Carbon nanotubes, nano-silica co-modified polyvinyl alcohol composite ultrafiltration membrane

Abstract

The invention discloses a carbon nano tube and nano silicon dioxide modified polyvinylalcohol composite ultrafiltration membrane. Poval serves as a membrane substrate, a certain amount of carbon nano tubes and nano silicon dioxide after carboxylation are added to film casting solution, wherein the carbon nano tubes and the nano silicon dioxide are dispersed by surface active agents, polyethylene glycol serves as a pore-foaming agent, and the membrane is prepared through an immersion precipitated phase inversion method. The prepared membrane keeps hydrophilicity of the poval, and therefore the membrane has good anti-pollution capacity, and meanwhile strength and toughness of inorganic materials are kept so that the defects that a poval wet membrane is low in strength and unpressurized are overcome. The composite ultrafiltration membrane is good in anti-pollution capacity, high in water flux, good in hold back characteristics, capable of being used repeatedly and long in service life.

Description

technical field [0001] The invention relates to an ultrafiltration membrane used in a separation process, in particular to a composite ultrafiltration membrane of carbon nanotubes and nano silicon dioxide co-modified polyvinyl alcohol. 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 method or freezing method; (2 ) The equipment is small in size, simple in structure, and low in investment costs; (3) The process is simple and easy t...

AI Technical Summary

Problems solved by technology

Because PVA has high hydrophilicity, good pollution resistance and film-forming property, and low price, 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.