Degradation of Cationic Red GTL by Catalytic Wet Air Oxidation over Mo–Zn–Al–O Catalyst under Room Temperature and Atmospheric pressure

To overcome the drawback of catalytic wet air oxidation (CWAO) with high temperature and high pressure, the catalytic activity of Mo–Zn–Al–O catalyst for degradation of cationic red GTL under room temperature and atmospheric pressure was investigated. Mo–Zn–Al–O catalyst was prepared by coprecipitation and impregnation. XRD, TG-DTG, and XPS were used to characterize the resulting sample. Central composition design using response surface methodology was employed to optimize correlation of factors on the decolorization of cationic red GTL. The results show that the optimal conditions of pH value, initial concentration of dye and catalyst dosage were found to be 4.0, 85 mg/L and 2.72 g/L, respectively, for maximum decolorization of 80.1% and TOC removal of 50.9%. Furthermore, the reaction on the Mo–Zn–Al–O catalyst and degradation mechanism of cationic red GTL was studied by Electron spin resonance (ESR) and GC-MS technique. The possible reaction mechanism was that the Mo–Zn–Al–O catalyst can efficiently react with adsorbed oxygen/H₂O to produce ·OH and ¹O₂ and finally induce the degradation of cationic red GTL. GC-MS analysis of the degradation products indicates that cationic red GTL was initiated by the cleavage of NN and the intermediates were further oxidized by ·OH or ¹O₂

Volumetric, Viscometric, and Refractive Index Behavior of 7‑Hydroxy-4-methylcoumarin in Aqueous Ethanol or 1‑Propanol Solutions in the Temperature Range of (293.15 to 313.15) K

Densities and viscosities of the pseudo binary system 7-hydroxy-4-methylcoumarin + (ethanol or 1-propanol) + water at temperatures of (293.15, 298.15, 303.15, 308.15, and 313.15) K and refractive indices of this system at <i>T</i> = 298.15 K have been measured as a function of the molality of 7-hydroxy-4-methylcoumarin. The density data have been used to compute the apparent molar volume and limiting partial molar volume. The viscosity <i>B</i>-coefficients and variation of <i>B</i> with temperature have been calculated from the viscosity data according to the Jones–Dole equation. Molar refractions of the investigated system have been obtained from the refractive index data. These parameters and their variation tendencies have been expounded in terms of the interactions between solutes and solvents. The results have shown that 7-hydroxy-4-methylcoumarin plays a structure-making role in the given solution

Extracellular Polymeric Substances Induced Porous Polyaniline for Enhanced Cr(VI) Removal from Wastewater

Extracellular polymeric substances (EPS) of bacteria were used as templates for synthesizing unique polyaniline nanocomposites, i.e., porous EPS-modified polyaniline (EPS@PANI). The proteins were responsible for forming porous structure, while polysaccharides for the fiber morphology of EPS@PANI. The specific surface area (53.2 m²/g) of these unique EPS@PANI with an optimal EPS loading of 2 wt % was ∼2 times larger than that of pristine PANI. The PANI in EPS@PANI stayed as the emeraldine form and acted as the electron donor for reduction of Cr­(VI) to Cr­(III). Herein, 1.0 mg/L Cr­(VI) was completely reduced to Cr­(III) by 600 mg/L of EPS@PANI within 10 min, which was much faster than the pristine PANI (1 h). A maximum Cr­(VI) removal capacity of 913.2 mg/g was achieved by these unique EPS@PANI nanocomposites and was ∼4.7 times higher than the pristine PANI (193.8 mg/g). Moreover, the isoelectric point (pI) was decreased from pH 7.5 for pure PANI to ∼4.5 for these porous EPS@PANI nanocomposites due to the low pI of polysaccharides remained in the composites. This lowered pI facilitated further Cr­(III) removal on the surface of EPS@PANI from the wastewater

Additional file 1: Figures S1–S6. of Facile Fabrication of Bi2WO6/Ag2S Heterostructure with Enhanced Visible-Light-Driven Photocatalytic Performances

The EDS, BET surface area, and Zeta potential analysis for the as-formed heterostructures, the XRD pattern of Ag2S, and the temporal evolution of Rh B absorption spectra over Bi2WO6/Ag2S heterostructure at different pH values. Figure S1. Elemental mapping and EDX spectra of the Bi2WO6/Ag2S heterostructure. Figure S2. EDS spectra of the composite photocatalysts Bi2WO6/Ag2S. Figure S3. Nitrogen adsorption-desorption isotherms and the pore size distribution curve (inset) of sample (a) Bi2WO6 and (b) Bi2WO6/Ag2S. Figure S4. XRD pattern of Ag2S. Figure S5. Zeta potential for a suspension containing 1 g L of sample Bi2WO6/Ag2S in the presence of KCl (10−3 M) at different pH values. Figure S6. The temporal evolution of Rh B absorption spectra over Bi2WO6/Ag2S heterostructure at different pH values

Ultrasonic Pretreated Sludge Derived Stable Magnetic Active Carbon for Cr(VI) Removal from Wastewater

