Use of polyurethane foams for the removal of the Direct Red 80 and Reactive Blue 21 dyes in aqueous medium

Neta, Julieta de Jesus da Silveira; Moreira, Guilherme Costa; Silva, Carlos Juliano da; Reis, César; Reis, Efraim Lázaro

doi:10.1016/j.desal.2011.07.041

Cited by 68 publications

(11 citation statements)

References 34 publications

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“…The p K a values of individual sulphonic acids range from −2 to +1, and the p K a value corresponding to acid dissociation of phenolic hydroxyl groups in RR120 molecules is >12.5 because of intramolecular hydrogen bonding between the phenolic hydroxyl groups and azo groups. The existence of sulphonic groups in RB71 gives rise to a low p K a value . Therefore, at pH 3–11 and 50 °C, at least one sulphonic group was present in the form of a sulphonate group, while the phenolic hydroxyl groups were hardly ionised.…”

Section: Resultsmentioning

confidence: 99%

Study of the desorption of hydrolysed reactive dyes from cotton fabrics in an ethanol–water solvent system

Hang

2013

Coloration Technology

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The factors influencing the desorption of hydrolysed dyes resulting from reactive cotton dyeings in an ethanol–water solvent system, including the volume ratio of ethanol to water, pH, and temperature, were investigated. The maximum desorption was achieved when the volume ratio of ethanol to water was optimised to 4:6. Desorption increased with an increase in pH and temperature. The kinetic curves of dye desorption at three different temperatures fit a two‐step kinetic model. The dye desorbability at 60 °C in an ethanol–water system was similar to that observed using conventional water washing in the presence of detergent at 95 °C. Findings suggest that wash‐off in an ethanol–water system can be considered as an alternative, more effective process for removing hydrolysed dyes from reactive cotton dyeings.

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Section: Resultsmentioning

confidence: 99%

Study of the desorption of hydrolysed reactive dyes from cotton fabrics in an ethanol–water solvent system

Hang

2013

Coloration Technology

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“…It was observed that about 64.94% MB was removed from solution in 70 minutes. It may be accredited to the adsorption of MB on cellular CPUF as polyurethane has been extensively reported for adsorption processes [22][23][24][25][26][27][28]. This adsorption of dye molecules may facilitate the redox process in the presence of ascorbic acid.…”

Section: Reduction Of Methylene Blue (Mb) With Cpuf Andmentioning

confidence: 99%

Ecofriendly Reduction of Methylene Blue with Polyurethane Catalyst

Sultan

Waheed

Bibi

et al. 2019

International Journal of Polymer Science

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A number of physical, chemical, and biological technologies have been developed to address the issue of synthetic dyes in wastewater. One of the important chemical methods involves reduction of these stringent pollutants into less hazardous products. In this study, a cross-linked polyurethane foam (CPUF) was prepared from toluene diisocyanate (TDI), tetraethylenepentamine (TEPA), and polycaprolactone diol (PCL; Mw: 1000 g/mole). To avoid harmful reducing agents, ecofriendly reduction of methylene blue (MB) was executed with CPUF as catalyst where ascorbic acid and fresh juice extracts were applied as reducing agents. The FTIR and SEM analysis confirmed the chemical composition and porous morphology of CPUF, respectively. The 100% reduction of MB was recorded in just 15 minutes with ascorbic acid and CPUF, while similar result was obtained in 37 minutes in blank experiment composed of only MB and ascorbic acid. Thus, catalytic role of CPUF in reduction process was proved. Fresh fruit extracts also participated in the reduction process, but rate of reaction was accelerated in the presence of CPUF. The reusability study of the catalyst supported its stability and efficiency. All the successful reduction processes followed 1st-order kinetics with highest apparent rate constant for ascorbic acid. Furthermore, phytotoxicity evaluation proved safe reduction of MB with 60% germination index. Hence, it can be concluded that catalytic role of CPUF has been established with safe and biodegradable reducing agents which can be extended to other redox processes.

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“…A capacidade máxima de adsorção foi estimada pelo modelo de Langmuir, sendo de 4,91 mg g -1 para DR 80, e 11,13 mg g -1 para RB 21, resultados superiores aos encontrados em outro estudo que trata da adsorção dos corantes RB 21 e DR 80 por espumas de poliuretano (Neta et al, 2011), e para adsorção de azul de metileno por caulinita (Leal et al, 2011).…”

Section: Coranteunclassified

Remoção dos corantes Reactive Blue 21 e Direct Red 80 utilizando resíduos de sementes de Mabea fistulifera Mart. como biossorvente

et al. 2012

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Neste estudo empregou-se resíduos de Mabea fistulifera Mart. como bioadsorvente para a remoção dos corantes Reactive Blue 21 (RB 21) e Direct Red 80 (DR 80) em soluções aquosas e em amostras de efluentes reais fortificados com estes corantes. Foram investigados os ensaios da influência do pH, cinéticos e adsortivos para a remoção dos corantes por meio de uma série de experimentos de batelada. O bioadsorvente exibiu máxima adsorção em pH = 2,0 para ambos os corantes. O tempo de equilíbrio da adsorção foi estabelecido em 300 minutos para o DR 80 e 120 minutos para o RB 21. O modelo de Langmuir descreveu com maior fidelidade o comportamento do sistema sortivo, apresentando coeficiente de determinação (R 2) superior a 0,98. Por meio da Isoterma de Langmuir, foi possível obter a capacidade máxima de adsorção dos corantes Direct Red 80 e Reactive Blue 21 pelo bioadsorvente sendo encontrados os valores de 4,92 mg g-1 e 11,13 mg g-1 , respectivamente. O modelo cinético de pseudo-segunda ordem melhor descreveu o processo de adsorção do corante RB 21 sob o bioadsorvente, embora a difusão intra-partícula também esteja envolvida no mecanismo de adsorção. Já para o corante DR 80 o modelo de difusão de Morris e Weber sugeriu que a difusão intra-partícula é predominante em todo o processo de adsorção. Depois de otimizadas as condições adsortivas, o bioadsorvente foi empregado a amostras de efluentes têxteis reais fortificadas com soluções aquosas dos corantes, obtendo-se 85 % de remoção do RB 21 e 94 % de remoção do DR 80 na matriz do efluente.

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Use of polyurethane foams for the removal of the Direct Red 80 and Reactive Blue 21 dyes in aqueous medium

Cited by 68 publications

References 34 publications

Study of the desorption of hydrolysed reactive dyes from cotton fabrics in an ethanol–water solvent system

Study of the desorption of hydrolysed reactive dyes from cotton fabrics in an ethanol–water solvent system

Ecofriendly Reduction of Methylene Blue with Polyurethane Catalyst

Remoção dos corantes Reactive Blue 21 e Direct Red 80 utilizando resíduos de sementes de Mabea fistulifera Mart. como biossorvente

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