Facile approach to synthesize chitosan based composite—Characterization and cadmium(II) ion adsorption studies

•Fly ash/chitosan (A-FA/Ch) composite was synthesized successfully.•Composite materials successfully sorb Cd (II) from aqueous solutions at pH 8.•Sorbents are efficient for Cd(II) recovery.•South African coal fly ash was used successfully to remove Cd2+ ions from aqueous solution.•Composite shows new trends for the benefit of environmental pollution control. In this present study, the physicochemical properties, nature and morphology of prepared composite materials involving Activated Eskom fly ash (A-FA) and biopolymer–chitosan (Ch) for two components composite materials were investigated. The nature, morphology, elemental characterizations of these materials were carried out by means of modern analytical methods such as scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray fluorescence (XRF), UV–vis spectroscopy (UV–vis), and Fourier transform infrared spectroscopy (FTIR. Other physicochemical characterizations undertaken were carbon, nitrogen and hydrogen (CNH) analysis, and ash content. The precursors and composite materials were then applied to the sorption of cadmium (Cd2+) from aqueous water. Maximum Cd2+ adsorption capacity (Qmax) was recorded to be 87.72mg/g at pH 8. The adsorption kinetics of the composite materials fitted well with the pseudo second-order kinetic model while the adsorption isotherm data could be well described by the Langmuir isotherm model.