In this work the sorption of As(III) and As(V) on different natural iron oxides (hematite, magnetite, and goethite) has been studied as a function of different parameters. The sorption kinetics for the three iron oxides shows that equilibrium is reached in less than 2 days and the kinetics of sorption seems to be faster for goethite and magnetite than for hematite. The variation of the arsenic sorbed on the three different sorbents as a function of the equilibrium arsenic concentration in solution has been fitted with a non-competitive Langmuir isotherm. The main trend observed in the variation of the arsenic sorbed with pH is the decrease of the sorption on the three sorbents at alkaline pH values, which agrees with results found in the literature. Highest As(III) sorption was observed on hematite surface in all the pH range compared to goethite and magnetite. Natural minerals studied in this work had similar sorption capacities for arsenic than synthetic sorbents.
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http://dx.doi.org/10.1016/j.jhazmat.2006.07.020 | DOI Listing |
ACS Earth Space Chem
December 2024
Department of Chemistry and Biochemistry, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States.
As wildfire events become more frequent, there is a need to better understand the impact of smoke on the environment and human health. Smoke, or biomass burning aerosol (BBA), can undergo atmospheric processing changing its chemical and optical properties. We examined the interactions between four lignin pyrolysis products (catechol, syringol, syringic acid, and vanillic acid) and three BBA-relevant iron oxide mineral phases (hematite, maghemite, and magnetite) using attenuated total reflectance-Fourier transform infrared spectroscopy and dissolved iron measurements to better understand how atmospheric processing changes concentrations of soluble iron, iron oxidation state, and brown carbon abundance.
View Article and Find Full Text PDFGeobiology
December 2024
Géosciences Montpellier, CNRS, Université de Montpellier, Montpellier, France.
Banded iron formations (BIFs) are chemical sedimentary rocks commonly utilized for exploring the chemistry and redox state of the Precambrian ocean. Despite their significance, many aspects regarding the crystallization pathways of iron oxides in BIFs remain loosely constrained. In this study, we combine magnetic properties characterization with high-resolution optical and electron imaging of finely laminated BIFs from the 2.
View Article and Find Full Text PDFSci Total Environ
December 2024
Environmental Hydro-geochemistry Laboratory, Department of Environmental Sciences, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, PO 45320, Pakistan. Electronic address:
Geochemical surveys conducted on groundwater within the Punjab floodplains revealed high contamination of Arsenic (As). Although the spatial distribution of As and the mechanism of its release have been largely studied and understood however uncertainties still remain regarding its source and derivation. In this research, sediment samples from four boreholes were collected to study As contamination and main sediment phases that host As.
View Article and Find Full Text PDFACS Appl Mater Interfaces
December 2024
Corrosion@Manchester, Department of Materials, The University of Manchester, Nancy Rothwell Building, Oxford Road, Manchester M13 9PL, U.K.
Water Res
November 2024
School of Civil and Environmental Engineering, Georgia Institute of Technology, 790 Atlantic Drive, N. W., Atlanta, GA, 30332-0355, Georgia. Electronic address:
The presence of microplastics in aquatic environments threatens the ecological system and human health. This study investigates the transport and retention of polystyrene microplastics (PSMPs) in clean sand, and hematite-, goethite-, and magnetite-coated iron oxide - sands as a function of size ratio and ionic strength. The breakthrough curves (BTCs), retention profiles, and hydraulic pressure were measured through soil-column experiments, and the retention of PSMPs was assessed from the observed BTCs, RPs and first-order attachment coefficients.
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