2019).įor the real-water environment, the dissolved chromium mainly exists in the form of free hydrated ions or complexes (with inorganic or organic ligands). Thus, the elimination of Cr(III) ions from water is critical ( Eyvazi et al. 2016), which improves the toxicity of Cr(III). Furthermore, Cr(III) could be converted into more toxic Cr(VI) during the changes in Eh and pH states ( Luther et al. Many studies have shown that the excess accumulation of Cr(III) in humans can decrease immune system activity ( Wang et al. The toxicity and essentiality of Cr depend on its oxidation state ( Novotnik et al. In the environment, chromium was mainly in the form of trivalent chromium (Cr(III)) and hexavalent chromium (Cr(VI)). The worldwide use of Cr in many industries, such as electroplating, tannery, metallurgy and organic chemical synthesis, has received great concerns because of its potential threats to environmental safety ( Egodawatte et al. The results highlighted that the FNMs/APTES as a potential adsorbent can be applied for the minimization of Cr(III)–EDTA chelates from water.Ĭhromium (Cr) pollution of the aquatic environment is widely perceived as an environmental problem due to its nonbiodegradability and toxicity properties ( Guan et al. The Cr(III)–EDTA-saturated adsorbent can be readily regenerated in HCl solution and 83.03% of the initial Cr(III)–EDTA adsorption capacity remains after four adsorption–regeneration experiment cycles. Cr(III)–EDTA was anchored on FNMs/APTES through electrostatic interaction between protonated amino groups of adsorbents and Cr(III)–EDTA anions, and Cr(III)–EDTA chelates were adsorbed as a whole on the adsorbent. Adsorption of Cr(III)–EDTA on the adsorbent was not affected in the presence of Na +, K + and Ca 2+ even at 100 mmol The adsorption isotherm of FNMs/APTES for Cr(III)–EDTA conforms to the Freundlich model, and the adsorption kinetic model accords with the pseudo-second-order kinetic model. The maximum capacities of FNMs/APTES for Cr(III)–EDTA adsorption at 15, 25 and 35 ☌ and pH 4.0 were 12.58, 13.13 and 14.00 mg The characterization of FNMs/APTES showed that the prepared adsorbent with a magnetic mesoporous structure was successfully grafted by APTES, which has good stability under acid conditions. The 3-aminopropyltrimethoxysilane-modified magnetic mesoporous adsorbent (FNMs/APTES) was synthesized and applied to remove Cr(III)–EDTA chelates from water.
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