Tremendously enhanced catalytic performance of Fe(III)/peroxymonosulfate process by trace Cu(II): A high-valent metals domination in organics removal.

Dissolved copper and iron ions are regarded as friendly and economic catalysts for peroxymonosulfate (PMS) activation, however, neither Cu(II) nor Fe(III) shows efficient catalytic performance because of the slow rates of Cu(II)/Cu(I) and Fe(III)/Fe(II) cycles. Innovatively, we observed a significant enhancement on the degradation of organic contaminants when Cu(II) and Fe(III) were coupled to activate PMS in borate (BA) buffer. The degradation efficiency of Rhodamine B (RhB, 20 µmol/L) reached up to 96.3% within 10 min, which was higher than the sum of individual Cu(II)- and Fe(III)- activated PMS process. Sulfate radical, hydroxyl radical and high-valent metal ions (i.e., Cu(III) and Fe(IV)) were identified as the working reactive species for RhB removal in Cu(II)/Fe(III)/PMS/BA system, while the last played a predominated role. The presence of BA dramatically facilitated the reduction of Cu(II) to Cu(I) via chelating with Cu(II) followed by Fe(III) reduction by Cu(I), resulting in enhanced PMS activation by Cu(I) and Fe(II) as well as accelerated generation of reactive species. Additionally, the strong buffering capacity of BA to stabilize the solution pH was satisfying for the pollutants degradation since a slightly alkaline environment favored the PMS activation by coupling Cu(II) and Fe(III). In a word, this work provides a brand-new insight into the outstanding PMS activation by homogeneous bimetals and an expanded application of iron-based advanced oxidation processes in alkaline conditions.

Fluorogenic Rhodamine-Based Chemigenetic Biosensor for Monitoring Cellular NADPH Dynamics.

Ratiometric biosensors employing Förster Resonance Energy Transfer (FRET) enable the real-time tracking of metabolite dynamics. Here, we introduce an approach for generating a FRET-based biosensor in which changes in apparent FRET efficiency rely on the analyte-controlled fluorogenicity of a rhodamine rather than the commonly used distance change between donor-acceptor fluorophores. Our fluorogenic, rhodamine-based, chemigenetic biosensor (FOCS) relies on a synthetic, protein-tethered FRET probe, in which the rhodamine acting as the FRET acceptor switches in an analyte-dependent manner from a dark to a fluorescent state. This allows ratiometric sensing of the analyte concentration. We use this approach to generate a chemigenetic biosensor for nicotinamide adenine dinucleotide phosphate (NADPH). FOCS-NADPH exhibits a rapid and reversible response toward NAPDH with a good dynamic range, selectivity, and pH insensitivity. FOCS-NADPH allows real-time monitoring of cytosolic NADPH fluctuations in live cells during oxidative stress or after drug exposure. We furthermore used FOCS-NADPH to investigate NADPH homeostasis regulation through the pentose phosphate pathway of glucose metabolism. FOCS-NADPH is a powerful tool for studying NADPH metabolism and serves as a blueprint for the development of future fluorescent biosensors.

Photocatalytic Degradation of Organic Dyes by Magnetite Nanoparticles Prepared by Co-Precipitation.

Iron oxide nanoparticles were synthesized by co-precipitation using three different iron salt stoichiometric mole ratios. Powder X-ray diffraction patterns revealed the inverse cubic spinel structure of magnetite iron oxide. Transmission electron microscopic images showed Fe3O4 nanoparticles with different shapes and average particle sizes of 5.48 nm for Fe3O4-1:2, 6.02 nm for Fe3O4-1.5:2, and 6.98 nm for Fe3O4-2:3 with an energy bandgap of 3.27 to 3.53 eV. The as-prepared Fe3O4 nanoparticles were used as photocatalysts to degrade brilliant green (BG), rhodamine B (RhB), indigo carmine (IC), and methyl red (MR) under visible light irradiation. The photocatalytic degradation efficiency of 80.4% was obtained from Fe3O4-1:2 for brilliant green, 61.5% from Fe3O4-1.5:2 for rhodamine B, and 77.9% and 73.9% from Fe3O4-2:3 for both indigo carmine and methyl red. This indicates that Fe3O4-2:3 is more efficient in the degradation of more than one dye. This study shows that brilliant green degrades most effectively at pH 9, rhodamine B degrades best at pH 6.5, and indigo carmine and methyl red degrade most efficiently at pH 3. Recyclability experiments showed that the Fe3O4 photocatalysts can be recycled four times and are photostable.

