Synthesis of Conch-Like Layered Carbon Nanosheets by Ball-Milling Assisted Ultrasonic Exfoliation for Highly Selective Removal of Cd(II) from Multiple Water Matrices

•Highly efficient conch-like carbon-nanosheets (CNSs) having layered framework was synthesized.•The resulted CNSs showed higher surface area 368.9 m2 g−1 and thickness range of ∼6–8 nm.•CNSs showed excellent adsorption capacity, selectivity and reusability towards Cd(II).•The strong efficiency of CNSs was also evident in complex water matrices (tap, ground and river water).