Preparation method of carbon nanotube nanosilica co-modified polyvinyl alcohol composite ultra-filtration membrane

Abstract

The invention discloses a preparation method of a carbon nanotube nanosilica co-modified polyvinyl alcohol composite ultra-filtration membrane. The preparation method comprises the following steps of: adding a certain amount of carboxylated carbon nanotubes and nanosilica which are dispersed by a surfactant, to a casting membrane solution by adopting polyvinyl alcohol as a membrane substrate material; and preparing the membrane by adopting polyethylene glycol as a pore-foaming agent through an immersion-precipitation phase transformation process. The prepared membrane not only has the hydrophily of the polyvinyl alcohol to achieve strong anti-pollution capacity, but also keeps the strength and toughness of inorganic materials to make up the defects of low strength and inability of resisting pressure of the polyvinyl alcohol wet membrane. The composite ultra-filtration membrane has strong anti-pollution capacity, high water flux and better retaining characteristic, can be repeatedly used and is long in service life.

Description

technical field [0001] The invention relates to a preparation method of an ultrafiltration membrane used in a separation process, in particular to a preparation method of a carbon nanotube and nano silicon dioxide co-modified polyvinyl alcohol composite ultrafiltration membrane. Background technique [0002] Ultrafiltration is like sieve filtration. Under a certain pressure (0.1-1.6MPa), it only allows solvents and solutes smaller than the membrane pore size to pass through, while preventing solutes larger than the membrane pore size from passing through, so as to complete the purification, separation and concentration of the solution. The ultrafiltration process has the following main features: (1) There is no interphase change, and it can be separated at normal temperature and low pressure, so the energy consumption is low, which is about 1 / 2 to 1 / 5 of the evaporation or freezing method; (2 ) The equipment is small in size, simple in structure, and low in investment costs;...

AI Technical Summary

Problems solved by technology

Because PVA has high hydrophilicity, good pollution resistance and film-forming property, and is cheap, it is very suitable as pervaporation membrane, reverse osmosis membrane, nanofiltration membrane, dialysis membrane, enzyme membrane, gas separation membrane, micro There have been many related research and development reports on membrane materials such as capsule membranes, but there are still few researches and developments on PVA as an ultrafiltration membrane material.

[0004] Pure PVA base membrane is easy to swell in water, has poor wet membrane strength, and is not pressure-resistant, which limits its industrial application to a large extent. Therefore, it must be modified to obtain a PVA ultrafiltration membrane with good strength and low water swelling.