Industrial solid waste, Fe(III)/Cr(III) hydroxide, was investigated to assess the capacity for the removal of phosphate from aqueous solution. Langmuir and Freundlich isotherms were used to model the adsorption equilibrium data. The system follows both isotherms. Adsorption capacity was found to be 6.5 mg/g. Kinetic studies show that the adsorption obeyed second order kinetics. Thermodynamic parameters were evaluated. Overall adsorption process was endothermic and spontaneous. Optimum pH for phosphate adsorption was found to be 4.0. Effect of coexisting anions has also been examined.
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http://dx.doi.org/10.1016/j.jhazmat.2005.03.037 | DOI Listing |
Environ Res
May 2024
School of Environment and Energy, South China University of Technology, Guangzhou, 510006, China; The Key Laboratory of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, Guangzhou, 510006, China; The Key Laboratory of Environmental Protection and Eco-Remediation of Guangdong Regular Higher Education Institutions, Guangzhou, 510006, China; Guangdong Provincial Key Laboratory of Solid Wastes Pollution Control and Recycling, Guangzhou, 510006, China. Electronic address:
Chemosphere
March 2024
School of Environment and Energy, Guangdong Provincial Key Laboratory of Solid Wastes Pollution Control and Recycling, South China University of Technology, Guangzhou, Guangdong, 510006, PR China. Electronic address:
Chromium-containing wastewater causes serious environmental pollution due to the harmfulness of Cr(VI). The ferrite process is typically used to treat chromium-containing wastewater and recycle the valuable chromium metal. However, the current ferrite process is unable to fully transform Cr(VI) into chromium ferrite under mild reaction conditions.
View Article and Find Full Text PDFEnviron Sci Technol
December 2023
School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
Photoexcitation of natural semiconductor Fe(III) minerals has been proven to generate Fe(II), but the photogeneration of Fe(II) in Fe-rich surface soil as well as its role in the redox biogeochemistry of Cr(VI) remains poorly understood. In this work, we confirmed the generation of Fe(II) in soil by solar irradiation and proposed a new mechanism for the natural reductive detoxification of Cr(VI) to Cr(III) in surface soil. The kinetic results showed that solar irradiation promoted the reduction of Cr(VI) in Fe-rich soils, while a negligible Cr(VI) reduction was observed in the dark.
View Article and Find Full Text PDFEnviron Sci Pollut Res Int
December 2023
The Guangxi Key Laboratory of Theory and Technology for Environmental Pollution Control, Guilin University of Technology, Guilin, 541004, China.
Biochar-supported nano-zero-valent iron (BC-nZVI) composites have been extensively investigated for the treatment of Cr(VI)-containing wastewater. However, the inherent oxygen-containing groups with negative charges on BC exhibit electrostatic repulsion of the electronegative Cr(VI) species, limiting Cr(VI) removal. To overcome this limitation, this study prepared and used amino-modified bamboo-derived BC (AMBBC) as a supporting matrix to synthesize a novel AMBBC-nZVI composite.
View Article and Find Full Text PDFLuminescence
March 2023
National Oil Company, Iraq Drilling Company, Baghdad, Iraq.
A simple, rapid, sensitive and inexpensive approach is described in this work based on a combination of solid-phase extraction of 8-hydroxyquinoline (8HQ), for speciation and preconcentration of Cr(III) and Cr(VI) in river water, and the direct determination of these species using a flow injection system with chemiluminescence detection (FI-CL) and a 4-diethylamino phenyl hydrazine (DEAPH)-hydrogen peroxide system. At different pH, the two forms of chromium [Cr(III) and Cr(VI)] have different exchange capacities for 8HQ, therefore two columns were constructed; the pH of column 1 was adjusted to pH 3 for retaining Cr(III) and column 2 was adjusted to pH 1 for retaining of Cr(VI). The sorbed Cr(III) and Cr(VI) species were eluted from columns using 3.
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