Study on the effect of pretreatment agents on the ion exchange removal capacity of water regeneration systems
When conducting long-term experimental verification of urine regeneration using ground equipment of manned space water regeneration system,it was found that the ion exchange removal ability of the water regeneration system is also affected when the pre-treatment agent changes.Therefore,the influence behavior and mechanism of pre-treatment agent changes on the ion exchange removal capacity of water regeneration systems were studied through small sample experiments,water quality composition analysis,and other means.The results showed that with the increase of CrO3 content in the pre-treatment agent,the organic acid content in distilled water increased,leading to an increase in the conductivity,an increase in the organic carbon content,and a decrease in pH value of distilled water.Organic acids have low degree of dissociation in water,and their selectivity coefficients are low when exchanging with strong alkaline anion exchange resins.This results in a slow ion exchange rate of the acid ion.As the organic acid content in distilled water increases,the ion exchange band of acid ion widens and shifts backwards,causing resin penetration,resulting in a decrease in the ion exchange removal ability of the water regeneration system.
water regenerationpre-treatment agentdistilled waterion exchange resinimpact mechanism