Confined Metastable 2‐Line Ferrihydrite for Affordable Point‐of‐Use Arsenic‐Free Drinking Water

Abstract

Arsenic-free drinking water, independent of electrical power and piped water supply, is possible only through advanced and affordable materials with large uptake capacities. Confined metastable 2-line ferrihydrite, stable at ambient temperature, shows continuous arsenic uptake in the presence of other complex species in natural drinking water and an affordable water-purification device is made using the same.

Interference of Phosphate in Adsorption of Arsenate and Arsenite over Confined Metastable Two-Line Ferrihydrite and Magnetite

“…Figure A-a shows a transmission electron microscopy (TEM) image of CM2LF. The image suggests that the material is composed of amorphous particles, in agreement with the literature . To further investigate the morphology of the CM2LF aggregates, transmission electron tomographic reconstruction was performed for CM2LF and its composites with As­(III) and As­(V).…”

“…The materials, magnetite, ,, and two-line ferrhydrite , nanoparticles embedded into organic matter (chitosan and cellulose) are stable in the pH range of 5–9. Previous spectroscopic (XPS and Mossbauer) studies suggest that phosphate-adsorbed wet magnetite nanoparticles remain as magnetite after drying. ,, Kumar et al studied arsenic-adsorbed CM2LF (in the dry state) using X-ray powder diffraction and electron energy-loss spectroscopy . These studies demonstrated that there is no phase change in two-line ferrihydrite.…”

“…The image suggests that the material is composed of amorphous particles, in agreement with the literature. 31 To further investigate the morphology of the CM2LF aggregates, transmission electron tomographic reconstruction was performed for CM2LF and its composites with As(III) and As(V). Accordingly, a series of two-dimensional (2D) projections were collected between ±69°with a 3°i ncrease (see Supporting Information 2 for details).…”

Low‐Spin‐State Hematite with Superior Adsorption of Anionic Contaminations for Water Purification

“…Furthermore, FTMC exhibits fast adsorption rate in the range of 1100–1600 mg (g min) −1 , and maximum uptake as high as 1540–1781 mg g −1 for other organic dyes (widely used in printing and dyeing industry) like Congo Red (CR), Eosin Y (EY), Pyrosine B (PB), Acid Blue (AB), and Methyl Blue (MB), which are 120–380 and 8–14 times higher than those of AC, respectively (Figure 4c,d). In addition, FTMC is much better than AC in the adsorption of Cefoperazone Sodium (CS, one widely used broad‐spectrum antibiotics drug), arsenate (As(V)), and arsenite (As(III)) from the aspects of maximum uptake and adsorption rate, and is among the best adsorbents reported . Especially FTMC exhibits stable adsorption capacity to arsenate and arsenite in the pH < 7.0 solution (Figure S13, Supporting Information) and is tolerant to competition of various inorganic anions (Figure S14, Supporting Information).…”

Industrial Utilization of Capacitive Deionization Technology for the Removal of Fluoride and Toxic Metal Ions (As3+/5+ and Pb2+)

“…[ 14,15 ] Efforts have been made to remove F − from drinking water using activated alumina, but it is ineffective due to low adsorption capacity and lack of regeneration and reusability without side effects. Activated alumina, [ 16 ] hybrid graphene oxide (GO)‐ferric hydroxide composite, [ 17 ] magnetite‐reduced graphene oxide (M‐rGO) composite, [ 18 ] iron oxide, [ 19 ] functionalized graphene nanosheets, [ 20 ] 3D hybrid graphene‐carbon nanotube‐iron oxide composite, [ 21 ] iron oxyhydroxide‐chitosan composite, [ 22 ] activated carbon, [ 23 ] silicon dioxide, [ 24 ] and cellulose‐based materials [ 6 ] have been used to remove arsenic from water in the recent past. Among the different heavy metals, Pb has also been widely found in drinking water, which is also highly toxic to human health.…”