carried out in duplicate at room temperature 25 u00b1 5 u00b0 c the concentration of mb was determined by uv vis spectrophotometry spectronic 20d f thermo scientific at 665 nm h 2 o 2 concentration was determined using the ceric sulfate titration method chemical oxygen demand cod was measured according to standard method total organic carbon toc analysis was carried out with toc shimadzu toc 5000 a ph was measured with a phm 210 ph meter radiometer the voltage v across on the external resistor was monitored with 30 min intervals using a digital multimeter model 2700 keithley instruments inc cleveland ohio usa current i power p iv and coulombic efficiency ce were calculated as previously described current or power density was calculated based both on the projected surface area of cathode in describing the embodiments of the invention specific terminology will be resorted to for the sake of clarity however the invention is not intended to be limited to the specific terms so selected and it is understood that each specific term includes all technical equivalents which operate in a similar manner to accomplish a similar purpose when describing the embodiments of the present invention the combinations and permutations of all possible embodiments have not been explicitly described nevertheless the.