Background: Contamination of water by heavy metals and dyes is a severe environmental and health concern, and traditional treatment methods are not effective. Graphene oxide (GO) has high adsorption potential, but its application suffers from aggregation and recovery issues.

Aim: This study aims to develop and assess functionalized magnetic graphene oxide (FMGO) nanocomposites as sustainable adsorbent materials for water purification applications.

Methods: Graphene oxide (GO) was synthesized using the modified Hummers’ method, and was functionalized by the incorporation of Fe₃O₄ nanoparticles and a chitosan–methacrylic acid matrix. Characterization was completed using FT-IR, XRD, SEM, TEM, BET and VSM techniques. Batch adsorption studies were employed to assess the pollutant removal efficiency, adsorption kinetics, isotherms and reusability.

Results: FMGO nanocomposites exhibited enhanced surface area, porosity, and magnetic properties. High adsorption capacities were observed for heavy metals (Pb²⁺, Cd²⁺, Cr³⁺, As³⁺/As⁵⁺) and dyes (methylene blue, methyl orange), with maximum removal efficiencies above 95% under optimized conditions. Adsorption followed pseudo-second-order kinetics and Langmuir isotherms, indicating chemisorption and monolayer adsorption. Reusability studies demonstrated retention of over 80% adsorption capacity after five cycles.