Mesoporous TiO2@nitrogen-doped carbon nanosheets implanted in flexible and robust chitosan membrane with dual-function for efficient adsorption of iodide and methyl orange from aqueous solution

• CCM/TiO 2 @NC membranes serve as dual-function adsorbnets for both I − and MO adsorption. • The membrane adsorbent exhibits high flexibility and toughness. • Excellent I − and MO removal efficiency is obtained. • The adsorbent shows good reusability for both I − and MO adsorption. • Multiple mechanisms of I − and MO adsorption are fully discussed. Radioactive iodide (I − ) and methyl orange (MO) are two leading pollutants in wastewater, posing significant health risks. Crosslinked chitosan membranes (CCM) combined with TiO 2 @nitrogen-doped carbon nanosheets (CCM/TiO 2 @NC) were prepared as efficient I − and MO adsorbents in wastewater. These membranes leverage multiple interactions between I − /MO and functional groups (−NH 2 , nitrogen-doped carbon, and TiO 2 ) within the membrane. As expected, CCM/TiO 2 @NC exhibited high I − removal efficiencies of nearly 82 % across a wide pH range (pH 3 − 11) and an exceptional MO removal efficiency of 96.1 % at a neutral condition. The adsorption behaviors followed the Langmuir isotherm and pseudo-second order kinetic model for both species, achieving maximum adsorption capacities of 1.383 mmol/g (175.6 mg/g) for I − and 661.4 mg/g for MO, respectively. Additionally, CCM/TiO 2 @NC maintained a high absorption efficiency for both I − and MO through five regeneration cycles. The I − adsorption mechanism of CCM/TiO 2 @NC involves electrostatic attraction, anion-π interaction, and hydrogen bonding, while MO adsorption involves electrostatic attraction, n/π-π interactions, and hydrogen bonding. This study offers feasible guidance on developing chitosan/nanomaterial composites as promising adsorbents for removing I − and MO from wastewater.