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Robust and reusable magnetic chitosan/calcium alginate double-network hydrogel beads (CSMAB) with an environmentally benign biocomposite material synthesis approach were used adsorption of surfactant and removal of methylene blue dye sequentially for the first time. Double network hydrogel structure with sodium alginate and chitosan and acidification of the surface with HCl provided the reusability of the beads at the pollutant removal in water. The CSMAB beads were characterized for structural analysis by FESEM, EDX, BET, VSM, and FTIR techniques. They were used for the adsorption of cationic hexadecylpyridinium chloride (HDPCl) and anionic sodium dodecyl sulfate (SDS) surfactants and reused in the removal of cationic methylene blue dye without any pretreatment. The effect of pH, adsorbent dose, and temperature on surfactant removal efficiency was analyzed and pH was found the statistical significance. The adsorption capacity of CSMAB beads with a surface area of 0.65 m 2  g -1 was calculated as 1.9 mg g -1 for HDPCl, and 1.2 mg g -1 for SDS, respectively. The SDS and HDPCl adsorption followed the pseudo-second-order kinetic and Freundlich isotherm model. The thermodynamic results showed that the surfactant adsorption process is an exothermic and spontaneous process. SDS-reacted CSMAB beads showed higher efficiency with 61 % in the removal of methylene blue dye., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Ficus carica (common fig) dried fruit extract was used to synthesize iron oxide nanoparticles in this study. Biomaterials in the common fig dried fruit extract synthesized the iron nanoparticles by reducing the iron precursor salt and then acted as capping and stabilizing agents. The nanoparticles were produced smaller than 20 nm diameters and oxidized due to the high phenolic compound content in the common fig dried fruit extract. Nanoparticles were characterized by energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), UV-visible spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS). First, color change and pH reduction occurred immediately due to the iron nanoparticle synthesis. TEM images showed that the nanoparticles were at 9 ± 4 nm diameters and the metallic core-oxide shell form. The nanoparticles were in spherical shapes with a monodisperse distribution. EDX, XRD and FTIR analysis signals showed the iron oxyhydroxide/oxide formation. Absorption peaks were detected at 205 nm and 291 nm due to the iron metallic core hydrolysis products. The intensity-average diameter of nanoparticles was calculated at 475 nm diameter by DLS analysis. Colloid stability was determined as moderate at 20.7 mV., (Copyright © 2018 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.)