Sustainable large-scale Fe3O4/carbon for enhanced polystyrene nanoplastics removal through magnetic adsorption coagulation

• Published in: Journal of water process engineering 2024-02, Vol.58, p.104919, Article 104919
• Main Authors: Kouchakipour, Sediqe, Hosseinzadeh, Majid, Qaretapeh, Milad Zarghami, Dashtian, Kheibar
• Format: Article
• Language: English
• Subjects: Carbon/Fe3O4 nano-adsorbent; Magnetic adsorption coagulation; Polystyrene nanoplastics; Wastewater remediation
• ISSN: 2214-7144; 2214-7144
• DOI: 10.1016/j.jwpe.2024.104919

The omnipresence of nanoplastics in natural water sources raises significant environmental and health concerns due to their challenging removal and potential to transport harmful pollutants. These particles pose threats to terrestrial and aquatic ecosystems, as well as human health, inducing inflammation and oxidative stress. In response, this study focused on an innovative Fe3O4/C nano-adsorbent, derived from discarded printer cartridge toner, for tackling the removal of polystyrene nanoplastics (PS-NPs) through magnetic adsorption coagulation (MAC) with polyaluminum chloride (PACl) as a coagulant. Extensive experimentation achieved a remarkable 99 % removal efficiency at a desirability function value of 0.868 under optimum conditions (pH = 8, adsorbent dosage 2.5 mg, contact time 2 min, PACl concentration 17.5 mg/L, PS-NPs concentration 75 mg/L) with an R2 = 0.9997, a CV% = 0.730 and an Adeq Precision = 122.837. The dominant removal mechanism involved adsorption bridging and electrostatic interaction between PS-NPs and Fe3O4/C in the presence of PACl. Findings covered adsorption kinetics, isotherms, and thermodynamics, adhering to the pseudo-second-order model (R2 = 0.996), Langmuir (R2 = 0.9912) isotherm and negative value of ΔG° (−8.899) as an endothermic adsorption process. The results demonstrated a maximum adsorption capacity of 523 mg/g, showcasing the effectiveness of the approach. Furthermore, the Fe3O4/C material exhibited robust reusability and stability, owing to its magnetite properties. The primary goal was to engineer a magnetic recoverable nano-adsorbent from discarded toner, contributing to cost reduction, streamlined coagulation processes, reduced coagulant consumption, and significantly improved micro/nanoplastics removal. [Display omitted] •Nanoplastics present significant threats to ecosystems and human health.•Eco-friendly Fe3O4/C adsorbent from discarded toner applied for nanoplastics removal.•Utilizing MAC with PACl achieved an exceptional 99 % nanoplastics removal efficiency.•The magnetite properties of the Fe3O4/C material ensure cost-efficiency