Fibroid Sorbents for Water Purification

Abstract

Polyester filters are produced and widely used in various countries for removal of dust from air. The process of filter production includes their treatment by acrylonitrilic emulsion for improving their mechanical characteristics. We have developed the technology of modification of polyester filters for production of ion-exchange and carbonic fibroid sorbents. The production of cation-exchange sorbents involved the treatment of ppolyester fibroid filters by a 20–25% solution of NH2NH2H2O at 70–90°C and a 5% solution of NaOH at 40°C. Anion-exchange sorbents were made by treatment of cation-exchange sorbents with a 1–5% solution of polyethylenimine at ambient temperature. These new types of sorbents are used for the removal of radionuclides, heavy metal ions, and organic contaminants from wastewater and drinking water. We have investigated the main properties of these sorbents and their ability to remove 57Co, 60Co, 65Zn, 89Sr, 90Sr, 134Cs, 137Cs, and other radionuclides, heavy metal ions (Zn, Ni, Cu, Sb, Pb, Cd, Cr, U, etc.), organic molecules M (pesticides, phenols, dioxins, benzene, toluene, etc.), radio-labeled organic molecules M-32P, M-131I, M-99Mo+99mTc, M-14C, etc. The influence of pH and concentration of K+, Na+ and other ions on percentage removal, as well as the decrease of saturation capacity with increasing number of regenerations and other characteristics are described. The static exchange capacity is 1–2 meq/g for cationic sorbents and 0.5–1 meq/g for anionic sorbents. The capacity of the carbonic sorbents for removal of benzene is 100 mg/g. The developed sorbents are effective in removing low concentrations of contaminants from water (lower than 100–200 mg/L).