Development Of CNFs/PVDF Microporous Membrane And Its Application In Space Bathing Wastewater Treatment

The space station has no water source,and the volume of the water storage system in the spacecraft is limited,so the transportation between heaven and earth alone is expensive,and the cost of transportation and load is high.If the water supply is not timely,the consequences will be serious.Therefore,the treatment and reuse of the waste water(bath waste water,condensate water and urine,etc.)produced in the space station and spacecraft is the key way to ensure the sustainability and economy of space water.In this paper,using space bath wastewater as the treatment object,the anti-pollution cellulose nanofiber/polyvinylidene fluoride(CNFS/PVDF)blend ultrafiltration membrane was prepared by thermal-induced phase separation method,and the three-dimensional electrocatalysis-ultrafiltration short process low waste treatment process was established,and the treatment effect of this process on simulated bath wastewater was studied.The main research contents and conclusions are as follows:1.Using dibutyl phthalate(DBP)as a single diluent and DBP and dioctyl phthalate(DOP)as binary diluents,the effects of diluent concentration,ratio and PVDF concentration on the microstructure and properties of PVDF membrane were studied.The experimental results showed that when DBP:DOP=2:3 and PVDF concentration was 30wt%,the pure water flux reached 429.1L/(m~2·h),and the BSA retention rate was 42.24%.2.Organic nanoparticle cellulose nanofiber(CNFs)was used as a hydrophilic modifier to prepare CNFs/PVDF blend membranes to improve the anti-pollution property of PVDF microporous membranes.the experimental results showed that when the CNFs content was 0.1wt%,the pure water flux of the prepared membrane increased by 25%compared with the original membrane,the BSA retention rate increased by 48%,the water contact angle decreased from 93.2°to 69.8°,and the flux recovery rate increased by 53%.3.A 3d electrocatalysis-ultrafiltration short process was established to study the treatment effect of 3d electrocatalysis and membrane process on simulated bath wastewater,respectively.The experimental results showed that:(1)when the electrode spacing was 7cm,the treatment voltage was 9V,the treatment time was 2h,and the activated carbon content was 10g,the 3d electrocatalysis had the best effect on COD removal in bath wastewater.The experimental parameters were optimized by response surface analysis,and relatively good process parameters were obtained.(2)Using CNFs/PVDF blend membrane to conduct interception experiment on three-dimensional electrocatalytic water production,it was found that the water quality closed the reverse osmosis inlet standard.