Ag-Doped Zr(IV) and Al(III) Oxyhydroxides Adsorbents for Water Treatment

A promising method is the use of multifunctional sorbents to simultaneously desalinate and disinfect water. Silver nanodispersion stabilized by sodium alginate (Ag0-AlgNa) was chosen as an antibacterial agent. Ag-doped Zr(IV) and Al(III) oxyhydroxides adsorbents were synthesized by combination of sol-gel and reagentless plasma-chemical methods. The offered technique allows to receive the highly homogenized metal oxyhydroxides sols with Ag0 impurities, which is confirmed by the presence of a peak at 410 nm in composite sols. The absence of free Ag+-ions in sols during their aging proves full introduction of Ag0 and Ag+ additives into metal oxyhydroxides structure due to the formation of silver chloride complexes and the partial hydrolysis of Ag+ with following formation of Ag20. XRD-patterns showed that the resulting composite modified by AgO-AlgNa additive has weak crystalline phases at 38.1° and 44.30° and 32.3°, 46.3° and 57.70°, which correspond to Ag0 and Ag2O phases. Proposed method allows to obtain nanostructured adsorbents, which are characterized by high surface area from 310 to 540 m2/g and pore size >2 nm with a point of zero charge at pH=6.0÷6.8. Water treatment test of adsorbents shows their high efficiency to reduce total solids, manganese ions, colony count 22°C and Coliform bacteria in the natural underground water.