FRETting about CRISPR-Cas Assays: Dual-Channel Reporting Lowers Detection Limits and Times-to-Result.

Clustered Regularly Interspaced Short Palindromic Repeats-CRISPR-Associated Protein (CRISPR-Cas) systems have evolved several mechanisms to specifically target foreign DNA. These properties have made them attractive as biosensors. The primary drawback associated with contemporary CRISPR-Cas biosensors is their weak signaling capacity, which is typically compensated for by coupling the CRISPR-Cas systems to nucleic acid amplification. An alternative strategy to improve signaling capacity is to engineer the reporter, i.e., design new signal-generating substrates for Cas proteins. Unfortunately, due to their reliance on custom synthesis, most of these engineered reporter substrates are inaccessible to many researchers. Herein, we investigate a substrate based on a fluorescein (FAM)-tetramethylrhodamine (TAMRA) Förster resonant energy-transfer (FRET) pair that functions as a seamless "drop-in" replacement for existing reporters, without the need to change any other aspect of a CRISPR-Cas12a-based assay. The reporter is readily available and employs FRET to produce two signals upon cleavage by Cas12a. The use of both signals in a ratiometric manner provides for improved assay performance and a decreased time-to-result for several CRISPR-Cas12a assays when compared to a traditional FAM-Black Hole Quencher (BHQ) quench-based reporter. We comprehensively characterize this reporter to better understand the reasons for the improved signaling capacity and benchmark it against the current standard CRISPR-Cas reporter. Finally, to showcase the real-world utility of the reporter, we employ it in a Recombinase Polymerase Amplification (RPA)-CRISPR-Cas12a DNA Endonuclease-Targeted CRISPR Trans Reporter (DETECTR) assay to detect Human papillomavirus in patient-derived samples.

Rapid eco-friendly selective dye removal using modified chitosan-based sponges: Synthesis, characterization, and application.

The ongoing challenge of water scarcity persists alongside a concerning rise in water pollution driven by population expansion and industrial development. As a result, urgent measures are imperative to address the pressing need for a clean and sustainable water supply. In this study, a sustainable and green approach was utilized to prepare four chitosan-based sponges from a chemically modified chitosan with different alkyl chains in aqueous medium and at room temperature. The resulting sponges displayed excellent stability in water with outstanding dye removal efficiency. The adsorption capacity was associated with the alkyl chain length incorporated to the polymer backbone. All sponges displayed a high adsorption capacity of methyl orange (MO) ranges between 238 and 380 mg g-1, while a low capacity were obtained for methylene blue (MB) and Rhodamine B (RB). Competitive adsorption experiments were conducted on binary and ternary mixtures to assess the selective removal of MO from a mixture of dyes in which the separation factor was found to be ranging between 1.6 and 32. The adsorption kinetics isotherms of all sponges followed the pseudo-second-order, and the Langmuir model was found to be more suitable than the Freundlich for the adsorption of MO on the sponges. The chitosan-based sponges showed stable performance, robustness and reusability over 5 adsorption-desorption cycles, indicating their great potential for water treatment applications.

A dual-modality sensing probe of fluorescent and colorimetric for detection of cobalt ion based on silver nanoparticles functionalized rhodamine 6G derivatives.

