Degradation Rate Research Articles

Synthesis, characterization of FeNi3@SiO2@CuS for enhance solar photocatalytic degradation of atrazine herbicides: Application of RSM

This study was focused on the response surface methodology modeling (RSM) for the removal of Atrazine residue (ATZ) using nanocomposite. The FeNi3@SiO2@CuS nanocomposite was fabricated by co-precipitation and sol-gel methodologies, and their properties were studied by XRD, FTIR, VSM, and SEM techniques. The synthesis core-shell composite was used to degrade atrazine herbicide (ATZ) from synthetic wastewater. The efficiency of FeNi3@SiO2@CuS was calculated as a function of different input parameters (pH, ATZ concentration, catalyst concentration, H2O2 concentration, and reaction time by using a central composite design (CCD) adapted from response surface methodology. The CCD created a matrix of 60 runs of the experiment to look into how the five input elements interacted with one another. A reduced quadratic model was created using the findings and demonstrated good predictability of outcomes consistent with the research findings. Variance analysis (ANOVA) indicated that the chosen model was highly significant (p < 0.0001), and the coefficients of determination R2, adjusted R2, and predicted R2 were 0.9587, 0.9513, and 0.9380, respectively, confirming that the second-order regression model had been satisfactorily adjusted to obtained data. Furthermore, the findings provide validation that the degradation rate of ATZ adheres to a pseudo-first-order kinetic model, exhibiting an impressive R2 value surpassing 0.98. Through the use of a numerical optimization technique, a 95.24 % ATZ elimination was represented by the desirability of 81.12 %. This study suggests that sunlight, catalyst, and H2O2 together have a significant influence on ATZ degradation. Additionally, RSM was an appropriate process for optimizing the factors related to the elimination of ATZ by a solar-induced photocatalytic process.

Composite additives regulate physicochemical and microbiological properties in green waste composting: A comparative study of single-period and multi-period addition modes

Composting additives can significantly enhance green waste (GW) composting. However, their effectiveness is limited due to the short action duration of a single-period addition. Therefore, this study proposes that multi-period additive modes to prolong the action duration, expedite lignocellulose degradation, reduce composting time, and enhance product quality. This study conducted six treatments (T1–T6), introducing a compound additive (BLP) during the mesophilic (MP) and cooling periods (CP). Each treatment consistently maintained 25% total BLP addition of GW dry weight, with variations only in the BLP distribution in different periods. The composition of BLP consists of Wbiochar: Wlactic acid: Wpond sediment in a ratio of 10:1:40. Specifically, T1 added 25% BLP in CP, T2 added 5% in MP and 20% in CP, T3 added 10% in MP and 15% in CP, T4 added 15% in MP and 10% in CP, T5 added 20% in MP and 5% in CP, and T6 added 25% in MP. In this study, composting temperature, pH value, electrical conductivity, total porosity, the contents of lignin, cellulose, hemicellulose, and nutrient, scanning electron microscopy images, germination index, and the successions of different bacteria and fungi at the phylum and genus levels were detailed. Results showed T4 achieved two thermophilic periods and matured in just 25 days. T4 enhanced lignocellulose degradation rates (lignin: 16–53%, cellulose: 14–23%, hemicellulose: 9–48%) and improved nutrient content. The above results, combined with correlation analysis and structural equation model, indicated that T4 may promote the development of dominant bacteria (Proteobacteria, Firmicutes, Actinobacteria, Bacteroidetes) by regulating compost physicochemical properties and facilitate the growth of dominant fungi (Ascomycota and Basidiomycota) by modulating nutrient supply capacity. This ultimately leads to a microbial community structure more conducive to lignocellulose degradation and nutrient preservation. In summary, this study reveals the comprehensive effects of single-period and multi-period addition methods on GW composting, providing a valuable basis for optimizing the use of additives and enhancing the efficiency and quality of GW composting.

