Adsorption and detection of heavy metals from aqueous water by PVDF/ATP-CDs composite membrane

Abstract

The irreversibility, long-term and toxicity variability of heavy metal ion pollution make it necessary to eliminate it through reasonable detection methods and control methods. carbon dots (CDs) are an efficient fluorescent probe widely used in the detection of heavy metal ions, but the difficulty of recycling nanomaterials limits its practicability. Herein, by reacting CDs with attapulgite (ATP) in the PVDF/ATP hybrid membrane, we successfully prepared a PVDF/ATP-CDs composite membrane with dual functions of adsorption and detection of heavy metal ions. Due to the super-hydrophilic nature of CDs, PVDF/ATP-CDs composite membrane exhibit significantly high wettability (contact angle reduced to 0 ° within 6 s) and permeability (110 L/m2h), which is conducive to its application in water treatment. The addition of ATP significantly improves the adsorption capacity of the composite membrane for Hg2+ (0.99 mg/g), Cu2+ (0.73 mg/g) and Fe3+ (0.60 mg/g), which also overcomes the difficulty of ATP recovery and secondary pollution problems. After being adsorbed, the heavy metal ions are complexed with the CDs on the surface of the composite membrane, quenching the fluorescence of the CDs for detection of heavy metal ions. With its high-efficiency ion adsorption and detection capabilities, PVDF/ATP-CDs composite membranes, which have the advantages of fast, stable, environmentally friendly, simple and inexpensive, will become a promising heavy metal ion detection and adsorption material.