Fast and effective uptake of mercury(II) from aqueous solution using waste carbon black-supported CuS composites and reutilization of spent adsorbent for photodegradation of rhodamine B

Nowadays, water pollution caused by mercury(II) has been a burning problem for environment and human health. Therefore, it is urgent to develop new materials to remove mercury(II) ions from wastewater. Herein, copper sulfide (CuS) particles were loaded on the modified carbon black obtained from used tires to develop an efficient C/CuS adsorbent for removing of mercury(II) from aqueous solution. The structure and morphology of the C/CuS composite were characterized by FT-IR, TG, XRD, SEM, TEM and BET. The influence of several experimental factors such as pH, initial concentration, contact time and coexisting ions on the adsorbent C/CuS was studied. The experimental results showed that the adsorbent C/CuS exhibited high adsorption capacity, fast removal rate and excellent selectivity for mercury(II) ions. The removal rate and adsorption capacity of adsorbent C/CuS for mercury(II) ions reached 96.06% and 240.10 mg/g within 60 min. The coexisting cations had almost no competitive effect for removal of mercury(II). Adsorption process of C/CuS toward mercury(II) ions were in good agreement with the pseudo-second-order model, and the adsorption equilibrium data of adsorbent C/CuS were consistent with the Langmuir model. Finally, the waste adsorbent C/CuS/HgS (10 mg) as a photocatalyst was used to degrade 20 mL of rhodamine B (20 mg/g), and the corresponding degradation rate was 84.56%.