Effective and reusable 3D CuxS nanocluster structured magnetic adsorbent for mercury extraction from wastewater

The elimination of mercury from polluted water using an effective, cost-economic, and sustainable method was investigated in this work. A modulated multilayer magnetic Hg2+ extractor was prepared with a self-assembly engineering that permitting robust anchoring and uniform distribution of the negatively charged 3D CuxS nanocluster onto a polydopamine (PDA) covered positively strengthened Fe3O4 surface. The developed PAD@Fe3O4 supported copper sulfide composite (CuxS/PAD@Fe3O4) presented an unparalleled Hg2+ uptake performance with adsorption capacity of 1394.61 mg/g (without saturation), and extraordinary selectivity with distribution coefficient value K-d of 17419.2 mL/g. A complexation reaction during Hg2+ affinity was taken place on CuxS/PAD@Fe3O4 surface, and almost no components losses occurring during the adsorption. Furthermore, the as-prepared CuxS/PAD@Fe3O4 micron-adsorbent can be easily magnetic recovery and recycled with hydrochloric acid elution. The purification of 50 L Hg2+ containing wastewater, initial concentration of 20 mu g/L can be achieved with CuxS/PAD@Fe3O4 dosage of 0.1 g and treatment cost of 0.077 US $. The outlet Hg2+ concentration met drinking water standard of the United States Environmental Protection Agency. The CuxS/PAD@Fe3O4 magnetic adsorbent can be fabricated cheaply and holds promise for scale-up applications.