Pyrite autotrophic denitrification (PAD) is considered a promising method for nitrate removal from wastewater and groundwater. However, the results of PAD studies have been contradictory for two decades, and the mechanism is unclear. Here, we investigated mineral properties of two kinds of natural pyrite (YP and TP), their PAD performances, and microbial community shift in their column reactors in parallel. Both pyrite are highly pure crystalline pyrite, but their other mineral properties are quite different. Both batch and column experiments found that PAD of YP occurred but that of TP did not. Thus, the contradictory results of PAD were presented for the first time at the same study. The dominant bacteria in YP and TP columns finally were Thiobacillus (24.55±8.67%) and Flavobacterium (21.11±10.59%), respectively, though their initial microbial communities cultured were similar. Reduced sulfur species and oxide impurities on the surface of pyrite, and small DO in water did not change autotrophic denitrification characteristic of the pyrite itself. This research indicates that mineral property of pyrite caused the contradictory result of PAD. Among pyrite properties, the main crystal plane exposed and chemical state of surficial sulfur and iron were considered the decisive parameters for PAD. The study provides guidelines for selection of pyrite minerals for PAD applications.

黄铁矿自养反硝化（PAD）被认为是一种从废水和地下水中去除硝酸盐的有前景的方法。然而，PAD研究的结果已经矛盾了20年，机制尚不清楚。在这里，我们平行研究了两种天然黄铁矿（YP 和 TP）的矿物特性、它们的 PAD 性能和微生物群落在其柱反应器中的变化。两种黄铁矿都是高纯度的结晶黄铁矿，但它们的其他矿物性质却大不相同。批次和柱实验均发现 YP 发生 PAD 而 TP 没有发生 PAD。因此，在同一项研究中首次提出了 PAD 的矛盾结果。YP和TP柱中的优势菌最终为硫杆菌属（24.55±8.67%）和黄杆菌属(21.11±10.59%)，尽管它们最初培养的微生物群落相似。黄铁矿表面的硫物质和氧化物杂质减少，水中溶解氧量小，并没有改变黄铁矿本身的自养反硝化特性。这项研究表明，黄铁矿的矿物特性导致了 PAD 的矛盾结果。在黄铁矿性质中，暴露的主晶面和表面硫和铁的化学状态被认为是 PAD 的决定性参数。该研究为选择用于 PAD 应用的黄铁矿矿物提供了指南。