Utilização de biossorventes na adsorção de manganês em sistema aquoso

Abstract

Water is the most abundant substance on earth, covering more than 70% of its surface, still less than 1% of the total volume of water is available for human consumption. So, to ensure not only our quality of life but also of future generations, preservation of this resource is needed. However, many human activities have caused a rampant pollution, further diminishing the availability of this essential resource for sustaining life. Among these activities, there are the industrial and agricultural, which discharge into the environment, waste with high concentrations of heavy metals and easily reach the water sources. As a result, manganese concentrations are found in groundwater well above the acceptable value and thus appear serious drawbacks such as fouling in the pipes used in the distribution of water and contamination of people causing neurological problems. Thus, it is necessary to use effective techniques in removing the manganese present in these water bodies. This work was performed Mn adsorption study of natural polymers obtained from straw of corn, soybeans and wheat. Therefore, the adsorbents were kept in contact with 10 mg/L Mn solutions for set times and the final solutions were analyzed by Atomic Absorption Spectrometry (AAS). The polymers were not as effective in the adsorption of copper, and the material obtained from wheat straw showed the best result, removing about 20% of the metal present in the solution. These adsorbents were also chemically modified with ethylenediaminetetraacetic acid (EDTA), an excellent complexing agent, in order to obtain better results in the adsorption. The modified materials were submitted to analysis of total nitrogen content, mass and infrared spectroscopy with Fourier transform (FTIR), which showed that the chelating was incorporated into the straw fibers. Then, it was made the adsorption test using the new adsorbents, which are more efficient. Among them presented the best result was the modified polymer derived from soybean straw, having removed 40% of the solution metal. So, all these materials can be used for treating water bodies of cities near Campo Mourão – PR displaying the contamination problem mentioned above, providing satisfactory results.