CN113457640B - Method and device for preparing modified sponge with high amino content and algae removal application - Google Patents

Method and device for preparing modified sponge with high amino content and algae removal application Download PDF

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CN113457640B
CN113457640B CN202110550297.9A CN202110550297A CN113457640B CN 113457640 B CN113457640 B CN 113457640B CN 202110550297 A CN202110550297 A CN 202110550297A CN 113457640 B CN113457640 B CN 113457640B
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sponge
modified
algae
extrusion
algae removal
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CN113457640A (en
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叶林顺
刘洁生
杨维东
欧浩楠
黄隽萍
梁泽雄
王雅妮
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Jinan University
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Jinan University
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/22—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising organic material
    • B01J20/26—Synthetic macromolecular compounds
    • B01J20/265—Synthetic macromolecular compounds modified or post-treated polymers
    • B01J20/267—Cross-linked polymers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/28—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties
    • B01J20/28014—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties characterised by their form
    • B01J20/28042—Shaped bodies; Monolithic structures
    • B01J20/28045—Honeycomb or cellular structures; Solid foams or sponges
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/28—Treatment of water, waste water, or sewage by sorption
    • C02F1/285—Treatment of water, waste water, or sewage by sorption using synthetic organic sorbents
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2303/00—Specific treatment goals
    • C02F2303/20—Prevention of biofouling

Abstract

The invention belongs to the technical field of high molecular adsorption materials, and particularly discloses a method and a device for preparing modified sponge with high amino content and an algae removal application. According to the invention, a uniform reaction liquid thin layer is formed on the surface of the sponge, and the polyethyleneimine and the epoxy crosslinking agent in the thin layer are crosslinked under mild conditions, so that a stable and uniform polyethyleneimine-epoxy crosslinked material is formed on the surface of the sponge. The modified sponge has high amino content, environment friendliness and low sponge modification cost, and has good prospect in the application fields due to the special structure of the sponge. The algae removal speed is high, the algae removal effect is good, the recycling and regeneration are easy.

Description

Method and device for preparing modified sponge with high amino content and algae removal application
Technical Field
The invention belongs to the technical field of high molecular adsorption materials, and particularly relates to a method and a device for preparing a modified sponge with high amino content and an application of the modified sponge in removing algae.
Background
Polymeric artificial sponges are a class of three-dimensional elastic materials with high porosity, low density and large specific surface area. Compared with the traditional form adsorbent, the artificial sponge has outstanding advantages in adsorption and liquid absorption.
There are two routes for sponge manufacture for adsorption and liquid absorption purposes: firstly, modifying the sponge by taking the existing sponge as a carrier; and secondly, directly manufacturing a new sponge body. The direct freeze-drying method and the method using crushed ice crushed to a certain size as a template method, both of which require freeze-drying and are extremely expensive. Both the two methods and the preparation of the porous material by taking salt crushed to a certain size as a template need a nonpolar or low-polar organic solvent, and are not environment-friendly preparation processes. Although it is worth exploring to directly manufacture a new sponge, the former has far less advantages in manufacturing cost, process and unique properties of the sponge than the existing sponge such as polyurethane PU sponge, melamine sponge, polystyrene sponge, etc. mature excellent sponge. The direct preparation of a sponge from polyethylenimine and an epoxy crosslinking agent is a patent. The patent prepares the cross-linked sponge through cross-linking at the low temperature of-10 to-20 ℃, and only the cross-linking reaction takes 1 to 3 days. Even if a sponge can be produced, the production is expensive and has no practical value unless it is used very specially. The PU sponge in the prior sponge body is most prominent, so the method for modifying the PU sponge has a very good application prospect.
