Efficiency of eggshell as a low-cost adsorbent for removal of cadmium: kinetic and isotherm studies

Eggshell (ES) is an alternative source of calcium carbonate that efficiently removes heavy metals in aqueous solution. The adsorption capacity ES depends on their physico-chemical properties and the influence experimental conditions, but majority reports, not all reaction parameters related to process are available, mechanism systematically studied. In this contribution, use waste reported establish overall performance trend cadmium ion (Cd2+) from Different physicochemical techniques Brunauer–Emmett–Teller (BET), Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), thermogravimetric analysis (TGA), X-ray diffraction (XRD) used characterize studied as a function contact time, pH, concentration, adsorbent dosage. highest capacity, 217.4 mg.g?1, obtained 10 min at initial pH = 5 with dose 0.8 g.L?1, mainly attributed high specific surface area eggshell work. Adsorption kinetics described by pseudo-second-order model, good agreement data, sorption follows isotherm model Langmuir, characterized chemical homogeneous monolayer Cd2+ adsorbents. desorption efficiency ions efficient presence nitric acid. outcomes provided study confirm effective inexpensive material, offering for removal.