Sorption characteristics of lead cations on microporous organo-birnessite

• TMA-birnessite was a hybrid organic-inorganic sorbent for the removal of Pb ions.
• TMA-birnessite had high affinity and removal efficiency for Pb ions.
• pH was an important parameter influencing the sorption capacity of TMA-birnessite

The aim of this study was to examine the adsorption characteristics of cationic surfactant modified-birnessite for removal of Pb. For this purpose, Na-birnessite and tetramethylammonium (TMA) cation were used as an inorganic host and cationic surfactant, respectively. Na-birnessite was synthesized by the oxidation of Mn2 + under alkaline condition, and TMA cation was intercalated in the interlayer of H-birnessite prepared from Na-birnessite.Batch isotherm tests were carried out to investigate the adsorption capacity of the TMA-birnessite for Pb. The characterization of all synthetic birnessites was carried out with powder X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), and Brunauer–Emmett–Teller (BET) specific surface area measurements. Also, Fourier transform infrared spectroscopy (FT-IR) was used to investigate sorption behavior of Pb onto TMA-birnessite. TMA-birnessite was found to have higher adsorption ability for Pb than synthetic Na-birnessite and commercial granular activated carbon (GAC). This result suggests that the synthetic organo-birnessites could be effective sorbents for removal of heavy metals from groundwater.