Effects of different substrates on the adsorption behavior of supported-adsorbents: A case study of MoS for Ag adsorption.

Supported-adsorbents growing on the substrate in situ are equipped with the advantages of high adsorption capacity, excellent regeneration performance, and adaptability to complex wastewater. However, the effects of substrate on the adsorption properties of supported-adsorbent are rarely considered, which will hinder its development and scale-up applications. In this study, the influences of different substrates (Ti, Mo, W, CC) on the Ag adsorption behavior of supported-MoS adsorbents were investigated. The adsorption kinetics, adsorption mechanism, and the renewability of these supported-MoS were compared orderly. As a result, MoS grown on a tungsten substrate (MoS-W) exhibits a remarkable adsorption capacity for Ag (1.98 mg cm and 598.80 mg g), which is 6.38-33 times more than the other three supported-MoS. Moreover, the MoS-W also possesses an ultrahigh distribution coefficient (24.80 mL cm) for Ag, and the selection coefficient can reach 1984. XRD and electrochemical characterization analysis indicated that Ag adsorption performance of supported-MoS is positively correlated with the degree of its amorphous structure. Substrate W with the terrific electrical properties which may facilitate the disordered growth of MoS, resulting in more active sites exposed, and endow MoS-W with outstanding Ag capture performance. Finally, the supported-MoS retains a high removal efficiency of Ag after 5 cycles of adsorption and desorption. This study provides a novel perspective for promoting the practical application of supported-sorbents to recycle heavy metals.