Removal of Trace Metals from Acid Mine Drainage Using a Sequential Combination of Coal Ash-Based Adsorbents and Phytoremediation by Bunchgrass (Vetiver [Vetiveria zizanioides L]); [Entfernung von Spurenmetallen aus saurem Grubenwasser durch sequenzielle Kombination aus Adsorbenzien aus Kohleaschen und Pflanzenbehandlung mit Bunch-Gras (Vetiver [Vetiveria zizanioides L])]; [La remoción de metales traza desde drenaje ácido de minas usando una combinación secuencial de adsorbentes en base a ceniza de carbón y fitorremediación por hierba (Vetiver [Vetiveria zizanioides L])]

被引：0

作者：

Gwenzi W. ^{[1
]}

Mushaike C.C. ^{[1
]}

Chaukura N. ^{[2
]}

Bunhu T. ^{[3
]}

机构：

[1] Biosystems and Environmental Engineering Research Group, Department of Soil Science and Agricultural Engineering, University of Zimbabwe, P.O. Box MP167, Mt. Pleasant, Harare

[2] Nanotechnology and Water Sustainability Research Unit, College of Engineering, Science and Technology, University of South Africa, Johannesburg

[3] Department of Chemistry, Chinhoyi University of Technology, P. Bag 7724, Chinhoyi

来源：

Mine Water and the Environment | 2017年 / 36卷 / 4期

关键词：

Adsorption; Batch; Hydrothermal activation; Semi-batch system; Zeolites;

D O I：

10.1007/s10230-017-0439-3

中图分类号：

学科分类号：

摘要：

Potentially scalable low-cost treatment methods for acid mine drainage (AMD) are very limited. We used a sequential combination of adsorption and phytoremediation by bunchgrass (Vetiver [Vetiveria zizanioides L]) in a semi-batch system to remove Zn, Mn, Ni, and Cu from AMD. The objectives were: (1) to compare the removal of these metals by raw and NaOH-activated coal ash (NaOH-CA); and (2) to determine the effect of sequencing adsorption and phytoextraction on metal removal. The NaOH-CA adsorbed significantly more metals than raw coal ash (RCA) in both batch and semi-batch fixed column experiments, demonstrating the effectiveness of NaOH hydrothermal activation, which forms zeolites. Adsorption by NaOH-CA removed 59.1, 95.7, 67.6, and 77.9% of the Zn, Mn, Ni, and Cu, respectively, compared to 50.6, 95.1, 30.2, and 60.5% for the RCA. Metal removal by phytoremediation was generally less than that by adsorption, accounting for between 3.4 and 54.6% for both adsorbents. Phytoremediation following adsorption by NaOH-CA removed 89.2–99.9% of the metals compared to 70.8–98.5% when phytoremediation followed adsorption by RCA. Overall, relatively high metal removal efficiencies were attained, considering the acidic conditions (pH <4), at hydraulic residence times of 1 to 5 days. Using coal ash to treat AMD is potentially a low-cost and environmentally friendly option for minimizing the adverse public health and environmental risks associated with both wastes. © 2017, Springer-Verlag Berlin Heidelberg.

引用

页码：520 / 531

页数：11