Cr(VI) detoxification from water using a regenerable fullerene-based hybrid adsorbent with in vivo safety assessment

Hexavalent chromium contamination remains a serious challenge for industrial water and wastewater treatment due to its high toxicity, mobility and resistance to conventional remediation methods. Here we report an adsorption-based detoxification approach using a regenerable hybrid nanoadsorbent (GO-C 60 -PEI) that integrates graphene oxide, [60]fullerene and branched polyethyleneimine. Microscopy and spectroscopic analyses (SEM/TEM, FT-IR, XPS, CHNS) together with N 2 –sorption confirm successful construction of the hybrid architecture. Cr(VI) uptake is rapid (equilibrium within 45 min) and best described by a Langmuir monolayer model, giving a maximum capacity of 380 mg g –1 at pH 1.5. The GO-C 60 -PEI adsorbs quantitative Cr(VI) even under an unfavorable aqueous environment of high ionic strength of the solution (up to 3M of NaNO 3 ), and in the presence of million-fold co-existing ions in relation to Cr(VI). The material can be regenerated within 5 min using 1.5 mL of 2M NH 3(aq) assisted by ultrasonication, allowing efficient Cr(VI) recovery. Finally, in vivo toxicological studies using the Drosophila melanogaster model confirmed the absence of toxicity for both the pristine nanomaterial and its Cr(VI)-loaded form, indicating effective detoxification of the treated water. Therefore, the obtained GO-C 60 -PEI represents a promising and eco-friendly platform for the purification and detoxification of Cr(VI) in water treatment systems. • A novel hybrid nanoadsorbent GO-C 60 -PEI was developed toward Cr(VI) adsorption. • Short adsorption time and high adsorption capacity. • Highly selective adsorption in the presence of co-existing ions at large excess. • Simple regeneration and reuse for at least 12 adsorption cycles. • Reduction of Cr(VI) toxicity in the Drosophila model, remaining non-toxic in vivo.