Removability Efficiency of Heavy Metals with Modified Humate from Aqueous Media

Abstract

<p>The main aim of this work was to study the possibility of using amine-modified humate as a sorbent for the purification of water from heavy metal ions (Cu&Co). One of the effective methods of creating new sorbents of humic acids is chemical modification based on the high reactivity of the functional groups in the composition of humic acids. The possibility of modification of humic acid with bis(3-aminopropyl) amine was illustrated. Modification was carried out with the aim of increasing its sorption capacity. Metal-humate complexes were also obtained by an ion-exchange procedure with modified humate (Mod-Hum) by employing metal salts such as Cu(CH<sub>3</sub>COO)<sub>2</sub>·H<sub>2</sub>O, Co(CH<sub>3</sub>COO)<sub>2</sub>·4H<sub>2</sub>O. Maximum sorption percentages of Mod-Hum achieved were about 99.2% for Cu (II) and 90% for Co (II). The sorption degree depending on pH changes was studied in the range of 2 to 8, the sorption ability of the sorbents was stated to increase with the increase in pH. The degree of sorption of copper (ІІ) on Mod-Hum in the studied range of рН 5 was higher and of cobalt (II) for which the sorption is optimal at higher values (рН 7-8). It is stated that sorption degree increases with the increase in time from 15 min to 2 h. The adsorption of toxic metal ions with Mod-Hum was measured by atomic absorption spectroscopy (AAS). The experimental results on determination of the adsorption isotherm were evaluated with the Langmuir equation. It is shown that the sorbent develops a high sorption capacity in regard to ions of Cu (18.42 mg/g) and Со (16.25 mg/g). All the obtained complex compounds were analyzed and characterized by FT infrared spectroscopy (FTIR), scanning electron microscopy (SEM).</p>