Natural fluorapatite dissolution kinetics and Mn2+ and Cr3+ metal removal from sulfate fluids at 35 °C.
Natural fluorapatite dissolution kinetics and Mn2+ and Cr3+ metal removal from sulfate fluids at 35 °C.
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DOI：
10.1016/j.jhazmat.2020.122150
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发表时间：
2020-01
影响因子：
13.6
通讯作者：
Veerle Vandeginste;C. Cowan;R. Gomes;Tharwat Hassan;J. Titman
中科院分区：
文献类型：
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作者：
Veerle Vandeginste;C. Cowan;R. Gomes;Tharwat Hassan;J. Titman
鉴于全球变暖和人口增长的后果，获得安全饮用水成为一个越来越大的挑战，特别是在干旱地区的中低收入国家。此外，采矿可能造成酸性矿井排水和重金属污染，给有限水资源的管理带来进一步压力。因此，开发具有成本效益的水处理方法至关重要。在这里，使用间歇反应器实验，我们研究了在35 °C下使用天然氟磷灰石从硫酸盐流体中去除二价Mn和三价Cr的动力学和机制。结果表明，氟磷灰石的溶解速率取决于流体的pH值，溶解是流体的pH值低于4的主导机制。因此，磷灰石可以作为补救措施，以中和酸性流体。4-6的流体pH触发溶解-沉淀机制，在某些情况下，在仅溶解期之后，形成金属磷酸盐。在这些实验中，铬的去除速度是两到十倍，Mn去除类似的溶液pH值。结果表明，天然磷灰石是一种有前途的，成本效益高的材料，用于被动修复采矿引起的污染的土壤和地下水在干旱地区。
In light of the consequences of global warming and population growth, access to safe drinking water becomes an ever greater challenge, in particular in low to middle income countries in arid regions. Moreover, mining which may cause acid mine drainage and heavy metal contamination puts further pressure on management of limited water resources. Hence, the development of cost effective water treatment methods is critical. Here, using batch reactor experiments we investigate the kinetics and mechanisms behind divalent Mn and trivalent Cr removal from sulfate fluids using natural fluorapatite at 35 °C. The results show that the fluorapatite dissolution rate depends on fluid pH, and that dissolution is the dominant mechanism in fluids with pH below 4. Apatite can thus serve as remediation to neutralize acidic fluids. Fluid pH of 4–6 triggers a dissolution-precipitation mechanism, in some cases following upon a dissolution-only period, with the formation of a metal phosphate. In these experiments, Cr removal is two to ten times faster than Mn removal given similar solution pH. The results demonstrate that natural apatite represents a promising, cost effective material for use in passive remediation of mining-induced contamination of soils and groundwater in arid regions.