Application of microbial fuel cells in the degradation of 2,4,5,6-tetrachloroisophthalonitrile (chlorothalonil)

Abstract

Pesticide’s persistence in the environment due to the relatively slow degradation mechanism leads to their bio-accumulation which in turn has adverse impacts on human health. Bio-remediation involves utilization of microbes from nature to the breakdown of organic molecules. The purpose of this study is to investigate the potential of microbes in degrading chlorothalonil. Aerobic-anaerobic combined conditions in an H-shaped double chamber microbial fuel cell (MFC) were employed for the breakdown of chlorothalonil. Decomposing tomatoes were used as the major substrate with their proximate properties being analyzed using standard method.  Glucose loaded with different concentrations of chlorothalonil was introduced to the cells on day 10 when voltage production had stabilized. The voltage and current generated were monitored using a digital multi-meter while pesticide concentrations were obtained using a UV-Vis spectrophotometer. The highest voltage readings were obtained on day 9 of degradation, with values ranging from 0.463 to 0.537 V. The current ranged from 0.002 to 0.076 mA. Higher voltage and current values were recorded in solutions with lower pesticide concentration. The obtained degradation level was highest in 10 g glucose at 95.95 and 98.75% for day 10 and 20 respectively. The lowest breakdown was observed in the cells without glucose at 10.54 and 31.04% on day 10 and 20 respectively. The results demonstrate that MFC technology can be employed in mineralization of chlorinated pesticides as an alternative for incineration and photo-degradation