Removal of Cr(VI) by corn stalk based anion exchanger: the extent and rate of Cr(VI) reduction as side reaction

Cao, Wei; Wang, Zhenqian; Ao, Hanting; Yuan, Baoling

doi:10.1016/j.colsurfa.2017.12.049

Cited by 48 publications

(13 citation statements)

References 46 publications

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“…Besides heavy metals as a natural form of food crop adulteration [12], their pathway into the environment would not be limited to the indiscriminate disposal of household wastes, livestock manure, and unused metallic parts [13]. The bioaccumulation of heavy metals, such as copper (Cu), cadmium (Cd), zinc (Zn), and chromium (Cr), in human tissues results in various levels of toxicity [5,14] causing illnesses like cancers, hypertension, and genetic material alteration [15,16]. When the permissible legal limits are exceeded, the heavy metals like iron (Fe), mercury (Hg), manganese (Mn), lead (Pb), and arsenic (As) exert serious health toxic effects [5,14,17].…”

Section: Introductionmentioning

confidence: 99%

Quantification of Heavy Metals and Pesticide Residues in Widely Consumed Nigerian Food Crops Using Atomic Absorption Spectroscopy (AAS) and Gas Chromatography (GC)

Omeje

Ezema

Okonkwo

et al. 2021

Toxins

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More still needs to be learned regards the relative contamination of heavy metals and pesticide residues, particularly those found in widely consumed Nigerian food crops like cereals, vegetables, and tubers. In this current study, the heavy metals and pesticide residues detectable in widely consumed Nigerian food crops were respectively quantified using atomic absorption spectroscopy (AAS) and gas chromatography (GC). Specifically, the widely consumed Nigerian food crops included cereals (rice, millet, and maize), legume (soybean), tubers (yam and cassava), as well as leaf (fluted pumpkin, Amaranthus leaf, waterleaf, and scent leaf) and fruit vegetables (okro, cucumber, carrot, and watermelon). Results showed that the detected heavy metals included arsenic (As), cadmium (Cd), chromium (Cr), cobalt (Co), iron (Fe), lead (Pb), manganese (Mn), mercury (Hg), and nickel (Ni), whereas the pesticide residues included Aldrin, Carbofuran, g-chlordane, Chlorpyrifos, DichloroBiphenyl, Dichlorodiphenyldichloroethane (DDD), Dichlorodiphenyltrichloroethane (DDT), Dichlorvos, Endosulfan, Heptachlor, Hexachlorobenzene (HCB), Isopropylamine, Lindane, t-nonachlor, and Profenofos. Across the studied food crops, the concentrations of heavy metals and pesticides were varied, with different trends as they largely fell below the established maximum permissible limits, and with some exceptions. Our findings suggest there could be a somewhat gradual decline in the concentration of the heavy metals and pesticide residues of these studied food crops when compared to previously published reports specific to Nigeria. To help substantiate this observation and supplement existing information, further investigations are required into the concentration of these heavy metals and pesticide residues specific to these studied food crops at other parts of the country.

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Section: Introductionmentioning

confidence: 99%

Quantification of Heavy Metals and Pesticide Residues in Widely Consumed Nigerian Food Crops Using Atomic Absorption Spectroscopy (AAS) and Gas Chromatography (GC)

Omeje

Ezema

Okonkwo

et al. 2021

Toxins

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“…Recently, many methods have been applied to remove Cr(VI) from wastewater, including chemical precipitation, electrolysis, ion exchange, membrane filtration, adsorption, and photocatalytic reduction [ 7 , 8 , 9 , 10 ]. The adsorption method is regarded as one of the most popular methods due to its advantages of simple operation, low energy consumption, and environmental friendliness [ 11 ].…”

Section: Introductionmentioning

confidence: 99%

Removal of Cr(VI) from Wastewater Using Graphene Oxide Chitosan Microspheres Modified with α–FeO(OH)

