Hydrous oxides of cerium, aluminum, nickel and copper were prepared by alkaline precipitation method. Langmuir adsorption isotherm was studied and specific surface area was measured by BET method through N2 adsorption-desorption process. IR characterization of hydrous metal oxides before and after fluoride adsorption was also studied. Results show that different hydrous metal oxides have different specific surface areas and their pore size distributions also are not all the same. Adsorption capacity is not directly dependent on the specific surface area. Isotherm study indicates that the adsorption follows Langmuir model and shows the feature of monolayer adsorption. IR study before and after fluoride adsorption shows that different hydrous metal oxides have similar adsorption sites in the same IR region as well as adsorption sites in the different IR region. The comprehensive interaction of these adsorption sites with fluoride ions results in the different adsorption capacity of different hydrous metal oxides.
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J Hazard Mater
January 2025
MOE Key Laboratory of Surficial Geochemistry, School of Earth Sciences and Engineering, Nanjing University, Nanjing, Jiangsu 210023, China. Electronic address:
Agricultural soils in karst regions present a remarkable paradox where high geochemical background levels of heavy metals correspond with unexpectedly low crop uptake, challenging traditional risk assessment frameworks and limiting agricultural development. To decode this paradox, we investigated the geochemical speciation of cadmium (Cd), nickel (Ni), and zinc (Zn) in soil-rice systems in southwestern China, which collectively constitute the world's largest continuous karst region and represent diverse soil weathering stages. We employed three chemical extraction methods that revealed reactive pools ranking as Cd (58.
View Article and Find Full Text PDFSci Total Environ
December 2024
Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China.
Despite many studies on the environmental cycling of As, Fe, and S, sulfide (S(-II))-induced hydrous ferric arsenate (HFA) transformation remains to be elucidated. Herein, we investigated the anaerobic reaction of HFA with S(-II) at three environmental concentrations (1, 10, and 50 mM) at pH 48. Changes in solid-phase As, Fe, and S speciation were investigated by XRD, FTIR, Raman, XPS, synchrotron XANES, SEM, and TEM.
View Article and Find Full Text PDFEnviron Sci Pollut Res Int
December 2024
Department of Soil and Water, Faculty of Agriculture, Ain Shams University, Hadayek Shoubra, P.O. Box 68, Cairo, 11241, Egypt.
The present study involved the preparation of a nano-polymer based on shrimp wastes as a biodegradable chitosan nanoparticle (Cs) incorporated into titanium oxide nanoparticles (TiO) in an aqueous medium and carried on the specific polymer to form thin films. The spectroscopic properties of chitosan/TiO/Polymer thin films were estimated by transmission electron microscopy (TEM) and Fourier transform infrared (FTIR) spectroscopy. The fabricated films were then examined for their potential to eliminate iron (Fe) and chromium (Cr) from solutions.
View Article and Find Full Text PDFJ Environ Sci (China)
May 2025
Hubei Key Laboratory of Environmental and Health Effects of Persistent Toxic Substances, Institute of Environment and Health, Jianghan University, Wuhan 430056, China; University of Chinese Academy of Sciences, Beijing 100049, China. Electronic address:
Chemosphere
November 2024
Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA. Electronic address:
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