New color changing sorption material for effective removal of heavy metals from wastewater

Relevance. The need to purify water resources from Me(II) cations. Obtaining effective and cheap sorbents is one of the priority areas for water purification for various purposes. Namely, the sorbents, allowing the detection and adsorbing heavy metal cations in drinking or tap water and, at the same time, systematic monitoring of water quality in the environment. Aim. Synthesis of sorption material for effective removal of Me(II) cations from wastewater, study of the main parameters of new sorption material. Objects. Shanghai natural zeolite and its forms modified with polyethylene polyamine, 1,2-pyridylazonaphthol and epoxy resin (ED-20). Methods. Spectrophotometry. Results. A sorbent is proposed based on a combination of a surface layer of polyethylene polyamine, 1,2-pyridylazonaphthol and ED-20 epoxy resin, which is then successfully immobilized on zeolite for adsorption of metal cations Me(II)) from water. The synthesized sorbent makes it possible to diagnose its own efficiency by color changing of the surface after sorption of Me(II) cations. Competing cations of alkali and alkaline earth metals (water hardness salts) do not interfere with the adsorption of Me(II) cations. The maximum sorption capacity was 220 mg/g, which is comparable to other common sorbents. The sorbent also demonstrated the possibility of reuse after 10–12 cycles of desorption and regeneration of the color-forming component 1,2-pyridylazonaphthol. Desorption was carried out using 0.20 M HCl, then the sorbent was ready for being used without significant loss of its characteristics after washing with water. Restoration of the ability to color change was achieved by treating the sorbent in a 10–3 M aqueous solution of 1-(2-pyridylazo)-2-naphthol for 10 minutes.