The amino group is an important adsorption group, and the preparation of solid or sponge with high amino content and the introduction of high-density amino group on the surface of the solid have been the focus of research. From technical analysis of amine group introduction, the polymeric amine with the highest amine group content is polyethyleneimine, and the monomer is ethyleneimine. The polymer is directly polymerized and introduced on the solid phase surface, and has insurmountable inherent defects, such as main polymerization of the ethyleneimine occurs in a gas phase, the polymerization proportion on the solid phase is low, and the process is difficult to realize. The method for introducing the amino groups through multiple grafting has high cost and the effect is rapidly reduced along with the grafting times. Therefore, the formation of a cross-link of polyethylenimine with a cross-linking agent on the solid surface is a technical choice for introducing high amine content. At present, in the polymerization or cross-linking grafting reaction of solid surface modification, the liquid phase main body inevitably also reacts in the same way due to the coexistence of the liquid phase main body and the solid phase. The recovery rate of raw materials is low, the post-treatment of modified solids and residual liquid are difficult to treat, and the environment is not protected. The ring-opening crosslinking reaction condition of the polyethyleneimine and some crosslinking agents containing epoxy is mild, the environment is friendly, and the amine content of the crosslinked material is high. The layer of crosslinked material must have good stability. Although polyethyleneimine can be reacted with epoxy-containing cross-linking agents to produce sponge directly, this approach has far from advantages in terms of manufacturing cost, process and unique properties of the sponge.
Algae removal in water remains a long-felt worldwide need. The conventional algae removal technology cannot meet the requirements of continuous and stable quick algae removal, low cost, strong algae removal capability, usability of small water bodies and large water bodies and less secondary pollution.
The method can be used for efficiently and rapidly taking out and separating the algae cells from water, and performing off-line harmless treatment on the algae cells is an effective way for reducing secondary pollution in algae removal, and has special significance in particular for preventing microcystis aeruginosa from releasing microcystin. The adsorption method removes algae, and the adsorbent is easy to recycle and regenerate. There is currently no such algaecide.
Disclosure of Invention
In order to overcome the disadvantages and shortcomings of the prior art, a primary object of the present invention is to provide a method for preparing a modified sponge with high amine group content.
The invention also aims to provide the modified sponge with high amino content prepared by the method,
it is still another object of the present invention to provide the use of the above-described high amine group content modified sponge in the field of algae removal.
A further object of the present invention is a method for removing algae by the above-mentioned modified sponge having a high amine group content
It is still another object of the present invention to provide an apparatus for preparing a modified sponge having a high amine group content.
The aim of the invention is achieved by the following scheme:
the method for preparing the modified sponge with high amino content comprises the following preparation steps:
(1) Putting the pre-cooled sponge into a wetting extrusion device from an inlet, mixing the pre-cooled polyethyleneimine solution with 1, 4-butanediol diglycidyl ether ethanol solution to obtain a mixed solution, and adding the mixed solution into a charging port of the wetting extrusion device;
(2) Pushing a piston in the wetting extrusion device from bottom to top to extrude the sponge and the mixed solution, so that the surface of the sponge is completely immersed in the mixed solution; maintaining the extrusion state, releasing pressure, recovering the natural state of the sponge, and forming a uniformly distributed reaction liquid film on the surface of the sponge;
(3) The sponge with the surface forming the evenly distributed reaction liquid film is stood under the airtight condition for crosslinking reaction; washing until the pH value is unchanged after the reaction is finished, and drying to obtain the modified sponge with high amino content.
The sponge in the step (1) is a sponge with hydrogen bonds on the surface, and is preferably PU sponge.
The concentration of the polyethyleneimine solution in the step (1) is 0.05-0.5 g/mL, preferably 0.1-0.4 g/mL, more preferably 0.1g/mL; the imine chain unit content in the polyethyleneimine solution is 2.33-9.32 g/mL, preferably 2.33mmol/mL; the molecular weight of the polyethyleneimine is 1800-70000, preferably 20000; the solvent of the polyethyleneimine solution is a mixed solvent of water and ethanol, and the volume ratio of the ethanol to the water is 0.5-1, preferably 1.
The concentration of the 1,4 butanediol diglycidyl ether ethanol solution in the step (1) is 0.15-0.25 g/mL, preferably 0.157g/mL; the epoxy concentration of the 1, 4-butanediol diglycidyl ether ethanol solution is 1.0-1.5 mmol/mL, preferably 1.16mmol/mL, calculated by epoxy number 0.74.
The molar ratio of the imine chain unit mole number in the polyethyleneimine in the mixed solution in the step (1) to the epoxy group mole number in the 1,4 butanediol diglycidyl ether is 8-16:1, preferably 10:1.
The pre-cooling in step (1) is preferably performed by means of an ice salt bath.
The density of the PU sponge in the step (1) is 20-80 mg/mL, preferably 22-60 mg/mL, more preferably 22mg/L and 60mg/L. The PU sponges with the densities of 22mg/L and 60mg/L are respectively selected into full open pores and half open pores correspondingly. The porosity is greater than 99%. The PU sponge is cooled and then put into the mixed solution for soaking, extrusion and surface uniform wetting.