Characteristics and degradability of laser print waste paper fiber reinforced PLA resin matrix composite materials

AbstractAs is well known, Laser print paper is usually produced with high‐quality chemical wood pulp. The laser print waste paper fiber (LPWF) is a high‐quality secondary fiber, and the research and development of high‐value utilization technology for laser print waste paper has attracted much attention in the field of renewable resource recycling. In this study, LPWF was used to reinforce poly(lactic acid) (PLA) composites in the field, and the composites were modified with bioenzyme, cationic polyacrylamide (CPAM), and nano‐silicon carbide (Nano‐SiC) to enhance the interfacial compatibility of LPWF/PLA composites. The study systematically investigated the effects of various modification methods on the characteristics and degradability of composites made from laser print waste paper fiber reinforced PLA resin matrix. The results showed that the mechanical properties of the composites treated with CPAM and Nano‐SiC were significantly improved, with tensile strengths of 54.3 and 59.5 MPa, and flexural strengths of 85.1 and 91.5 MPa, respectively, and the water absorption of the composites was reduced after the modification treatment, while the thermal stability was improved. The degradation performance of the composites in various water environments indicated that the inclusion of LPWF accelerated the water degradation rate of the composites, with the maximum degradation rate of the composite reaching 1.26% in 30 days.Highlights Laser print waste paper is an excellent quality recyclable fiber resource. Four modifiers were used to modify LPWF/PLA composites. Characteristics and degradability of the composites were investigated. Significantly improved properties of CPAM and Nano‐SiC modified composites. The degradation rate of composites is increased by the addition of LPWF.

Biodegradation Characteristics and Mechanism of Aflatoxin B1 by Bacillus amyloliquefaciens from Enzymatic and Multiomics Perspectives.

Aflatoxin B1 (AFB1), a mycotoxin and natural carcinogen, commonly contaminates cereals and animal feeds, posing serious health risks to human and animal. In this study, Bacillus amyloliquefaciens ZG08 isolated from kimchi could effectively remove 80.93% of AFB1 within 72 h at 37 °C and pH 7.0. Metabolome and transcriptome analysis showed that metabolic processes including glycerophospholipid metabolism and amino acid metabolism were most affected in B. amyloliquefaciens ZG08 exposed to AFB1. The adaptation mechanism likely involved activation of the thioredoxin system to restore intracellular redox equilibrium. The key genes, tpx and gldA, overexpressed in Escherichia coli BL21, achieved degradation rates of 60.15% and 47.16% for 100 μg/kg AFB1 under optimal conditions of 37 °C and pH 8.0 and 45 °C and pH 7.0, respectively. The degradation products, identified as AFD1, were less cytotoxic than AFB1 in HepG2 cells. These findings suggest potential strategies for utilizing probiotics and engineered enzymes in AFB1 detoxification.

“Optimizing solar-driven dye degradation: Ag6Si2O7/WSe2 nanocomposites via S-scheme photocatalysis”

BackgroundThe implementation of semiconductor photocatalyst engineering offers a promising solution to combat water pollution and energy crises by efficiently converting solar energy into chemical energy for organic dye decomposition. MethodsBy hydrothermal method nanostructures of Ag6Si2O7/WSe2 were synthesized and investigated their effectiveness in solar-driven photo-degradation of rhodamine B (RhB) and Methylene Blue (MB) dyes. Ag6Si2O7/WSe2 nanocomposites were developed by varying the weight percentage of WSe2 from 0 to 25 % in the Ag6Si2O7 matrix. The physicochemical properties of the nanocomposites were analyzed by using various techniques such as XRD, FE-SEM, and TEM/HRTEM. Additionally, the optical properties were investigated using UV–Vis, PL, and EIS. Significant findingsAccording to the BET study, the AgWS-c composite exhibited the highest BET surface area at 47.56 m2/g and outperformed other composites by achieving degradation rates of 96.24 % for RhB and 97.70 % for MB within 50 min. The rate constant of AgWS-c (0.0513 min−1) was 16.54 times higher than that of Ag6Si2O7 and 2.63 times more than WSe2 pristine, indicating its efficacy in dye degradation. ESR analysis assessed ROS species activity, LC/MS identified degradation intermediates, and a degradation mechanism pathway for RhB was proposed. The findings suggest that AgWS-c is a promising candidate for rapid and efficient wastewater treatment.

