Assessment of raw clays from Maghnia (Algeria) for their use in the removal of Pb2+ and Zn2+ ions from industrial liquid wastes: a case study of wastewater treatment

Homogenized samples of raw clays resulting from two (2) different lots of natural clays from Maghnia (Algeria) have been assessed for their potential use in the removal of Pb2+ and Zn2+ ions from industrial liquid wastes (LW). Raw and acid-activated samples have been characterized by powder X-ray diffraction, FT-IR spectroscopy, electron microscopy (SEM), and X-ray fluorescence (XRF) and used as adsorbents for the removal of Pb2+ and Zn2+ ions from aqueous system using adsorption method under different conditions. The effect of factors including contact time, pH, and dosage on the adsorption properties of Pb2+ and Zn2+ ions onto clays was investigated at 25 degrees C. The obtained results revealed that the removal percentages of Pb2+ and Zn2+ ions, from both aqueous solution (AS) and LW, were varying between 90 and 98% for 40 min and optimal pH values ranged from 5 to 6 for Pb2+ and Zn2+ ions, respectively. The kinetics of both Pb2+ and Zn2+ ion adsorption fitted well with the pseudo-second-order model. Langmuir, Freundlich, and Temkin adsorption isotherms were used, and their constants were evaluated. The values of thermodynamic parameters, Delta H degrees, Delta S degrees, and Delta G degrees indicated that the adsorption of Pb2+ and Zn2+ ions was spontaneous and exothermic process in nature. The adsorption and desorption isotherms indicated that Pb2+ and Zn2+ adsorption to raw clays was reversible. The experimental results obtained showed that the raw clays from Maghnia (Algeria) had a great potential for removing Pb2+ and Zn2+ ions from industrial liquid wastes using adsorption method.