Integrated tea polyphenols and polydopamine functionalized graphene anode for improved bioelectricity generation and Cr(VI) reduction in microbial fuel cells.

Microbial fuel cells (MFCs) have the dual advantage of mitigating Cr(Ⅵ) wastewater ecological threats while generating electricity. However, the low electron transfer efficiency and the limited enrichment of active electrogens are barriers to MFCs advancement. This study describes the synthesis of the TP-PDA-RGO@CC negative electrode using tea polyphenol as a reducing agent and polydopamine-doped graphene, significantly enhances the roughness and hydrophilicity of the anode. The charge transfer resistance was reduced by 94%, and the peak MFC power was 1375.80 mW·m-2. Under acidic conditions, the Cr(Ⅵ) reduction rate reached 92% within 24 h, with a 52% increase in coulombic efficiency. Biodiversity analysis shows that the TP-PDA-RGO@CC anode could enrich electrogens, thereby boosting the electron generation mechanism at the anode and enhancing the reduction efficiency of Cr(Ⅵ) in the cathode chamber. This work emphasizes high-performance anode materials for efficient pollutant removal, energy conversion, and biomass reuse.

Natural tea polyphenol functionalized graphene anode for simultaneous power production and degradation of methyl orange dye in microbial fuel cells.

The microbial fuel cell (MFCs) has dual functions, capable of achieving dye decolorization and synchronous power generation. Despite these advantages, the MFCs have faced challenges related to low electron transfer efficiencies and limited dye treatment capacity in wastewater applications. This work introduces an innovative approach by employing reduced graphene oxide-modified carbon cloth (TP-RGO@CC) anodes, utilizing tea polyphenols as the reducing agent. This modification significantly enhances the hydrophilicity and biocompatibility of the anodes. The MFC equipped with the TP-RGO@CC anode demonstrated a remarkable increase in the maximum power density, reaching 773.9 mW m-2, representing a 22% improvement over the plain carbon cloth electrode. The decolorization rate of methyl orange (50 mg L-1, pH 7) reached 99% within 48 h. Biodiversity analysis revealed that the TP-RGO@CC anode selectively enriched electrogens producing and organic matter-degrading bacteria, promoting a dual mechanism of dye decolorization, degradation, and simultaneous electro-production at the anode. This work highlights advanced anode materials that excel in effective pollutant removal, energy conversion, and biomass reuse.

Wave-atoms-based multipurpose scheme via perceptual image hashing and watermarking.

This paper presents a novel multipurpose scheme for content-based image authentication and copyright protection using a perceptual image hashing and watermarking strategy based on a wave atom transform. The wave atom transform is expected to outperform other transforms because it gains sparser expansion and better representation for texture than other traditional transforms, such as wavelet and curvelet transforms. Images are decomposed into multiscale bands with a number of tilings using the wave atom transform. Perceptual hashes are then extracted from the features of tiling in the third scale band for the purpose of content-based authentication; simultaneously, part of the selected hashes are designed as watermarks, which are embedded into the original images for the purpose of copyright protection. The experimental results demonstrate that the proposed scheme shows great performance in content-based authentication by distinguishing the maliciously attacked images from the nonmaliciously attacked images. Moreover, watermarks extracted from the proposed scheme also achieve high robustness against common malicious and nonmalicious image-processing attacks, which provides excellent copyright protection for images.