Elimination of 4-chlorophenol from industrial wastewaters using bioprocesses

D. BARBOSA; E. GÓMEZ; M. GÓMEZ; C. PAISIO; P. GONZÁLEZ; E. AGOSTINI

Sevilla

Congreso; Congreso Internacional de Ingeniería Química de ANQUE (ANQUE-ICCE 2012); 2012

Elimination of 4-chlorophenol from industrial wastewaters using bioprocesses D. Barbosa1, E. Gómez1(*), M. Gómez1, C. Paisio2, P. González2, E. Agostini2 1 Departamento de Ingeniería Química, Universidad de Murcia, 30071 Murcia, Spain, Tel:+34 868887352. Fax: + 34868884148 (*)e-mail egomez@um.es 2 Departamento de Biología Molecular, FCEFQN, Universidad Nacional de Río Cuarto, Ruta 36 Km 601, CP 5800 Río Cuarto, Córdoba, Argentina Tel: +54 358 4676537; fax: +54 358 4676232 T9. Bioprocesses and Biocatalysis: Characterization and Improvement of Biocatalysts. Introduction Phenol and its derivatives are versatile raw materials in chemical industry and are widely used in many industrial activities such as petrochemical industries, kraft pulp mills, olive oil production, and various other chemical manufacturing industries. As a result, phenols are extensively present in effluents of these manufacturing plants and they can be introduced to the environment. In the present work, the elimination of 4 chlorophenols by means of a discontinuous tank reactor using different peroxidases has been studied. A comparative study of two Total Peroxidase Extracts (TPE), i.e. extracted from turnip (Brassica napus) and tobacco (Nicotiana tabacum cv. Wisconsin) hairy roots (HR), and a commercial soybean peroxidase (SBP), has been carried out. Methodology The comparative study of the 4-chlorophenol elimination has been carried out in a discontinuous stirred (100 rpm) tank reactor (50 ml), working at room temperature (≈ 25 ºC). Three experimental series have been done for each peroxidase, both TPE and the commercial SBP. The first series focuses on the influence of the enzymatic activity units (U/ml) in the reactor, keeping constant the concentration of both substrates, 4 chlorophenol and hydrogen peroxide (2.0 mM). In the second series, the influence of the initial substrate concentration (from 0.5 to 4.0 mM), keeping constant the enzymatic activity units in the reactor (100*103 U/ml) has been studied. The third series has been dedicated to the study of the influence of the initial hydrogen peroxide concentration (from 1.5 to 3.0 mM), keeping constant the enzymatic activity units (100*103 U/ml) and the concentration of 4-chlorophenol (2.0 mM). Additionally, for each peroxidase, a test with wastewater coming from tannery industries using 100*103 U/ml and 2.0 mM of both substrates has been carried out. To follow the time course of the reaction, concentrations of residual 4-chlorophenol have been measured by the aminoantipirine (AAP) colorimetric method [1]. Results and discussion Figure 1 presents a comparison of the 4-chlorophenol conversion over time for a synthetic sample and an industrial effluent using both TPE (from turnip and tobacco HR) and the commercial SBP. Figura 1 4-chlorophenol conversion along time for a synthetic sample and an industrial effluent. using different peroxidase sources.♦ synthetic sample ▲ industrial effluent. (A) SBP, (B) TPE from turnip HR and (C) TPE from tobacco HR. In the mentioned figure, an increase of the 4-chlorophenol elimination when treating both the synthetic samples and the industrial effluent with both TPE can be observed. Also, higher conversions are attained with the industrial effluent in all cases. These results confirm that the tested peroxidases can be efficiently used for the discontinuous removal of 4 chlorophenol present in industrial wastewaters. According to the study of Flock et al. [2], the higher increase of 4 chlorophenol elimination when treating industrial wastewaters, compared to synthetic samples, may be due to an apparent increase in catalytic activity resulting from dissolved substances present in industrial effluents such as residual organic matter (proteins unstructured mucoproteins, keratin, fats), lime, salt, heavy metals, surfactants, etc... References [1] Standard Methods for the examination of water and wastewater, 19th Edition. (1995). Method 5530, Section 5, 36-39. [2] Flock C., Bassi A., Gijzen M. (1999). Removal of aqueous phenol and 2 chlorophenol with purified soybean peroxidase and raw soybean hulls. Journal of Chemical Technology and Biotechnology. 74, 303-309. Acknowledgements This work was supported by 08683/PI/08 Project from Fundación Séneca (Spain); CONICET (Argentine); SECyT-UNRC (Argentine). Besides D. Barbosa is beneficiary of scholarships from MICINN.