Efficiency and the possibility of using zeolite and apatite purifying water for irrigation and remedation of contaminated soil

Abstract

Knowledge of the mobility of heavy metals and radionuclides, such as Pb, Cd, Zn and U, represents one of the goals of protection, regulation, rational use and irrigation of agricultural soils from the aspect of safe food production. The aim of this work was investigation of efficiency of natural mineral materials based on zeolite and apatite from domestic deposits in the mobility of heavy metals and radionuclides in the waters and soils of the different physico-chemical characteristics (pseudogley and chemozem). The affinity, efficiency, zeolite adsorption mechanisms and apatite adsorption precipitation were determined in a constant- pressure column system at 300 mg 1 for different pH values (5.00 and 7.00) of the basic contaminated solution (Pb, Cd, Zn, U) at time intervals of 30, 60, 90, 120, 180 minutes. In all experiments, significant changes in the pH of the filtrate occurred. The most significant changes in the pH of the filtrate, minimal fluctuations in the time interval, at pH = 5.00, recorded the basic solutions of Pb (7.69-7.87) and U (7.77-7.93) during leakage through the column with apatite, while slightly lower changes for Cd and Zn were observed. Changes also occurred in the column with the zeolite, but with a much lower intensity compared to the column of apatite, and with the trend of changes U> Pb Cd Zn. The trend of changes between apatite and zeolite also occurred in the basic contaminated solution with initial pH-7.00. Zeolite and apatite adsorption/precipitation processes successfully immobilized Pb at both tested pH values of stock solution. Our investigation showed that in colonies, apatite better immobilized U, zeolite is better for immobilization of the Cd, while for the Zn both materials showed a very similar affinity. Zeolite and apatite were added in amount of 20 gkg soil to reduce the content of water-soluble and easily accessible forms of Pb, Cd and Zn in uncontaminated and contaminated soil.