Conocarpus lancifolius Leaves as Low-Cost, Green and Sustainable Sorbent Material for Simultaneous Removal of Cadmium, Chromium, and Lead Ions from Aqueous Samples

Water contamination with various kinds of pollutants is a global challenge. Heavy metal contamination causes several health and environmental issues. Several technologies have been developed for the removal of heavy metals from water. The adsorption is advantageous because of its high efficiency, simple operation, and relatively low cost. Natural sorbents are preferable over synthetic sorbents because of the toxicity concerns and leaching issues during the adsorption process. The plant-derived sorbents are easily available, renewable, biodegradable, and in most cases, non-toxic compared to synthetic sorbents. They can present a viable solution for water treatment in low-resource setups. In this work, Conocarpus lancifolius leaves were employed as sorbent for the simultaneous removal of cadmium, chromium, and lead ions from aqueous samples. The sorbent was prepared simply by washing, drying, and grinding the leaves of C. lancifolius and did not involve the use of chemicals and solvents. The sorbent was characterized by Fourier-transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray, and X-ray diffraction. The characterization revealed the presence of several functional groups and relatively a rough and porous morphology. The effect of various parameters such as pH, sorbent dosage, contact time, and adsorbate concentration on the percentage removal of metals was investigated. The best results for simultaneous removal were obtained at pH 6, a sorbent dosage of 300 mg, and a contact time of 45 min. It also showed good performance in a column study, and it was capable of completely removing both low- (100 µg/L) and high-level (10 mg/L) concentrations of the metals. The sorbent also showed good reusability potential.