<p>The pollution of hexavalent chromium (Cr(VI)) in water would threaten ecosystems and human health. To remove Cr(VI), we synthesized a novel sodium alginate-based magnetic biochar(BFes) by pyrolyzing SA-Fe³⁺ gel spheres (SAFe) obtained using alginate and FeCl₃ under different temperatures. Batch experiments were conducted with contact time, initial Cr(VI) concentrations, and varying pH. BFes displayed faster removal kinetics than other BFes, reaching equilibrium at 15&#xa0;min. BFe300 exhibited the best Cr(VI) removal among BFes, where the experimental maximum removal capability for BFe300, BFe400, and BFe500 reached 68.94, 40.51, and 13.25&#xa0;mg/g, respectively. BFes’s Cr(VI) removal efficiency remained relatively stable across the pH range of 3 to 9. The pseudo-first-order kinetic model accurately described the adsorption kinetic data, while the Freundlich isotherm model effectively described the adsorption isotherm data, respectively. XPS spectra revealed that the adsorbed Cr on BFe300 is mainly in the form of Cr(III)(72.7%). Cr(VI) was removed through adsorption, redox, precipitation, and complexation according to the XRD pattern, FTIR spectra, and XPS spectra before and after adsorption. Based on the results of the removal of Cr(VI), BFes may be an option for the elimination of Cr(VI) from wastewater.</p> Graphical Abstract <p></p>