Magnetic adsorption separation process: an alternative method of mercury extracting from aqueous solution using modified chitosan coated Fe₃O₄ nanocomposites

BACKGROUND In the present work, Hg ( II ) is considered as one of the most dangerous elements being released excessively into the environment from various sources. Therefore, the aim of this study is the removal of Hg ( II ) from wastewater effluent by synthesizing a magnetic chitosan modified with glutaraldehyde ( MCS‐GA ) as an adsorbent. The composite structure was characterized using SEM / EDAX , FTIR , and XRD techniques. The adsorbent was tested by a batch system to determine the optimum conditions for removing Hg ( II ) under real conditions. RESULTS The results showed that 0.5% GA effectively enhanced the removal efficiency. The maximum adsorption capacity of MCS‐GA was 96 mg g −1 at pH 5.0 and 25 °C. The adsorption isotherm data obeyed the Langmuir model ( R 2 >0.981) and pseudo‐second‐order ( R 2 >0.996) kinetic models. It was also found that Hg ( II ) adsorption on MCS‐GA is inherently exothermic and occurs spontaneously. The reusability of MCS‐GA was approved over 12 sequential cycles of adsorption–desorption. ANOVA analysis showed that the contact time has a synergistic effect on Hg ( II ) removal, whereas pH and initial concentration have antagonistic effects. CONCLUSION Overall, the synthesized adsorbent was able to remove Hg ( II ) efficiently under both experimental and real conditions.