Water purification from metal ions using carbon nanoparticle-conjugated polymer nanocomposites

The paper deals with a novel method of obtaining nanocarbon-conjugated polymer nanocomposites (NCPC) using nanocarbon colloids (NCC) and polyethylenimine (PEI) for water purification from metal ions. Size of NCC, process of NCPC synthesis, its chemical characteristics, ratio of NCC and PEI in NCPC, speed of coagulation of NCPC, mechanism of interaction of metal ions with NCPC, ability of removing metal ions from water by NCPC against pH have been studied. NCPC has a bonding capacity of 4.0-5.7 mmol/g at pH 6 for most of the divalent metal ions. Percent of sorption of Zn²⁺, Cd²⁺, Cu²⁺, Hg²⁺, Ni²⁺, Cr⁶⁺ ions is higher than 99%. Lifetime of NCPC before coagulation in the treated water is 1 s-1000 min and depends on the ratio of polymeric molecules and carbon nanoparticle concentrations. Results of laboratory tests of the method are described.