Ordered mesoporous carbons as effective sorbents for removal of heavy metal ions

• A functionalized carbon sorbents were synthesized and characterized.
• The carbon sorbents were used for removal of heavy metal ions (Pb, Cu, Zn, Cd).
• Excellent adsorption capacity with respect to heavy metal ions was confirmed.
• Usefulness of the sorbents towards removal of heavy metal ions form waters was shown.

Herein, we report the systematic study on adsorption of heavy metal ions by ordered mesoporous carbon CMK-3. This sorbent has been obtained by hard templating using SBA-15 and subsequently, oxidized (by treatment with (NH4)2S2O8/H2SO4) and amino-functionalized (by treatment with N-(3-trimethoxysilylpropyl)diethylenetriamine). Pristine, oxidized and amino-functionalized carbons have been characterized by nitrogen sorption, X-ray diffractometry, X-ray photoelectron spectroscopy, scanning and transmission electron microscopy and tested for their ability to adsorb heavy metal ions (Pb, Zn, Cu, Cd) from the aqueous solutions. The observed static sorption capacities are very high up to 0.8 mmol/g and were at least twice higher than the values corresponding to the commercial activated carbon Norit® SX2. Adsorption kinetics is also very fast – for majority of the systems ∼90–95% of the equilibrium amount is adsorbed after several minutes. Desorption efficiencies of the adsorbed heavy metals vary from 41% (for Zn) to 99% (for Pb).

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