NaBH_(4)对施氏矿物-黄铁矾生物化学合成的影响及矿物在催化降解甲基橙中的应用

Effect of NaBH_(4)on the biochemical synthesis of schwertmannite-jarosite and the application of the minerals in the catalytic degradation of methyl orange

利用嗜酸性氧化亚铁硫杆菌合成施氏矿物,由于大量Fe3+残留于溶液中,致使矿物合成量较低。通过在生物合成施氏矿物的滤液中分3个批次加入NaBH_(4),探究了NaBH_(4)的投加量对施氏矿物生物合成及其向黄铁矾转化的影响。结果表明:在连续分3个批次各加入1.25 g·L^(-1)和1.67 g·L^(-1)NaBH_(4)后,2个处理组的总Fe沉淀率分别达到47.00%和62.67%,次生铁矿物生成量分别为8.92 g·L^(-1)和10.34 g·L^(-1)。生成的矿物分别是施氏矿物(第1批次)、施氏矿物与黄钠铁矾混合物(第2批次)、黄钠铁矾(第3批次),在加入1.25 g·L^(-1)和1.67 g·L^(-1)NaBH_(4)的2个处理组中3个批次合成矿物的比表面积分别为14.17 m^(2)·g^(-1)和20.02 m^(2)·g^(-1)(第1批次)、32.95 m^(2)·g^(-1)和42.74 m^(2)·g^(-1)(第2批次)、0.84 m^(2)·g^(-1)和13.68 m^(2)·g^(-1)(第3批次)。在催化降解甲基橙的实验中,当矿物比表面积为4.94~42.74 m^(2)·g^(-1)时,能够显著提高甲基橙的去除率。以上研究结果可为次生铁矿物合成及其应用提供参考。

The yield amount of schwertmannite synthesized by A. ferrooxidans is relatively low, a large amount of Fe3+ remained in the solution. In this study, NaBH4 was added to the filtrate produced from the traditional biosynthesis schwertmannite in three batches, and the effect of NaBH4 on the synthesis of schwertmannite and its transformation to jarosite was explored. The results showed that after adding 1.25 g·L-1 and 1.67 g·L-1 NaBH4 to two treatment groups in three batches, the total Fe precipitation rate reached 47.00% and 62.67%, and the yield amounts of secondary iron minerals reached 8.92 g·L-1 and 10.34 g·L-1, respectively. The yield minerals were schwertmannite in the first batch, a mixture of schwertmannite and jarosite in the second batch,jarosite in the third batch, respectively. The specific surface areas of synthesized minerals when adding 1.25 g·L-1 and 1.67 g·L-1 NaBH4 to two treatment groups in three batches were 14.17 m2·g-1 and 20.02 m2·g-1 in the first batch, 32.95 m2·g-1 and 42.74 m2·g-1 in the second batch, 0.84 m2·g-1 and 13.68 m2·g-1 in the third batch,respectively. In the experiments of catalytic degradation of methyl orange, the removal rate of methyl orange could be significantly improved by minerals at its specific surface area of 4.94~42.74 m2·g-1. The results of this study can provide reference for the secondary iron minerals synthesis and application.