Adsorption of Pb(II) Using Magnetic Titanate Nanotubes Prepared via Two‐Step Hydrothermal Method

Abstract

Magnetic titanate nanotubes (MTNTs) have been prepared by a two‐step hydrothermal method and used as adsorbents for the removal of Pb(II) from aqueous solution. The MTNTs are characterized by N2 adsorption–desorption analysis, transmission electron microscopy, powder X‐ray diffraction, vibrating sample magnetometer, zeta potentials analysis, X‐ray photoelectron spectra (XPS), and Fourier transform infrared (FT‐IR) spectroscopy. The results indicate that CoFe2O4 is formed in the hydrothermal process and implanted into the entangled network of nanotubes. The saturation magnetization of MTNTs is 9.20 emu g−1, which makes MTNTs can be readily recovered in an external magnetic field. The adsorption of Pb(II) over MTNTs is very fast and follows the pseudo‐second‐order kinetic model. Additionally, Pb(II) adsorption is strongly pH dependent and the maximum adsorption capacity of MTNTs for Pb(II) reaches 442.5 mg g−1 at pH 5.0. FT‐IR and XPS analysis suggest that the adsorption mechanism of MTNTs is ionic exchange between Pb(II) and Na+/H+ in the interlayer of nanotubes. Furthermore, Pb(II)‐loaded MTNTs can be regenerated by saturated EDTA‐2Na solution at pH 2.5 and the adsorbents can be used repeatedly.

Pb(II) adsorption on magnetic γ-Fe2O3/titanate nanotubes composite

“…6 Fe 2 . 4 O 4 micro-particles [11], and Zinc 23 oxide-functionalized MCM-41 (ZM) [12]. 24 As one of the most intensively investigated materials, titanate 25 nanotubes (TNTs) have been used in photocatalysis [13], ion- 26 exchange [14], adsorption [15], and dye-sensitized solar cells [16].…”

“…As an alternative, 44 magnetic separation has been proved to be a very promising 45 method of separation [22]. In our previous paper [23] The Pb(II) adsorption amounts q t at time t and equilibrium 112 adsorption amounts q e were calculated by: [30], respectively:…”

Wastewater Treatment from Lead and Strontium by Potassium Polytitanates: Kinetic Analysis and Adsorption Mechanism

“…In summary, the sorption capacity of potassium polytitanate sorbent obtained in this study was significantly higher than the capacity of the most ceramic materials synthesized previously [38][39][40][41][42][43][44][45][46][47]. Despite better sorption of metal cation on carbon-based sorbents [15][16][17], ceramic materials are more preferable because of their re-use for various practical applications.…”

Highly Sensitive and Selective PbTiO3 Gas Sensors with Negligible Humidity Interference in Ambient Atmosphere

“…The DRIFT spectra of P25-PT in different environments are shown in Figure . The band from 3680 to 3000 cm –1 was observed when the sensor was exposed to a humid atmosphere (red and blue lines), which corresponds to the hydroxyl groups related with Ti elements. − The peak at approximately 1630 cm –1 (red and blue lines) corresponds to the bending vibration of water molecules, which indicates the adsorption of H 2 O. , On taking into account the formation of the OH group in the DRIFT spectra, the increase in the sensor resistance, and the decrease in the gas response with the increase in humidity, it is considered that the H 2 O interacts with the adsorbed O – to form a hydroxyl group on the surface and release electrons. This is in line with the mechanism reported in the extant literature.…”

“…45−47 The peak at approximately 1630 cm −1 (red and blue lines) corresponds to the bending vibration of water molecules, which indicates the adsorption of H 2 O. 48,49 On taking into account the formation of the OH group in the DRIFT spectra, the increase in the sensor resistance, and the decrease in the gas response with the increase in humidity, it is considered that the H 2 O interacts with the adsorbed O − to form a hydroxyl group on the surface and release electrons. This is in line with the mechanism reported in the extant literature.…”