Environmental Engineering Laboratory, College of Resource and Environment, Shanxi Agricultural University, Taigu, People's Republic of China.
Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, People's Republic of China.
Environ Technol. 2022 Oct;43(24):3706-3718. doi: 10.1080/09593330.2021.1933200. Epub 2021 May 28.
The effect of pH regulation on schwertmannite bio-synthesis and its As removal ability were investigated in this study. The total Fe precipitation efficiency in a conventional schwertmannite bio-synthesis system (CK) reached 26.5%, with a mineral weight of 5.21 g/L and a mineral specific surface area of 3.18 m/g. The total Fe precipitation efficiency increased to 88.4-95.8%, the mineral weight increased to 17.10-18.62 g/L, and the specific surface area increased to 3.61-90.67 m/g of five different treatments in which the system pH was continually adjusted to 2.50, 2.70, 2.90, 3.10, and 3.30 every 3 h, respectively. The very small amounts of schwertmannite were transformed to goethite when the system pH was periodically adjusted to 2.90, 3.10 and 3.30. The increased specific surface area of bio-schwertmannite was due to the contribution of mesopores, with most pores having a diameter of 2-20 nm. For actual As-containing groundwater (27.4 μg/L), the As removal rate was 52.9% for bio-schwertmannite collected from the CK system. However, the removal rate of As increased to 92.7-97.8% for minerals which were collected after five adjusted pH treatments. The outcomes of this study provide a fresh insight into the bio-synthesis regulation of schwertmannite, and have great significance for the treatment of As-containing groundwater.
本研究考察了 pH 值调节对水铁矿生物合成及其除砷能力的影响。在传统水铁矿生物合成系统（CK）中，总铁沉淀效率达到 26.5%，矿物重量为 5.21g/L，矿物比表面积为 3.18m/g。在分别将系统 pH 值每 3 小时连续调节至 2.50、2.70、2.90、3.10 和 3.30 的五种不同处理中，总铁沉淀效率提高到 88.4-95.8%，矿物重量增加到 17.10-18.62g/L，比表面积增加到 3.61-90.67m/g。当系统 pH 值周期性调节至 2.90、3.10 和 3.30 时，少量水铁矿转化为针铁矿。生物水铁矿比表面积的增加是由于中孔的贡献，大多数孔的直径为 2-20nm。对于实际含砷地下水（27.4μg/L），从 CK 系统收集的生物水铁矿的砷去除率为 52.9%。然而，经过五次 pH 值调节处理后收集的矿物的砷去除率提高到 92.7-97.8%。本研究的结果为水铁矿的生物合成调控提供了新的见解，对含砷地下水的处理具有重要意义。
