Carbon nanotubes and graphenes as adsorbents for adsorption of lead ions from water: a review

Nanomaterials have wide applications as sorbents for water purification as they have high selectivity as well as capacity for organic/inorganic pollutants and contaminants in aqueous solutions. Nonessential toxic heavy metals present in water have become a major cause of many diseases, ageing, and genetic problems. Carbon-based nanomaterials have generated great interest in their use as sorbent materials for removal of heavy metals from water/wastewater as they are stable, have limited reactivity, wide surface area, and are strong antioxidants. This study explored the possibility of ranking different carbon-based nanomaterials for efficient removal of lead ions from water which are routinely detected in water samples. Lead may be introduced in water because of its intensive use in many products. The adsorbents based on graphenes and carbon nanotubes have been analyzed on the basis of adsorption capacity, reusability, toxicity/biocompatibility, and cost. The effects of surface area of sorbent, pH of water, thermodynamics/kinetic studies have also been analyzed to evaluate the efficiency of sorbents. The information can be utilized to select the appropriate, most efficient and safe sorbents for removal of lead ions from water.