Enhanced degradation of tetracycline by gas-liquid discharge plasma coupled with g-C3N4/TiO2

Abstract Plasma-catalysis is considered as one of the most promising technologies for antibiotic degradation in water. In the plasma-catalytic system, one of the factors affecting the degradation effect is the performance of the photocatalyst, which is usually restricted by the rapid recombination of electrons and holes as well as narrow light absorption range. In this research, a photocatalyst g-C3N4/TiO2 was prepared and coupled with gas-liquid discharge (GLD) to degrade tetracycline (TC). The performance was examined, and the degradation pathways and mechanisms were studied. Results show that a 90% degradation rate is achieved in the GLD with g-C3N4/TiO2 over a 10 min treatment. Increasing the pulse voltage is conducive to increasing the degradation rate, whereas the addition of excessive g-C3N4/TiO2 tends to precipitate agglomerates, resulting in a poor degradation efficiency. The redox properties of the g-C3N4/TiO2 surface promote the generation of oxidizing active species (H2O2, O3) in solution. Radical quenching experiments showed that ·OH, hole (h+), play important roles in the TC degradation by the discharge with g-C3N4/TiO2. Two potential degradation pathways were proposed based on the intermediates. The toxicity of tetracycline was reduced by treatment in the system. Furthermore, the g-C3N4/TiO2 composites exhibited excellent recoverability and stability.&amp;#xD;Keywords: Gas-liquid discharge; Plasma-catalysis; g-C3N4/TiO2; TC degradation

Synergistic utilization of cost-effective glycerophosphate and biologically active zein for innovative minimally invasive smart thermo-responsive hydrogels for potential hard tissue engineering applications

Skeletal defects are the second-leading cause of disability worldwide, prompting the development of smart solutions for treatment. Calcium glycerophosphate (Ca–GP), chitosan (CS), hydroxyapatite (HA), and zein (ZN) were used to fabricate these thermo-responsive hydrogels. Ca–GP, an economically viable and bioactive glycerophosphate source, remains relatively underexplored. Natural protein ZN and the gold standard bone regenerative biomaterial HA were incorporated as reinforcing agents. The resulting composite hydrogels (HGs) exhibit a sol phase at 4 °C–10 °C and transition to gels at body temperature within 4–6 min. Their good injectability and the ability to be easily shaped into complex structures further support their great potential as minimally invasive solutions for treatment. The addition of ZN significantly improved the mechanical and biological properties of the HGs. The highest ZN concentration resulted in the strongest mechanical strength, measuring 52.2 MPa at 40% strain. HGs exhibited optimal swelling and degradation rates. Scanning electron microscopy analysis supported their porous nature. In vitro cell culture assays and wound healing assays demonstrated their excellent biocompatibility and regenerative potential. Drug-loaded HGs exhibited up to 90% drug release and antibacterial activity. All these results support their promising potential to support the regeneration of skeletal defects in a minimally invasive manner.

Photodegradation of Organic Solar Cells under Visible Light and the Crucial Influence of Its Spectral Composition.

While wavelength-dependent photodegradation of organic solar cells (OSCs) under visible light is typically discussed in terms of UV/blue light-activated phenomena, we recently demonstrated wavelength-dependent degradation rates up to 660 nm for PM6:Y6. In this study, we systematically investigated this phenomenon for a broad variety of devices based on different donor:acceptor combinations. We found that the spectral composition of the light used for degradation, tuned in a spectral range from 457 to 740 nm and under high irradiances of up to 30 suns, has a crucial influence on the device stability of almost all tested semiconductors. The relevance of this phenomenon was investigated in the context of simulated AM1.5 illumination with metal halide lamps and white LEDs. It is concluded that the current stability testing protocols in OSC research have to be adjusted to account for this effect to reveal the underlying physics of this still poorly understood mechanism.

