adsorption, ferro-precipitate, goethite process, heavy metals, zeta potential

This paper deals with the problem of waste sludge from the production of zinc chloride in the company Bochemie. Waste sludge was treated under laboratory conditions, using the goethite precipitation process. Selected ferro-precipitate was used as immobilization agent for removing heavy metals from aqueous solutions. Lead, cooper and chromium were used as model metals. The simultaneous measurements of the heavy metals adsorption and zeta potential determination of the (adsorption) suspensions were carried out. The adsorption isotherms were found to be of typical Langmuir type; values of the heavy metals adsorption capacities have been calculated (am = 0.76 mmol/ g for lead, 0.58 mmol/g for cooper, 0.38 mmol/ g for chromium, respectively).