Mathematical modeling based evaluation and simulation of boron removal in bioelectrochemical systems

Boron removal is an arising issue in desalination plants due to boron's toxicity. As an emerging treatment concept, bioelectrochemical systems (BES) can achieve potentially cost-effective boron removal by taking advantage of cathodic-produced alkali. Prior studies have demonstrated successful removal of boron in microbial desalination cells (MDCs) and microbial fuel cells (MFCs), both of which are representative BES. Herein, mathematical models were developed to further evaluate boron removal by different BES and understand the key operating factors. The models delivered very good prediction of the boron concentration in the MDC integrated with Dorman Dialysis (DD) system with the lowest relative root-mean-square error (RMSE) of 0.00%; the predication of the MFC performance generated the highest RMSE of 18.55%. The model results of salt concentration, solution pH, and current generation were well filled with experimental data fur RMSE values mostly below 10%. The lung term simulation of the MDC-DD system suggests that the accumulation of salt in the catholyteistripping solution could have a positive impact on the removal of boron clue to osmosis-driven convection. The current generation in the MDC may have little influence on the boron removal, while in the MEC the current-driven electromigration can contribute up to 40% of boron removal. Osmosis-induced convection transport of boron could be the major driving force for boron removal to a low level <2 mg L-1. The ratio between the anolyte and the catholyte flow rates should be kept >22.2 in order to avoid boron accumulation in the anolyte effluent. (C) 2016 Elsevier B.V. All rights reserved.