Pore-Matched Sponge for Microorganisms Pushes Electron Extraction Limit in Microbial Fuel Cells.

Microbial fuel cells (MFCs) are of great potential for wastewater remediation and chemical energy recovery. Nevertheless, limited by inefficient electron transfer between microorganisms and electrode, the remediation capacity and output power density of MFCs are still far away from the demand of practical application. Herein, a pore-matching strategy is reported to develop uniform electroactive biofilms by inoculating microorganisms inside a pore-matched sponge, which is assembled of core-shell polyaniline@carbon nanotube (PANI@CNT). The maximum power density achieved by the PANI@CNT bioanode is 7549.4 ± 27.6 mW m-2 , which is higher than the excellent MFCs with proton exchange membrane reported to date, while the coulombic efficiency also attains a considerable 91.7 ± 1.2%. The PANI@CNT sponge enriches the exoelectrogen Geobacter significantly, and is proved to play the role of conductive pili in direct electron transfer as it down-regulates the gene encoding pilA. This work exemplifies a practicable strategy to develop excellent bioanode to boost electron extraction in MFCs and provides in-depth insights into the enhancement mechanism.

Metagenomics revealing biomolecular insights into the enhanced toluene removal and electricity generation in PANI@CNT bioanode.

Microbial fuel cells (MFCs) have significant potential for environmental remediation and energy recycling directly from refractory aromatic hydrocarbons. To boost the capacities of toluene removal and the electricity production in MFCs, this study constructed a polyaniline@carbon nanotube (PANI@CNT) bioanode with a three-dimensional framework structure. Compared with the control bioanode based on graphite sheet, the PANI@CNT bioanode increased the output voltage and toluene degradation kinetics by 2.27-fold and 1.40-fold to 0.399 V and 0.60 h-1, respectively. Metagenomic analysis revealed that the PANI@CNT bioanode promoted the selective enrichment of Pseudomonas, with the dual functions of degrading toluene and generating exogenous electrons. Additionally, compelling genomic evidence elucidating the relationship between functional genes and microorganisms was found. It was interesting that the genes derived from Pseudomonas related to extracellular electron transfer, tricarboxylic acid cycle, and toluene degradation were upregulated due to the existence of PANI@CNT. This study provided biomolecular insights into key genes and related microorganisms that effectively facilitated the organic pollutant degradation and energy recovery in MFCs, offering a novel alternative for high-performance bioanode.

Deciphering heterojunction layered double hydroxide-polyaniline-carbon nanotubes for phosphorus capture in capacitive deionization.

The capacitive deionization (CDI) has emerged as a robust technology due to its effective performance in removing and recovering phosphate in wastewater. However, there are still challenges in achieving fast charge transfer and high capacity phosphorus storage simultaneously. In this study, a layered double hydroxide-polyaniline-carbon nanotubes composite material (ZnFe-PANI/CNT) with heterojunction and pseudocapacitive characteristics was fabricated via a simple and effective precipitation strategy. The existence of heterojunction and pseudocapacitance of ZnFe-PANI/CNT was confirmed through material performance testing Moreover, with its fast charge transfer and high ion storage performance, it was achieved high phosphate adsorption efficiency (94 %) and sustainable electrode regeneration in low concentration phosphate wastewater. Ultraviolet photoelectron spectroscopy (UPS) and density functional theory revealed the ability to accelerate charge transfer, which was contributed by the heterojunction ZnFe-PANI/CNT. In addition, it was found that the synergies of electrostatic attraction, ligand exchange and surface complexation contributed to the high phosphate capture ability in the acidic environments. The binuclear bidentate or mononuclear bidentate structures dominated the surface configuration of phosphate adsorption at pH 4-9.

Silver embellished PANI/CNT nanocomposite for antimicrobial activity and sequestration of dye based on RSM modelling.

Silver doped PANI/CNT (Ag-PANI/CNT) nanocomposite was synthesized and investigated as adsorbent for its possible application in the elimination of organic dye Brilliant Blue G (BBG). The morphological characteristics of Ag-PANI/CNT were studied using Fourier transform infrared, scanning electron microscopy, elemental mapping, transmission electron microscopy and X-ray diffraction. The response of operational parameters given as adsorbent dosage, concentration, pH and contact time for dye removal were investigated by using Response Surface Methodology (RSM). The results from RSM suggested that the efficiency of BBG elimination is 98.7 under the optimum conditions of experimental factors. The adsorption studies showed that the equilibrium data fitted well with Langmuir isotherm model compared to Freundlich. Finally, the antimicrobial activities of Ag-PANI/CNT were tested against bacterial strain Escherichia coli and Salmonella typhi and fungal strains Aspergillus niger.

Photodegradation of diethyl phthalate with PANi/CNT/TiO2 immobilized on glass plate irradiated with visible light and simulated sunlight-effect of synthesized method and pH.

Diethyl phthalate (DEP) is one of the most common phthalates for industrial use and has widely spread in environment. A series of PANi/CNT/TiO2 potocatalysts immobilized on glass plate irradiated with visible light were presented to degrade DEP in this study. The PANi/CNT/TiO2 potocatalysts were fabricated by co-doping with polyaniline (PANi) and two functionalized CNT (CNT-COCl and CNT-COOH) onto TiO2 followed by a hydrothermal synthesis and a sol-gel hydrolysis. Doping of PANi resulted in the absorption edge of the fabricated potocatalysts shifting to 421-437nm and the most distinguished red-shift effect was found in hydrothermal synthesized photocatalysts. The best DEP degradation of 41.5-59.0% and 44.5-67.4% was found in the simulated sunlight system irradiated for 120min for sol-gel hydrolysis PANi/CNT/TiO2 photocatalysts and hydrothermal synthesized ones, respectively. The optimum pH was determined at 5.0 and 7.0 for the two PANi/CNT/TiO2 photocatalysts mentioned above, respectively. The reusability of the sol-gel hydrolyzed photocatalysts up to 5 times was observed no decline in the photodegradation efficiency but less photocatalytic stability of the hydrothermal synthesized ones was found. Meanwhile, the active species of OH radicals generated in the DEP degradation system was identified by free radical scavenging experiments.