The combination of phytoremediation and electrokinetics remediation technology on arsenic contaminated remediation in tailing storage facilities from gold mine

摘要

This research aims to study the effects of combining Mott dwarf Napier grass cultivation and electrokinetic (EK) treatment on arsenic (As) mobility and remediation of As-contaminated mine tailings. Experimental groups were treated with 0, 1, 2, and 4 V/cm for 15 days–120 days. Groups treated with 1 and 2 V/cm electromagnetic field had better As remediation efficiency than the control group with no electromagnetic field treatment. However, electromagnetic field treatment at 4 V/cm inhibited plant growth and had an effect on As uptake in the form of solution at a low level. Plants in experimental group treated with 1 V/cm electromagnetic field for 90 days had significantly high As accumulation (7.69 ± 0.16 mg/kg) in their roots. Their relative growth rate was close to that of the control group with the highest biomass (15.09 ± 0.65 g) recorded on day 120. Mobility and accumulation of As and other elements in the plants were investigated using micro-X-ray fluorescence technique (Beamline BL6b). It was found that very low As concentrations could not be detected although energy emitted from its innermost electron shell (K alpha (Kα1&2) and K beta (Kβ1)) were equal to 10.54 and 11.72 keV. In general, As accumulation in plants occurs primarily in the roots and stems, with greater accumulation around the cortex, epidermis, and xylem. This is similar to the patterns of iron and phosphate accumulation, which occurs through phosphate transporters. In addition, high aluminum mobility and accumulation were found in the stems and leaves of Mott dwarf Napier grass. However, As accumulation in the roots of Mott dwarf Napier grass was higher than in the stem and leaves.