The combination of fluorescent probe and colorimetric technique has become one of the most powerful analytical methods due to the advantages of visualization, minimal measurement errors and high sensitivity. Hence, a novel dual-modality sensing probe with both colorimetric and fluorescent capabilities was developed for detecting cobalt ions (Co2+) based on homocysteine mediated silver nanoparticles and rhodamine 6G derivatives probe (AgNPs-Hcy-Rh6G2). The fluorescence of the AgNPs-Hcy-Rh6G2 probe turned on due to the opening of the Rh6G2 spirolactam ring in the presence of Co2+ by a catalytic hydrolysis. The fluorescent intensity of probe is proportional to Co2+ concentration in the range of 0.10-50 µM with a detection limit of 0.05 µM (S/N = 3). More fascinatingly, the color of AgNPs-Hcy-Rh6G2 probe changed from colorless to pink with increasing Co2+ concentration, which allowing colorimetric determination of Co2+. The absorbance of AgNPs-Hcy-Rh6G2 probe is proportional to Co2+ concentration in the range from 0.10 to 25 µM with a detection limit of 0.04 µM (S/N = 3). This colorimetric and fluorescent dual-modal method exhibited good selectivity, and reproducibility and stability, holding great potential for real samples analysis in environmental and drug field.

Regulating band structure, charge transfer and separation, oxygen adsorption and activation by surface ion modification.

As a most promising environmental technology, the substantial enhancement of photocatalytic efficiency is still a big challenge for practical applications. In this work, the surface of Bi2O2CO3 (BOC) nanotubes are modified by Cl and I. The as-obtained samples at different hydrothermal temperatures (T) are designated as T-X-BOC (X = Cl, I). X-ray diffraction (XRD), energy dispersive X-ray (EDX) spectroscopy and X-ray photoelectron spectroscopy (XPS) prove that Cl and I merely chemically adsorb on the BOC surface, rather than dope into the crystal lattice. The surface modification of Cl and I slightly increases light absorption range, while significantly promotes the photoelectron migration from bulk to the surface that greatly enhances the carrier separation efficiency. Density functional theory (DFT) calculations further prove that surface Cl and I have adjusted band structure and surface charge distribution. Besides, the surface Cl and I favor the O2 adsorption and trap the surface photoelectrons, thus promoting the formation of •O2-; while the surface Cl and I impede the surface adsorption of H2O, thus refraining the generation of •OH. In the degradation of rhodamine B (RhB), holes and •O2- radicals play the crucial role. Under ultraviolet light irradiation (λ < 420 nm) for 45 min, the RhB degradation ratios over 150-Cl-BOC (94%) and 150-I-BOC (85%) are 4.2 and 3.7 times higher than that of original BOC (18%), respectively. This work demonstrates that the simple surface halogenation modification greatly improves the photocatalytic activity.

Development of a high-performance liquid chromatography using rhodamine B hydrazide as the derivatization reagent for determination of ß propiolactone residues in inactivated COVID-19 vaccines.

ß-propiolactone (BPL) is an alkylating agent used for inactivation of biological samples such as vaccines. Due to its known carcinogenic properties, complete hydrolysis of BPL is essential, and the detection of trace amounts is crucial. In this study a novel High-Performance Liquid Chromatography-Ultraviolet (HPLC-UV) method was developed. Rhodamine B hydrazide (RBH) was synthesized and utilized as a derivatizing reagent to react with BPL. The reaction was optimized in a weak acidic solution, resulting in a high yield. The separation of the RBH-derivatized BPL was achieved on a C8 column and detected by a UV detector at a wavelength of 560 nm. The method's validation demonstrated a high linearity (r2 > 0.99) over a concentration range of 0.5-50 µg/mL, with detection and quantification limits of 0.17 µg/mL and 0.5 µg/mL, respectively. The average recovery of samples was 85.20 % with a relative standard deviation (RSD) of 1.75 %. This method was successfully applied for BPL residue analysis in inactivated COVID-19 vaccines. This novel derivatization method offers a promising solution for monitoring BPL residues in the vaccine production process for quality control purposes and compliance with regulatory standards.

HaloTag as a substrate-based macroautophagy reporter.

