Geração sonoquímica de oxidantes em solução aquosa saturada de tetracloreto de carbono

Borges, Sivanildo da Silva; Korn, Mauro

doi:10.1590/s0100-40422002000400009

Cited by 20 publications

(5 citation statements)

References 20 publications

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“…Therefore, the sonication of an aqueous solution of chloroalkanes is a potential source of Cl − , Cl 2 and HClO. 14,15 The tendency for one or other species to prevail depends on the physical and chemical properties of the precursor, specially the hydrophobicity, vapour pressure, molar mass and concentration. 2,16 …”

Section: Resultsmentioning

confidence: 99%

Production of chloride and hypochlorite for analytical purposes by sonochemical degradation of organochlorines

Korn¹,

Acevedo²,

Borges³

et al. 2005

J. Braz. Chem. Soc.

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Neste trabalho foram enfatizadas as potencialidades da geração sonoquímica de reagentes pela irradiação ultra-sônica de resíduos de organoclorados de efluentes laboratoriais com a produção de soluções de cloreto e hipoclorito para propósitos analíticos. Foi avaliada a dependência entre a produção de cloreto obtida pela sonicação de efluentes contendo organoclorados e o tempo de irradiação para CCl 4 , CHCl 3 , CH 2 Cl 2 e do inseticida Thiamethoxam ® . Sob condições de saturação pôde ser observada a maior produção de cloreto para CHCl 3 . O processo sonoquímico de geração de cloreto mostrou boa precisão (RSD < 10%). A extensão da geração sonoquímica de hipoclorito foi também avaliada quando conduzida em presença de concentrações diferentes de NaOH. O hipoclorito gerado pela degradação de resíduos foi monitorado pelo método de Berthelot, empregado para a determinação de NH 4 + . Os resultados da produção de azul de indofenol obtidos com soluções de hipoclorito geradas sonoquimicamente foram comparados, para diferentes concentrações de NH 4 + , com solução comercial do reagente e nenhuma diferença significativa (nível de confiança de 95%) foi constatada.This work was aimed at highlighting the potentialities of the reagent generation by ultrasonic irradiation to produce chloride and hypochlorite solutions for analytical purposes derived from the residues of organochlorines of laboratory effluents. The dependence between the production of chloride obtained from the sonication of effluents containing organochlorines and the irradiation time was evaluated for CCl 4 , CHCl 3 , CH 2 Cl 2 and Thiamethoxam ® . It was observed that under saturation conditions the production of chloride was highest for CHCl 3 . Additionally, good precision related to the sonochemical generation of chloride was achieved (RSD < 10%). The extent of sonochemical generation of hypochlorite was also evaluated in the presence of different NaOH concentrations. The hypochlorite generated by the degradation of CCl 4 residues was monitored by the reference Berthelot method for NH 4 + determination. The results obtained with hypochlorite solution sonochemically generated for different NH 4 + concentration were compared with the conventional reagent and no significant difference (95% confidence level) was found.

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Section: Resultsmentioning

confidence: 99%

Production of chloride and hypochlorite for analytical purposes by sonochemical degradation of organochlorines

Korn¹,

Acevedo²,

Borges³

et al. 2005

J. Braz. Chem. Soc.

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“…Ultrasound energy using ultrasonic cleaning baths has been employed in analytical chemistry for bottle cleaning and in several different applications [10], such as extraction [11][12][13], reagent generation [14][15][16][17][18][19] and to improve mass transport in solution and reaction rates [17,20,21]. Ultrasound energy has also been used in conjunction with the reduction of the internal pressure of reaction vessels to obtain salts with a high degree of purity [22,23].…”

Section: ð2þmentioning

confidence: 99%

Influence of ultrasonic waves in the reduction of nitrate to nitrite by hydrazine–Cu(II)

Silva¹,

Korn²,

Andrade³

2007

Ultrasonics Sonochemistry

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Colorimetric methods are still important for determining nitrate and nitrite. A critical step in the use of these methods to determine nitrate in low concentrations is the reaction time required to totally reduce nitrate to nitrite, i.e., 24h in the dark. This work involved a study of the influence of ultrasonic irradiation on the nitrate reduction reaction by hydrazine. Our findings indicated that ultrasonic irradiation, associated with copper(II) ion as a catalyst, increased the redox reaction rate, decreasing the reaction time to about 10min when the power of the ultrasonic irradiation was set in 14.0357W. The strong influence of the ultrasonic irradiation in the reduction reaction rates can be sustained by an excellent linear correlation (R(2)=0.9993) between the kinetic constants and ultrasonic powers. Nitrate conversion also increased from 68% to 98% at the latter conditions. It thus become clear that high intensity ultrasound is very beneficial for this reduction reaction to proceed in good yield and in short reaction time in comparison to its silent reaction.

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“…Diversos artigos têm sido publicados para ilustrar o emprego de ultra-sons na degradação de tetracloreto de carbono em efluentes [39][40][41]; fenóis em amostras de águas [42][43][44][45]; corantes em efluentes industriais [46,47]; fenantreno [48] e hidrocarbonetos voláteis [49] em águas; além de compostos organoclorados [41,[50][51][52][53][54], organofluorados [55][56][57] e aromáticos [58][59][60] e explosivos [61] em águas.…”

Section: Ultra-sons No Preparo De Amostras E Tratamento De Efluentesunclassified

Algumas aplicações analíticas dos ultra-sons

Korn¹,

Pereira²,

Borges³

2005

BSPQuimica

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Geração sonoquímica de oxidantes em solução aquosa saturada de tetracloreto de carbono

Cited by 20 publications

References 20 publications

Production of chloride and hypochlorite for analytical purposes by sonochemical degradation of organochlorines

Production of chloride and hypochlorite for analytical purposes by sonochemical degradation of organochlorines

Influence of ultrasonic waves in the reduction of nitrate to nitrite by hydrazine–Cu(II)

Algumas aplicações analíticas dos ultra-sons

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