Heavy metals are present in ground water and are usually Nickel, Lead, Cadmium and Zinc. These metals are present in water at ppb level under cationic form such as Zn2+, Ni2+, Cd2+ and Pb2+. Reverse Osmosis can be performant at removing low level of heavy metals, although in aerobic conditions metal oxides can clog the membranes. Also, RO is not a very cost efficient method, unless the water salt content requires further demineralisation.
The best method for groundwater heavy metal removal is the use of a selective ion exchange resin. Typical disadvantage of lack a of the selectivity towards heavy metal ions and alkali and alkaline earth metal ions of most widely used functionalized ion exchangers such as Chelex 100 is overcome by introducing chelating ligands capable of removing selective metal ions. It exhibits high affinity for heavy metal ions: Cu2+ > Hg2+ > Pb2+ > Ni2+ > Zn2+ > Cd2+ > Co2+ > Fe2+ > Mn2+ > Ca2+ > Mg2+ > Sr2+ > Ba2+ >>> alkali ions > H+.
I want to recommend you our Lanlang ® CH020 used for cooper, nickel, cobalt, zinc removal. It is a sort of chelating resin which has weakly acidic iminodiacetic acid [-CH2N-(CH2OOH)2] in the styrene / DVB copolymer with special macroporous structure. This product can fix and chelating one or several kinds certain cation in a great range even in the solution with high content. It is used mainly to separate and recover the precious metals ion, especially for the secondary refining of salt brine when the content of Strontium is near or higher than the content of calcium in the process of ion membrane alkaline producing. CH020 is also used to remove cooper, nickel, cobalt, zinc from waste water.
If you want to know more about this chelating resin, welcome to contact us! Lanlang with 15 years of experience in water treatment field will offer you best solutions!