Organic coagulant combined with magnetite nanoparticles for the treatment of mercury-contaminated waters

Abstract

The use of nanomaterials together with natural compounds improves the removal of metals from water, it recovers the coagulating agent, and reduces post-treatment waste. The objective of this study was to determine the efficacy of a natural coagulant based on cocoa shell–CCN–51 (Theobroma cacao L.) with the inclusion of magnetite nanoparticles in removing mercury and taking advantage of a by-product of the cocoa industry and promote the recycling of materials, thus contributing to more environmentally friendly practices. The natural coagulant was characterized by infrared spectroscopy (IR) and scanning electron microscopy (SEM). In samples contaminated in the laboratory, different concentrations of the combination were inoculated. The contaminant was removed by coagulation-flocculation and sedimentation processes in Jar Test equipment. Post-treatment for magnetite recovery was carried out with a neodymium magnet. The results show up to 84.24 % Hg removal, i.e., better results than previous studies (moringa nanofiber, with 81.6 % removal efficiency). A comparative analysis was carried out between the combinations, showing no significant differences, which could be due to the degree of acidity of the samples (pH = 3). This combination of natural coagulant and magnetic nanoparticles adds a practical component to the water treatment process, facilitating waste management and reuse of materials.

Keywords

• Nanoparticles
• Hg removal
• Natural coagulant
• Mercury
• Water
• Contamination