| Polysulfone(PSF) is commonly used in the industry as a kind of ultrafiltration material.However, PSF ultrafiltration membranes often show a poor anti-pollution and short service life because PSF has strong hydrophobicity. The research object of this paper was PSF ultrafiltration membranes and the main research task was improving their hydrophilicity. Different PSF ultrafiltration membranes which had different casting membrane solution were prepared and tested. Besides, the test results were analyzed and comprehensively evaluated by fuzzy mathemayic analysis in order to identify the best overall performance film. Papers showed the effects of additives on the structure and properties of the film in theory, which could provide theoretical guidance to get PSF ultrafiltration membranes which have good permeability,excellent stain resistance and strong hydrophilicity.In this study, different PSF flat membranes were prepared with the phase inversion method using N, N-Dimethylacetamide(DMAc) as solvent through adjusting the concentration and species of additives. Polyethylene glycol(PEG) which has different molecular,polyvinylpyrrolidone(PVP), mixing of cellulose and LiCl, mixing of PVP and LiCl, were additive. Then the films’ water flux, contact angle, mean pore size, contamination index,equilibrium water content, morphology were tested. The best overall performance film which had high flux, the fouling resistance good hydrophilicity were got through analysis of the test results.It is showed that with the increase of PVP- K30 content, the contact angle of the film falls from 79.13 ° to 71.21 °, the contact angle of the film and amount of PVP are negative correlation.The average pore size gradually increase, when the content of PVP is up to 8 %, the average pore size increases to 21 nm, at this moment, the flux is up to 231.4 L/(m2·h) and the interception rate reduces to the lowest value. It is showed that PVP- K30 as the additive, when its concentration is 8 %, the film obtains the best overall performance, including high water flux, good hydrophilicity, retention capacity exhibited through fuzzy mathematical analysis. With the increase of PEG content and molecular, the contact angle of the film becomes smaller. PEG will affect the average pore size of the membrane, and the pore size becomes larger with the increase of PEG contents and molecular. In this range of variation, water flux shows an increasing trend,while the rejection of the film shows a downward trend. It is showed that choosing PEG- 400 as the additive, when its concentration is 10 %, the film obtains the best overall performance,including high water flux, good hydrophilicity, retention capacity exhibited by fuzzy mathematical analysis. PEG- 2000 as the additive, when its concentration is 10 %, the film obtains the best overall performance. PEG- 6000 as the additive, when its concentration is 6 %,the film obtains the best overall performance. PEG- 20000 as the additive, when its concentration is 6 %, the film obtains the best overall performance. When the content of PVP-K30 is 6 %, with the gradual increase concentration of the second additive LiCl, the contact angle decreases, when the concentration of LiCl is 3 %, the water flux reaches up to 223.2L/(m2·h), retention at the minimum. When PVP’s concentration is 10 %, 5 % of LiCl as the second additive, the film obtains the best overall performance by fuzzy mathematical analysis.When the content of LiCl is 3 %, with increasing cellulose content of the second additive, the contact angle of the film decreases from 73.71 ° to 65.23 °. Water flux from 189.26 L/(m2·h)increases to 402.52 L/(m2·h), while interception rate decreases. When LiCl’s concentration is3 %, 2 % of cellulose as the second additive, the film obtains the best overall performance by fuzzy mathematical analysis. |
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