Applications of goethite nanoparticles for removal of arsenic and mercury toxic ions from synthetic wastewater

Abstract

<span class="fontstyle0">Contamination of water resources with toxic elements is one of the challenges of the<br />today's world. In this research, application of Goethite nanoparticles in removing<br />contamination of arsenic and mercury from synthetic wastewater in a batch mode is<br />investigated. For this purpose, the effect of different factors including pH, adsorbent dosage,<br />contact time, and initial concentration on the extent of adsorption of arsenic and mercury by<br />the Goethite nanoparticles was studied. The maximum extent of arsenic adsorption in this<br />study being 99.95% occurred at pH=4, adsorbent dose of 4 g/L, initial concentration of 10<br />mg/L and after 120 min from the beginning of the reaction. Examination of the effect of pH<br />on the extent of mercury adsorption showed that the maximum mercury adsorption occured<br />at pH=8. Furthermore, the adsorbent dose of 3 g/L with initial concentration of<br />10 mg/L, following 30 min from the beginning of the reaction caused mercury removal<br />from aqueous solution by up to 72.45%. Investigation of the equation of isotherms of<br />Langmuir and Freundlich adsorption for arsenic and mercury shows better congruence of<br />these ions with Langmuir isotherms. The kinetic studies showed that the As and Hg<br />adsorption mechanism was well described by pseudo-second-order kinetic model. This<br />study indicates that Goethite nanoparticles could be used for removing the toxic arsenic and<br />mercury ions from wastewater.</span> <br /><br />