Simultaneous speciation of chromium by spectrophotometry and multicomponent analysis

Soares, Ricardo; Carneiroa, Manuel Castro; Monteiro, Maria Inês Couto; Henrique, Sérgio de Souza; Pontes, Fernanda Veronesi Marinho; Silva, Lílian Irene Dias da; Neto, Arnaldo Alcover; Santelli, Ricardo Erthal

doi:10.3184/095422909x466095

Cited by 29 publications

(17 citation statements)

References 23 publications

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“…Melaku et al [13] found Cr(VI) concentration in the range 25.1-45.5 ppb in wastewater samples, attributed to effluent discharges from tanneries (Table 3). In another study [14] Cr(VI) concentrations in industrial effluent were found in the range 1.2-6.7 ppm ( Table 3). The reported higher concentrations vis-à-vis current studies were attributed to the use of Cr in the tanning industries.…”

Section: Cr +6 Concentrations Vis-à-vis Studies From Wastewatermentioning

confidence: 90%

Determination of Hexavalent Chromium (Cr(VI)) Concentrations via Ion Chromatography and UV-Vis Spectrophotometry in Samples Collected from Nacogdoches Wastewater Treatment Plant, East Texas (USA)

Onchoke

Sasu

2016

Advances in Environmental Chemistry

110

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The concentration of hexavalent chromium (Cr(VI)), a toxic environmental pollutant and carcinogen, was determined in samples collected from Nacogdoches Wastewater Treatment Plant (NWWTP) using ion chromatography and UV-visible spectrophotometry (IC, UV-Vis). On reaction with 1,5-diphenylcarbazide (DPC) Cr+6forms a 1,5-diphenylcarbazide-Cr(VI) complex, which is then analyzed at 530 nm and 540 nm, respectively. Via ion chromatography Cr(VI) concentrations were in the range of0.00190±0.0020and0.0010±0.0006 ppm at the influent and effluent, respectively. With the use of standard addition wastewater samples were spiked with a 0.5 ppm Cr(VI) standard of various amounts and subsequently analyzed with UV-Vis spectrophotometry. The spiked concentrations gave Cr(VI) concentrations in the range of0.0090±0.0060 ppm and0.0040±0.0061 ppm at the influent and influent wastewater, respectively. The determined Cr(VI) concentrations through the ion chromatography and UV-Vis spectrophotometry are below the maximum USEPA contaminant concentration of 0.1 ppm. From the analysis, the NWWTP efficiently removes Cr(VI) before discharge into the environment through La Nana Creek. The removal efficiency for Cr(VI) was determined to be ≥92.8% along the wastewater treatment stages from the influent (aeration stage) to the effluent stages prior to discharge into the La Nana Creek.

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Section: Cr +6 Concentrations Vis-à-vis Studies From Wastewatermentioning

confidence: 90%

Determination of Hexavalent Chromium (Cr(VI)) Concentrations via Ion Chromatography and UV-Vis Spectrophotometry in Samples Collected from Nacogdoches Wastewater Treatment Plant, East Texas (USA)

Onchoke

Sasu

2016

Advances in Environmental Chemistry

110

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“…Samples of the mixtures were taken out at regular times and were centrifuged immediately (4000 rpm) for <3 min. The amount of chromate in the isolated supernatant ( C t ; mmol/L) was determined with UV-visible spectrometry according to the experimental method described by Soares et al (2009). The quantity of chromate retained ( q t ; mmol/g) was deduced from equation 1: where C o (mmol/L) is the initial concentration of chromate, V is the volume of solution (L) and m is the weight of adsorbent (g).…”

