Mining and industrial use over recent decades have released tellurium (Te) into the environment where it potentially contaminates soils, water supplies and food sources. Therefore, it is important to find ways of removing mobile and bioavailable Te from aqueous environments. We report aqueous Te(IV) removal by siderite at varying Te concentrations (2, 6 and 10 mg mL⁻¹ Te(IV)) and pH values (7, 7.9 and 9), together with associated isotope fractionation (ε¹³⁰Te/¹²⁵Te). Our results show effective immobilization of Te(IV) that follows pseudo-first order rate kinetics. Formation of magnetite indicates reduction of Te(IV) on siderite surfaces and the formation of Te(0). The overall isotope fractionation (ε) is small (−0.23 ± 0.06‰) providing evidence that it is primarily controlled by adsorption of Te(IV) occurring simultaneously with reduction of Te(IV). Therefore, Te(IV) removal by siderite under mildly reducing ferruginous conditions may be identifiable by the characteristically small isotopic fractionation during both natural attenuation and active remediation. To our knowledge, this is the first study reporting reaction mechanisms of Te(IV) immobilization by an environmentally relevant Fe(II) mineral.

近几十年来，采矿和工业使用已将碲 (Te) 释放到环境中，可能会污染土壤、供水和食物来源。因此，重要的是找到从水环境中去除可移动和生物可利用的 Te 的方法。我们报告了菱铁矿在不同的 Te 浓度（2、6 和 10 mg mL ^-1 Te(IV)）和 pH 值（7、7.9 和 9）以及相关的同位素分馏（ε ¹³⁰ Te/ ¹²⁵特）。我们的结果表明 Te(IV) 的有效固定遵循准一级速率动力学。磁铁矿的形成表明菱铁矿表面的 Te(IV) 减少和 Te(0) 的形成。总同位素分馏 (ε) 很小 (-0.23 ± 0.06‰)，这表明它主要受 Te(IV) 吸附和 Te(IV) 还原同时发生的控制。因此，在轻度还原铁质条件下，菱铁矿对 Te(IV) 的去除可以通过在自然衰减和主动修复过程中特征性的小同位素分馏来识别。据我们所知，这是第一项报告环境相关的 Fe(II) 矿物固定 Te(IV) 的反应机制的研究。