Backgrounds and objectives: Today 's World is faced with the environmental problems associated with heavy metal contamination as one of the main issues of concern. Mercury, known as one of the most toxic heavy metals, has gained a lot of attention due to its sustainability and bioaccumulation in the food chain as well as having detrimental health problems such as kidney failure and gastrointestinal damages. This study is centered on the removal of Hg (II) ions from aqueous solutions using a magnetite/biosilica/sodium alginate nanocomposite as an efficient adsorbent.
Materials and methods: Within this study, the magnetite/biosilica/sodium alginate nanocomposite was successfully synthesized via a co-precipitation method. The structure and morphology of the prepared adsorbent were confirmed by SEM, XRD and VSM analyses. The parameters affecting the adsorption process such as pH, contact time, adsorbent amount, temperature and initial concentration of Hg (II) ions were all evaluated.
Findings: The optimum conditions obtained were as follows: pH 5, adsorbent dosage 0.2 g/L, contact time 80 min, temperature 45 °C. The results revealed that the removal efficiency dropped by increasing Hg(II) concentration. The adsorption of Hg (II) obeyed the Langmuir isotherm (R² 0.9998) and pseudo-second kinetic model (R² 0.9997). Additionally, the thermodynamic studies demonstrated that the adsorption process is of endothermic and spontaneous nature.
Conclusions: All in all, the synthesized adsorbent was applied for the removal of Hg (II) ions from the aquatic environment. Ease of separation from the aqueous solution due to its magnetic properties as well as high level of Hg (II) recovery are amongst the unique feature of the adsorbent.