纳米零价铁耦合氢自养反硝化去除水中硝酸盐

首先采用液相还原法制备纳米零价铁粒子,然后将制得的纳米零价铁与氢自养反硝化菌进行耦合,组成纳米零价铁-氢自养反硝化耦合体系,考察了不同温度、pH值、Fe/N值、初始硝酸盐浓度和H2对耦合体系去除硝酸盐的影响,并对硝酸盐去除机理进行了讨论。结果表明,纳米零价铁-氢自养反硝化耦合体系对硝酸盐有很好的去除作用,反应速率高于单一的化学还原或生物反硝化过程。Fe/N值对硝酸盐还原速率的影响不大,却对反应产物影响显著,试验条件下,纳米零价铁的最佳投量为10 mL。不同pH值条件下耦合体系对硝酸盐的去除趋势非常接近。温度对耦合体系降解硝酸盐的速率有一定影响,温度越高,硝酸盐的去除速率越快,但整体差别不大。初始硝酸盐浓度为25、65、105和150 mg/L时,对硝酸盐的平均去除速率分别为13. 64、11. 63、16. 55和13. 73 mg/(L·h)。给予耦合体系充足氢气的情况下,硝酸盐的降解速率较快,高于不额外供给氢气的耦合体系。

Nitrate Removal by Coupled Nanoscale Zero-valent Iron and Autohydrogenotrophic Denitrifying Bacteria

Nanoscale zero-valent iron was prepared using the liquid reduction method. The nitrate removal process by the coupled nanoscale zero-valent iron and autohydrogenotrophic denitrifying bacteria (nZVI-AB) system was investigated. Influences of temperature, p H, Fe/N ratio, initial nitrate concentration,and H2 on nitrate removal effect were investigated. The results showed that n ZVI-AB system had excellent efficiency in nitrate removal,and the reaction rate was much higher than uncoupled systems. The effect of Fe/N ratio on the reaction reduction rate was insignificant,but was significant on the nitrate reaction products. Under the experimental conditions,the optimal dosage of nanoscale zerovalent iron was 10 mL. The removal patterns of nitrate by the coupled system under different pH values were very close. Temperature had a partial effect on the degradation rate of nitrate in the coupled system.The higher the temperature was,the faster the removal rate of nitrate was,but the difference was mild overall. When the initial nitrate concentration was 25 mg/L,65 mg/L,105 mg/L,and 150 mg/L,the average removal rates of nitrate were 13. 64 mg/(L·h),11. 63 mg/(L·h),16. 55 mg/(L·h),and 13. 73 mg/(L· h),respectively. When sufficient hydrogen was provided to the coupled system,the degradation rate of nitrate was faster than that without additional hydrogen supply.