The ratio of ethanol to water of the mixed solvent in step (1) is selected depending on the requirement that the crosslinking agent is completely dissolved at low temperature.
The volume ratio of the mixed solution and the PU sponge in the step (2) is 0.144-0.313:1;
in the extrusion state in the step (2), the extrusion rate of the sponge is 65% -87.5%. Preferably 65% and 87.5%;
the holding time of the extrusion state in the step (2) is 1-3 min. The sponge can reach a normal shape by decompression, and the steps are repeated until the mixed solution forms a uniform liquid film layer on the surface of the sponge.
The temperature of the cross-linking in the step (3) is 35-50 ℃, and the time of the cross-linking is 90-120 min. Preferably, the temperature is 40 ℃. The crosslinking time is 90min and 120min, and is determined by the heat transfer influencing properties of the reaction vessel and the sponge, the structural parameters and the thickness of the liquid film. More preferably, the sponge is turned 180 ° every 3 to 6min 25 to 35min before the crosslinking process. Therefore, uneven distribution of reactants caused by downward flow of gravity of the liquid film can be reduced before polyethyleneimine and the cross-linking agent in the liquid film are fully cross-linked.
And (3) drying at the temperature of 45-50 ℃ under normal pressure or under reduced pressure until the weight is constant.
Further explanation of the process parameters in the above modification step:
the molecular weight of the polyethyleneimine is 20000. The modification was also performed with two kinds of polyethyleneimines having molecular weights 70000 and 1800, and neither of these molecular weights was suitable from the viewpoint of the swelling property of the crosslinked material, the molecular weight of the crosslinked material, and the fluidity of the reactant molecules in the liquid film layer. The crosslinking reaction is carried out in the thin liquid film under mild conditions, the requirement on the crosslinking agent is high, and the original sponge basic form is still required to be maintained in the modified sponge. The modification effects of 1, 4-butanediol diglycidyl ether and polyethylene glycol diglycidyl ether were compared by experiments, and the former was better.
The weight concentration of polyethyleneimine or the concentration of imine chain links, the weight concentration of 1, 4-butanediol diglycidyl ether ethanol solution and the concentration of epoxy are selected so as to ensure that no crosslinking reaction occurs during wetting and ensure that the reaction solution is uniformly wetted at low temperature. These several concentration choices are also related to the amount of crosslinks formed in the thin film layer of sponge surface per unit area, as well as to the fluidity of the thin film layer of reactant. The flowability affects the uniformity of the crosslinks in the liquid film. In addition, the influence on the swellability of the crosslinked material, the pore size and the washing effect is also considered.
The ratio of the number of imine links to the number of epoxy groups is 10:1, which is a reasonable parameter derived from the degree of crosslinking and the amine group content of the crosslinks. Obviously less than 10:1, is unfavorable for ensuring the relatively high amino content in the crosslinked material, obviously more than 10:1, is unfavorable for forming the crosslinked material with high molecular weight, and reduces the stability of the crosslinked material on the surface of the sponge.
The sponge extrusion rate operating value is related to the density of the sponge, the ratio of the volume of the reaction mixture (mL)/the volume of the sponge (mL), the opening ratio of the sponge, the size of the sponge in operation, the swelling performance of the sponge by the solvent and the reactant, and the connectivity of pores.
The crosslinking time is related to the molecular weight of the crosslinked material, the stability of the crosslinked material attached to the surface of the sponge, the maintenance of the morphology of the sponge, the preheating time required for different sponge sizes, the geometry of the sponge, the heat transfer effect of the reactor, etc.
The wash squeeze shrinkage is different from the wetting operation, which is related to the swelling properties of the wet crosslinks, the sponge open cell content, pore connectivity, the density of the sponge, and the like.
A modified sponge with high amino content is prepared by the method.
The application of the modified sponge with high amino content in algae removal; the algae is preferably blue algae, green algae and diatom.
The method for removing algae by the modified sponge with high amino content comprises the following steps: and placing the modified sponge with high amino content in the algae-polluted water body to adsorb the algae.
Preferably, the modified sponge after adsorbing algae is recovered, regenerated and amino-protonated for recycling.