A novel 3D nitrogen-doped porous carbon supported Fe-Cu bimetallic nanoparticles composite derived from lignin: an efficient peroxymonosulfate activator for naphthalene degradation.

A novel 3D nitrogen-doped porous carbon supported Fe-Cu bimetallic nanoparticles composite (Fe-Cu-N-PC) was prepared via direct pyrolysis by employing black liquor lignin as a main precursor, and it was utilized as a novel catalyst for PMS activation in degrading naphthalene. Under the optimum experimental conditions, the naphthalene degradation rate was up to 93.2% within 60 min in the Fe-Cu-N-PC/PMS system. The porous carbon framework of Fe-Cu-N-PC could facilitate the quick molecule diffusion of reactants towards the inner bimetallic nanoparticles and enriched naphthalene molecules from the solution by a specific adsorption, which increased the odds of contact between naphthalene and reactive oxygen species and improved the reaction efficiency. The quenching reaction proved that the non-free radical pathway dominated by 1O2 was the main way in naphthalene degradation, while the free radical pathway involving SO4·- and ·OH only played a secondary role. Moreover, owing to its high magnetization performance, Fe-Cu-N-PC could be magnetically recovered and maintained excellent naphthalene degradation rate after four degradation cycles. This research will offer a theoretical basis for the construction of facile, efficient, and green technologies to remediate persistent organic pollutants in the environment.

A two-dimensional Aurivillius oxide for enhanced solar energy driven hydrogen evolution and waste water treatment

Bi2WO6 has attracted extensive attention in photocatalysts in recent years as a typical Aurivillius oxide. However, it suffers from severe electron-hole recombination due to the large charge transfer distance from bulk to surface. Unfortunately, strong chemical bonds between the neighboring layers in Aurivillius oxides lead to difficulties in the construction of 2D materials. Here, a facile NaBH4-assisted hydrothermal method is developed to construct 2D Bi2WO6 nanosheets with adjustable thickness from 4.03 to 1.51 nm and O vacancies density (named as BWO-x, x = 15, 30, 45, 60). By balancing the thickness and the O vacancy density in the nanosheets, the charge separation efficiency can be tuned and consequently, the photocatalytic activity can be optimized, leading to over 11 times enhancement in photocatalytic hydrogen evolution. Furthermore, the best performed nanosheets demonstrate universality in dye polluted water treatment. Nearly 100% degradation can be reached after only 5, 50, and 30 min with degradation rate constant of 29.73, 3.21, and 6.62 min−1g−1 for Rhodamine B, methyl orange, and methylene blue, respectively. This work provides a comprehensive approach to produce ultrathin 2D nanosheets of Aurivillius photocatalysts for enhanced charge separation and photocatalytic activity.

Construction of Rod-Like Bi4O5I2/NaYF4:Yb,Tm Composite and its Improved Photocatalytic Degradation Performance Under Near-Infrared Light

Photocatalytic technology exhibits promising prospects in environmental remediation owing to its sustainable and environmentally friendly advantages. Among the bismuth-rich halide oxides, Bi4O5I2 has demonstrated remarkable efficacy in dye degradation due to its favorable valence band and conduction band positions. In this study, we successfully synthesized Bi4O5I2/NaYF4:Yb,Tm composites through a solvothermal method. When exposed to visible light, the Bi4O5I2/NaYF4:Yb,Tm composite achieved an impressive degradation rate of 86.7% for RhB solution after 60[Formula: see text]min of light-induced reaction. Moreover, the incorporation of NaYF4:Yb,Tm into Bi4O5I2 extended the utilization of near-infrared (NIR) spectroscopy. Under 980[Formula: see text]nm NIR light irradiation, the degradation rate of Rhodamine B (RhB) solution by the Bi4O5I2/NaYF4:Yb,Tm composite reached 43.0% after 240[Formula: see text]min of light reaction. Free radical capture experiments confirmed that h[Formula: see text] and •[Formula: see text] O[Formula: see text] played a significant role as the primary active species in the degradation process of RhB by the Bi4O5I2/NaYF4:Yb,Tm composites. Furthermore, we explored the mechanism behind the photocatalytic degradation of RhB solution using the Bi4O5I2/NaYF4:Yb,Tm composites. Bi4O5I2/NaYF4:Yb,Tm holds great potential as a promising candidate for utilization of NIR light for photocatalytic reactions.

