Sixteenth International Conference on Environmental, Cultural, Economic & Social Sustainability

Abstract

Magnetite (Fe3O4) nanoparticles and thiourea were employed to modify sodium alginate microbeads for adsorption of Hg ions from aqueous solution. The Fe3O4 nanoparticles were initially synthesized by the co-precipitation method. Fourier infrared spectroscopy (FTIR) determined the presence of hydroxyl, carboxyl, thiol and amine functional groups in the microbead molecular structure. According to BET and BJH methods, the MAT microbeads had surface area, pore diameter and volume of 7.3472 m2/g, 12.9058 nm and 0.0255 cm3/g, respectively. Scanning electron microscopy (SEM) equipped with an EDX system allowed to obtain morphological information of the MAT microbeads, in which was observed the main elements introduced by the presence of thiol groups and iron ions. The result of saturation magnetization (Ms) performed by a vibrating sample magnetometer (VSM), is common for superparamagnetic materials, which slightly decreased due to the low amount of magnetic nanoparticles in the microbead structure. Adsorption kinetics showed that highest rate was about 98% in the ﬁrst 20 min, and then decreased to zero. Pseudo-ﬁrst order was the model that better ﬁtted to experimental data with a value about 2.6mg/g. Meanwhile, adsorption isotherm was better described using Langmuir model, suggesting that the Hg ions adsorption was mainly given by electrostatic interaction and chemical bonding among the functional groups, as well as the formation of a saturated layer onto the microbead surface occupying all the available sites.