The device for realizing the preparation method of the modified sponge with high amino content comprises the following components:
wetting the extrusion device and the auxiliary device;
the wetting extrusion device comprises a device wall, a piston closely contacted with the device wall, a pressurizing device, a charging port and a liquid outlet.
Preferably, the auxiliary devices comprise buffer bottles and safety bottles, tail gas washing and absorbing devices.
The device can be used for forming other uniform reaction liquid films on the surface of the sponge or modifying the sponge by dip-coating method to manufacture and wash the sponge. In actual operation, the piston extrudes the sponge from bottom to top until the sponge is completely immersed in the reaction liquid, so that the reaction liquid is uniformly distributed on the surface of the sponge.
The invention has the beneficial effects that:
according to the invention, a uniform reaction liquid thin layer is formed on the surface of the PU sponge, and the polyethyleneimine and the epoxy crosslinking agent in the thin layer are crosslinked under mild conditions, so that a stable and uniform polyethyleneimine-epoxy crosslinked material is formed on the surface of the sponge. The modified sponge has high amino content, environment friendliness and low sponge modification cost. And the modified sponge has good prospect in the application fields because of the special structure of the sponge. The algae removal speed is high, the algae removal effect is good, the recycling and regeneration are easy.
Drawings
Fig. 1 is a diagram of an apparatus used in the present invention.
FIG. 2 shows the change in N-H and C-H infrared absorption intensity before and after sponge modification.
FIG. 3 is a comparison of the sponge modification with the absorption peaks of the O-H, N-H infrared signature in the starting material.
FIG. 4 shows the change in infrared absorption peak of epoxy before and after the reaction of raw material B.
FIG. 5 shows the change in pore size of the sponge as such and the modified sponge, wherein (a) is a sponge as such having a density of 22mg/mL, (b) is a sponge modified sample prepared in example 2, (c) is a sponge as such having a density of 60mg/mL, and (d) is a sponge modified sample prepared in example 3.
FIG. 6 shows the results before and after modification of the sponge and the crosslinked product.
FIG. 7 is a graph showing the ratio of the volume of water to the volume of sponge (V w /V s ) Visual image of algae removal effect; control group without sponge and V from left to right w /V s ＝18.75、V w /V s ＝9.38、V w /V s ＝6.25、V w /V s ＝4.69、V w /V s ＝3.13。
FIG. 8 is a visual chart of adsorption time versus algae removal effect; from left to right, 0min, 1min, 5min, 10min, 20min, 30min, 60min, and 90min respectively.
FIG. 9 is a comparison of the algae removal effect of different density sponges; wherein (a) is a water sample graph of the sponge in example 1 after algae removal at different times, (b) is a water sample graph of the sponge in example 3 after algae removal at different times, (c) is a physical graph of the sponge in example 1 after algae removal, and (d) is a physical graph of the sponge in example 3 after algae removal.
FIG. 10 shows the color of the liquid algae eluted from the regenerated liquid by the modified sponge obtained in example 1.
The figure 11 shows the algae removal effect of the stock solution and the modified sponge obtained in example 1 after 1 to 5 times of regeneration from left to right.
Fig. 12 shows the appearance of the modified sponge obtained in example 1 after 1 to 5 regenerations, in order from left to right.
FIG. 13 is a comparison of the algae removal effect of two density-modified sponges before and after amine-based protonation; wherein (a) is the modified sponge prepared in example 1; (b) A modified sponge prepared in example 3.
FIG. 14 is a front-to-back comparison of different size modified sponges with microcystis aeruginosa; wherein (a) and (c) are the modified sponges prepared in example 2, the left is before removing algae, and the right is after removing algae; (b) and (d) are modified sponges obtained in example 1.
Detailed Description
The present invention will be described in further detail with reference to examples and drawings, but embodiments of the present invention are not limited thereto. The reagents used in the examples are commercially available as usual unless otherwise specified.
In the examples, the sponge weight W 0 The weight gain DeltaW, the weight gain rate beta and the reaction yield zeta of the modified sponge are calculated as follows:
sponge extrusion rate η:
wherein: v (V) 0 -the volume of the sponge before extrusion; v (V) s -the volume of the sponge after extrusion.
