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Oxidative Degradation of Tannic Acid in Aqueous Solution by UV/S2O82? and UV/H2O2/Fe2+ Processes: A Comparative Study
摘要： Tannic acid (TA) is a major pollutant present in the wastewater generated from vegetable tanneries process and food processing. This work studied TA degradation by two advanced oxidation processes (APOs): UV irradiation at the wavelength of 254 nm in the presence of hydrogen peroxide (H2O2) and ferrous iron (photo-Fenton) and in the presence of potassium persulfate. The in?uence of certain experimental parameters such as K2S2O8, H2O2, Fe2+, and TA concentrations, initial pH and temperature was evaluated in order to obtain the highest ef?ciency in terms of aromatics (decay in UV absorbance at 276 nm) and TOC removals. Chemical oxidation of TA (0.1 mM) by UV/persulfate achieved 96.32% of aromatics removal and 54.41% of TOC removal under optimized conditions of pH = 9 and 53.10 mM of K2S2O8 after 60 min. The treatment of TA by photo-Fenton process successfully led to almost complete aromatics removal (99.32%) and high TOC removal (94.27%) from aqueous solutions containing 0.1 mM of TA at natural pH = 3 using 29.4 mM of H2O2 and 0.18 mM of Fe2+ at 25 ?C after 120 min. More ef?cient degradation of TA by photo-Fenton process than UV/persulfate was obtained, which con?rms that hydroxyl radicals are more powerful oxidants than sulfate radicals. The complete removal of organic pollution from natural waters can be accomplished by direct chemical oxidation via hydroxyl radicals generated from photocatalytic decomposition of H2O2.
关键词： hydroxyl radicals,degradation,photo-fenton,mineralization,UV/persulfate,sulfate radicals,Tannic acid
更新于2025-09-23 15:22:29
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Invisible-ink-assisted pattern and written surface-enhanced Raman scattering substrates for versatile chem/biosensing platforms
摘要： In recent years, highly sensitive surface-enhanced Raman scattering (SERS) integrated with flexible substrates has drawn increasing attention for label-free detection. In this study, an invisible ink-inspired process was developed for the fabrication of plasmonic Au-based SERS substrates through an on-site redox strategy. Tannic acid (TNA), a common green reagent, was used not only for fabricating various SERS absorbents through a confinement reduction of a Au-TNA complex, but also for supplying an amphiphilic inorganic–organic surface structure for outstanding SERS enhancement at micromolar to nanomolar concentrations for a wide range of compounds. In addition to label-free sensing, this TNA/Au-based SERS substrate provides a versatile analysis platform for studies of chemical and biological reactions. A combination of TNA ink with different metal ions allows for a reliable procedure for the synthesis of a bimetallic AuAg SERS substrate that further enhances the SERS intensity of analyte molecules and extends the lower limit of detection.
关键词： bimetallic AuAg SERS substrate,invisible ink,tannic acid,label-free detection,SERS,plasmonic Au-based SERS substrates,surface-enhanced Raman scattering
更新于2025-09-23 15:21:21
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Ferrous-Supply-Regeneration Nanoengineering for Cancer Cell Specific Ferroptosis in Combination with Imaging-Guided Photodynamic Therapy
摘要： Non-apoptotic ferroptosis is of clinical importance because it offers a solution to surmount the inevitable bio-carriers of traditional apoptotic therapeutic means. Inspired by industrial Electro-Fenton technology featured with electrochemical iron cycling, we construct a ferrous-supply-regeneration nanoengineering to intervene tumorous iron metabolism for enhanced ferroptosis. Fe3+ ion and naturally derived tannic acid (TA) spontaneously form network-like corona onto sorafenib (SRF) nanocore. The formed SRF@FeIIITA nanoparticles can respond to lysosomal acid environment with corona dissociation, permitting SRF release to inhibit GPX4 enzyme for ferroptosis initiation. TA is arranged to chemically reduce the liberated and the ferroptosis-generated Fe3+ to Fe2+, offering iron redox cycling thus to effectively produce lipid peroxide required in ferroptosis. Sustained Fe2+ supply leads to long-term cytotoxicity, which is identified to be specific to H2O2-overloaded cancer cells but minimal in normal cells. SRF@FeIIITA-mediated cell death proves to follow ferroptosis pathway and strongly inhibits tumor proliferation. Moreover, SRF@FeIIITA provides a powerful platform capable of versatile integration between apoptosis and non-apoptosis means. Typically, photosensitizer-adsorbed SRF@FeIIITA demonstrates rapid tumor imaging owing to the acid-responsive fluorescence recovery. Together with ferroptosis, imaging-guided photodynamic therapy induces complete tumor elimination. This study offers ideas about how to advance anticancer ferroptosis through rational material design.
关键词： iron redox cycling,iron-tannic acid network,photodynamic therapy,ferroptosis,Electro-Fenton technology
更新于2025-09-23 15:21:01
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Fabrication of pH-responsive TA-keratin bio-composited hydrogels encapsulated with photoluminescent GO quantum dots for improved bacterial inhibition and healing efficacy in wound care management: In vivo wound evaluations
摘要： Wounds origins serious complications of lives of human beings which may leads to death. The important issue for the problem is infection during wound care management which delays wound healing process. These kinds of infections may be caused by the overuse or misuse of antibiotics, antidotes, usage of new drugs, not properly sterilized surgical instruments, not appropriate for pH level and imperfect wound dressing etc. during or after surgery. Hence in this report, antimicrobial action of pH responsive TA/KA composited hydrogel crosslinked with GO-QDs (TA/KA-GOQDs) using citric acid as cross- linker has been reported by demonstrating in-vitro and in-vivo studies for wound care management. The prepared samples of GOQDs, TA/KA hydrogel and TA/KA-GOQDs were characterized using FT-IR, XRD, SEM and TEM techniques. pH responsive hydrogel property of TA/KA was evaluated by swelling studies. In-vitro antibacterial studies was carried out by direct contact test method. Further, the prepared samples were tested in a wound healing model of rate with the wound of size 1.5 cm2 for in-vivo studies. After 16 days of treatment, the prepared samples for wound healing causes 100% wound areas closure. Histological observations were made by MT and HE staining process which proves keratinocytes proliferation by biocompatible and biocomposited TA/KA-GOQDs. The pH responsive TA/KA-GOQDs proved as efficient wound healing agent by faster keratinocytes proliferation within a compact period.
关键词： pH responsive hydrogel,Tannic acid,Graphene oxide,Wound Care Management
更新于2025-09-12 10:27:22