VERFAHREN ZUR FORMUNG DER OBERFLAECHE VON AUS FLUESSIGKEITSGEMISCHEN IN EINEM SCHRITT FREI VERSCHAEUMTEN POLYMEREN

For the purification of effluents containing heavy metal compounds, these waters are contacted with an element selected from those more electropositive than hydrogen. The reduction reaction must be carried out at a pH less than or equal to 3. The water to be treated is caused to flow through one or more columns filled with the more electropositive element in the form of granules, beads, strips, shavings or any form compatible with the dimensions of said column. If, for example, the waters to be treated contain chromates, the element used is iron. In this case, the exit pH from the reduction system is kept below the value corresponding to that at which the iron is precipitated as hydroxide. In this way, purification of the waters is achieved with a reduced consumption of more electropositive elements, in this example, iron.