Hydrothermally synthesis of a green SnS-Carbon microplate adsorbent for the removal of mercury ion from water samples

Abstract

Mercury ion (Hg²⁺) finds a broad industrial application and due to its significant toxicity to both humans and aquatic life, development of highly effective adsorbents for its removal holds considerable importance. This study introduces a green adsorbent consisting of tin sulfide (SnS)‑carbon microplates synthesized through a straightforward one-step hydrothermal process followed by its application for the removal of Hg²⁺ from water samples. The synthesized adsorbent is characterized using Fourier Transform Infrared Spectrophotometry (FT-IR), Field Emission Scanning Electron Microscopy (FESEM), Energy-Dispersive X-ray spectroscopy (EDX), Thermogravimetric analysis (TGA), Brunauer–Emmett–Teller (BET) and X-Ray diffraction analysis (XRD). Through the optimization of crucial parameters and with thanks to the effective interaction between S atoms (soft base) of SnS-C adsorbent and Hg²⁺ (soft acid), an impressive Hg²⁺ removal percentage of approximately 99.0 % is achieved for 100 mg L⁻¹ Hg²⁺. Interpreting of isotherm models indicate that Hg²⁺ adsorption conforms to the Langmuir isotherm with a maximum adsorption capacity of 238.1 mg/g. Finally, the SnS-Carbon microplate adsorbent exhibits notable advantages, including a green and convenient synthesis route (achieved through a one-step hydrothermal method) and high efficiency, making it a potent adsorbent for the decontamination of Hg²⁺ from water samples.