不同磁黄铁矿自养反硝化脱氮除磷作用

Autotrophic denitrification over different pyrrhotites for simultaneous nitrate and phosphate removal

氮磷排放标准日趋严格,开发高效廉价脱氮除磷材料已成为研究热点.采用黄铁矿与赤铁矿在管式炉中氮气气氛下600℃煅烧,得到硫化赤铁矿形成的磁黄铁矿、黄铁矿热分解形成的磁黄铁矿,构建磁黄铁矿-方解石体系处理含氮磷模拟废水,对比不同方式制备的磁黄铁矿、天然磁黄铁矿、黄铁矿、硫磺脱氮除磷性能,考察不同磁黄铁矿晶体结构和结晶度差异及其对脱氮除磷影响,探究不同体系中矿物结构和微生物群落变化.结果表明:黄铁矿热分解产物以六方磁黄铁矿为主;硫化赤铁矿产物以低结晶度的单斜磁黄铁矿为主,因而表现出优异的脱氮除磷活性,氮磷去除率分别为99.8%和96.8%.铁硫化物与微生物反应产物的XRD、SEM和FE-TEM分析结果表明,微生物能有效利用磁黄铁矿进行脱氮,磷酸盐主要以FePO_(4)形式被去除.群落分析结果表明铁硫化物脱氮除磷体系中的主要功能菌属为Thiobacillus和Sulfurimonas,结晶度低的单斜磁黄铁矿更有利于Thiobacillus定向富集.

With the discharge standard for nitrate(NO_(3)^(-)-N)and Phosphate(PO_(4)^(3-)-P)become more stringent,the development of nitrate and phosphate removal materials with high efficiency and low-cost has been a hotspot.In this study,two types of pyrrhotites formed by thermally decomposed pyrite and sulfurized hematite can be simultaneously obtained by calcining pyrite and hematite under nitrogen atmosphere at 600℃.Meanwhile,the pyrrhotite-calcite system was developed to treat the simulated wastewater containing nitrate and phosphate.The comparison of simultaneous NO_(3)^(-)-N and PO_(4)^(3-)-P removal efficiency over pyrrhotites,natural pyrrhotite,pyrite,and sulfur were studied.The effects of crystal structures and crystallinity of different pyrrhotites on NO_(3)^(-)-N and PO_(4)^(3-)-P removal were investigated.Moreover,the variations of mineral structure and microbial community were also explored.The results showed that the hexagonal pyrrhotite was the main product of the thermally decomposed pyrite.Meanwhile,the monoclinic pyrrhotite with low crystallinity formed by the sulfurization of hematite displayed excellent NO3--N and PO_(4)^(3-)-P removal activity(99.8%and 96.8%,respectively).Results of XRD,SEM,and FE-TEM observation of solid products indicated that pyrrhotite can be effectively utilized by the microbes for denitrification,while the phosphate was mainly removed in the form of FePO_(4).The microbial community analysis results showed that Thiobacillus and Sulfurimonas were the main functional bacterial genera,in which Thiobacillus was more likely to be enriched in the case of the monoclinic pyrrhotite system.