In this paper, the adsorption properties of wheat straw (WS) and corn straw (CS) for Cr(VI) and Cr(III) in solution were studied. The effects of adsorption time, pH of the solution, temperature, and initial concentration of metal ions on adsorption capacity were investigated. The adsorption mechanism was discussed. The results showed that the adsorption isotherms of WS and CS for Cr(VI) and Cr(III) satisfied the Langmuir equation. By fitting the Langmuir equation, the saturated adsorption capacity of WS for Cr(VI) and Cr(III) can reach 125.6 and 68.9 mg g, and that of CS for Cr(VI) and Cr(III) can reach 87.4 and 62.3 mg g , respectively. The adsorption kinetics conformed to the pseudo-second-order kinetic equation. The effect of temperature on the adsorption capacity was not significant. Physical diffusion and chemical adsorption coexist in the process of adsorption of metal ions by straws, and chemical adsorption is dominant, and the effect of physical diffusion on the chemical adsorption rate can be neglected. It can be seen from the experimental results that the treatment of chromium-containing wastewater by using cheap and easily available wheat straw and corn straw had a remarkable effect. The adsorbed straw could be completely desorbed and had excellent recyclability, indicating that the straws are ideal adsorbents.
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http://dx.doi.org/10.1021/acsomega.9b04356 | DOI Listing |
J Colloid Interface Sci
December 2024
Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes 748, São Paulo 05508-000, Brazil. Electronic address:
In this study, kapok fiber (KF) a hollow and hydrophobic fiber, was modified with cetyltrimethylammonium bromide (CTAB) or cetylpyridinium chloride (CPC), rendering adsorbed amount of ∼0.75 × 10 mol/g. Small-angle X-ray scattering (SAXS) measurements of dry KF/CTAB and KF/CPC evidenced a periodic distance of ∼2.
View Article and Find Full Text PDFMass Spectrom (Tokyo)
December 2024
Department of Applied Chemistry for Environment, School of Science and Technology, Kwansei Gakuin University, Gakuen-Uegahara-1, Sanda, Hyogo 669-1330, Japan.
A simple and rapid analytical method was developed for the simultaneous determination of two chromium species, Cr(III) and Cr(VI), in the environmental waters by high-performance liquid chromatography-inductively coupled plasma-mass spectrometry (HPLC-ICP-MS). This study incorporated a chelating pretreatment with 2,6-pyridinedicarboxylic acid (PDCA) to convert Cr(III) species into a stable Cr(III)-PDCA anion complex, which was then separated from Cr(VI) oxyanion using an anion exchange column. Building on the fundamental analytical approach proposed by Shigeta .
View Article and Find Full Text PDFJ Hazard Mater
December 2024
Department of Soil and Environmental Sciences, National Chung Hsing University, Taichung 40227, Taiwan; Innovation and Development Center of Sustainable Agriculture, National Chung Hsing University, Taichung 40227, Taiwan. Electronic address:
The reduction of Cr(VI) to Cr(III) is key to lowering environmental toxicity and mobility, but the reverse process remains less understood. We investigated Cr(III) oxidation mechanisms across various pH levels and light wavelengths (185, 254, and 358 nm) in the presence of Fe(III). At pH 3.
View Article and Find Full Text PDFMolecules
December 2024
Key Laboratory of Subsurface Hydrology and Ecological Effects in Arid Region, Ministry of Education, Chang'an University, Xi'an 710054, China.
The extensive application of chromium (Cr) in many industries has inevitably resulted in the release of Cr(VI) into the groundwater environment, thus posing damage to the ecosystem and human health. Nano zero-valent iron (nZVI) has been widely studied and applied in the remediation of Cr(VI)-contaminated water as an ideal material with high reductive capacity, which enables the transformation of teratogenic and carcinogenic Cr(VI) into less toxic Cr(III). This review comprehensively summarizes the preparation and modification methods of nZVI Cr(VI) removal performance and mechanisms by nZVI and modified nZVI materials.
View Article and Find Full Text PDFSci Rep
December 2024
Faculty of Mining and Geology, University of Belgrade, Đušina 7, Beograd, Serbia.
The study focuses on validating reference methods such as ICP-OES and ICP-MS for detecting ultra-trace levels of chromium in groundwater, where concentrations are typically very low. Additionally, it verifies a hyphenated technique, IC-ICP-MS, for determining naturally occurring Cr(VI) in tested waters. The validation process involved various chromium analysis variants, including isotopes Cr and Cr in ICP-MS and IC-ICP-MS techniques, along with specific emission lines in the ICP-OES technique.
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