Mechanochemical synthesis of sulfur nanoparticles from industrial waste for enhanced Hg(II) adsorption

In this study, sulfur extracted from gas industry waste was utilized as an adsorbent for mercury ions (Hg²⁺) in aqueous solutions. To enhance its adsorption capacity, a mechanical wet grinding process using a water–alcohol medium was employed to reduce particle size and increase surface area. Compared to dry grinding, the wet method significantly improved performance. BET analysis revealed an increase in specific surface area from 3.1 m²/g (untreated sulfur) to 26.7 m²/g after wet milling. BJH analysis showed the development of uniform micro- and mesopores in the 1–10 nm range, ideal for heavy metal adsorption. XRD and FTIR confirmed the preservation of sulfur’s crystalline structure and the formation of S–S bonds, while SEM images reveald nanoparticles ranging from 30–100 nm. Batch adsorption experiments demonstrated an increase in mercury ion removal efficiency from 45% (raw sulfur) to 91% (wet-milled sulfur), and the adsorption capacity rose from 12 mg/g to 26 mg/g. These results confirm that wet grinding in a water–alcohol system is an effective strategy for enhancing the physicochemical properties and adsorption performance of sulfur for mercury remediation.