Biodegradação de fenol e p-nitrofenol em reator batelada utilizando casca de ovo como suporte para crescimento de biofilme

Abstract

Industrial effluents that are dumped incorrectly in the environment in large urban centers can cause contamination of soil and water resources, compromising the quality of life of the population. Among the different types of contaminants created in the industries, organic compounds with a phenolic characteristic have been highlighted, these contaminants are easily found in industries such as cellulose paper, petrochemicals, pesticides, paints and resins, and others. In places where the generation of effluents is not controlled the presence of organic pollutants such as phenol and p-nitrophenol may result in significant impacts on the environment due to their high toxicity, damaging the fauna, flora and causing deleterious effects on human health. From this perspective, the development and use of technologies that provide adequate treatment of effluents is extremely relevant, always with the aim of reducing and controlling pollution. Among the various technologies currently used, biodegradation has been shown as an option in order to minimize the contamination of waters and areas polluted by toxic effluents. therefore, the present work aimed to evaluate the efficiency of the removal of phenol and p-nitrophenol from synthetic wastewater, using batch reactor biodegradation, having as immobilization material for the formation of the biofilm the egg shell. The phenol and p-nitrophenol concentrations evaluated were: 5, 10 and 15 mg L-1 and initial pH in the range of 6.84 - 6.97 for phenol and between 7.23 - 7.63 for p- nitrophenol. The results show that the phenol-containing bioreactor presented better performance in the removal of phenol, possibly due to the higher amount of biomass adhered to the support (23.24 mg g-1 support), reaching 100% phenol biodegradation, concentration analyzed in 420 minutes of reaction, when compared to the bioreactor containing p-nitrophenol that presented (19.03 mg g support-1) the maximum removal in the three concentrations was obtained in approximately 660 minutes. Regarding the kinetic parameters, the KA value of the phenol compound indicated higher affinity for the effluent of lower concentration, however, for the compound p-nitrophenol, the KA value indicated higher affinity for the more concentrated effluent. As regards the variable avRmA, for the phenol compound, it was higher for the more concentrated compound, that is, for the more concentrated compound the consumption of substrate was faster, however for the compound p-nitrophenol, the variable was higher for the less concentrated compound, indicating that substrate consumption was faster by the compound of lower concentration. Evaluating the results, it can be concluded that there is efficiency in the use of biofilms supported in eggshell for the removal of toxic contaminants such as phenol and p-nitrophenol, in a batch system of mechanical agitation, it was also observed that the amount of biofilm supported interferes with the removal of the contaminant, and consequently of the biofilm-containing material used in the removal of the phenolic compounds. The biodegradation technology can be pointed out with good efficiency for the treatment of effluents containing phenolic compounds.