Macroautophagy is a conserved cellular degradation pathway that, upon upregulation, confers resilience toward various stress conditions, including protection against proteotoxicity associated with neurodegenerative diseases, leading to cell survival. Monitoring autophagy regulation in living cells is important to understand its role in physiology and pathology, which remains challenging. Here, we report that when HaloTag is expressed within a cell of interest and reacts with tetramethylrhodamine (TMR; its ligand attached to a fluorophore), the rate of fluorescent TMR-HaloTag conjugate accumulation in autophagosomes and lysosomes, observed by fluorescence microscopy, reflects the rate of autophagy. Notably, we found that TMR-HaloTag conjugates were mainly degraded by the proteasome (~95%) under basal conditions, while lysosomal degradation (~10% upon pharmacological autophagy activation) was slow and incomplete, forming a degraded product that remained fluorescent within a SDS-PAGE gel, in agreement with previous reports that HaloTag is resistant to lysosomal degradation when fused to proteins of interest. Autophagy activation is distinguished from autophagy inhibition by the increased production of the degraded TMR-HaloTag band relative to the full-length TMR-HaloTag band as assessed by SDS-PAGE and by a faster rate of TMR-HaloTag conjugate lysosomal puncta accumulation as observed by fluorescence microscopy. Pharmacological proteasome inhibition leads to accumulation of TMR-HaloTag in lysosomes, indicating possible cross talk between autophagy and proteasomal degradation.

Dehydroabietylamine-substituted trifluorobenzene sulfonamide rhodamine B hybrids as anticancer agents overcoming drug resistance.

Attachment of a conjugate assembled from a novel fluorinated carbonic anhydrase inhibitor and rhodamine B onto dehydroabietylamine (DHA) or cyclododecylamine led to first-in-class conjugates of good cytotoxicity; thereby IC50 values (from SRB assays; employed tumor cell lines A2780, A2780Cis, A549, HT29, MCF7, and non-malignant human fibroblasts CCD18Co) between 0.2 and 0.7 µM were found. Both conjugates showed similar cytotoxic activity but the dehydroabietylamine derived conjugate outperformed its cyclododecyl analog in terms of tumor cell/non-tumor cell selectivity. Both conjugates accumulate intracellular, and the DHA conjugate was able to overcome drug resistance which is effective independent of the expression status of carbonic anhydrase IX.

Analysis of optical properties and response mechanism of H2S fluorescent probe based on rhodamine derivatives.

H2S plays a crucial role in numerous physiological and pathological processes. In this project, a new fluorescent probe, SG-H2S, for the detection of H2S, was developed by introducing the recognition group 2,4-dinitrophenyl ether. The combination of rhodamine derivatives can produce both colorimetric reactions and fluorescence reactions. Compared with the current H2S probes, the main advantages of SG-H2S are its wide pH range (5-9), fast response (30 min), and high selectivity in competitive species (including biological mercaptan). The probe SG-H2S has low cytotoxicity and has been successfully applied to imaging in MCF-7 cells, HeLa cells, and BALB/c nude mice. We hope that SG-H2S will provide a vital method for the field of biology.

CeO2 nanospheres incorporated with Bi2MoO6/g-C3N4 enhanced photocatalysis towards environmental pollutant Rhodamine B removal.

We have adopted a novel CeO2/Bi2MoO6/g-C3N4-based ternary nanocomposite that was synthesized via hydrothermal technique. The physiochemical characterization of as-prepared samples was examined through various analytical techniques such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy TEM, photoluminescent spectra (PL), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET), and ultraviolet diffuse reflectance spectroscopy (UV-DRS) technique. In addition, the photocatalytic performance was carried out by degradation of Rhodamine B dye under visible light irradiation using this nanocatalyst. The ternary nanocomposite achieved 94% of the degradation efficiency within 100 min which is higher than the pristine and binary composites under the predetermined condition pH = 7, Rhodamine B dye = 5 mg/L, and catalyst concentration = 150 mg/L. The experimental synergetic effect of CeO2/Bi2MoO6/g-C3N4 ternary nanocomposite has been ascribed to the interfacial charge carrier migration between CeO2, Bi2MoO6, and g-C3N4. The optical absorption range of CeO2/Bi2MoO6/g-C3N4 ternary nanocomposite was enhanced, and the band gap was reduced up to 2.2 eV. In addition, scavenger trapping experiment proves that the super oxide anions (O2-.) and photogenerated holes are the major active species. The reusability and stability experiment proved the CeO2/Bi2MoO6/g-C3N4 ternary nanocomposite keeps good durability during the photocatalytic degradation process after the five successive cycles. Furthermore, based on the results, the charge carrier transfer photocatalytic mechanism was also discussed. This CeO2/Bi2MoO6/g-C3N4 ternary nanocomposite may offer the cheapest material and extend the great opportunity for clean and environmental remediation approach under the visible light irradiation.

