Overview of electroactive microorganisms and electron transfer mechanisms in microbial electrochemistry.

Electroactive microorganisms acting as microbial electrocatalysts have intrinsic metabolisms that mediate a redox potential difference between solid electrodes and microbes, leading to spontaneous electron transfer to the electrode (exo-electron transfer) or electron uptake from the electrode (endo-electron transfer). These microbes biochemically convert various organic and/or inorganic compounds to electricity and/or biochemicals in bioelectrochemical systems (BESs) such as microbial fuel cells (MFCs) and microbial electrosynthesis cells (MECs). For the past two decades, intense studies have converged to clarify electron transfer mechanisms of electroactive microbes in BESs, which thereby have led to improved bioelectrochemical performance.

Amoxicillin separation from aqueous solution by negatively charged silica composite membrane.

Silica composite membranes were successfully prepared by acid/ base-catalyzed sol-gel method and characterized by SEM, FTIR, AFM and contact angle Low isoelectric point of the silica layers provided negatively charged composite membranes, resulting electrostatic repulsion forces between membrane surface and amoxicillin molecules at higher pHs. The rejection rate of amoxicillin was studied systematically at different pHs, solute concentrations, transmembrane pressures and temperatures. It was found that acid-catalyzed membrane has higher amoxicillin rejection ratio compared to base-catalyzed membrane.