| In view of the serious problem of the internal concentration polarization and the anti-diffusion of the positive infiltration technique,a new type of foward osmosis[PAH/PSS]n/EHT-PSF membrane was prepared with polyanion cation Polyallylamine hydrochloride?PAH?,sodium polystyrenesulfonate?PSS?/polysulfone membrane by charged with hydrotalcite charge plate?EHT?as additive and used layer-by-layer self-assembly?LBL?technology.The effects of[PAH/PSS]n/EHT-PSF composite membrane on its desalination performance and its law were explored by using inorganic salt solution and intelligent hydrogel as draw solution respectively.The SEM characterization and hydrophilic contact angle analysis were carried out to investigate the removal of oxytetracycline from[PAH/PSS]n/EHT-PSF composite membranes.The following aspects were studied:?1?The effects of assembly time,number of assembled layers,concentration of polyelectrolyte NaCl and the amount of EHT on the desalination performance of[PAH/PSS]n/EHT-PSF membrane were investigated and the stability of membrane performance was investigated.The results showed that the composite membrane of[PAH/PSS]n/EHT-PSF was infiltrated by LBL technology.The assembly time was 20min,the number of assembly layers was 2,the concentration of polyelectrolyte was 1.2 mg/mL,the concentration of polyelectrolyte was 1mol/L,the initial membrane flux reached44 L/m 2·h,which was 2 times higher than that of the membrane prepared by HTI Company.The optimum conditions were 0.01 mol/L NaCl?1 mol/L NaCl?,The retention rate reached 95%,which is 1.8 times higher than the literature value.The composite membrane prepared under these conditions has a smooth and dense surface and a sponge-like structure.The hydrophilic contact angle?35°?was lower than the HTI commercial membrane?76°?,it significantly improves the hydrophilicity of the support membrane.?2?The removal of oxytetracycline from[PAH/PSS]2/EHT-PSF forward osmosis membrane was investigated.The effects of antibiotic concentration in feed solution,NaCl concentration in draw solution,draw solution flow rate effect of LBLforward osmotic membrane on oxytetracycline removal.The results showed that the flux of positive osmotic membrane reached 42L/m2·h when the concentration of oxytetracycline was 20mg/L,the concentration of NaCl in the draw solution was1mol/L,the feed flow rate was 189.15mL/min,the draw flow rate was 236.55mL/min,[PAH/PSS]2/EHT-PSF forward osmotic membrane of oxytetracycline reached 97%,it was1.6 times higher than the literature value.?3?LBL forward osmotic hybridization was carried out on the[PSS/PAH]2/PSS-EHT membrane build-up layer used a smart hydrogel prepared from polyvinyl alcohol?PVA?and hyaluronic acid?HAA?.The effects of OTC concentration,experimental temperature,liquid flow rate and amount of hydrogel on OTC performance of[PSS/PAH]2/PSS-EHT membrane were investigated.The hydrogel and NaCl solution of the FO performance comparison,and investigated the hydrogel regeneration performance.The results showed that the membrane flux reached 10.7L/m2·h and the rejection reached 97%when the amount of hydrogel was 80mg/cm2,the temperature was 20?,the peristaltic pump was 189.15mL/min and the oxytetracycline concentration was 50mg/L.Hydrogel as a draw solution can effectively eliminate the solute reverse diffusion phenomenon.The hydrogel regenerative experiment was repeated 5 times for 5h each,and the water flux of the 5th time use was less than 1%compared with that of the first time,which indicated that the intelligent hydrogel had good reproducibility. |
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