A dual-labeling fluorescent probe to track lysosomal polarity and endoplasmic reticulum dynamics during ferroptosis.

A polarity-sensitive probe was developed to simultaneously label lysosomes and endoplasmic reticulum (ER) via its dansylamide and rhodamine fluorescence, respectively, enabling ratiometric polarity detection and stable dual-labeling. The fragmented ER network and increased lysosomal polarity during ferroptosis were revealed, which facilitates the understanding of ferroptotic mechanisms.

Fe(III)-Based Fluorescent Probe for High-Performance Recognition, Test Strip Analysis, and Cell Imaging of Carbon Monoxide.

Fluorescence sensing and imaging techniques are being widely studied for detecting carbon monoxide (CO) in living organisms due to their speed, sensitivity, and ease of use to biological systems. Most fluorescent probes used for this purpose are based on heavy metal ions like Pd, with a few using elements like Ru, Rh, Ir, Os, Tb, and Eu. However, these metals can be expensive and toxic to cells. There is a need for more affordable and biologically safe fluorescent probes for CO detection. Drawing inspiration from the robust affinity exhibited by heme iron toward CO, in this work, a rhodamine derivative called RBF was developed for imaging CO in living cells by binding to Fe(III) and could be used for CO sensing. A Fe(III)-based fluorescent probe for CO imaging in living cells offers advantages of cost effectiveness, low toxicity, and ease of use. The fluorescence detection using the RBF-Fe system showed a direct correlation with increasing levels of CORM-3 (LOD = 146 nM) or the exposure time of CO gas, displaying reduced fluorescence. A CO test paper based on RBF-Fe was created for simple on-site CO detection, where fluorescence would diminish in response to CO exposure, allowing rapid (2 min) visual identification. Imaging of CO in living cells was successfully conducted using the probe system, showing a decrease in fluorescence intensity as CORM-3 concentrations increased, indicating its effectiveness in monitoring CO levels accurately within living cells.

Label-free fluorescent biosensor based on AuNPs etching releasing signal for miRNA-155 detection.

Quantitative microRNA (miRNA) detection is crucial for early breast cancer diagnosis and prognosis. However, quick and stable fluorescence sensing for miRNA identification is still challenging. This work developed a novel label-free detection method based on AuNPs etching for quantitatively detecting miRNA-155. A layer of AuNPs was grown on the surface of mesoporous silica nanoparticles (MSN) loaded with Rhodamine 6G (R6G) using seed-mediated growth, followed by probe attachment. In the presence of miRNA-155, the MSN@R6G@AuNP surface loses the protection of the attached probe, rendering AuNPs susceptible to etching by hydrochloric acid. This results in a significant fluorescent signal being released in the free space. The encapsulation with AuNPs effectively reduces signal leakage, while the rapid etching process shortens detection time. This strategy enables sensitive and fast detection with a detection range of 100 fM to 100 nM, a detection limit of 2.18 fM, and a detection time of 30 min. The recovery rate in normal human serum ranges from 99.02 % to 106.34 %. This work presents a simple biosensing strategy with significant potential for application in tumor diagnosis.

Bimetallic Ag/Fe-MOG derived flake-like Ag2O/Fe2O3 p-n heterojunction for efficient photodegradation organic pollutants within a wide pH range.

