Elimination of unwanted Ions from Wastewater by Glasses

초록

Several ions such as Pb2+, SO42- and CO32-ions in a solution were eliminated by surface active glasses For Pb2+ ion removal, a surface active glass with the composition of 44.9% SiO2-5.2%P2O5-23.7%Na2O-26.2%CaO (mole%) was reacted in the solutions with pH 1∼4 containing 150 ppm of Pb2+ ions for 20 hours. Pb2+-containing Pb10(PO4)6(OH)2 crystal was formed on the glass sufrace in the solutions with pH 2 and 3. In this way, Pb2+ ions were removed from the solution effectively. For the removal of SO42- and CO32-ions, glasses having various compositions in the system of SiO2-Na2O-B2O3-RO (R=Mg, Ca, Sr, Ba) were reacted with the solution containing SO42- and CO32-ions. The pH of the reacting solution ranged from 1 to 12.5. Both SO42- and CO32-ions in the solution were combined with divalent ions which were leached out of the glass, and precipitated on the glass surface as sulfate crystals and carbonate crystals, respectively. In this way these ions were also removed from the solution.