Abstract
Column and shake-batch leaching tests were compared. Leaching of organic and inorganic pollutants were studied. The organics were analysed using a GC/MS. Different extraction methods were compared. The anorganics were analysed using ICP/MS. The influence of different leaching parameters (contact time, pH-value, the use of cosolvents,) on leaching was studied.Heavy metal leaching happens quickly and is mainly a function of pH-value. Methanol as a cosolvent plays a crucial role in the leaching of inorganic components by decreasing the pH-value of the eluates. Only iron, copper, zinc and lead (for PSR-II) and aluminum, iron, zinc and lead (for EU-11) leach out in important amounts at an alkaline pH-value.
Leaching of PAHs happens much slower than leaching of inorganic components. Leaching happens slower for PSR-II than EU-11. High-molecular PAHs are extracted more difficultly than low-molecular ones. A shift takes place from a high concentration of low-molecular PAHs in the eluate to a high concentration of high molecular ones. Methanol as cosolvent causes a much higher PAH-concentration in the eluate.
The main difference between our experiments and the others is the use of an organic acid (formic acid). Possibly, the affinity of the organics for the solvent is raised by this means.
Compared to SPE, liquid-liquid extraction yields a much higher extraction level.
The experiments show that batch-shaking tests, in most cases, cause a much more significant leaching of organic as well as inorganic pollutants than the column leaching tests.
| Date of Award | 2003 |
|---|---|
| Original language | Dutch |
| Supervisor | Alfons Buekens (Promotor) & Kathleen Schroyens (Co-promotor) |
Keywords
- leaching
- heavy metals