Use of Geopolymers in the Treatment of Water Contaminated by Industrial Waste

The present research aimed to study the use of geopolymers in the removal of heavy metals in water contaminated by an industrial waste. The geopolymer was synthesized and characterized beforehand in the laboratory while the industrial waste is the so-called zinc ferrite that comes from a zinc processing industry in southern Italy. It is known that this waste contains within it a variety of elements that over time can be released if in contact with water. The study was carried out preparing different aqueous systems containing predetermined quantities of zinc ferrite and geopolymer. The systems were stirred for different reaction times and at room temperature. Subsequently, after the established time the systems were filtered and the resulting solution was analyzed by a mass spectrometer (ICP-Ms). The variation in the concentration of various elements (such as Fe, Zn, Pb, Mn, Ca, Mg, Na and K) was followed as a function of contact times. The obtained data allowed to evaluate the effectiveness of geopolymers in the removal of metals released by zinc ferrite in water. In particular, the geopolymers, in the systems studied, have shown particular propensity in the abatement of iron and zinc which has reached 100%, followed by an abatement of about 95% for Mn and Pb after a 1.5-hour contact time.