Estudo experimental empregando processo contínuo e batelada para tratamento de uma corrente líquida contendo surfactante

Abstract

The liquid effluent while discharged into water sources, containing its pollutants characteristic, cause quality change into them, therefore its pollution or degradation. This fact, along with increasing water demand and fountains pollution, encourages, each day more, the various sectors society concern, which is mobilized to ensure a more harmonious relationship between their activities and water resources. A way to treat industrial liquid waste, before returning into the water sources, is by means of adsorption employment. Thus, in this thesis, were conducted anionic surfactant adsorption studies, sodium lauryl sulfate (SLS), broadly utilized in cleaning products industries, using continuous and discontinuous processing systems. Experiments were performed in order to be tested two types of materials adsorbent: activated carbon (AC) of various grain sizes (48, 60,100,115 and 300 mesh) and commercial resins (Purolite) ion exchange of three species: anionic resin (AR) cationic resin (CR) and mixed resin (MR). The assays were conducted at room temperature (25ºC ±3), in batch and fixed bed reactor, and the following variables were evaluated: pH, conductivity, turbidity and absorbance in a spectrophotometer (UV-VIS) wave length of 650 nm, to check SLS removal from residual water. In addition, it was measured the morphological characterization of the CA by ESM analysis (Electronic Scanning Microscopy). A statistical analysis called analysis of variance was used in order to verify the influence (reduction) of the following parameters on the variables mentioned above: time decanting and stirring the treated mass, spin, coal particle size, AC mass contained in the reactor, species resin and the filtering time in continuous system. The treatment answers allowed to notice both adsorbent materials were effective in removing the middle SLS. In discontinous process in batch reactor, by comparing the particle sizes 48, 60, 100 and 115, it was observed the 115 mesh was indicated to be the most efficient. Furthermore, the mass of 0.15 g was sufficient to reduce the concentration of surfactante, besides, when folding the mass, no substantial changes observed. The most favorable speed was 600 rpm, the minimum settling time of the system was 22 hours and the stirring time ought to be at least 1 hour for any particle size. Among the resin species of ion exchange, which showed greater reduction in absorbance values was the anion, since it is the same species as the SLS, with higher affinity. Related to fixed bed reactor, it was observed that the filtration time did not affect the conductivity values. The optimum surfactante concentration for disposal was achieved between 3 and 4 hours of filtration, in contrast, adequate turbidity was only achieved after 6 hours. RA highlighted in SLS adsorption, as well as the 60 to 100 CA granulometry. Finally, in general, the obtained results in this study were satisfactory, they demonstrate promising paths for removing SLS from residual water, thereby, contributing to environmental impact reduction caused by cleaning of hygienic materials and manufacturing industries.