Example 1
The preparation method of the aminated low-density modified sponge specifically comprises the following preparation steps:
(1) Feeding in a wet extrusion device
A solution of polyethylenimine (ethanol: water=1) having a molecular weight of 20000 was used as the raw material A reaction solution, and the concentration by weight was 0.1g/mL, and the concentration of the imine chain unit was 2.33mmol/mL. The 1,4 butanediol diglycidyl ether ethanol solution is used as the reaction solution of the raw material B, the weight concentration is 0.157g/mL, and the epoxy concentration is 1.16mmol/mL according to the epoxy number of 0.74. The imine chain number/epoxy number is 10:1, the corresponding volumes of the reaction liquid A and the reaction liquid B are taken, and the mixture is mixed and stirred uniformly under the cooling of an ice salt bath. A pre-cooled PU sponge of size 2X 2cm and density 22mg/mL was placed into the wet extrusion apparatus from the sponge inlet. The reaction mixture was fed from the feed port to the wetting apparatus as shown in FIG. 1. The ratio of the volume (mL) of the reaction mixture/the sponge volume (mL) was 0.144;
(2) Liquid film wetting treatment for forming sponge surface
The PU sponge and the reaction mixture were extruded from the bottom to the top in the apparatus shown in FIG. 1 at a sponge extrusion rate of 87.5% so that the surface of the sponge was completely immersed in the reaction mixture. When the piston is in the extrusion position, the piston stays for 1min, then the pressure is relieved, and the sponge returns to the normal shape. And when the pressure is released, the point C is closed, and the point A is communicated with the point B. The reaction solution is repeated for three times, so that a uniform liquid film layer is formed on the surface of the sponge.
(3) Cross-linking reactions in liquid film layers on sponge surfaces and microscopic characterization of cross-linking reactions
The sponge of the uniformly wetted reaction mixture is placed in a sealed reactor preheated at 40 ℃ and having good heat transfer performance, and crosslinked for 90min at 40 ℃. The sealed reactor is turned up and down 180 degrees once every 5min for the first 30min, and the chemical reaction formula of the crosslinking is shown as the formula I.
(4) Washing of modified sponge
After the reaction is finished, transferring the product into an ice salt cooling bath for cooling, transferring the cooled sponge into a washing device, adding washing water according to the volume of 2 times of the sponge, washing for 15min in a shaking table (rotary type, shaking speed is 140 r/min), taking out the sponge after the washing time is up, extruding the modified sponge in an extruding device, wherein the sponge extrusion rate is 25%, and then adding the washing water for washing. The washing and extrusion are carried out for 3 to 4 times until the pH value of the washing liquid is unchanged, and the pH value of the yielding water is slightly more than 7.
(5) Modified sponge drying
After washing, the sponge is extruded and dried at 45-50 deg.c under normal pressure or reduced pressure to constant weight.
Example 2
The difference between this example and example 1 is that the sponge has a size of 10X 2cm, a density of 22mg/mL, a sponge extrusion rate of 87.5% and a crosslinking time of 120min; the wash squeeze rate was 25%.
Example 3
The difference between this example and example 1 is that the sponge size is 2X 2cm, the density is 60mg/mL, the sponge extrusion rate is 65%, and the crosslinking time is 110min; the wash squeeze rate was 50%.
Example 4
The difference between this example and example 1 is that the sponge has a size of 10X 2cm, a density of 60mg/mL, a sponge extrusion rate of 65% and a crosslinking time of 120min; the wash squeeze rate was 50%.
TABLE 1 Effect of modification of modified sponges obtained in examples 1 to 4
In examples 2 and 3, the starting materials wereThe infrared spectra of the crosslinked material and the two kinds of density sponges before and after modification are shown in figures 2-4. Wherein 22 sponge as such refers to the unmodified sponge in example 2, 22 modified sponge refers to the modified sponge prepared from example 2, 60 sponge as such refers to the unmodified sponge in example 3, and 60 modified sponge refers to the modified sponge prepared from example 3. From FIGS. 2 and 3, it is seen that the absorption peak of the hydroxyl newly generated after the epoxy ring-opening is overlapped with the N-H absorption peak to form 3600cm -1 The absorption intensity is significantly increased by the broad peak at the N-H absorption wavenumber position, and the maximum absorption is at the N-H absorption wavenumber position. The intensity of the C-H characteristic absorption peak is obviously increased. From FIG. 3 it is seen that raw African B is at 3499cm -1 The hydroxyl absorption peak is different from that of modified sponge and crosslinked matter, and the modified sponge and crosslinked matter have one superposed hydroxyl and N-H radical absorption peak, so that the butanediol material has less hydroxyl radical completely etherified with glycidol. From fig. 4, it can be seen that the epoxy characteristic absorption peak in the raw material B has disappeared in both the crosslinked material and the modified sponge, confirming that the epoxy group in the crosslinking agent has sufficiently reacted with the amine group in the polyethyleneimine. The pore structure changes before and after sponge modification in examples 2 and 3 are shown in FIG. 5. As can be seen from FIG. 5, the pores of both densities are reduced as a whole after the sponge modification. The physical diagram of the original sponge, the modified sponge and the crosslinked product is shown in fig. 6. The crosslinks are also white in color and insoluble in water. No obvious change before and after modification of the sponge was seen from the color.