In this paper, we reported a facile and clean strategy to prepare the flake-like Ag2O/Fe2O3 bimetallic p-n heterojunction composites for photodegradation organic pollutants. The surface morphology, crystal structure, chemical composition and optical properties of Ag2O/Fe2O3 were characterized by SEM, high-resolution TEM images with EDX spectra, XRD, XPS, FT-IR and UV-vis DRS spectra respectively. The formation of Ag2O/Fe2O3 p-n heterojunction facilitated the interfacial transfer of electrons as well as the separation of charge carries. Hence, the as-synthesized Ag2O/Fe2O3-3 composites exhibited ultra-high photocatalytic activity. Under the experimental conditions of catalyst dosage of 0.4 mg mL-1 and irradiation time of 60 min, the degradation conversion rate of rhodamine B reached 96.1 %, which was 5.0 and 2.8 times of pure phase Ag2O and Fe2O3, respectively. Meanwhile, the degradation performance of Ag2O/Fe2O3-3 was not limited by pH, and it can achieve high degradation efficiency under 3-11. In addition, Ag2O/Fe2O3-3 also showed superb degradation ability for other common anionic dyes, cationic dyes and antibiotics. XPS and FT-IR spectra showed that Ag2O/Fe2O3-3 retained a carbon skeleton that facilitated electron transport and light absorption conversion. And the analyses of quenching experiment and EPR demonstrated •O2-, •OH and h+ were crucial reactive oxidant species contributing to the rapid organic pollutant degradation. This work provides new insights into obtaining p-n photocatalysts heterojunction with excellent catalytic activity for removing organic pollutants from wastewater.

Boosted photocatalytic performance of cobalt ferrite anchored g-C3N4 nanocomposite toward various emerging environmental hazardous pollutants degradation: insights into stability and Z-scheme mechanism.

In this study, a highly efficient CoFe2O4-anchored g-C3N4 nanocomposite with Z-scheme photocatalyst was developed by facile calcination and hydrothermal technique. To evaluate the crystalline structure, sample surface morphology, elemental compositions, and charge conductivity of the as-synthesized catalysts by various characterization techniques. The high interfacial contact of CoFe2O4 nanoparticles (NPs) with g-C3N4 nanosheets reduced the optical bandgap from 2.67 to 2.5 eV, which improved the charge carrier separation and transfer. The photo-degradation of methylene blue (MB) and rhodamine B (Rh B) aqueous pollutant suspension under visible-light influence was used to investigate the photocatalytic degradation activity of the efficient CoFe2O4/g-C3N4 composite catalyst. The heterostructured spinel CoFe2O4 anchored g-C3N4 photocatalysts (PCs) with Z-scheme show better photocatalytic degradation performance for both organic dyes. Meanwhile, the efficiency of aqueous MB and Rh B degradation in 120 and 100 min under visible-light could be up to 91.1% and 73.7%, which is greater than pristine g-C3N4 and CoFe2O4 catalysts. The recycling stability test showed no significant changes in the photo-degradation activity after four repeated cycles. Thus, this work provides an efficient tactic for the construction of highly efficient magnetic PCs for the removal of hazardous pollutants in the aquatic environment.

Industrial dye absorption and elimination from aqueous solutions through bio-composite construction of an organic framework encased in food-grade algae and alginate: Adsorption isotherm, kinetics, thermodynamics, and optimization by Box-Behnken design.

A potential bio-adsorbent material for removing Rhodamine B (RB) from aqueous solution is Ru-MOF@FGA/CA beads. The adsorption capability of the material is probably enhanced by the use of a natural substance made of food-grade algae (FGA) and calcium alginate (CA), which has been cross-linked and loaded with ruthenium metal-organic frameworks (Ru-MOF). The Ru-MOF@FGA/CA beads were analyzed by XPS, PXRD, FT-IR, and SEM. The nitrogen adsorption-desorption isotherm analysis of the Ru-MOF@FGA/CA beads before and after the adsorption of RB revealed that had a surface area of 682 m2/g, a pore size of 2.92 nm, and a pore volume of 1.62 cc/g, that decreased after adsorption as the surface area reduced to 468.62 m2/g, while the pore volume reduced to 0.76 cc/g. indicating that the RB molecules occupied the available space within the pores of the material. The decrease in both surface area and pore volume specifies that the Ru-MOF@FGA/CA beads' pores were able to effectively adsorb the RB molecules. The adsorption of RB against the Ru-MOF@FGA/CA beads is affected by pH, adsorbent dose, starting RB concentration, and salinity. Controlling these factors can enhance the adsorption capability and effectiveness of the beads for RB removal. With an adsorption energy of 22.6 kJ/mol, the adsorption of RB onto the Ru-MOF@FGA/CA beads was determined to be a chemisorption process, demonstrating a strong bond among the adsorbent and the adsorbate. The pseudo-second-order kinetics and Langmuir isotherms were used to suit the adsorption process. Because the adsorption procedure was endothermic, it increased as the temperature increased. By using this information, the adsorption conditions may be improved, and the beads' ability to absorb RB can be increased. Up to six reuses of the Ru-MOF@FGA/CA beads are possible without affecting their chemical makeup and maintaining analogous PXRD and FT-IR data after each reuse. The adsorption process can be optimized through the application of the Box-Behnken design (BBD) approach and may entail H-bonding, electrostatic forces, n-π stacking, and pore filling. The exceptional stability of the beads makes them useful for creating long-lasting and efficient adsorbents that remove contaminants from water.