A stable magnetic carbon was synthesized using activated sludge as the carbon precursor. The ultrasonic pretreatment was used to destroy the cells in the activated sludge and to release the soluble carbon source, which was responsible for the improved stability of the synthesized magnetic carbon. 800 W was demonstrated as the optimized ultrasonication power for the pretreatment of activated sludge. Then, the carbonization parameters, such as pyrolysis temperature, heating rate, and dwell time were optimized as 800 °C, 10 °C/min, and 60 min, respectively. To be more specific, this activated sludge derived magnetic carbon can reduce almost all the hexavalent chromium (Cr­(VI)) (2.0 mg/L) in 10 min and has a maximum capacity as high as 203 mg/g. The iron release rate of the synthesized activated sludge derived magnetic carbon was decreased, which improved the electron utilization of zerovalent iron (ZVI). This composite was demonstrated to have a good stability and recyclability as well. Finally, the Cr­(VI) removal mechanisms were clarified under the acidic and the natural conditions

Rheological Behavior of Aqueous Solutions of An Ionic Liquid As A Surfactant

<div><p>The rheological properties of aqueous solutions of an ionic liquid as a surfactant, 1-tetradecyl-3-methylimidazolium bromide (C₁₄mimBr), in the presence of sodium salicylate (NaSal), have been studied by rheological measurements. For these C₁₄mimBr/NaSal systems, zero-shear viscosity as a function of NaSal concentration shows the maxima behavior. The effect of the concentration ratio, C_NaSal/C_C14mimBr, on the maximum was determined, and the scaling relations were obtained. Network structures could be formed in the aqueous C₁₄mimBr solutions containing NaSal. ¹H NMR spectra analysis indicates that the main interaction between C₁₄mimBr and NaSal molecules is electrostatic attraction, which leads to the formation of an ion pair.</p></div

DataSheet1_Granular activated carbon enhances volatile fatty acid production in the anaerobic fermentation of garden wastes.docx

Garden waste, one type of lignocellulosic biomass, holds significant potential for the production of volatile fatty acids (VFAs) through anaerobic fermentation. However, the hydrolysis efficiency of garden waste is limited by the inherent recalcitrance, which further influences VFA production. Granular activated carbon (GAC) could promote hydrolysis and acidogenesis efficiency during anaerobic fermentation. This study developed a strategy to use GAC to enhance the anaerobic fermentation of garden waste without any complex pretreatments and extra enzymes. The results showed that GAC addition could improve VFA production, especially acetate, and reach the maximum total VFA yield of 191.55 mg/g VSadded, which increased by 27.35% compared to the control group. The highest VFA/sCOD value of 70.01% was attained in the GAC-amended group, whereas the control group only reached 49.35%, indicating a better hydrolysis and acidogenesis capacity attributed to the addition of GAC. Microbial community results revealed that GAC addition promoted the enrichment of Caproiciproducens and Clostridium, which are crucial for anaerobic VFA production. In addition, only the GAC-amended group showed the presence of Sphaerochaeta and Oscillibacter genera, which are associated with electron transfer processes. Metagenomics analysis indicated that GAC addition improved the abundance of glycoside hydrolases (GHs) and key functional enzymes related to hydrolysis and acidogenesis. Furthermore, the assessment of major genera influencing functional genes in both groups indicated that Sphaerochaeta, Clostridium, and Caproicibacter were the primary contributors to upregulated genes. These findings underscored the significance of employing GAC to enhance the anaerobic fermentation of garden waste, offering a promising approach for sustainable biomass conversion and VFA production.</p

Solvent and pH Dependences of Mixing Enthalpies of <i>N</i>‑Glycylglycine with Protocatechuic Acid

Protocatechuic acid (PA) is a natural phenolic compound which has been proven to have chemopreventive property against chemically induced carcinogenesis. The mixing enthalpies of PA with <i>N</i>-glycylglycine in sodium phosphate and potassium phosphate buffer solutions with different pH values have been investigated by mixing-flow isothermal microcalorimetry at <i>T</i> = 298.15 K. The heterotactic enthalpic interaction coefficients (<i>h</i>_<i>xy</i>) in the pH range of phosphate buffer solution from 3.0 to 8.0 have been calculated according to the McMillan–Mayer theory. Trends of the enthalpic pairwise interaction coefficients (<i>h</i>_<i>xy</i>) with increasing pH in both phosphate buffer solutions were obtained. The solvent and pH dependence of the <i>h</i>_<i>xy</i> were discussed in terms of molecular interactions between solvated solute molecules

Polyaniline Coated Ethyl Cellulose with Improved Hexavalent Chromium Removal

The ethyl celluloses (ECs) modified with 5.0, 10.0, and 20.0 wt % polyaniline (PANI) (PANI/ECs) prepared by homogeneously mixing the EC and PANI formic acid solutions have demonstrated a superior hexavalent chromium (Cr­(VI)) removal performance to that of pure EC. Having an increased Cr­(VI) removal percentage with increased PANI loading, the PANI/ECs with 20.0% PANI loading were noticed to remove 2.0 mg/L Cr­(VI) completely within 5 min, much faster than the pristine EC (>1 h). A chemical redox of Cr­(VI) to Cr­(III) by the active functional groups of PANI/ECs was revealed from the kinetic study. Meanwhile, isothermal study demonstrated a monolayer adsorption behavior following the Langmuir model with a calculated maximum absorption capacity of 19.49, 26.11, and 38.76 mg/g for the 5.0, 10.0, and 20.0 wt % PANI/ECs, much higher than that of EC (12.2 mg/g). The Cr­(VI) removal mechanisms were interpreted considering the functional groups of both PANI and EC, the valence state fates of Cr­(VI), and the variation of solution acidity