Nanostructured Carbon Florets as Scavenger of As³⁺, Cr⁶⁺, Cd²⁺, and Hg²⁺ for Water Remediation

Anthropogenically triggered escalating contamination of water by heavy-metal ions (As3+, Cr6+, Cd2+, and Hg2+) demands newer and efficient types of adsorbents for their comprehensive scavenging. The wide pH range (pH 2–13) at which such contamination persists makes it challenging to realize a single-step remediation approach. Addressing these escalating demands, a singular adsorbent capable of capturing multiple heavy metal ions with high adsorption capacity across a wide range of pH is herewith reported for sustainable water remediation. Three-dimensional dendritic mesoporous nanostructured carbon florets (NCFs) with high specific surface area (936 m2/g) and easily accessible open-ended pore structure (1.23 cm3/g) achieve highly efficient removal of multiple heavy metal ions (As3+, Cr6+, Cd2+, and Hg2+). The hydrophilic surface of NCF ensures extensive and efficient interfacing with the water feedstock, while its chemical stability ensures its effectiveness as an adsorbent over a wide pH range (pH 2 to pH 13). The synergistic combination of these factors enables excellent adsorption efficiency (AE; ranging from 80% to 90%) and uniformly high adsorption capacity (qe) toward a variety of heavy-metal ions such as Hg2+ (395 ± 4 mg/g), Cd2+ (402 ± 5 mg/g), Cr6+ (436 ± 3 mg/g), and As3+ (412 ± 4 mg/g). Moreover, the gravity-driven purification of water does not demand any external source of electrical power and is scalable for on-site implementation. Facile regeneration of the NCF and its reusability over multiple cycles is also demonstrated for practical and sustainable application in water remediation.