 2%, and the pH was adjusted to 12. A pre-contaminated membrane separation element was selected and the calcium ion content before cleaning was determined using EDTA titration. The membrane separation element was then installed in a membrane cleaning device. The solid cleaning agents obtained in Examples 1-5 and Comparative Example 1 were respectively delivered to the membrane using a cleaning pump. The solid cleaning agents obtained in Examples 1-5 and Comparative Example 1 were circulated or soaked for 12 hours to ensure sufficient contact between the solid cleaning agents and the membrane separation element for cleaning. After cleaning, the residual calcium ion content on the membrane separation element was determined using EDTA titration. The calcium ion removal efficiency (%) = (calcium ion content before cleaning - calcium ion content after cleaning) / calcium ion content before cleaning × 100%. The results of the calcium ion removal efficiency are shown in Table 3.

[0087] Table 3 Calcium ion removal efficiency (%)

[0088]

[0089] As shown in Table 3, the higher calcium ion removal efficiency of Examples 2-3 compared to Example 1 is due to the use of sodium α-olefin sulfonate as the anionic surfactant in Example 1, while Examples 2-3 replaced sodium α-olefin sulfonate with sodium amidocarboxylate. The higher calcium ion removal efficiency of Example 2 compared to Example 3 is due to the reduced amount of sodium amidocarboxylate used in Example 3. This demonstrates that using sodium amidocarboxylate as the anionic surfactant in preparing solid cleaning agents can effectively improve the calcium ion removal efficiency within membrane separation elements.

[0090] The calcium ion removal efficiency of Examples 4-5 is higher than that of Example 2 and Comparative Example 1 because, in the preparation of the solid cleaning agent, Examples 4-5 not only use amidocarboxylic acid sodium salt to replace α-olefin sulfonate sodium as the anionic surfactant, but also use modified sodium polymethacrylate to replace sodium polymethacrylate as the cleaning aid; Example 2 only uses amidocarboxylic acid sodium salt to replace α-olefin sulfonate sodium, and Comparative Example 1 only uses modified sodium polymethacrylate to replace sodium polymethacrylate. The calcium ion removal efficiency of Example 4 is higher than that of Example 5 because, in the preparation of the solid cleaning agent, Example 5 reduces the amount of modified sodium polymethacrylate used. This shows that in the preparation of the solid cleaning agent using amidocarboxylic acid sodium salt as the anionic surfactant, further using modified sodium polymethacrylate as a cleaning aid can further improve the calcium ion removal efficiency inside the membrane separation element.

[0091] 5. Aluminum ion removal efficiency

[0092] When using membrane separation elements for water purification, aluminum ions coexisting in the water combine with organic matter to form a composite fouling layer on the membrane surface, affecting the proper function of the membrane separation element. The solid cleaning agents obtained in Examples 1-5 and Comparative Example 1 were added to pure water containing less than 100 mg / L of total dissolved solids at 25°C to a final concentration of 2%, and the pH was adjusted to 12. A pre-contaminated membrane separation element was selected, and the aluminum ion content of the membrane separation element before cleaning was determined using the chrome azuro blue S ultraviolet spectrophotometer method. The membrane separation element was then installed in a membrane cleaning device, and the solid cleaning agents obtained in Examples 1-5 of the present invention and Comparative Example 1 were respectively delivered into the membrane through a cleaning pump. The elements were circulated or soaked for 12 hours to allow the solid cleaning agents obtained in Examples 1-5 of the present invention and Comparative Example 1 to fully contact the membrane separation element for cleaning. After cleaning, the residual aluminum ion content on the membrane separation element was determined using the chrome azuro blue S ultraviolet spectrophotometer method. The aluminum ion removal efficiency (%) = (aluminum ion content before cleaning - aluminum ion content after cleaning) / aluminum ion content before cleaning × 100%. The results of the aluminum ion removal efficiency are shown in Table 4.

[0093] Table 4 Aluminum ion removal efficiency (%)

[0094]

[0095] As shown in Table 4, the higher aluminum ion removal efficiency in Examples 2-3 compared to Example 1 is due to the use of sodium α-olefin sulfonate as the anionic surfactant in Example 1, while Examples 2-3 replaced sodium α-olefin sulfonate with sodium amidocarboxylate. The higher aluminum ion removal efficiency in Example 2 compared to Example 3 is due to the reduced amount of sodium amidocarboxylate used in Example 3. This demonstrates that using sodium amidocarboxylate as the anionic surfactant in preparing the solid detergent effectively improves the solid detergent's aluminum ion removal efficiency from membrane separation elements.

[0096] The aluminum ion removal efficiency of Examples 4-5 is higher than that of Example 2 and Comparative Example 1 because, in the preparation of the solid cleaning agent, Examples 4-5 not only use amidocarboxylic acid sodium salt to replace α-olefin sulfonate sodium as the anionic surfactant, but also use modified sodium polymethacrylate to replace sodium polymethacrylate as the cleaning aid; Example 2 only uses amidocarboxylic acid sodium salt to replace α-olefin sulfonate sodium, and Comparative Example 1 only uses modified sodium polymethacrylate to replace sodium polymethacrylate. The aluminum ion removal efficiency of Example 4 is higher than that of Example 5 because, in the preparation of the solid cleaning agent, Example 5 reduces the amount of modified sodium polymethacrylate used. This shows that in the preparation of the solid cleaning agent using amidocarboxylic acid sodium salt as the anionic surfactant, further using modified sodium polymethacrylate as a cleaning aid can further improve the aluminum ion removal efficiency inside the membrane separation element.

