Search

CN-122011283-A - Preparation method and application of cassava starch flocculant

CN122011283ACN 122011283 ACN122011283 ACN 122011283ACN-122011283-A

Abstract

The invention relates to the technical field of water treatment flocculating agents, and discloses a preparation method and application of a tapioca starch flocculating agent. The preparation method comprises the following steps of uniformly mixing NaCl, naOH solution and tapioca starch to obtain starch slurry, stirring and reacting epichlorohydrin with the starch slurry, adding sodium hydroxide solution to adjust pH to be neutral to obtain crosslinked starch, mixing the crosslinked starch with monomer acrylamide, and then adding ammonium persulfate and sodium bisulphite to react to obtain the tapioca starch flocculant. The cassava starch flocculant prepared by the method can be used for adsorbing Pb (II) in water, and the structural stability of the cassava starch flocculant is enhanced and the flocculation rate is improved.

Inventors

  • ZHANG HUIXIANG
  • GUO YANLAN
  • HUANG YUTING
  • LIANG WEIWU
  • Yang Lingnan
  • LI ZIYUAN

Assignees

  • 桂林理工大学

Dates

Publication Date
20260512
Application Date
20260330

Claims (10)

  1. 1. The preparation method of the cassava starch flocculant is characterized by comprising the following steps of: (1) Adding tapioca starch into a mixed solution I consisting of NaCl solution and NaOH solution, and uniformly stirring to obtain starch slurry; (2) Adding epichlorohydrin into the starch slurry obtained in the step (1) for reaction, adjusting the pH value to be neutral after the reaction is finished, washing the precipitate with absolute ethyl alcohol, and drying to obtain crosslinked starch; (3) Gelatinizing the crosslinked starch prepared in the step (2) to obtain gelatinized starch, adding a monomer acryloyl into the cooled gelatinized starch under the condition of continuously introducing nitrogen, uniformly stirring, then adding a sodium bisulfate solution, uniformly stirring, finally adding ammonium persulfate, stirring and reacting to obtain a precipitate, and washing and drying the precipitate to obtain a coarse flocculant; (4) And (3) wrapping the crude flocculant obtained in the step (3) with filter paper, then placing the wrapped crude flocculant into a mixed solution II composed of glacial acetic acid and ethylene glycol for reflux extraction, washing the wrapped crude flocculant with absolute ethyl alcohol to be neutral, and drying the wrapped crude flocculant to obtain the cassava starch flocculant.
  2. 2. The preparation method of the tapioca starch flocculant according to claim 1, wherein in the step (1), the solid-to-liquid ratio of tapioca starch to the mixed solution I is (10:19) - (15:22), the unit is g: mL, the volume ratio of NaCl solution and NaOH solution in the mixed solution I is (10:1) - (35:3), the concentration of NaCl in the NaCl solution is 0.005-0.02 g/L, and the concentration of NaOH in the NaOH solution is 0.1-0.3 g/L.
  3. 3. The method for preparing the tapioca starch flocculant according to claim 1, wherein the stirring in the step (1) is carried out at a temperature of 30-45 ℃.
  4. 4. The method for preparing the tapioca starch flocculant according to claim 1, wherein the volume ratio of epoxy chloropropane to starch slurry in the step (2) is (2-4) to 20.
  5. 5. The method for preparing the cassava starch flocculant according to claim 1, wherein the reaction condition in the step (2) is that the reaction is carried out for 2-3 hours under the conditions that the pH is 10-11.5 and the temperature is 40-60 ℃.
  6. 6. The preparation method of the tapioca starch flocculant is characterized in that in the step (3), the mass ratio of crosslinked starch to monomer acrylamide is 1 (5.1-7), the mass ratio of crosslinked starch to ammonium persulfate is 1000 (5.7-11.4), the solid-to-liquid ratio of crosslinked starch to sodium bisulfite solution is 1 (1-1.5), the unit is g/mL, and the concentration of sodium bisulfite solution is 0.05-0.1 mol/mL.
  7. 7. The preparation method of the tapioca starch flocculant according to claim 1, wherein the condition of gelatinizing the crosslinked starch in the step (3) is that the reaction is carried out for 20-40 min at 70-90 ℃ under the condition of introducing nitrogen.
  8. 8. The preparation method of the tapioca starch flocculant according to claim 1, wherein the stirring reaction condition in the step (3) is 30-40 ℃ for 6-8 hours.
  9. 9. The preparation method of the tapioca starch flocculant is characterized in that the volume ratio of glacial acetic acid to ethylene glycol in the mixed solution II in the step (4) is 1:2-3:2.
  10. 10. The application of the tapioca starch flocculant prepared by the method of any one of claims 1-9 in adsorbing Pb (II) in water.

