Activated Alumina As Adsorbent for Fluoride and Nitrate Ions Removal from Synthesized Photovoltaic Cells Manufacturing Effluents

Considerable volumes of ultrapure water and chemicals are necessary during photovoltaic cells manufacturing, consequently a large amount of wastewater needs to be treated. The present study investigates the activated alumina for fluoride and nitrate ions contaminate adsorptions. Analyses of experimental data were done in order to understand the adsorption phenomena in which pollutants forms intermediates molecules by reacting onto the adsorbent surface, that intermediates reaction can be expressed by Langmuir and Freundlich's adsorption isotherms models. While both ions were found to be adsorbed following the Langmuir model, the nitrates' elimination was found to be more so consistent with the Freundlich model. A significant nitrate ions removal percentage (near to 67%), and an adsorption capacity more than 1.8 mg/g were attained; while for the fluoride ions removal an additional treatment is necessary since a lower removal percentage was obtained with an adsorption capacity of 0.2 mg/g, and using a longer treatment time; also the concentration of fluoride ions in the treated solutions are higher than that recommended by World Health Organization. These results can be used to improve the pollutants removal recoveries at continuous mode and at a large scale. When one considers an additional suitable treatment, the obtained treated ultrapure water can be envisaged to be recycled into the process. Furthermore, from a techno-economic point of view, the cost of the photovoltaic cells production should decrease considerably, since ultrapure water is expensive and its consumption is high in this industry.