The modified sponges of examples 1 to 4 were immersed in water, 0.5M sulfuric acid aqueous solution and 0.5M sodium hydroxide aqueous solution at normal temperature for 48 hours without weight loss. The crosslinks attached to the sponge surface were crosslinked products of polyethylenimine and crosslinker (number of imine linkages/number of epoxy=10:1). The crosslinked material, although containing a large amount of hydrophilic amine groups and hydroxyl groups newly generated after ring opening, is insoluble in water, which indicates that the molecular weight of the crosslinked material is large, and the crosslinked material has abundant hydrogen bonds between the amine groups and the hydroxyl groups in the molecule. The amino and hydroxyl groups in the cross-linked material and the structural unit-NHCOO-on the surface of the PU sponge also have rich hydrogen bonds. Therefore, the layer of crosslinked material attached to the surface of the PU sponge has good stability. Therefore, the sponge modification is not limited to PU sponge, and can prepare the crosslinking matter modified layer with similar stability through the invention as long as the surface of the sponge and the crosslinking matter have rich hydrogen bonds. After 50 times of back and forth extrusion after the sponge is modified, the included angle and the side length of the tetragonal body are measured, and the shape is proved to be unchanged.
Example 5
The obtained modified sponge is completely squeezed, then the modified sponge is squeezed and wetted for 15min by using 1/4 of the volume of the sponge and 0.25M dilute hydrochloric acid solution, the amino groups of the modified sponge are completely protonated, and then the protonated modified sponge is put into a water body polluted by algae. The algae-containing water samples of the following (1) to (5) mainly comprise blue algae, green algae and diatom. The modified sponges used in the following (1) to (5) were each square with a size of 2X 2 cm. The water sample of (6) is a copper-containing green microcystis water sample.
(1) The ratio of the volume of different water bodies to the volume of sponge (V w /V s )
V w /V s The values were set to 3.13, 4.69, 6.25, 9.38 and 18.75, and the modified sponge obtained by protonation in example 1 was put into an algae-contaminated water body at a pH of about 7 at normal temperature without light shielding, and the water body was shaken at a low speed of 50r/min for 20min to perform an adsorption test. FIG. 7 is V w /V s Visual image of algae removal effect.
(2) Different algae sucking time
The algae absorption time is set to 0, 1min, 5min, 10min, 20min, 30, 60min, 90min, and the modified sponge of the embodiment 1 is put into the algae polluted water body with pH=7 at normal temperature and in no light shielding, V w /V s The adsorption test was performed by shaking at a low speed of 50r/min at a speed of 6.25.
From fig. 8, it can be seen that when the algae suction time is 20min, although the best algae removal rate has not been achieved yet, the algae removal effect is already good, and the algae removal rate is 82% calculated as the chromaticity removal rate. The rapid algae removal is beneficial to meeting the time requirement of emergency algae removal. The algae removal is not carried out in a dark way, is a condition for removing algae in situ, has good algae removal effect, and proves that the algae suction speed of the modified sponge has a competitive advantage on the natural algae propagation speed.
