Radiation synthesis, characterization and dye adsorption of alginate–organophilic montmorillonite nanocomposite

In this paper, the preparation, characterization and dye adsorption properties of nanocomposite (calcium alginate/organophilic montmorillonite) (CA/OMMT) were investigated. A new nanocomposite consisting of alginate and OMMT was prepared by polymerization using γ-rays irradiation as initiator. Physical characteristics of CA/OMMT were studied using X-ray diffraction (XRD), infrared spectrophotometery (IR), thermal gravimetric analysis (TGA), transmission electron microscopy (TEM) and the corresponding selected area electron diffraction (SAED). Two textile dyes, acid green B and direct pink 3B, were used as model anionic dye. Factors affecting dye sorption, such as pH, sorbent concentration and temperature of each dye solution were extensively investigated. It was found from the study that the sorption of dyes by the nanocomposite is pH-dependent and maximum sorption was obtained at pH 2. The thermodynamic data showed that dye adsorption onto alginate was spontaneous, exothermic, and a physisorption reaction. On the basis of the data of the present investigation, one could conclude that the as-prepared adsorbents exhibited excellent affinity for the dye, and can be applied to treat wastewater containing anionic dyes.