Remoção do Cd2+ de efluente sintético utilizando polímeros aniônicos a base de acrilamida

Abstract

Industrial activity has been increasing heavy metal levels in natural aquatic ecosystems. These metals come from activities such as mining, electroplating industries, and the disposal of domestic effluents. However, in recent years there has been a considerable increase in the society's awareness of the disastrous effects of discards of industrial effluents contaminated with heavy metals in the environment, impelling research to find decontamination techniques to ensure the environmental suitability of toxic waste. In this context, the present dissertation aims to evaluate the efficiency of the use of acrylamide based anionic polymers to remove Cd2+ from a synthetic effluent using a method of removal of metals by dissolubilization followed by flocculation / filtration. Polymer AN 977 SH, AN 934 SH and AN 905 SH, which presented different anionicities, were used. The parameters mean temperature, solution pH and polymer concentration were evaluated. The 100 ppm metal solution was added to the polymer solution at 1000 ppm, keeping the volume of the metal cation solution constant and the volume of the polymer solution varying, in order to obtain different concentrations in each sample. After the 5 minutes period under stirring, flocculation occurred and then filtration of the effluent. The filtrate was analyzed in the atomic absorption spectrophotometer, allowing to evaluate the percentage removal of cadmium ions. The action of pH variation on the medium directly affects the adsorption process, while the temperature has less significant results. The polymers used proved to be efficient in the removal of cadmium, but due to the different ionic charges, lead to varying percentages of removal, resulting from the interaction between the metal ions and the polymer chain. Analyzing the percentage of removal of the cadmium ions when the temperature has changed, the polymer AN 905 SH was the one that presented better results, however when the variation of the values of pH for the conditions of these tests the greater beneficiary was the polymer AN 977 SH due to having higher ionic charge, together with pH variation that had high removal percentages without any addition of the polymers due to the precipitation effect of the metal in the form of hydroxides. The results obtained in this dissertation showed that it is possible to apply these polymers in the treatment of effluents containing heavy metals.