In the presented paper, the ability of commercially available gel and macroporous polystyrene anion exchangers for the removal of copper(II), zinc(II), nickel(II), and cadmium(II) complexes with 1-hydroxyethane-1,1diphosphonic acid (HEDP) from aqueous solutions was investigated under various experimental conditions. In the experiments, the strongly basic anion exchangers Lewatit MonoPlus M 600, Lewatit MonoPlus MP 500, and Amberlite IRA 402 with the quaternary ammonium functional groups as well as the medium basic anion exchanger Lewatit MonoPlus MP 64 with the quaternary ammonium/tertiary amine functional groups were used. Special attention was paid to the concentration of heavy metal ions, M(II)-HEDP molar ratio, pH of solutions, temperature, and the physicochemical properties of the anion exchangers used. The effect of the interfered ions such as Ca(II), Mg(II), Cl -, NO 3 -, and SO 4 2on the efficiency of heavy metal complexes with HEDP sorption was also investigated. It was found that polystyrene anion exchangers rapidly sorbed the test metal complexes with HEDP, and the process became saturated in 20 min. The sorption kinetic data showed pseudo-second-order reaction kinetics rather than the pseudo-first-order kinetics. The adsorption behavior of Cu(II), Zn(II), Ni(II), and Cd(II) complexes with HEDP was studied in single as well as in multicomponent competitive systems. The obtained data were fitted well by the Langmuir adsorption isotherm model. Maximum sorption capacities for Cu(II), Zn(II), Ni(II), and Cd(II) complexes with HEDP occurred for strongly basic anion exchanger Lewatit MonoPlus M 600 at the optimal pH 11.5 and were found to be 96. 15, 80.64, 70.42, and 142.85 mg/g, respectively. For binary and quaternary metal complexes solutions, these values were smaller than those from single metal solutions. The presence of Cu(II) and Zn(II) complexes more strongly inhibited Ni(II) and Cd(II) once sorption occured which indicates their greater affinity than that of the remaining complexes for the anion exchangers.

Polymer superabsorbents commonly known as hydrogels are cross-linked highly molecular compounds able to absorb water from physicochemical fluids in the amounts from 10-fold to 100-fold larger than their dry mass. Numerous investigations have shown that they can help reduce irrigation water consumption, lower the death rate of plants, improve fertilizer retention in soil and increase plant growth rate. Besides water absorption and retention, the superabsorbent polymers have many advantages over conventional ones, such as a sustained supply of nutrition to plants for a longer time, thus increasing the phosphate fertilizer use efficiency and decreasing application frequency. The aim of this study is to investigate the influence of chemical conditions on hydrogels, kinetic and absorption behaviour towards metal ions in the presence of the chelating agent of a new generation. In this group, there are IDS, EDDS, GLDA, MGDA, etc. In the chapter, the research on the applicability of the effective absorption of metal complexes with a biodegradable complexing agent will be presented. The possibility of the preparation of slow-release fertilizers of controlled activity of a new generation in such system will also be discussed.

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