Surface assembled graphene oxide–deep eutectic solvent based nanocomposite for multimodal adsorption-driven drug sequestration

Water drug contaminants (DCs) are often poorly removed by conventional water treatment processes, as many pharmaceuticals exhibit low biodegradability, weak sorption to activated sludge, and incomplete transformation during standard oxidation and disinfection steps, leading to their persistence in treated effluents. This study introduces a systematically engineered deep eutectic solvent-based graphene oxide (GO–DES) nanocomposite that promotes the development of conformal phosphoryl-carboxyl microdomains, thereby enhancing the efficient capture of tetracycline (TET) as a challenging model antibiotic and other selected co-spiked DCs from wastewater. Initially, a COSMO-RS screening, validated experimentally, encompassing 10 pharmaceuticals, 3 graphene materials, and 20 DES components, identified GO–TOPO:LevA (1:1) as the most efficacious adsorbent. Follow-up advanced characterization validated the effective anchoring of the DES onto GO. For TET, the nanocomposite showcased over 90% removal, ~2.4× adsorption capacity, and ~1.4× faster kinetics than pristine GO. Statistical-physics isotherms elucidated a single heterogeneous monolayer with two distinct sites, and DFT/MD showed electronic softening and a densified H-bond network. Moreover, an ensemble of neural networks enabled characterization of adsorption across a 4D parameter space (concentration, time, pH, temperature) and systematically incorporated quantified uncertainty, thereby enabling efficient and rational process design. To demonstrate its practical applicability, the GO–TOPO:LevA was developed into a binder-free laminar membrane adsorber and was subsequently evaluated in a real municipal wastewater treatment setting. The membrane adsorber demonstrated high DC uptake at low concentrations and retained approximately 70% of its capacity after 6 regeneration cycles.