Study of factors to improve the removal of trace metals/elements from mine effluents using low-cost adsorbents

采矿和其他工业活动产生的有毒微量元素对地表水和土壤的污染是一个主要的环境问题。与此同时，各种工业活动产生的大量废弃物的产生也成为一个日益紧迫的问题，因为它们不仅造成二次污染和审美问题，而且占用了大片宝贵的土地。这些废物的安全储存和处理是非常昂贵的。在本提案中，我们提出了一个同时解决这两个问题的研究计划，具体地将废物转化为有价值的资源，并将其作为有效材料从采矿废水中去除有毒元素或将其固定用于土壤修复。在之前的一些工作中，我们发现粉煤灰、饮用水污泥和红葡萄浆可以作为有毒金属和元素的初级低成本吸附材料。此外，这些废物中的杂质含量很低，通常不会在溶液中释放，因此这些材料适合作为初级吸附剂。溶液pH是一个需要考虑的关键因素，在最佳条件下，所研究的材料的吸附容量通常较高，吸附动力学相对较快。在这个提议中，我们打算提高我们对这些材料的改性条件的了解，以进一步提高这些参数。我们的目标是使修改过程简单，成本低。为了使这些低成本材料达到最大的吸附容量和截留率，将进一步详细研究金属与农业废物的吸附性能以及与改性粉煤灰的结合。将测试成型高效吸附剂的可能性，以使它们易于处理。配方应经济合理，吸附材料可多次重复使用。本研究的最终目标是：(1)开发低成本的吸附剂组合，用于去除矿山水中的有毒元素；(2)利用这些吸附剂作为钝化剂，固定土壤中的有毒金属，防止其进入食物链；(3)确定矿山选矿厂使用的材料是否可以回用。为了实现这些目标，将对不同材料单独和组合的特性进行系统的化学实验，以便最大限度地发挥它们在工业采矿环境或其他污染环境中的使用潜力。几种分析技术和仪器将作为检测工具。成型材料的机械阻力将在校准的压力机和其他仪器下进行评估。

The contamination of surface waters and soils by toxic trace elements from mining and other industrial activities is a major environmental problem. In the meantime, the production of large quantities of waste materials generated by various industrial activities also becomes an ever-pressing issue as they not only cause a secondary pollution and aesthetic problem, but also occupy vast areas of precious land. The safe storage and handling of these wastes is very costly. In this proposal, we present a research plan to address these two problems simultaneously, by specifically turning waste materials into valuable resources and using them as effective materials to remove toxic elements from mining wastewater or to immobilize them for soil remediation. In some previous work, we found that coal fly ash, drinking water sludge and red grape pulp can be used as primary low-cost adsorbent materials for toxic metals and elements. Furthermore, impurities in these wastes are very low and generally not releasable in solution, thus making these materials suitable as primary adsorbents. Solution pH is a critical factor to consider and at optimal conditions, the adsorption capacity of the studied materials were generally high and the kinetics of adsorption relatively fast. In this proposal, we intend to enhance our knowledge of the modification conditions of these materials to further enhance those parameters. Our objective is to make the modification processes simple and at low cost. Additional studies on the adsorption properties of metals with agricultural wastes and in combination with modified fly ash will be done in more detail to reach maximum adsorption capacity and retention by these low-cost materials. The possibility of molding efficient adsorbents to make them easy to handle will be tested. The formulation should be economically sound and the adsorbent material could be reused multiple times. The ultimate goals in this study are to: (1) develop low-cost combination of adsorbents for the removal of toxic elements from mining waters; (2) use these adsorbents as passivating agents to immobilize toxic metals in soil and prevent them entering the food chain; (3) determine if the materials used in mine treatment plants can be reused. To achieve these goals, systematic chemical experiments will be conducted on the properties of different materials both alone and in combination in order to maximize their potential for use in an industrial mining setting or other contaminated environments. Several analytical techniques and instruments will serve as detection tools. The mechanical resistance of molding material will be evaluated under calibrated press and other instruments.