Description

Preparation method and application of cassava starch flocculant Technical Field The invention relates to the technical field of water treatment flocculating agents, in particular to a preparation method and application of a tapioca starch flocculating agent. Background The water treatment is one of the core links in the field of environmental protection, wherein the flocculation method is simple and convenient to operate, saves cost, is one of the most commonly used technologies in the water treatment process, and the flocculant is used as a core functional material of the technology, and the performance of the flocculant directly determines the water treatment effect. The flocculant is a substance which can adsorb dispersed particles in a water body and promote coagulation and sedimentation of the dispersed particles so as to realize separation and removal, and can be divided into inorganic flocculant and organic flocculant according to chemical components. The inorganic flocculant has the advantages of easily available raw materials, simple preparation, low price, strong adaptability to water treatment of various complex components, and capability of effectively removing fine suspended particles, but large dosage in the wastewater treatment process can possibly cause excessive high concentration of residual metals in the water body, and the application range is limited. The organic flocculant has the advantages of high efficiency, low sludge content, high flocculation speed and small influence of environmental conditions, so the organic flocculant is also widely applied. The organic flocculant can be divided into two major categories of synthetic polymeric flocculant and natural polymeric flocculant, wherein the synthetic polymeric flocculant has the advantages of small application range, corrosion to instruments and non-biodegradability, and the residual polymeric polyacrylamide (Polyacrylamide, PAM) in the treated water can cause the defects of neurotoxicity, carcinogenesis and the like to limit the application, and the natural polymeric flocculant is more and more valued because of natural raw materials, easy natural degradation and safety. The starch flocculant is a flocculant commonly used in wastewater treatment, but has smaller molecular weight, is generally between 5 and 25 ten thousand, is insoluble in cold water, has low stability, is directly used as a flocculant, and is poor in use effect, and in order to obtain specific flocculation performance, modification by grafting copolymerization, esterification, etherification, crosslinking and other methods is generally required. Disclosure of Invention In order to overcome the defects in the prior art, one of the purposes of the invention is to provide a preparation method of a tapioca starch flocculant, which comprises the following steps: (1) Adding the cassava starch into a mixed solution I consisting of NaCl solution and NaOH solution, and uniformly stirring to obtain starch slurry. (2) Adding epichlorohydrin into the starch slurry obtained in the step (1) for reaction, adjusting the pH value to be neutral after the reaction is finished, washing the precipitate with absolute ethyl alcohol, and drying to obtain the crosslinked starch. (3) Pasting the crosslinked starch prepared in the step (2) to obtain gelatinized starch (the use mass of water is at least 10 times of the mass of the crosslinked starch during pasting), adding monomer acrylamide into the cooled gelatinized starch under the condition of continuously introducing nitrogen, stirring uniformly (in order to ensure that the monomer acrylamide is more quickly and fully mixed with the gelatinized starch, the monomer acrylamide can be prepared into a solution and then added), then adding sodium bisulfate solution, stirring uniformly, finally adding ammonium persulfate (in order to ensure that the ammonium persulfate is more quickly and fully mixed with the gelatinized starch, the ammonium persulfate can be prepared into the solution and then added), stirring and reacting to obtain a precipitate, washing the precipitate, and drying to obtain a crude flocculant; (4) And (3) wrapping the crude flocculant obtained in the step (3) with filter paper, then putting the wrapped crude flocculant into a mixed solution II consisting of glacial acetic acid and ethylene glycol (the dosage of the mixed solution II is not particularly required, and only the filter paper is fully submerged), washing the crude flocculant with absolute ethyl alcohol to be neutral, and drying the crude flocculant to obtain the cassava starch flocculant. Preferably, in the step (1), the solid-to-liquid ratio of the tapioca starch to the mixed solution I is (10:19) - (15:22), the unit is g: mL, the volume ratio of the NaCl solution to the NaOH solution in the mixed solution I is (10:1) - (35:3), wherein the concentration of NaCl in the NaCl solution is 0.005-0.02 g/L, and the concentration of NaOH in the NaOH solution is 0.1-0.3