固定床吸附柱处理含Mn2+酸性矿山废水

为了探究同步去除酸性矿山废水(AMD)中酸度及重金属离子的新型多功能矿物环保材料,确定最佳运行方式,在固定床操作条件下,对比研究复合颗粒吸附柱、锰砂柱、复合颗粒-锰砂混合填充柱对AMD中酸度、Mn2+的去除效果,确定小型连续流反应器的最佳吸附剂；在确定最佳吸附剂的基础上,对比研究升流淹没式、降流淹没式、降流非淹没式吸附柱对AMD中酸度、Mn2+的去除效果,确定小型连续流反应器的最佳运行方式；并结合SEM、XRD等微观分析揭示复合颗粒动态吸附去除重金属离子的规律及机理。实验结果表明:3种吸附材料对Mn2+的吸附容量关系为:PG柱(28.871 mg·g-1)>PG-MS柱(16.935 mg·g-1)>MS柱(2.194 mg·g-1)；3种运行方式对Mn2+的吸附容量关系为:降流非淹没式(28.817 mg·g-1)>升流淹没式(26.532 mg·g-1)>降流淹没式(23.479 mg·g-1)。因此,固定床吸附柱处理含Mn2+酸性矿山废水动态实验的最佳吸附材料为膨润土-钢渣复合颗粒,复合颗粒的最佳运行方式为降流非淹没式。PG在去除Mn2+的过程中不仅存在吸附、化学沉淀等作用,还存在聚沉作用,即具有吸附-聚沉协同作用,并且Mn2+在复合颗粒表面的赋存状态主要以Mn-Si-O相结合的矿物相以及CaMn7O12沉淀物存在。

Treatment of Mn2+ acid mine wastewater by fixed bed adsorption

To explore the optimal removal of acidity and heavy metal ions in acid mine drainage (AMD) and ascertain the optimum operation,with the condition of fixed bed operation, the optimum adsorbent for small continuous flow reactor was determined by comparing the effect of composite particle column, manganese sand column, composite particles and manganese sand mixing column on acidity and Mn2+ removal in AMD. Based on determining the best adsorbent, the optimal operation mode of small continuous flow reactor was determined by comparing the effect of upflow submerged and downflow submerged and downflow non-submerged on the acidity and Mn2+ removal in AMD. Combined with microscopic analysis such as SEM and XRD, the regularity and mechanism of heavy metal ions removed by dynamic adsorption of composite particles were revealed. The results showed that the adsorption capacity of Mn2+ adsorbate was PG column (28.871 mg·g-1)> PG-MS column (16.935 mg·g-1)> MS column (2.194 mg·g-1). The relationship between the total adsorption capacity of Mn2+ and the three run modes was downflow non-submerged (28.817 mg·g-1)> upflow submerged (26.532 mg·g-1)> downflow submerged (23.479 mg·g-1). Therefore, the best adsorption material for the dynamic treatment of AMD containing Mn2+ is bentonite-steel slag composite particles. The best way to perform composite particles is downflow non-submerged. In the process of removing Mn2+, addition of Mn2+ function as adsorption, chemical precipitation, accumulation and so on. Mn2+ on the surface of the composite particles mainly existes in combination with Mn-Si-O of the mineral phase and the CaMn7O12 precipitate present.