铁基阴离子黏土改性材料在地热水处理中的应用

曹耀武; 唐保春

doi:10.3799/dqkx.2022.342

地球科学 ›› 2023, Vol. 48 ›› Issue (03) : 1146 -1155. DOI: 10.3799/dqkx.2022.342

铁基阴离子黏土改性材料在地热水处理中的应用

曹耀武 ¹ ,
唐保春 ²^,³

作者信息 +

Application of Modified Iron-Based LDH Materials in Geothermal Water Treatment

Yaowu Cao ¹ ,
Baochun Tang ²^,³

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摘要

地热水常富集多种有害组分，以热泉形式非集中排泄时将威胁周边居民饮用水安全.本文制备了5种铁基阴离子黏土（Fe-LDH）改性材料，用于云南典型地热区热泉的处理中.结果显示Fe-LDH对砷的去除最佳，氟、钨次之，对锑、硼的去除受共存离子影响较大；而改性材料可有效缩小不同有害组分间的竞争吸附差距，表现为乳酸根插层的Fe-LDH能显著提高离子交换能力，对氟、硼的去除提升较大，而分层的Fe-LDH因暴露更多活性位点、增加层间接触面积，对与铁络合为主的砷、钨去除和离子交换为主的氟、硼去除均有明显提升；最后静态吸附表现最佳的吸附剂——L-天冬酰胺分层的Fe-LDH，作为小型水处理装置填充材料能动态、有效地去除热泉中多种有害组分.为地热水污染修复提供了切实可行的方法.

Abstract

Geothermal waters are generally enriched in multiple groups of harmful components, which threaten the safety of drinking water for the surrounding residents when non-concentrated discharged in the form of hot springs. In this paper, five iron-based LDH (Fe-LDH) modified materials were prepared and used in the treatment of hot springs in typical geothermal areas of Yunnan. The results show that Fe-LDH has the best removal of arsenic, followed by fluoride and tungsten, and the removal of antimony and boron was influenced by coexisting ions; whereas, the modified materials effectively narrow the gap of competitive sorption between different harmful components, which shows that ion exchange capacity of the lactate intercalated Fe-LDH was significantly improved and the removal of fluorine and boron was enhanced, while the delaminated Fe-LDHs exposed more active sites and increased the interlayer contact, thus it had a greater enhancement on the removal of arsenic and tungsten, which are primarily complexed with iron, along with the removal of fluoride and boron by ion exchange. Finally, the best sorbent in static sorption performance, L-asparagine delaminated Fe-LDH, could dynamically and effectively remove multiple groups of harmful components from hot springs as a filling material for small water treatment devices, which provides a practical method for the remediation of geothermal waters.