[0097] The conventional operations in the operating steps of the present invention are well known to those skilled in the art and will not be described in detail here.

[0098] The embodiments described above provide a detailed description of the technical solutions of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, supplements or similar substitutions made within the scope of the principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A solid cleaning agent comprising the following components in parts by mass: 1-5 parts of a biological enzyme preparation, 3-10 parts of a surfactant, 50-75 parts of a chelating agent, 1-5 parts of a cleaning aid, and 20-30 parts of an inorganic compound; the surfactant comprises an anionic surfactant and a nonionic surfactant; the anionic surfactant is an amidocarboxylic acid sodium salt, the amidocarboxylic acid sodium salt having a benzene ring and an amide group, and in the preparation of the amidocarboxylic acid sodium salt, octadecylamine, 4-vinylbenzoic acid methyl ester, and 1,4-cyclohexanediyl chloride are reacted in the presence of an acid binding agent, and then saponified with sodium hydroxide to obtain the amidocarboxylic acid sodium salt; the acid binding agent is triethylamine; the nonionic surfactant is coconut oil fatty acid diethanolamide; the cleaning aid is Modified sodium polymethacrylate. In the preparation of the modified sodium polymethacrylate, methacrylic acid and 4-vinylbenzoic acid are mixed, toluene is added, the mixture is stirred evenly, nitrogen is introduced for 20-60 minutes, azobisisobutyronitrile is added, the mixture is stirred and reacted at 60-100°C for 2-6 hours, sodium hydroxide solution is slowly added dropwise, the reaction solution is cooled to room temperature, washed with acetone for 2-5 times, vacuum filtered, and vacuum dried at 55-75°C for 6-18 hours to obtain the modified sodium polymethacrylate. The mass ratio of the anionic surfactant to the nonionic surfactant is 1:0.1-0.5; the molar ratio of octadecylamine to methyl 4-vinylbenzoate is 1:1-2, and the molar ratio of octadecylamine to 1,4-cyclohexanediyl chloride is 1:0.2-1.

2. A solid cleaning agent according to claim 1, characterized in that: The bio-enzyme preparation comprises alkaline protease, lipase and alpha-amylase, the mass ratio of the alkaline protease to the lipase is 1:1-2, and the mass ratio of the alkaline protease to the alpha-amylase is 1:1-2.

3. A solid cleaning agent according to claim 1, characterized in that: The chelating agent comprises tetrasodium ethylenediaminetetraacetate, sodium tripolyphosphate and sodium citrate, the mass ratio of the tetrasodium ethylenediaminetetraacetate to sodium tripolyphosphate is 1:1-2, and the mass ratio of the tetrasodium ethylenediaminetetraacetate to sodium citrate is 1:0.2-1.

4. A solid cleaning agent according to claim 1, characterized in that: The inorganic compound includes sodium hydroxide and sodium sulfate, and the mass ratio of the sodium hydroxide to the sodium sulfate is 1:0.2-1.

5. A method for preparing a solid cleaning agent, comprising weighing 1-5 parts of a biological enzyme preparation, 50-75 parts of a chelating agent, 1-5 parts of a cleaning aid, and 20-30 parts of an inorganic compound, crushing and sieving the mixture with a grinder, mixing them evenly to form a powdery mixture, transporting the mixture to a disc granulator or a drum granulator, spraying 3-10 parts of a surfactant onto the surface of the mixture by high-pressure spraying, performing rolling granulation, and then transporting the granules to a drying drum for drying, sieving and screening particles with a diameter of 1.5-3.5 mm to obtain a solid cleaning agent; the biological enzyme preparation comprises alkaline protease, lipase, and α-amylase; the chelating agent comprises tetrasodium ethylenediaminetetraacetic acid, sodium tripolyphosphate, and sodium citrate; the cleaning aid is modified sodium polymethacrylate; the inorganic compound comprises sodium hydroxide and sodium sulfate; the surfactant comprises an anionic surfactant and a nonionic surfactant, the anionic surfactant is a sodium salt of an amidocarboxylic acid, and the nonionic surfactant is coconut oil. Fatty acid diethanolamide; in the preparation of the amidocarboxylic acid sodium salt, octadecylamine, methyl 4-vinylbenzoate and 1,4-cyclohexanediyl chloride are reacted in the presence of an acid binding agent, and then saponified with sodium hydroxide to obtain the amidocarboxylic acid sodium salt; the acid binding agent is triethylamine; in the preparation of the modified sodium polymethacrylate, methacrylic acid and 4-vinylbenzoic acid are mixed, toluene is added, stirred evenly, nitrogen is introduced for 20-60 minutes, azobisisobutyronitrile is added, and the mixture is heated at 60-100°C. The reaction is stirred for 2-6 hours, and a sodium hydroxide solution is slowly added dropwise. After the reaction solution is cooled to room temperature, it is washed with acetone for 2-5 times, vacuum filtered, and vacuum dried at 55-75° C. for 6-18 hours to obtain modified sodium polymethacrylate; the molar ratio of octadecylamine to methyl 4-vinylbenzoate is 1:1-2, and the molar ratio of octadecylamine to 1,4-cyclohexanediyl chloride is 1:0.2-1; and the mass ratio of the anionic surfactant to the nonionic surfactant is 1:0.1-0.

5.

6. Use of the solid cleaning agent according to claim 1 in cleaning membrane separation elements.

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