COAL FLY-ASH AND ALGINATE FOR THE REMOVAL OF HEAVY-METALS FROM AQUEOUS-SOLUTIONS

The use of a basic coal fly ash in the removal of heavy metal ions fro m aqueous solutions has been investigated. It has been shown that the yields depend on ash dosage and metal concentration; the results are g enerally good and can be improved in some cases by pH lowering. As a m atter of fact, fly ash gives a basic pH to the metal solutions; heavy metals are removed principally by precipitation and adsorption on ash particles. The addition of sodium alginate sometimes makes it possible to reach higher yields at a low ash dosage, but its effect must be ca refully evaluated in the case of mixed ions.