The effective adsorption of tetracycline onto MoS2@Zeolite-5: Adsorption behavior and interfacial mechanism

The agglomeration and limited number of marginal adsorption sites have always been the restrictive factors for nano-MoS2 adsorption performance. In this study, modified zeolite supported nano-MoS2 (MoS2@Zeolite) with multiple adsorption sites was synthesized by combining ultrasonic and hydrothermal method, and utilized for tetracycline (TC) removal. MoS2 @Zeolite-5 exhibits the best adsorption performance with a maximum saturation adsorption capacity of 396.70 mg g(-1) (35 celcius). Meantime, MoS2@Zeolite-5 maintains a stable adsorption performance, which only decreased by 8.17% after four regeneration experiments. The structure characteristics and adsorption mechanism of adsorbents were also systematically investigated. The contact angle, crystal structure, micro-morphology analyses prove that modified zeolite plays the roles of enhancing the hydrophilia, restricting the growth of MoS2 along C-axis, and exposing more adsorptive sites of MoS2. The Pseudo-second order kinetics is suitable for the model adsorption process and the adsorption process is endothermic. The adsorption mechanism of composites mainly relied on the chelation by Mo and electrostatic interaction. Furthermore, the effect of H-bonding and 7C-7C action also existed. This study confirms that MoS2@Zeolite-5 is an efficient, stable, and promising adsorbent to treat TC-pollution of pharmaceutical wastewater.

Automated summary

This study synthesized modified zeolite supported nano-MoS2 (MoS2@Zeolite) with multiple adsorption sites, resulting in the best adsorption performance exhibited by MoS2@Zeolite-5 with high stability. The adsorption mechanism of the composites mainly relied on chelation by Mo and electrostatic interaction, with the presence of H-bonding and 7C-7C action. These findings confirm the potential application of MoS2@Zeolite-5 as an efficient and stable adsorbent for treating TC pollution in pharmaceutical wastewater.