Abstract：
Acid mine drainage (AMD) poses a significant threat to water quality worldwide, being amongst the most problematic environmental concerns of the millennium. This work reports for the first time the remediation of real AMD, from a Portuguese abandoned mine, in fixed bed column using porous red mud/fly ash-based geopolymeric spheres. Porous waste-based spheres (2.6 ± 0.2 mm) were obtained by a suspension-solidification method through the addition of optimum foaming agent dosage. The sorbent capacity in removing cations from AMD was evaluated by targeting selected hazardous elements: Zn, Cu, Co, Pb and Ni, based on their occurrence in the effluent and potential hazard. The spheres exhibited a dual mechanism of action, simultaneously neutralizing the acidic sample while removing cations through adsorption achieving removal efficiencies between 51 % and 80 %. Other elements present in high levels, such as iron were efficiently removed (>96 %). The role of precipitation, due to the pH neutralization, and adsorption was determined. The sorbent regeneration and reusability were evaluated for up to five cycles. Moreover, the effectiveness of waste-based geopolymers treating distinct AMD waters due to seasonal variations was also evaluated, further demonstrating the effectiveness of the proposed strategy to address environmental concerns stemming from mining activities.
摘要：
酸性矿井排水（AMD）对全球水质构成重大威胁，成为千年中最有问题的环境问题之一。这项工作首次报告了真正的AMD的补救，来自葡萄牙废弃的矿井，在固定床柱中使用多孔红泥/粉煤灰基地聚合物球。通过添加最佳发泡剂剂量，通过悬浮固化法获得了多孔废物基球体（2.6±0.2mm）。通过针对选定的有害元素：Zn，评估了从AMD中去除阳离子的吸附能力。Cu,Co,Pb和Ni,基于它们在废水中的发生和潜在危害。球体表现出双重作用机制，同时中和酸性样品，同时通过吸附去除阳离子，达到51％至80％的去除效率。其他元素以高水平存在，如铁被有效去除(>96%)。降水的作用,由于pH中和，并进行了吸附测定。对吸附剂再生和可重复使用性进行了多达五个循环的评估。此外，还评估了由于季节变化而处理不同AMD水域的废物基地质聚合物的有效性，进一步证明了拟议战略在解决采矿活动引起的环境问题方面的有效性。