(3) Comparison of algae sucking effects of different sponge densities
The algae sucking time is set to 0, 5min, 15min, 30, 60min and 90min. At normal temperature, without light shielding, the amino group protonated modified sponges of example 1 and example 3 were put into algae-contaminated water with ph=7, V w /V s The adsorption test was performed by shaking at a low speed of 50r/min for 20min at a speed of 6.25. The modified algaecide effect of the sponge with a density of 22mg/mL and the sponge with a density of 60mg/mL of the two examples is shown in FIG. 9. After equilibrium of algae absorption is reached, the chromaticity removal rate is 86.2% and 85.3%. It is also seen from fig. 9 that the chromaticity of the algae-containing water sample was reduced by about 8% after the same time of contact of the original sponge with the algae-containing water sample, and the color of the original sponge (unmodified sponge) was not greatly changed. FIG. 9 is a graph showing the comparison of the appearance of a sponge having a density of 22mg/mL and a modified sponge having a density of 60mg/mL after adsorption of algae. From the figure, it is seen that the color after absorbing algae by the sponge with low density of 22mg/mL is darker than that by the sponge with high density of 60mg/mL at the initial stage of absorption, but the colors are relatively close to each other at the later stage of algae absorption. This is because the pore size of the low-density sponge is larger than that of the high-density sponge, so that the diffusion resistance is smaller and the algae sucking speed is higher. The use of a low density sponge is more desirable from a cost standpoint.
(4) Regeneration of sponge and sponge reprotonation
The recycled sponge is extruded and wetted by 0.25M sodium hydroxide solution for 15min, the volume of the solution is 10 percent more than that of the protonated 0.25M hydrochloric acid solution, and the sponge after the alkali treatment is extruded after the wetting is finished, so that the regeneration operation is completed. FIG. 10 shows the color of the algae liquid eluted from the algae cells adsorbed by the sponge by the regeneration liquid compared with the color of the stock solution.
The regenerated modified sponge is fully protonated with 0.25M dilute hydrochloric acid solution and the alkali left in the liquid film layer after the regeneration treatment is exactly neutralized. FIG. 11 is a graph showing the algae removal effect of the modified sponge obtained in example 1 regenerated 1 to 5 times. (Normal temperature, pH=7, V) w /V s Low-speed shaking for 20min, not light-protected =6.25, 50 r/min). Fig. 12 shows the appearance of the sponge after 1-5 regenerations.
(5) Comparison of the algicidal Effect of acid-treated and non-acid-treated modified sponges
The amino group is a group with strong protonation capability, the amino group protonation is one of basic conditions of algae absorption, and V is not protected from light at normal temperature w /V s The modified sponges of examples 1 and 3, which had been subjected to the amine group protonation treatment and which had not been subjected to the amine group protonation treatment, were put into a water body contaminated with algae having a ph=7, and were agitated at a low speed of 50r/min for 60min, and subjected to an adsorption test. The algae removal effect is compared with the graph. As can be seen from FIG. 13, the protonation treatment effect is not obvious, and the algae removal effect is good. Therefore, the modified sponge of the invention can be used for removing algae without acid treatment. The sponge after absorbing the algae is extruded and then regenerated by dilute alkali liquor. The sponge for eluting and adsorbing algae cells is extruded, but a layer of dilute alkali solution is still on the surface of the sponge. In order to reduce the cost by washing, dilute acid solution can be directly used for neutralizing the dilute alkali of the liquid film to recover the protonation state of the spongy amino.
In summary, the algae removal operation and preferred conditions are as follows:
the sponge from which algae is removed for the first time can be treated without protonation. After the regeneration of the algae-absorbing sponge, the algae-absorbing sponge needs acid treatment to recover the protonation state of the spongy amino. Preferred conditions are: normal temperature, ph=7 or so, V w /V s Low-speed shaking of 3-9.38 and 50r/min, 20-60 min and no light shielding. Aiming at the actual water sample containing algae, the algae removal rate can reach 82 to 86.2 percent.
(6) Microcystis aeruginosa removed by modified sponges of different sizes
The protonated amine group is a small group, and can effectively prevent the damage of microcystis aeruginosa cells during the adsorption and algae removal, thereby reducing the risk of microcystin release to water. The modified sponge has high algae removal speed, and is also beneficial to preventing the risk of microcystin released into the water body.
Square modified sponges of example 1 size 2 x 2cm and example 2 size 10 x 2cm were directly added to a copper-green microcystis-containing water sample without protonation. The algae cell density of the water sample containing the microcystis aeruginosa is 6.53 multiplied by 10 6 The absorbance at 682nm was measured at each mL to calculate the algae removal rate. Algae removal conditions: normal temperature, ph=7 or so, V w /V s Is 6.25 and 50r/min and shake at low speed for 20min withoutAnd (5) light shielding. The former algae removal rate reaches 83% and the latter algae removal rate reaches 89% from the chromaticity removal rate. See fig. 14.
