Removal of mercury (II) from aqueous solution by powdered activated carbon nanoparticles prepared from beer barley husk modified with Thiol/ Fe3O4

In the present study, activated carbon from beer barley husk (PAC) using dual-stage chemical activation was magnetized with Fe3O4, and then thiol-modified through the facile and safe hydrothermal method which creates thiol magnetic activated carbon adsorbent (mPAC-SH). The physical and chemical properties of all samples were characterized by XRD, FT-IR, SEM, BET and VSM. The prepared adsorbent was used as an effective adsorbent to removal of mercury (II) from wastewater. The influence of adsorption parameters such as pH, initial concentration of mercury (II), contact time, mPAC-SH dose, and the effect of temperature on the removal of mercury (II) ions was investigated. The results of this study indicated that the highest rate for removal of mercury (II) about 99.44% was observed under optimum conditions in the pH= 6, mercury (II) concentrations about 20 mg L−1, adsorbent dose of 0.4 gL−1 and the contact time of 60 min. Based on the Langmuir model maximum adsorption capacity of Hg (II) was determined as 109.37 mg/g. The sorption mechanism of mPAC -SH on mercury (II) follows the Freundlich isotherm adsorption model with a correlation coefficient of 0.99. The kinetic data has the best correlation with the pseudo-second-order (PSO) kinetics equation with a correlation coefficient about 0.99. The thermodynamic study results showed that the adsorption of mercury (II) ions is endothermic and spontaneous. The mPAC-SH magnetic nanocomposite could be reused after five successive adsorption-desorption cycles of mercury (II) removal without any significant loss of adsorption capacity.