Polydopamine decorated carbon dots nanocomposite as an effective adsorbent for phenolic compounds

Abstract Carbon dots (CDs) with an average diameter of 2.3 ± 0.5 nm were prepared from red cabbage by a facile one‐step hydrothermal process. The CDs and polydopamine (PDA) were then subjected to ultrasonication to form a polymer composite namely, PDA‐doped CDs (PDA@CDs). The PDA@CDs with an average size of 5 μm was proven as effective adsorbents for p ‐chlorophenol ( p ‐CP) and p ‐cyanophenol ( p ‐CNP) as two probing models. The adsorption capacity of PDA@CDs was estimated to be 153 mg/g for p ‐CP and 178 mg/g for p ‐CNP, compared favorably with those of various adsorbents used in the literature, only 24–123 mg/g. The PDA@CDs significantly improved the adsorption rate of the two phenols at neutral pH and room temperature. The adsorption kinetics was governed by the pseudo second‐order and intraparticle diffusion models. The PDA@CDs were reused as an active adsorbent material for the adsorption of phenolic compounds with high adsorption capacities in wastewater.