The above examples are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above examples, and any other changes, modifications, substitutions, combinations, and simplifications that do not depart from the spirit and principle of the present invention should be made in the equivalent manner, and the embodiments are included in the protection scope of the present invention.

Claims (10)

1. The method for preparing the modified sponge with high amino content is characterized by comprising the following preparation steps:
(1) Putting the pre-cooled sponge into a wetting extrusion device from an inlet, mixing the pre-cooled polyethyleneimine solution with 1, 4-butanediol diglycidyl ether ethanol solution to obtain a mixed solution, and adding the mixed solution into a charging port of the wetting extrusion device;
(2) Pushing a piston in the wetting extrusion device from bottom to top to extrude the sponge and the mixed solution, so that the surface of the sponge is completely immersed in the mixed solution; maintaining the extrusion state, releasing pressure, recovering the natural state of the sponge, and forming a uniformly distributed reaction liquid film on the surface of the sponge;
(3) The sponge with the surface forming the evenly distributed reaction liquid film is stood under the airtight condition for crosslinking reaction; washing until the pH value is unchanged after the reaction is finished, and drying to obtain the modified sponge with high amino content.
2. The method according to claim 1, characterized in that:
the molar ratio of the imine chain unit number in the polyethyleneimine in the mixed solution in the step (1) to the epoxy group in the 1, 4-butanediol diglycidyl ether is 8-16:1.
3. The method according to claim 1, characterized in that:
the sponge in the step (1) is PU sponge;
the concentration of the polyethyleneimine solution in the step (1) is 0.05-0.5 g/mL;
the concentration of the 1, 4-butanediol diglycidyl ether ethanol solution in the step (1) is 0.15-0.25 g/mL.
4. A method according to claim 3, characterized in that: the density of the PU sponge in the step (1) is 22-80 mg/mL; the volume ratio of the mixed solution in the step (2) to the PU sponge is 0.144-0.313:1.
5. The method according to claim 1, characterized in that: in the extrusion state in the step (2), the extrusion rate of the sponge is 65% -87.5%; the holding time of the extrusion state in the step (2) is 1-3 min.
6. The method according to claim 1, characterized in that: the temperature of the cross-linking in the step (3) is 35-50 ℃, and the time of the cross-linking is 90-120 min.
7. A modified sponge having a high amine group content, prepared by the method of any one of claims 1 to 6.
8. Use of a modified sponge with a high amine content according to claim 7 for algae removal.
9. A method for removing algae by the modified sponge having a high amine group content as claimed in claim 7, comprising the steps of: the modified sponge with high amino content is placed in a water body polluted by algae to adsorb the algae.
10. An apparatus for realizing the preparation method of the modified sponge with high amino content as claimed in any one of claims 1 to 6, which is characterized by comprising a wetting extrusion device and an auxiliary device, wherein the wetting extrusion device comprises: the device comprises a device wall, a piston closely contacted with the device wall, a pressurizing device, a charging port and a liquid outlet;
the auxiliary device comprises a buffer bottle, a safety bottle and a tail gas washing and absorbing device.
CN202110550297.9A 2021-05-20 2021-05-20 Method and device for preparing modified sponge with high amino content and algae removal application Active CN113457640B (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5162404A (en) * 1989-08-18 1992-11-10 Rainer Norman B Ion-absorbent sponge product
JP2019017713A (en) * 2017-07-18 2019-02-07 東レ・ファインケミカル株式会社 Porous body compression molding
CN209208723U (en) * 2018-11-27 2019-08-06 南京林顿自动化设备有限公司 A kind of car washing machine
CN110845757A (en) * 2018-08-20 2020-02-28 日立化成株式会社 Preparation method of polymer sponge and polymer sponge

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5162404A (en) * 1989-08-18 1992-11-10 Rainer Norman B Ion-absorbent sponge product
JP2019017713A (en) * 2017-07-18 2019-02-07 東レ・ファインケミカル株式会社 Porous body compression molding
CN110845757A (en) * 2018-08-20 2020-02-28 日立化成株式会社 Preparation method of polymer sponge and polymer sponge
CN209208723U (en) * 2018-11-27 2019-08-06 南京林顿自动化设备有限公司 A kind of car washing machine

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