Chemical modification of a polysaccharide from artemisia vulgaris engenders a supersorbent for the removal of Cd²⁺ from spiked high-hardness groundwater

Development of novel and chemically modified-natural materials for toxic heavy metal ions uptake from aqueous environment is hot topic of research nowadays. Mucilage from the seeds of Artemisia vulgaris was chemically modified to succinate then to its sodic form. The materials were characterized by Fourier-transformed infrared, scanning electron microscopy-energy dispersive spectroscopy, and solid-state nuclear magnetic resonance spectroscopy. Batch series of experimen-tations were carried out to study the effects of sorbent dosage (10–90 mg/50 mL sorbate sample), pH (1–7), the concentration of Cd²⁺ (20–200 mg L^–1 ), contact time (2–90 min), and temperature (298– 338 K) on the sorption capacity of the sodic form of a hydrogel. Experimental sorption data were fitted to different isothermal and kinetic models. Langmuir isothermal model and pseudo-second-order kinetic model provided the best fit to the experimental data. Maximum sorption capacities of the sorbent (Q_max in mg g^–1 ) to sorb Cd²⁺ were found to be 263.15 mg g^–1 from distilled water and 243.90 mg g^–1 from spiked high hardness groundwater. The sorbent was found regenerable. The values of ΔG°, ΔH°, and ΔS° were found negative, which indicated that the sorption process is feasible, spontaneous, and exothermic.