Removal of nitrate from aqueous solutions using Saccharomyces cerevisiae biosorbent: Adsorption isotherms and kinetics

Nitrate is one of the pollutants of drinking water. High nitrate concentration in water is considered as a serious threat. When nitrate concentration exceeds from the standard (50 mg / l as NO3) in drinking water, it can cause methemoglobinemia in children, and also the formation of carcinogenic nitrosamines. To the best of our knowledge, no related study has been performed to use Saccharomyces cerevisiae for nitrate removal. In this study we investigate the possibility of using Saccharomyces cerevisiae as a low cost candidate for nitrate removal from aqueous solutions. This research is a laboratory study. We studied the influence of process variables such as adsorbent dose, initial NO3 concentration, pH and contact time on adsorption process. Langmuir and Freundlich isotherms and adsorption kinetic was also studied. Most of the experiments were done with 50 mg/l of initial nitrate. Our results showed that the maximum NO3 removal efficiency was achieved at pH = 4, adsorbent dose 1 g/100 ml and contact time 20 min. The result showed that the nitrate absorption by the Saccharomyces cerevisiae followed Langmuir isotherm and second- order kinetics.According to the results of this study Saccharomyces cerevisiae can be a suitable and economical candidate for the removal of nitrate with minimal technology.