Biochar supported Pseudomonas putida based globules for effective removal of Bisphenol A with a practical approach.

The widespread and inevitable use of plastic has led to prospective ecological problems through Bisphenol A (BPA), a synthetic chemical in plastic manufacturing. The present study addresses a unique methodology for eliminating BPA using the assistance of Pseudomonas putida. In the present work, biomass was torrefied to generate biochar with highly porous networks that could accommodate the bacterial species for effective colonization and multiplication. The designed biochar-bacterial globules demonstrated the ability to effectively remove BPA (96.88%) at a concentration of up to 2 g/L. The biochar-bacterial globules could effectively adsorb BPA at a low concentration of 20 mg/L. The alteration in pH did not impact the globule's performance, providing additional support for the practical utilization of these globules in polluted water bodies. In addition, the biochar-bacterial globules exhibited superior effectiveness in degradation compared to the standard levels, particularly in saline conditions. The simplicity and effectiveness of the approach make it promising for real-world implementation in addressing ecological problems associated with BPA contamination.

Triggering Redox Active Sites Through Electronic Structure Modulation in rGO Encapsulated Mixed Transition Metal Oxides Hybrid for Alkaline Hydrogen Evolution.

Designing and developing noble-metal-free catalysts are of current interest in clean hydrogen generation via water splitting. As carbonaceous species are ideal choices as templates for various electrocatalysis, an improved synthetic route and an in-depth understanding of their electrochemical performance are essential. Herein, we have investigated the catalytic performance of rGO-encapsulated Mn and V mixed oxide hybrid structures (MVG) on a NiFeP matrix, focusing on their potential for catalyzing hydrogen evolution in an alkaline environment. The hierarchical MVG hollow microspheres hybrids are synthesized via a simple one-step in situ solvothermal method and MVG/NiFeP coatings are developed by facile electroless plating technique. As evidenced from the X-ray photoelectron spectroscopy, the multiple redox active sites in the 3d-band of Mn and V in MVG hybrid structural coatings serve as electron pumps, and rGO facilitates electronic conductions during catalytic reactions. The modulated electronic structure and strong synergistic effects between NiFeP and MVG facilitate rapid electron transfer kinetics, and the hybrids demonstrate superior HER performance. Consequently, the structural hybrid coatings possess an enhanced electronic conducting path (lower RCT = 545.3 Ω) and large ECSA values with a lower overpotential of 85 mV at 10 mA cm-2 and a reduced Tafel slope of 64.1 mV dec-1 with Volmer-Heyrovsky mechanism in alkaline media.

Microbial-Inspired Surface Patterning for Selective Bacterial Actions for Enhanced Performance in Microbial Fuel Cells.

The performance of any bio-electrochemical system is dependent on the efficiency of electrode-microbial interactions. Surface properties play a focal role in bacterial attachment and biofilm formation on the electrodes. In addition to electrode surface properties, selective bacterial adhesion onto the electrode surface is mandatory to mitigate energy loss due to undesired bacterial interactions on the electrode surface. In the present study, microbial-patterned graphite scaffolds are developed for selective bacterial-electrode interactions. A power density as high as 1105 mW/m2 is achieved with mG-E (a graphite electrode patterned with Escherichia coli), which is about 3 times higher than that of the pristine graphite electrode (370 mW/m2). Initial mechanical pre-treatment of the graphite electrode, followed by bacterial patterning, results in the formation of a unique cobblestone topography with a tuned surface area of 127.12 m2/g. This provides suitable morphology with enhanced active sites for selective bacterial intercalation in graphite layers. This cannot be otherwise achieved by any mechanical or other means. A unique methodology of symbolic regression is adopted to validate a genetic algorithm suitable for predicting a perfect correlation between surface characteristics and electrochemical characteristics with a minimum root-mean-square error of 0.08. The bacterial intercalation onto the graphite electrode causes protuberance of the graphite layers that reduces the surface potential and resistance, leading to high electron transfer. The study presents a unique bacterial-inspired surface patterning on the anode, which is critical for the performance of a microbial fuel cell.

Tuning of Electrode Surface for Enhanced Bacterial Adhesion and Reactions: A Review on Recent Approaches.

The study of bacterial adhesion and its consequences has great significance in different fields such as marine science, renewable energy sectors, soil and plant ecology, food industry, and the biomedical field. Generally, the adverse effects of microbial surface interactions have attained wide visibility. However, herein, we present distinct approaches to highlight the beneficial aspects of microbial surface interactions for various applications rather than deal with the conventional negative aspects or prevention strategies. The surface microbial reactions can be tuned for useful biochemical or bio-electrochemical applications, which are otherwise unattainable through conventional routes. In this context, the present review is a comprehensive approach to highlight the basic principles and signature parameters that are responsible for the useful microbial-electrode interactions. It also proposes various surface tuning strategies, which are useful for tuning the electrode characteristics particularly suitable for the enhanced bacterial adhesion and reactions. The tuning of surface characteristics of electrodes is discussed with a special reference to the Microbial Fuel Cell as an example.

Tuning of Surface Characteristics of Anodes for Efficient and Sustained Power Generation in Microbial Fuel Cells.

The present study reports about the fabrication of a three-dimensional (3D) macroporous steel-based scaffold as an anode to promote specifically bacterial attachment and extracellular electron transfer to achieve power density as high as 1184 mW m-2, which is far greater than that of commonly used 3D anode materials. The unique 3D open macroporous configuration of the anode and the microstructure generated by the composite coating provide voids for the 3D bacterial colonization of electroactive biofilms. This is attributed to the sizeable interfacial area per unit volume provided by the 3D corrugated electrode that enhanced the electrochemical reaction rate compared to that of the flat electrode, which favors the enhanced mass transfer and substrate diffusion at the electrode/electrolyte interface and thereby increases the charge transfer by reducing the electrode overpotential or interfacial resistance. In addition, bacterial infiltration into the interior of the anode renders large reaction sites for substrate oxidation without the concern of clogging and biofouling and thereby improves direct electron transfer. A very low overpotential (-27 mV) with a very low internal resistance (7.104 Ω cm2) is achieved with the fabricated microbial fuel cell (MFC) that has a modified 3D corrugated electrode. Thus, easier and faster charge transfer at the electrode-electrolyte interface is confirmed. The study presents a revolutionary practical approach in the development of highly efficient anode materials that can ensure easy scale-up for MFC applications.