| Summary: | A multimode, dual functional nanomaterial, CNTs-Ag<sub>2</sub>S, comprised of carbon nanotubes (CNTs) and silver sulfide (Ag<sub>2</sub>S) nanoparticles, was prepared through the facile hydrothermal process. Before the deposition of Ag<sub>2</sub>S nanoparticles, hydrophobic CNTs were modified to become hydrophilic through refluxing with a mixture of concentrated nitric and sulfuric acids. The oxidized CNTs were employed to deposit the Ag<sub>2</sub>S nanoparticles for their efficient immobilization and homogenous distribution. The CNTs-Ag<sub>2</sub>S could adsorb toxic Cd(II) and completely degrade the hazardous Alizarin yellow R present in water. The adsorption efficiency of CNTs-Ag<sub>2</sub>S was evaluated by estimating the Cd(II) adsorption at different concentrations and contact times. The CNTs-Ag<sub>2</sub>S could adsorb Cd(II) entirely within 80 min of the contact time, while CNTs and Ag2S could not pursue it. The Cd(II) adsorption followed the pseudo-second-order, and chemisorption was the rate-determining step in the adsorption process. The Weber−Morris intraparticle pore diffusion model revealed that intraparticle diffusion was not the sole rate-controlling step in the Cd(II) adsorption. Instead, it was contributed by the boundary layer effect. In addition, CNTs-Ag<sub>2</sub>S could completely degrade alizarin yellow R in water under the illumination of natural sunlight. The Langmuir-Hinshelwood (L-H) model showed that the degradation of alizarin yellow R proceeded with pseudo-first-order kinetics. Overall, CNTs-Ag<sub>2</sub>S performed as an efficient adsorbent and a competent photocatalyst.
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