et al. 2022

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Graphene oxide and chitosan microspheres modified with α–FeO(OH) (α–FeO(OH)/GOCS) are prepared and utilized to investigate the performance and mechanism for Cr(VI) removal from aqueous solutions and the possibility of Fe secondary pollution. Batch experiments were carried out to identify the effects of pH, mass, and volume ratio (m/v), coexisting ions, time (t), temperature (T), and Cr(VI) initial concentration (C0) on Cr(VI) removal, and to evaluate adsorption kinetics, equilibrium isotherm, and thermodynamics, as well as the possibility of Fe secondary pollution. The results showed that Cr(VI) adsorption increased with C0, t, and T but decreased with increasing pH and m/v. Coexisting ions inhibited Cr(VI) adsorption, and this inhibition increased with increasing concentration. The influence degrees of anions and cations on the Cr(VI) adsorption in descending order were SO42− > PO42− > NO3− > Cl− and Ca2+ > Mg2+ > Mn2+, respectively. The equilibrium adsorption capacity of Cr(VI) was the highest at 24.16 mg/g, and the removal rate was 97.69% under pH = 3, m/v = 1.0 g/L, T = 298.15 K, and C0 = 25 mg/L. Cr(VI) adsorption was well fitted to a pseudo-second-order kinetic model and was spontaneous and endothermic. The best fit of Cr(VI) adsorption with the Langmuir and Sips models indicated that it was a monolayer and heterogeneous adsorption. The fitted maximum adsorption capacity was 63.19 mg/g using the Sips model under 308.15 K. Cr(VI) removal mainly included electrostatic attraction between Cr(VI) oxyanions with surface Fe–OH2+, and the adsorbed Cr(VI) was partially reduced to Cr(III) and then precipitated on the surface. In addition, there was no Fe secondary pollution during Cr(VI) adsorption.

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“…However, these adsorbents have uncontrollable morphologies and pore sizes, which are adverse to Cr(VI) adsorption (Di Natale et al, 2015). Thus, the materials with controllable morphologies and pore sizes would have wider applicability for Cr(VI) adsorption (Cao et al, 2018; Dong et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Application of zeolitic imidazolate framework for hexavalent chromium removal: A feasibility and mechanism study

Sheu

Verpoort

et al. 2021

Water Environment Research

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The mechanisms and effectiveness of using zeolitic imidazolate framework (ZIF‐8) [a sub‐family of metal‐organic framework (MOF)] particles on hexavalent chromium [Cr(VI)] removal were evaluated. The ultrasonic mixing method was applied for the preparation of ZIF‐8, and chemicals used for ZIF‐8 synthesis included ammonium hydroxide, zinc nitrate hexahydrate, and 2‐methylimidazole. ZIF‐8 particle had a clear rhombic dodecahedron morphology shape and a strong peak intensity with high crystallinity. The adsorption capacity (AC) of ZIF‐8 was 30.3 mg of Cr(VI)/g of ZIF‐8 [Cr(VI) = 50 mg/L]. The AC of Cr(VI) raised to 34.3 mg/g under acidic conditions (pH = 5), and the AC dropped to below 13.7 mg/g with a pH range from 7 to 11. It could be because of the competitive effects between CrO42− and hydroxide ions for adsorption locations of ZIF‐8. Cr(VI) removal relied on the amount of Cr(VI) adsorbed on the particles of ZIF‐8, and the mechanisms of Cr(VI) adsorption by ZIF‐8 included chemical/physical processes and the rate‐limiting step was the chemical adsorption. A fraction of sorbed Cr(VI) was reduced to Cr(III), and thus, ZIF‐8 could serve as a reducing agent during Cr(VI) reduction. Cr(VI) was removed effectively from the water phase by ZIF‐8 via adsorption and reduction mechanisms. Practitioner Points ZIF‐8 particles had an adsorption capacity of 30.33 mg of Cr(VI)/g of ZIF‐8. Cr(VI) sorption by ZIF‐8 has chemical (rate‐limiting step) and physical processes. ZIF‐8 can serve as a reducing agent for Cr(VI) reduction. Cr(VI) can be removed by ZIF‐8 via the adsorption and reduction mechanisms.

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Removal of Cr(VI) by corn stalk based anion exchanger: the extent and rate of Cr(VI) reduction as side reaction

Cited by 48 publications

References 46 publications

Quantification of Heavy Metals and Pesticide Residues in Widely Consumed Nigerian Food Crops Using Atomic Absorption Spectroscopy (AAS) and Gas Chromatography (GC)

Quantification of Heavy Metals and Pesticide Residues in Widely Consumed Nigerian Food Crops Using Atomic Absorption Spectroscopy (AAS) and Gas Chromatography (GC)

Removal of Cr(VI) from Wastewater Using Graphene Oxide Chitosan Microspheres Modified with α–FeO(OH)

Application of zeolitic imidazolate framework for hexavalent chromium removal: A feasibility and mechanism study

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