Photodegradation, kinetics and non-linear error functions of methylene blue dye using SrZrO3 perovskite photocatalyst

The degradation of methylene blue dye-contaminated wastewater via photocatalysis is an efficient approach towards environmental remediation. The SrZrO3 perovskite photocatalyst was synthesized using the modified Pechini sol-gel method, and characterized using XRD, FESEM, FTIR, and UV–visible spectrophotometer. Crystallite size obtained by the Scherrer and Williamson-Hall methods were 45.56 and 44.50 nm, respectively. The sample exhibited an orthorhombic crystal structure. The optical bandgap was estimated to be 5.31 eV. Kinetic study for the degradation of methylene blue dye using SrZrO3 in the presence of H2O2 showed complete decontamination of the methylene blue dye in the time interval of 90–120 min under visible light irradiation. The degradation efficiency was above 80.1 % under illumination and less than 40.1 % in dark. Kinetic studies were performed by varying the dose of photocatalyst and initial concentration of methylene blue. It was observed that higher dose of the photocatalyst and lower concentration of the contaminant produced higher rate of degradation. The solution pH 3 and catalysts dosage of 200 mg yielded the highest rate of degradation. The experimental data fitted best into the Psuedosecond order kinetic model with the highest R2 value, indicating a strong linear relationship. The experimental data was subjected into nonlinear error functions, where the Psuedo-second order kinetic model demonstrated lower values of error functions. The results suggest that the prepared SrZrO3 photocatalyst coupled H2O2 is a promising photocatalyst for the decontamination of methylene blue dye under visible light irradiation.

Enhanced adsorption and degradation kinetics of methylene blue by Ag–Ag2S–CdS hybrid nanowires

In this paper, silver nanowires (Ag NWs) were initially synthesized by the polyol synthesis method. A simple hybridization of silver sulfide (Ag2S) and silver was achieved by simply mixing as-prepared Ag NWs with different concentrations of Na2S aqueous solution (0.01 and 0.001 M). To study the properties of the nanomaterials, Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), energy dispersive x-ray spectroscopy (EDX), X-ray diffraction (XRD), Photoluminescence (PL) spectroscopy and UV–Visible (UV–Vis) spectroscopy were used. The ion exchange method was used to create Ag–Ag2S–CdS hybrid nanocatalysts. There has been no research further info on the degradation of methylene blue (MB) by an Ag– Ag2S–CdS nanocatalyst in the three environments (acid, neutral, alkaline). The MB dye was degraded for various minutes (min) in different pH degrees under the influence of sunlight using Ag–Ag2S–CdS. As a result of the experiments, the degradation efficiency of MB dye increased from 12.47 % to 57.02 % in the neutral, 40.58 %–80.08 % the in alkaline, and 91.87 %–97.92 % in the acid environment as time passed. The kinetics of the degradation process in each of the three settings was examined, and it was found that the neutral environment's photodegradation rate is a single value of 0.0029. This value varied depending on the time in a neutral and alkaline environment. As a result, the rate of degradation in the alkaline environment for the 60 min was 0.0071 (60–180 min), then 0.001 (120–300 min). The first degradation rate in an acidic environment was 0.0085 (60–120 min), then 0.0016 (120–300 min).

