A preparation method of modified polyethersulfone functionally gradient composite membrane

Abstract

Disclosed is a preparation method of a modified polyether sulfone functional gradient composite membrane. The preparation method mainly includes the following steps: firstly, twice chloroacetylation treatment are carried out on polyether sulfone; secondly, the chloroacetylated polyethersulfone and diethylene triamine pentaacetic acid and diethylenetriamine are subjected to a chemical bonding reaction to prepare a membrane casting solution for a polyether sulfone functional separation membrane with a polyaminocarboxylic acid functional group; thirdly, a membrane is formed by using a phase transfer technology; and finally, the surface of the separation membrane is coated with a polyethyleneimine / piperazine aqueous solution and a trimesoyl chloride n-heptane solution, and a dense nanofiltration ultrathin layer is formed by an interfacial polymerization reaction, which is the modified polyether sulfone functional gradient composite membrane. The method of the invention is simple and feasible, the coating process of the nanofiltration ultrathin layer is environmentally friendly, the prepared polyether sulfone functional gradient separation membrane realizes gradient treatment of pollutants, and water contaminated by heavy metals with high concentration can be directly discharged because the water reaches the standard or reused after being treated by the polyether sulfone functionalgradient separation membrane, thereby effectively reducing the construction cost. The modified polyether sulfone functional gradient composite membrane has good engineering application prospects.

Description

technical field [0001] The invention relates to a preparation method of a separation membrane, in particular to a preparation method of a modified polyethersulfone functional gradient composite membrane. Background technique [0002] In recent years, with the rapid growth of the national economy, it is objectively required that the progress and improvement of industries such as industrial development and intelligent manufacturing must be in step with it. The industrial fields represented by electric power, metallurgy, precision manufacturing, petrochemical, textile, and thermal power use water A sharp increase in the amount of heavy metal pollutants has resulted in an increase in the discharge of wastewater containing heavy metal pollutants, resulting in more serious heavy metal water pollution. Heavy metal pollutants such as lead, copper, mercury, nickel, and cadmium in water bodies are volatile in form and cannot be degraded by microorganisms, but can be passed through the...

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Problems solved by technology

The nanofiltration membrane has high permeability selectivity, good oxidation resistance and pollution resistance, and its interception effect on low-concentration heavy metal ion wastewater is obvious, but its effect on high-concentration heavy metal ion wastewater treatment is not good.

In addition, it has been reported that polyethersulfone with chloroacetyl groups is prepared first, and then the polyethersulfone with chloroacetyl groups is reacted with polyvinylamines such as tetraethylenepentamine to prepare polyvinylamine groups. Then, the polyvinylamine group of the separation membrane is phosphonated with paraformaldehyde and phosphorous acid, and finally, by means of interfacial polymerization, the polyethersulfone with aminophosphonic acid functional groups is separated. The surface of the membrane is coated with a nanofiltration separation thin layer, and then a new type of polyethersulfone functional composite membrane is prepared. This functional composite membrane can remove heavy metal pollutants in gradients, but the heavy metal adsorption efficiency of the inner adsorption layer is not ideal. Adsorption performance still needs to be greatly improved

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