A new combined green method for 2-Chlorophenol removal using cross-linked Brassica rapa peroxidase in silicone oil

Abstract

This study proposes a new technique to treat waste air containing 2-Chlorophenol (2-CP), namely an integrated process coupling absorption of the compound in an organic liquid phase and its enzymatic degradation. Silicone oil (47V20) was used as an organic absorbent to allow the volatile organic compound (VOC) transfer from the gas phase to the liquid phase followed by its degradation by means of Cross-linked Brassica rapa peroxidase (BRP) contained in the organic phase. An evaluation of silicone oil (47V20) absorption capacity towards 2-CP was first accomplished by determining its partition coefficient (H) in this solvent. The air-oil partition coefficient of 2-CP was found equal to 0.136 Pa m(3) mol(-1), which is five times lower than the air-water value (0.619 Pam(3) mol(-1)). The absorbed 2-CP was then subject to enzymatic degradation by cross-linked BRP aggregates (BRP-CLEAs). The degradation step was affected by four parameters (contact time; 2-CP, hydrogen peroxide and enzyme concentrations), which were optimized in order to obtain the highest conversion yield. A maximal conversion yield of 69% and a rate of 1.58 mg L(-1) min(-1)were obtained for 100 min duration time when 2-CP and hydrogen peroxide concentrations were respectively 80 mg L(-1) and 6 mM in the presence of 2.66 UI mL(-1) BRP-CLEAs. The reusability of BRP-CLEAs in silicone oil was assessed, showing promising results since 59% of their initial efficiency remained after three batches.

A combination of absorption and enzymatic biodegradation: phenol elimination from aqueous and organic phase

“…Figure 1 Although phenol degradation in the organic solvent, silicone oil (47V20), did occur with BRP-CLEAs as a catalyst, only 15% of removal was achieved after one hour when phenol concentration was 60 mg/L. Another phenomenon which altered negatively the degradation in the organic solvent was the accumulation of product degradation on the surface of BRP-CLEAs, which limited the access of the substrate to the active sites and the overall reaction rate [46,47].…”

Estudo Do Uso Da Lignina-Peroxidase Para Remoção De 2-Clorofenol Em Efluente Líquido

“…O crescimento mundial dos setores industrial e agrícola ocasionou inúmeros impactos ambientais, principalmente devido à disposição no ambiente de diversos compostos químicos utilizados em processos industriais e na agricultura que não participam dos ciclos naturais do carbono, do nitrogênio e do oxigênio, tais como: pesticidas, herbicidas, fungicidas, antissépticos, tintas e resinas, solventes e produtos farmacêuticos; e que tendem a se acumular no ambiente. As elevadas quantidades e a disposição inadequadas destes materiais no ambiente tem gerado um problema de poluição ambiental e de saúde pública (TANDJAOUI et al, 2016).…”

“…Neste contexto, o poder nocivo destes compostos, grupo no qual os organoclorados, tais como os clorofenóis se enquadram, só foi percebido após anos da sua utilização e, desde então, estudos vêm sendo feitos em vista de reduzir ou minimizar a quantidade dos componentes tóxicos e recalcitrantes liberados ao ambiente. Destacam-se os processos avançados de oxidação, o uso de solventes orgânicos, os processos de adsorção como os que utilizam carvão ativado, os processos de degradação microbiana, os processos de degradação fotoquímica, os processos de decomposição térmica catalisada e o uso de enzimas como catalisadores potenciais para a degradação de compostos fenólicos, como as peroxidases que podem levar a decomposição do mesmo até dióxido de carbono e água (TANDJAOUI et al, 2016;AJEEL et al, 2015;GAO;TEPLYAKOV, 2014;FREIRE et al, 2000;FLOCK et al, 1999).…”