Research project: Nanoparticles and associated metals in landfill leachates
Currently Active:
Yes
Landfill leachates contain a wide range of potentially toxic metals (e.g. Cr, As and Cd). Models of landfill systems are largely based on models in which contaminants are considered to be either dissolved or sorbed to solid phases. It is apparent, however, that nanoparticles interact with solid and dissolved phases and play an important role in the transport of organic matter and metals.
Hence, we aim to characterise nanoparticles in a UK municipal solid waste (MSW) leachate.
Project Overview
Preliminary Study
A sample of landfill leachate was passed through a 0.45 mm filter and then through the AF4 device (Fig 3).
Fractions were collected for analysis by HR-ICP-MS (Fig 2).
The highlighted peak at short retention time (RT) is made up of humic and fulvic acids with masses <33kDa. The peak at RT > 40 mins is made up of larger organic particles and coating on inorganic particles.
Conclusions/Further Work
Nanoparticles are heterogeneous in size and shape
Metals are mostly present bound to humic/fulvic acids
Ba, Ni and Pb are more strongly partitioned into larger particles
A silica-rich fraction of intermediate size is present, and is associated with Sr and Li
Future development will involve on-line measurement by HR-ICP-MS to provide more detailed information about the metal association in different size fractions and in leachates from a variety of landfill sites.