Ethylenediaminetetraacetic acid-modified halloysite nanotubes loaded with layered SnS2 for highly efficient removal of methylene blue.

Adsorption is an effective strategy for treating water pollution and natural clay mineral-based materials exhibit great potential for removing pollutants from wastewater. In this paper, halloysite nanotubes (HNTs) modified with ethylenediaminetetraacetic acid (EDTA) were thermally treated to serve as supports for loading SnS2 to construct SnS2/HNTs(C) (SHCx-y). Methylene blue (MB) was selected as a target pollutant to examine the removal efficiency of the obtained adsorbents. SHC0.04-500 could remove more than 90% of MB (50 mg L-1) within 18 min, which was 9 and 18 times higher than those of SnS2 and HNTs(C)-500, respectively. Moreover, the adsorbent SHC0.04-500 with good pH and temperature adaptability exhibited excellent adsorption performance toward cationic dyes and various antibiotics. The adsorption process of MB over SHC0.04-500 matched well with the Langmuir isotherm and the pseudo-first-order kinetic model. The adsorption mechanism investigation suggested that the carbon layer on HNTs made the surface of SHC0.04-500 more negative, which mostly contributed to the improved adsorption performance. This work provides a low-cost, environmentally friendly, and efficient adsorbent for removing pollutants from wastewater and contributes a new strategy to enhance the removal efficiency by a simple modification method.