Enhancing arsenic removal from acidic wastewater using zeolite‐supported sulfide nanoscale zero‐valent iron: the role of sulfur and copper

Abstract

Abstract BACKGROUND Modified nanoscale zero‐valent iron has been extensively used to treat wastewater. This study aimed to investigate the role of sulfur and copper in arsenic removal from CuSO 4 effluent via a new arsenic adsorbent, which is sulfide‐modified nanoscale zero‐valent iron (nZVI)‐supported ZSM‐5 zeolite composite (S‐nZVI@ZSM‐5). RESULTS S‐nZVI@ZSM‐5 can efficiently remove As(V) from acidic wastewater. It was observed that the introduction of sulfur increased the specific surface area of nZVI@ZSM‐5 from 35.3 to 45.7 m 2 g –1 . The As(V) removal performance was observed in the following order: S‐nZVI@ZSM‐5 > nZVI@ZSM‐5 > ZSM‐5. The leaching experiment showed that sulfur decreased iron leaching amount from 7.68 to 1.95 mg L –1 and increased As(V) removal percentage from 89.1% to 94.5%. It was also observed that copper positively impacted As(V) removal when Cu/As concentration ratio was in the range of 0–20, while the negative effect of copper was observed at a Cu/As ratio above 20:1. A high Langmuir As(V) adsorption capacity (204.36 mg g –1 ) and high structure stability of S‐nZVI@ZSM‐5 demonstrated that this adsorbent was effective and environmentally friendly. Kinetic results were observed to obey the pseudo‐second‐order model. The study proposed the mechanisms of As(V) removal. CONCLUSION Both sulfur and copper can extend the reactive life of Fe 0 and improve the As(V) adsorption performance of S‐nZVI@ZSM‐5. © 2021 Society of Chemical Industry (SCI).