Humic substance uptake by hydrotalcites and PILCs

Pollution of natural waters is usually concerned with the presence of undesirable toxic substances and heavy metals resulting from man made sources. However, there are already considerable concentrations of undesirable species in natural systems such as humic substances and heavy metals that occur in upland surface water. Synthetic hydrotalcite clays were found to be very effective in removing humic substances from upland surface water due to their anionic nature. Pillared interlayer clays (PILC's) removed humic substances, but to a much lesser extent and this was related to their cationic nature and to the interlayer spacing. Uptake of humic substances from upland surface water was more effective at lower pH values.