Abstract

This paper deals with the problem of waste sludge from the production of zinc chloride in the company Bochemie. This sludge contains a high degree of zinc (therefore it cannot be used to charge a blast furnace) and a significant amount of dangerous waste is created. 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). Shape of the adsorption isotherms was correlated with zeta potential values at the adsorption equilibrium. Addition of the heavy metals ionsaffects the value of ξ- potential, making the zeta potential values more positive.