Effect of Swine Manure Amendment on Pb2+, Cu2+, Zn2+, and Ni2+ Competitive Sorption onto Agricultural Soil

Abstract

Aims/Objectives: An agricultural tropical soil treated and untreated with swine manure was evaluated to Pb 2+ , Cu 2+ , Zn 2+ , and Ni 2+ competitive sorption dynamics. Study Design: Metal ion mobility patterns were evaluated by sorption-desorption reactions with the mineral and organic matter soil phases. Place and Duration of Study: Agronomic Institute of Parana (IAPAR) at Londrina city, ParanaState, Southern Brazil, in an experiment conducted since June 2008. Methodology: Soybean and corn were growing up in the experimental area in summer and winter, respectively. Swine manure (SM) was applied twice a year, and the amount was calculated according each crop necessity. Experiments were in batch, varying the metal ion concentration from 1.0 to 10 meq L −1 . After equilibrium, the solid phase was analyzed by EDXRF and liquid phase by ICP-OES. Metal ion mobility was evaluated by applying the dual-mode Langmuir-Freundlich mathematical model, in addition to rate removal and Gibb's free energy determination. Results: Sorption capacity increased after the SM amendment, and the retention sequence Pb 2+ >Cu 2+ >Zn 2+ >Ni 2+ was observed. The sorption capacity increased in 30%, 45%, 176%, and 231% for Pb 2+ , Cu 2+ , Zn 2+ , and Ni 2+ , respectively. The relative intensity of the fluorescence emission lines showed metal ion sorption increased after the amendment, keeping the same sequence observed for the adjustable parameters from the fitting by dual-mode Langmuir-Freundlich model. Conclusion: The possibility of a controlled release of micronutrients, considering low-affinity sorption sites, brings an excellent look to the swine manure amendment.