Section: Methodsmentioning

confidence: 99%

Adsorption capacity of sodic- and dendrimers-modified stevensite

et al. 2018

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The adsorption capacities of nano-sized organoclays composed of a stevensite-rich clay (R), phosphorus dendrimers (GC1 and GC2) and Na+-saturated clay were evaluated for their capacity to adsorb chromate and methylene blue (MB) in the range of 298–318 K. The adsorption kinetics and the isotherms were analysed based on kinetic equations and isotherm models and by adopting a non-linear regression procedure. In addition, the organoclays and the Na+-saturated clays were characterized principally by solid-state nuclear magnetic resonance spectroscopy. The pseudo-second-order rate equation described kinetics data well, and the adsorption rates were not limited by the intraparticle diffusion or by the liquid film diffusion. Both chemical species were adsorbed spontaneously (–31 < ΔG°T< –10 kJ/mol), but the adsorbents had a high affinity for MB species. The adsorption isotherms of chromate were fitted better by the Freundlich model, while those of MB followed the Langmuir model. Chromate adsorption took place at the edges and the free surfaces of stevensite, particularly at the protonated aluminols. MB was adsorbed as MBH2+ and MB+. The MB protonation occurred at the clay surfaces, and MB+ ions were located at the planar surfaces of stevensite as well as at the external surfaces of aggregates. Moreover, the tetrahedral sheet of stevensite involved in the formation of GC1-based organoclays was the subject of a partial chemical modification.

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“…20,26,27 Cd <LD 0,2 (1) Pb <LD 0,5 (1) Cr(III) 764±10 (2) 1,0 (1) Zn 2,0±0,3 5,0 (1) Cr(VI) 6±1 (2) 0,1 (1) Dureza (3) 1596±265 ------------ (1) Valores máximos permissíveis para efluentes segundo a resolução CONAMA nª 430. 31 (2) Valores obtidos por Soares et al 32 pH=9,6±0,4. Estão em negrito os resultados que ultrapassaram os VMPs.…”

Section: Caracterização Do Efluente De Curtumeunclassified

Evaluation of the Applicability of Aquatic Pollution Indices: A Case Study in Paraibuna River (Juiz de Fora, MG, Brazil)

Soares¹,

Machado

Campos

et al. 2016

Rev. Virtual Quim.

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Surface water contaminated by metals can configure serious risk to public health and the environment. The uncontrolled release of various pollutants in the aquatic environment is currently a priority issue for the preservation of drinking water sources in many countries around the world, including Brazil. The city of Juiz de Fora has a long industrial tradition, with emphasis on the existence of a metal and leather that dump waste without adequate treatment in the streams and rivers. A comparative assessment of different parameters in isolation provides only a limited idea of pollution with reference to that particular parameter. Therefore, in recent years has been growing interest in the use of pollution indices that incorporate the influence of different parameters simultaneously. The objective of this study was to evaluate the current status of pollution in surface waters of industrial stretch of the Paraibuna River, the city of Juiz de Fora (MG) and determine the applicability and limitations of two indices of water pollution as well documented. In this study, the results were statistically treated and showed that concentrations of Ca, Cd, Cu, Mn, Na and Zn by far exceeding the maximum permissible for some sample points making them unusable for human consumption and maintenance of an adequate environmental quality. Although the two pollution indices were statistically equal to use of the provided conflicting interpretations about the degree of pollution of surface water in these samples.

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Simultaneous speciation of chromium by spectrophotometry and multicomponent analysis

Cited by 29 publications

References 23 publications

Determination of Hexavalent Chromium (Cr(VI)) Concentrations via Ion Chromatography and UV-Vis Spectrophotometry in Samples Collected from Nacogdoches Wastewater Treatment Plant, East Texas (USA)

Determination of Hexavalent Chromium (Cr(VI)) Concentrations via Ion Chromatography and UV-Vis Spectrophotometry in Samples Collected from Nacogdoches Wastewater Treatment Plant, East Texas (USA)

Adsorption capacity of sodic- and dendrimers-modified stevensite

Evaluation of the Applicability of Aquatic Pollution Indices: A Case Study in Paraibuna River (Juiz de Fora, MG, Brazil)

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