典型矿山药剂及其降解产物作用下GCL重金属截污性能的变化规律及机制分析

The heavy metals retention capacity of geosynthetic clay liner (GCL) is an important parameter to determine if it can be used in barrier systems for tailing impoundments. Numerous studies have been conducted to evaluate the heavy metals retention capacity associated with GCL. However, there are very few leachate contain mineral reagents and their degradation products. In fact, these organic chemicals might make some effects on the heavy metals retention capacity of GCL. So, the hydraulic conductivity tests will be conducted to assess the impact of these mineral reagents on the hydraulic conductivity of GCL, and, the swelling behavior and hydrophobicity of the bentonite that contacted with mineral reagents will be examined in order to explain the mechanisms that responsible for the changes in hydraulic conductivity of GCL. The effects of mineral reagents and their degradation products on the heavy metals adsorption capacity of GCL will be evaluated through some batch sorption tests. The changes in the surface charge of bentonite and the complex reactions between heavy metals and mineral reagents degradation products will be tested and used to explain the changes behaviors of heavy metals adsorption capacity associated with bentonite. The implementation of this program will improve and perfect the evaluate method of the heavy metals retention capacity of GCL and improve accuracy. This program also can provide some guidance for the GCL barrier system design and environmental effect assessment for tailing impoundments.

土工合成黏土衬垫（Geosynthetic Clay Liner, GCL）对尾矿库渗滤液中重金属的截污性能（渗透特性和吸附能力），是判断其是否可以用作尾矿库防渗衬垫的重要依据。已有研究在对GCL的重金属截污性能进行评价时，忽略了尾矿库渗滤液中矿山药剂及其降解产物等有机组分对评价结果可能产生的影响。因此，本课题拟开展渗透试验，研究矿山药剂存在条件下GCL渗透特性的变化规律，通过分析GCL中膨润土的膨胀性及疏水性变化特征，揭示GCL渗透特性发生变化的内在机制。通过批式吸附试验，研究矿山药剂及其降解产物作用下GCL的重金属吸附能力变化情况，从膨润土表面电位变化特征、矿山药剂及其降解产物与重金属离子之间的络合效应两个方面，查明GCL重金属吸附能力发生改变的根本原因。课题的开展有利于完善GCL重金属截污性能的评价方法、提高评价结果的准确性，从而为尾矿库防渗系统的设计及环境风险评估提供理论依据。

土工合成黏土衬垫（Geosynthetic Clay Liner, GCL）对尾矿库渗滤液中重金属的截污性能，是判断其是否可以用作尾矿库防渗衬垫的重要依据。但是，目前在进行截污性能评价时，往往忽略了矿山药剂及其降解产物可能产生的影响。本项目以丁铵黑药以及苯酚和正丁醇为研究对象，开展了柔性壁渗透试验和批式吸附试验，研究上述有机物对膨润土防渗性能和吸附性能的影响。本项目获得以下结果：（1）积累了国内外尾矿库运行和闭库期间渗滤液中矿山药剂及其降解产物的种类和浓度；（2）获得了丁铵黑药溶液作用下GCL渗透系数变化规律，发现高浓度丁铵黑药溶液（500 mg/L）会导致GCL透系数轻微下降，而低浓度丁铵黑药溶液（10 mg/L）则不会改变GCL的防渗性能；（3）确定了丁铵黑药、苯酚和正丁醇影响下膨润土对Cu2+吸附性能的变化情况，发现丁铵黑药会导致膨润土对Cu2+的吸附性能下降，并改变其吸附模式，而苯酚和正丁醇对膨润土吸附Cu2+的性能和吸附模式几乎没有影响。.受此项目资助，发表SCI论文2篇，EI论文2篇，国际会议论文1篇，中文核心论文1篇。培养研究生4名，其中1人已经毕业，3人在读。.