<p>In this study, the composite of Seaweed as biomass and Anthracite @ Chitosan (MS-An@Cs) was successfully prepared for the removal of methyl orange as one of toxic azo dye from real and aqueous solutions. The physicochemical characteristics were investigated using X-ray diffraction, Fourier transform infrared spectroscopy, and thermogravimetric analysis. The effects of contact time, pH, adsorbent mass, agitation rate, initial dye concentration, and temperature were assessed through batch adsorption experiments, which revealed that the monolayer coverage was 38.2&#xa0;mg/g. Moreover, several intervening diffusion types, such as intra-particle diffusion, were associated with the regulating phase in the MO sorption process. The MO equilibrium data was also examined using the linear versions of the Freundlich, DR, and Langmuir isotherms; the results indicated that the Langmuir fit the data best, with an R² value of 0.92. Mo sorption kinetics onto MS-An@Cs were described by a pseudo-second-order model, and the linear and nonlinear regression analyses’ results matched well (R² &gt; 0. 0.965). It was proven by the thermodynamic parameters ΔH°, ΔS°, and ΔG° that the MO sorption process at 288–328&#xa0;K was spontaneous and endothermic.the removal percentage of MO from real sample reached 97.5%. It was shown that the composite could be recycled at least six times after its recyclability and regeneration were examined. Additionally, adsorption kinetics and thermodynamics were examined. The created composite is therefore thought to be a more effective adsorbent that can effectively and economically treat industrial wastewater in Egypt. Batch scale-up studies reveal that just 53.72&#xa0;g of the MS-An@Cs nanocomposite can effectively remove 95% of MO dye from 50&#xa0;L of contaminated water at the tested concentration, while cost analysis estimates a low production cost of $0.0174 per gram, demonstrating its superior cost efficiency over conventional water purification methods reported in prior this study.</p>