Preparation method for modifying nanofiltration membrane by utilizing carboxylated nanocellulose crystals

A nanocellulose, carboxylation technology, applied in chemical instruments and methods, membrane, membrane technology and other directions, can solve the problems of insufficient hydrophilicity of additives, human and environmental hazards, and toxic additives, and achieve good anti-pollution characteristics, Environmentally friendly, highly selective effects

Inactive Publication Date: 2020-08-18
HARBIN INST OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The present invention aims to solve the technical problems of toxicity of additives in the modification process of existing nanofiltration membranes, easy harm to the human body and the environment, and insufficient hydrophilicity of additives, and provides a method for modifying nanofiltration membranes using carboxylated nanocellulose crystals. Membrane Preparation Method

Method used

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  • Preparation method for modifying nanofiltration membrane by utilizing carboxylated nanocellulose crystals
  • Preparation method for modifying nanofiltration membrane by utilizing carboxylated nanocellulose crystals
  • Preparation method for modifying nanofiltration membrane by utilizing carboxylated nanocellulose crystals

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Experimental program
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Effect test

Embodiment 1

[0036] Embodiment 1: The carboxylated nanocellulose crystals used in this implementation are completed according to the following steps:

[0037] Step 1. Mix 500 mg of nanocellulose crystals with 50 mL of deionized water to obtain a suspension of nanocellulose crystals, then add 0.01 g of tetramethylpiperidine nitrogen oxide (TEMPO) and 0.21 g of sodium bromide;

[0038] Step 2, then stir at 200rpm for 5min, then use a sodium hypochlorite solution with a concentration of 1.24mol / L, adjust the pH value to 10 with hydrochloric acid, carry out the oxidation reaction for 45min under continuous stirring, terminate the oxidation reaction with methanol, and then add hydrochloric acid to adjust the pH value When the pH value is equal to 7, dialyze the water-insoluble substance for one week to remove impurities, and then freeze-dry to obtain carboxylated nanocellulose crystals. The diameter of the obtained carboxylated nanocellulose crystals is 15-30nm, and the length is 50-150nm. Rod-...

Embodiment 2

[0050] Example 2: The carboxylated nanocellulose crystals used in this implementation were prepared by the method in Example 1.

[0051] Utilize the preparation method of carboxylated nano-cellulose crystal modified nanofiltration membrane in this implementation to carry out according to the following steps:

[0052] Step 1. Add carboxylated nanocellulose crystals to 20 mL of a piperazine solution with a concentration of 0.5 wt%, and ultrasonically disperse until uniformly dispersed to obtain an aqueous solution of carboxylated nanocellulose crystals with a concentration of 0.02 wt% piperazine;

[0053] Step 2, using concentration as 0.15wt% Na 3 PO 4 12H 2 O solution adjusts the pH value of the piperazine aqueous phase solution obtained in step 1 to 11;

[0054] Step 3, immersing the polyethersulfone membrane in the piperazine aqueous phase solution treated in step 2, taking it out after immersing for 20 minutes, and then removing the excess solution on the surface;

[00...

Embodiment 3

[0057] Example 3: The carboxylated nanocellulose crystals used in this implementation were prepared by the method in Example 1.

[0058] Utilize the preparation method of carboxylated nano-cellulose crystal modified nanofiltration membrane in this implementation to carry out according to the following steps:

[0059] Step 1. Add carboxylated nanocellulose crystals to 20 mL of a piperazine solution with a concentration of 1.20 wt%, and ultrasonically disperse until uniformly dispersed to obtain an aqueous solution of carboxylated nanocellulose crystals with a concentration of 0.01 wt% piperazine;

[0060] Step 2, use concentration as 0.2wt% Na 3 PO 4 12H 2 O solution adjusts the pH value of the piperazine aqueous phase solution obtained in step 1 to 11;

[0061] Step 3, immersing the polyethersulfone membrane in the piperazine aqueous phase solution treated in step 2, taking it out after immersing for 15 minutes, and then removing the excess solution on the surface;

[0062...

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Abstract

The invention discloses a preparation method for modifying a nanofiltration membrane by utilizing carboxylated nanocellulose crystals and belongs to the field of membrane material preparation. The invention aims to solve the technical problems of toxicity, high possibility of harm to human bodies and the environment and insufficient hydrophilicity of an additive in the modification process of theconventional nanofiltration membrane. The method comprises the following steps: preparing a water phase from carboxylated nanocellulose crystals and a piperazine solution, carrying out polymerizationreaction on the water phase and oil phase trimesoyl chloride at an interface, and drying the reaction product to obtain the carboxylated nanocellulose crystal modified film composite nanofiltration membrane. According to the preparation method, the hydrophilicity of the carboxylated nanocellulose crystals is utilized, the carboxylated nanocellulose crystals are wrapped in the carboxylated nanocellulose crystals while interfacial polymerization reaction is carried out through the properties of water and oil, and the prepared membrane composite nanofiltration membrane increases the water transmittance and has high desalination rate and dye removal rate.

Description

technical field [0001] The invention belongs to the field of membrane material preparation; in particular, it relates to a preparation method of a nano-cellulose crystal modified nanofiltration membrane. Background technique [0002] Nanofiltration membrane is a pressure-driven membrane between ultrafiltration membrane and reverse osmosis membrane. The molecular weight cut-off of the nanofiltration membrane is 200-100 g / mol, and the pore diameter is 0.5-2.0 nm. Its surface charge can be tuned to be positive or negative and can be highly automated, requiring only a small factory footprint. These properties make nanofiltration membranes widely used in water treatment to achieve seawater desalination, ion separation, wastewater reuse and drinking water purification. The most advanced nanofiltration membranes are thin film composite (TFC) nanofiltration membranes. Some additives in TFC membranes are toxic to the environment and endanger human health, which limits their applic...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D61/02B01D67/00B01D69/02B01D71/30B01D71/34B01D71/42B01D71/68C02F1/44
CPCB01D61/027B01D67/0002B01D69/02B01D71/30B01D71/34B01D71/42B01D71/68B01D2325/36C02F1/442Y02A20/131
Inventor 白朗明梁恒张盟刘亚涛李圭白
Owner HARBIN INST OF TECH
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