<p>Continually intensifying contamination of hazardous dyes in natural water sources is one of the most serious problems that must be solved urgently, as these pollutants are persistent, carcinogenic and difficult to degrade, thereby requiring the development of sustainable materials. In the present work, novel materials were developed to meet a multifunctional adsorbent for sustainably practical wastewater-treatment. The composite materials were prepared by a green solid-state means by a green solid-state route, which avoided toxic solvent and reduced energy consumption, grinding activated carbon (AC) derived from waste sugarcane bagasse, magnetite (Fe₃O₄) and NiAl-layered double hydroxide (NiAl-LDH) or NiAl-layered double oxide (NiAl-LDO). Various investigation (XRD, FT-IR, SEM, elemental mapping, zeta potential, VSM and BET) could confirm the presence of three precursors in the products that could increase their magnetism, surface area and/or multiple active sites. The composite adsorbents exhibited efficiently multifunctional abilities to remove both anionic dye (eosin yellow), and cationic dye (basic fuchsin) in water, as well as blue reed-dye in real wastewater under easy magnetic separation. The adsorption was processed through <i>pseudo</i>-second order, and monolayer-coverage mechanism. The products showed the extraordinary characteristics on many recycles with keeping high performance on capacity, structure and magnetism. The green solid-state synthesis may provide a scalable and eco-friendly approach to produce multifunctional magnetic adsorbents that serve as efficient and practical materials for removing multiple dye species from wastewater.</p> Graphical Abstract <p></p>