Sodium alginate-encapsulated nano-iron oxide coupled with copper-based MOFs (Cu-BTC@Alg/Fe3O4): Versatile composites for eco-friendly and effective elimination of Rhodamine B dye in wastewater purification.

This study explores the effectiveness of Alginate-coated nano­iron oxide combined with copper-based MOFs (Cu-BTC@Alg/Fe3O4) composites for the sustainable and efficient removal of Rhodamine B (RhB) dye from wastewater through adsorption and photocatalysis. Utilizing various characterization techniques such as FTIR, XRD, SEM, and TEM, we confirmed the optimal synthesis of this composite. The composites exhibit a significant surface area of approximately 160 m2 g-1, as revealed by BET analysis, resulting in an impressive adsorption capacity of 200 mg g-1 and a removal efficiency of 97 %. Moreover, their photocatalytic activity is highly effective, producing environmentally friendly degradation byproducts, thus underlining the sustainability of Cu-BTC@Alg/Fe3O4 composites in dye removal applications. Our investigation delves into kinetics and thermodynamics, revealing a complex adsorption mechanism influenced by both chemisorption and physisorption. Notably, the adsorption kinetics indicate equilibrium attainment within 100 min across all initial concentrations, with the pseudo-second-order kinetic model fitting the data best (R2 ≈ 0.999). Furthermore, adsorption isotherm models, including Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich, elucidate the adsorption behavior, with the Temkin and Dubinin-Radushkevich models showing superior accuracy compared to the Langmuir model (R2 ≈ 0.98 and R2 ≈ 0.96, respectively). Additionally, thermodynamic analysis reveals a negative Gibbs free energy value (-6.40 kJ mol-1), indicating the spontaneity of the adsorption process, along with positive enthalpy (+24.3 kJ mol-1) and entropy (+82.06 kJ mol-1 K) values, suggesting an endothermic and disorderly process at the interface. Our comprehensive investigation provides insights into the optimal conditions for RhB adsorption onto Cu-BTC@Alg/Fe3O4 composites, highlighting their potential in wastewater treatment applications.

Visible light irradiation enhanced sulfidated zero-valent iron/peroxymonosulfate process for organic pollutant degradation.

This study developed a novel process named sulfidated zero-valent iron/peroxymonosulfate/visible light irradiation (S-mZVI/PMS/vis) for enhanced organic pollutant degradation. The S-mZVI/PMS/vis process exhibited remarkable catalytic activity, achieving a 99.6% rhodamine B (RhB) removal within 10 min. The degradation rate constant of RhB by the S-mZVI/PMS/vis process was found to be 6.49 and 79.84 times higher than that by the S-mZVI/PMS and PMS/vis processes, respectively. Furthermore, the S-mZVI/PMS/vis process worked efficiently across a wide pH range (3.0-9.0), and the result of five-cycle experiments demonstrated the excellent reusability and stability of S-mZVI. Radical quenching tests and electron paramagnetic resonance analysis indicated that ·O2-, 1O2, and h+ significantly contributed to the degradation of RhB through the S-mZVI/PMS/vis process. The visible light irradiation increased the Fe2+ concentration, improved the Fe3+/Fe2+ cycle, and consequently enhanced the PMS decomposition, reactive species production, and RhB degradation. This work offers a promising strategy to highly efficiently activate PMS for organic pollutants elimination from aqueous solutions.