The adsorption of arsenic (V) by granular iron hydro(oxides) has been proven to be a reliable technique. However, due to the low mechanical properties of this material, it is difficult to apply it in full scale water treatment. Hence, the aim of this research is to develop a methodology to anchor iron hydro(oxide) nanoparticles onto activated carbon, in which the iron hydro(oxide) nanoparticles will give the activated carbon an elevated active surface area for arsenic adsorption and also help avoid the blockage of the activated carbon pores. Three activated carbons were modified by employing the thermal hydrolysis of iron as the anchorage procedure. The effects of hydrolysis temperature (60-120 °C), hydrolysis time (4-16 h), and FeCl(3) concentration (0.4-3 mol Fe/L) were studied by the surface response methodology. The iron content of the modified samples ranged from 0.73 to 5.27%, with the higher end of the range pertaining to the carbons with high oxygen content. The materials containing smaller iron hydro(oxide) particles exhibited an enhanced arsenic adsorption capacity. The best adsorbent material reported an arsenic adsorption capacity of 4.56 mg As/g at 1.5 ppm As at equilibrium and pH 7.
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http://dx.doi.org/10.1016/j.watres.2012.03.026 | DOI Listing |
J Hazard Mater
September 2021
School of Environment, South China Normal University, Guangzhou, Guangdong 510006, China. Electronic address:
Sulfidation of nanoscale zero-valent iron (nZVI) has been frequently applied to enhance its reactivity, selectivity, and electron utilization efficiency. However, sulfidation of nZVI is generally carried out in aqueous solution, and formation of passivated iron (hydro)oxide species on the surface of S-nZVI due to the reaction between nZVI and water is inevitable. To mitigate this issue, sulfidation of nZVI with hydrogen sulfide dissolved in absolute ethanol was developed.
View Article and Find Full Text PDFSci Total Environ
February 2021
MOE Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China. Electronic address:
Adsorption and desorption of p-arsanilic acid (p-ASA) and roxarsone (ROX) on six soil minerals, including hematite (α-FeO), goethite (α-FeOOH), ferrihydrite (Fe(OH)), aluminum oxide (α-AlO), manganese oxide (γ-MnO), and kaolinite, were studied, and the impact of solution matrices on their adsorption was systematically evaluated. Adsorption of p-ASA/ROX on the metal (hydro)oxide and clay minerals occurred quickly (mostly within 2 h), and could be well described by the pseudo second-order kinetic model. The apparent maximum adsorption capacities of α-FeO, α-FeOOH, Fe(OH), α-AlO, γ-MnO, and kaolinite (at an initial pH of 7.
View Article and Find Full Text PDFEnviron Eng Sci
May 2019
Department of Civil and Environmental Engineering, Southern Methodist University, Dallas, Texas.
This study investigated the adsorptive removal of fluoride from simulated water pollution using various (hydro)oxide nanomaterials, which have the potential to be used as sorbents for surface water and groundwater remediation. Tested nanomaterials include hematite, magnetite, ferrihydrite, goethite, hematite-alpha, hydroxyapatite (HAP), brucite, and four titanium dioxides (TiO-A [anatase], TiO-B [rutile], TiO-C [rutile], and TiO-D [anatase]). Among 11 (hydro)oxide nanomaterials tested in this study, ferrihydrite, HAP, and brucite showed two to five times higher removal of fluoride than other nanomaterials from synthetic fluoride solutions.
View Article and Find Full Text PDFSci Total Environ
April 2019
Science Division, Canadian Light Source, 44 Innovation Bld., Saskatoon S7N2V3, Saskatchewan, Canada; CLS@APS Sector 20, Advanced Photon Source, 9700 South Cass Ave., Lemont, IL 60439, United States of America.
A previous long-term microcosm experiment showed mercury (Hg) in the aqueous phase of contaminated sediment was effectively stabilized through the addition of biochar. The present study focuses on the application of synchrotron-related methods to evaluate the distribution and speciation of Hg in the biochar particles reacted for 235, 387, and 1030 days. The study provided more information on Hg stabilization mechanisms in addition to the information obtained by the previous studies.
View Article and Find Full Text PDFIron (hydro)oxides, including poorly crystalline ferrihydrite and the more crystalline forms, hematite and magnetite, play an important role in the biogeochemical cycling of arsenic in aquatic environments. In this study, adsorption and oxidation experiments for As(III) were performed on ferrihydrite, hematite, and magnetite, respectively. The results showed that the three iron (hydro)oxides acted as a catalyst for the oxidation of As(III) in the presence of oxygen.
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