A facile yet versatile method for adsorption and relayed fluorescent detection of heavy metal ions

Abstract The versatile treatment of heavy metal wastewater is serious challenge in practical application if an efficient, low-cost, stable and eco-friendly removal/detection method cannot be widely employed. Herein, we report a facile and effective methodology for adsorption and relayed fluorescent detection of heavy metal ions by substitution reaction effect of hydroxyapatite/Fe3O4 (HAp/Fe3O4) composite combined with Tetracycline Hydrochloride (TCH). The HAp/Fe3O4 works as adsorbent for removal of heavy metal ions by substitution reaction, and the released Ca2+ from HAp acts as indicator for relayed detection of adsorption efficiency. The maximum removal efficiencies of heavy metal ions (Pb2+, Cd2+, Cu2+, Ni2+, Zn2+, Co2+) by HAp/Fe3O4 were over 96% in 100 mg/L. The low detection limitation (0.04 mg/L) and good linear relationship (0.1–100 mg/L) were obtained for Pb2+, and other heavy metal ions display similar trends. The substitution reaction effect provides a promising pathway for removal and indirect measurement of wastewater with superb performance.