Cost-effective copper removal by electrosorption powered by microbial fuel cells.

This work studied a cost-effective electrosorption that driven by microbial fuel cells (MFC-sorption) to remove Cu(2+) from wastewater without an external energy supply. The impact factors, adsorption isotherms and kinetics of the novel process were investigated. It indicated that a low electrolyte concentration and a high solution pH could enhance the Cu(2+) removal efficiency, while the adsorption capacity increased with the increase of numbers of MFCs in series and the initial Cu(2+) concentration. The adsorption isotherms study indicated that the monolayer adsorption in MFC-sorption was dominant. The kinetics study suggested the increase of initial Cu(2+) concentration could enhance the initial adsorption rate. The electrode characterizations verified the existence of Cu2O and Cu on the electrode surface of active carbon fibers (ACFs), suggesting that MFC-sorption was not only an adsorption process, but also a redox reaction process.

Simultaneous wastewater treatment, electricity generation and biomass production by an immobilized photosynthetic algal microbial fuel cell.

A photosynthetic algal microbial fuel cell (PAMFC) was constructed by the introduction of immobilized microalgae (Chlorella vulgaris) into the cathode chamber of microbial fuel cells to fulfill electricity generation, biomass production and wastewater treatment. The immobilization conditions, including the concentration of immobilized matrix, initial inoculation concentration and cross-linking time, were investigated both for the growth of C. vulgaris and power generation. It performed the best at 5 % sodium alginate and 2 % calcium chloride as immobilization matrix, initial inoculation concentration of 10(6) cell/mL and cross-linking time of 4 h. Our findings indicated that C. vulgaris immobilization was an effective and promising approach to improve the performance of PAMFC, and after optimization the power density and Coulombic efficiency improved by 258 and 88.4 %, respectively. Important parameters such as temperature and light intensity were optimized on the performance. PAMFC could achieve a COD removal efficiency of 92.1 %, and simultaneously the maximum power density reached 2,572.8 mW/m(3) and the Coulombic efficiency was 14.1 %, under the light intensity of 5,000 lux and temperature at 25 °C.

Characterization of a novel strain phylogenetically related to Kocuria rhizophila and its chemical modification to improve performance of microbial fuel cells.

It is certainly an important research area to discovery new exoelectrogens for microbial fuel cells (MFCs), and how to effectively manipulate its cell property to improve power performance is still a great challenge. In this study, a new electrochemically active bacterium phylogenetically related to Kocuria rhizophila was first isolated and found electrogenic in MFCs, which was identified through the combination methods of molecular biology, physiological, biochemical and morphological characteristics. The MFCs inoculated with this strain generated power from a wide variety of substrates, reached a maximum power density of 75mW/m(2) in the substrate of 1g/L glucose. And the electron transfer mechanism was confirmed to be dominantly direct biofilm mechanism. Chemical treatment with five reagents was verified to be a feasible strategy to improve the power density of MFCs, increasing approximately 1.75 fold at most after treated with lysozyme. This enhancement was contributed to the significant enhancement on cell permeability, cell membrane fluidity and Coenzyme Q10 (the electron carrier). Thus this work offered a novel Gram-positive electrogenic bacterium and proved chemical treatment was a feasible strategy to improve electron transfer for application in MFCs.

Recent updates on electrochemical degradation of bio-refractory organic pollutants using BDD anode: a mini review.

Boron-doped diamond (BDD) is playing an important role in environmental electrochemistry and has been successfully applied to the degradation of various bio-refractory organic pollutants. However, the review concerning recent progress in this research area is still very limited. This mini-review updated recent advances on the removal of three kinds of bio-refractory wastewaters including pharmaceuticals, pesticides, and dyes using BDD electrode. It summarized the important parameters in three electrochemical oxidation processes, i.e., anodic oxidation (AO), electro-Fenton (EF), and photoelectro-Fenton (PEF) and compared their different degradation mechanisms and behaviors. As an attractive improvement of PEF, solar photoelectro-Fenton using sunlight as UV/vis source presented cost-effectiveness, in which the energy consumption for enrofloxacin removal was 0.246 kWh/(g TOC), which was much lower than that of 0.743 and 0.467 kWh/(g TOC) by AO and EF under similar conditions. Finally the existing problems and future prospects in research were suggested.

Electrosorption driven by microbial fuel cells to remove phenol without external power supply.

This work studied the operating parameters (pH, electrolyte concentration, initial phenol concentration, MFCs connection numbers and mode), adsorption isotherms and kinetics of a novel electrosorption driven by microbial fuel cells (MFC-Sorption) to remove phenol without external electric grid energy supply. It proved that high electrolyte concentration and low solution pH promoted the performance of phenol removal. 3 MFCs connections in series achieved a adsorption capacity of 1.76 mmol/g, which was much higher than that in parallel connection (1.46 mmol/g). Well fitted with Langmuir isotherm, the maximum adsorption capacity by MFC-Sorption and electrosorption was observed 48% and 65% higher than that by conventional adsorption. The phenol removal by MFC-Sorption was supposed to be more suitable for a pseudo-second-order kinetics, and with the increase of initial phenol concentration from 20 mg/L to 300 mg/L, the initial adsorption rate increased 26.99-fold. It concluded that the MFC-Sorption system could cost-effectively remove pollutant of phenol.