Shafeer Kalathil

Granular activated carbon based microbial fuel cell for simultaneous decolorization of real dye wastewater and electricity generation

Decolorization of dye wastewater before discharge is pivotal because of its immense color and toxicities. In this study, a granular activated carbon based microbial fuel cell (GACB-MFC) was used without using any expensive materials like Nafion membrane and platinum catalyst for simultaneous decolorization of real dye wastewater and bioelectricity generation. After 48 hours of GACB-MFC operation, 73% color was removed at anode and 77% color was removed at cathode. COD removal was 71% at the anode and 76% at the cathode after 48 hours. Toxicity measurements showed that cathode effluent was almost nontoxic after 24 hours. The anode effluent was threefold less toxic compared to original dye wastewater after 48 hours. The GACB-MFC produced a power density of 1.7 W/m(3) with an open circuit voltage 0.45 V. One of the advantages of the GACB-MFC system is that pH was automatically adjusted from 12.4 to 7.2 and 8.0 at the anode and cathode during 48 hours operation.

Efficient decolorization of real dye wastewater and bioelectricity generation using a novel single chamber biocathode-microbial fuel cell.

Large scale applications of microbial fuel cells (MFCs) have been severely hindered by several problems such as high internal resistance, low power output, expensive materials, and complicated configuration. To address these issues, a granular activated carbon based single chamber microbial fuel cell (GACB-SCMFC) has been designed using GAC-biocathodes without using any expensive materials for the simultaneous decolorization of real dye wastewater and electricity generation. The GACB-SCMFC produced a power density of 8 W/m(3) which indicates the GAC-biocathode can be a good alternative to platinum and other chemical catalysts. The dye wastewater was primarily treated at the anode and further polishing steps were occurred at the aerobic cathode. Toxicity measurement shows that the effluent after GACB-SCMFC operation was much less toxic compared to the original dye wastewater. Additional advantage of the GACB-SCMFC is that pH was automatically adjusted from 12.2 to 8 during 48 h of hydraulic retention time (HRT).

Electrochemically active biofilm-mediated synthesis of silver nanoparticles in water

Silver nanoparticles 1–7 nm in size were synthesized within 2 h in water by challenging an electrochemically active biofilm (EAB) with a solution containing AgNO3 as precursor and sodium acetate as an electron donor. The electrochemically active bacteria present on the anaerobic biofilm act as a catalyst to oxidise the sodium acetate by producing electrons for the reduction of Ag+ ions. The high monodispersity, rapidity, and extracellular nature of this synthesis, together with the production of smaller nanoparticles that are easily separated, make this protocol highly significant in the area of nanoparticle synthesis.

Production of bioelectricity, bio-hydrogen, high value chemicals and bioinspired nanomaterials by electrochemically active biofilms.

Microorganisms naturally form biofilms on solid surfaces for their mutual benefits including protection from environmental stresses caused by contaminants, nutritional depletion or imbalances. The biofilms are normally dangerous to human health due to their inherited robustness. On the other hand, a recent study suggested that electrochemically active biofilms (EABs) generated by electrically active microorganisms have properties that can be used to catalyze or control the electrochemical reactions in a range of fields, such as bioenergy production, bioremediation, chemical/biological synthesis, bio-corrosion mitigation and biosensor development. EABs have attracted considerable attraction in bioelectrochemical systems (BESs), such as microbial fuel cells and microbial electrolysis cells, where they act as living bioanode or biocathode catalysts. Recently, it was reported that EABs can be used to synthesize metal nanoparticles and metal nanocomposites. The EAB-mediated synthesis of metal and metal-semiconductor nanocomposites is expected to provide a new avenue for the greener synthesis of nanomaterials with high efficiency and speed than other synthetic methods. This review covers the general introduction of EABs, as well as the applications of EABs in BESs, and the production of bio-hydrogen, high value chemicals and bio-inspired nanomaterials.

Gold Nanoparticles Produced In Situ Mediate Bioelectricity and Hydrogen Production in a Microbial Fuel Cell by Quantized Capacitance Charging

Oppan quantized style: By adding a gold precursor at its cathode, a microbial fuel cell (MFC) is demonstrated to form gold nanoparticles that can be used to simultaneously produce bioelectricity and hydrogen. By exploiting the quantized capacitance charging effect, the gold nanoparticles mediate the production of hydrogen without requiring an external power supply, while the MFC produces a stable power density.