Development of a γ-Al2O3-Based Heterogeneous Fenton-like Catalyst and Its Application in the Advanced Treatment of Maotai-Flavored Baijiu Wastewater

Heterogeneous Fenton technology was employed for the advanced treatment of Maotai-flavored Baijiu wastewater. Novel catalysts were prepared by loading different active ingredients (Mn, Fe, and Cu) on γ-Al2O3 using an impregnation method. The effects of active ingredient, reaction time, initial pH, H2O2 dosage, catalyst dosage, and other factors on the reaction were examined. The properties of the new catalysts were analyzed using BET analysis, XPS, and SEM. Moreover, the mechanisms of Fenton-like oxidation and its reaction kinetics were explored through experiments and analyses including GC–MS and intermediate active species scavenging by tertiary butyl alcohol (TBA) and/or para-benzoquinone. The results revealed that the most effective removal of organic matter was achieved with a Mn-Fe/Al (2:1 wt%) catalyst dosage of 30 g/100 g water, pH of 5.0, H2O2 dosage of 0.3 g/L, and reaction time of 60 min; the effluent COD value was 12 ± 1 mg/L, and the degradation rate was 65.7 ± 3%, approximately 14% higher than that of the conventional Fenton catalyst under similar conditions; moreover, the catalytic efficacy remained high after seven cycles. Kinetic analysis indicated that the heterogeneous Fenton oxidation reaction followed a third-order kinetics model, with R2 = 0.9923 and K = 0.0006 min−1.

Localized delivery of metformin via 3D printed GelMA-Nanoclay hydrogel scaffold for enhanced treatment of diabetic bone defects

BackgroundDiabetic bone defects present significant challenges for individuals with diabetes. While metformin has been explored for bone regeneration via local delivery, its application in treating diabetic bone defects remains under-explored. In this study, we aim to leverage 3D printing technology to fabricate a GelMA-Nanoclay hydrogel scaffold loaded with metformin specifically for this purpose. The objective is to assess whether the in situ release of metformin can effectively enhance osteogenesis, angiogenesis, and immunomodulation in the context of diabetic bone defects. Materials and methodsUtilizing 3D printing technology, we constructed a GelMA-Nanoclay-Metformin hydrogel scaffold with optimal physical properties and biocompatibility. The osteogenic, angiogenic, and immunomodulatory characteristics of the hydrogel scaffold were thoroughly investigated through both in vitro and in vivo experiments. ResultsGelMA10%-Nanoclay8%-Metformin5mg/mL was selected as the bioink for 3D printing due to its favorable swelling rate, degradation rate, mechanical strength, and drug release rate. Through in vitro investigations, the hydrogel scaffold extract, enriched with metformin, demonstrated a substantial enhancement in the proliferation and migration of BMSCs within a high-glucose microenvironment. It effectively enhances osteogenesis, angiogenesis, and immunomodulation. In vivo experimental outcomes further underscored the efficacy of the metformin-loaded GelMA-Nanoclay hydrogel scaffold in promoting superior bone regeneration within diabetic bone defects. ConclusionsIn conclusion, while previous studies have explored local delivery of metformin for bone regeneration, our research is pioneering in its application to diabetic bone defects using a 3D printed GelMA-Nanoclay hydrogel scaffold. This localized delivery approach demonstrates significant potential for enhancing bone regeneration in diabetic patients, offering a novel approach for treating diabetic bone defects. The translational potential of this articleOur study demonstrates, for the first time, the successful loading of the systemic antidiabetic drug metformin onto a hydrogel scaffold for localized delivery. This approach exhibits significant efficacy in mending diabetic bone defects, presenting a promising new avenue for the treatment of such conditions.

Photodegradation of Bisphenol A (BPA) in Coastal Aquaculture Waters: Influencing factors, Products, and Pathways

Bisphenol A (BPA), an endocrine-disrupting contaminant, is ubiquitous in the environment due to its presence in plastics, wastewater, and agricultural runoff. This study investigated the photodegradation behavior of BPA in coastal aquaculture waters near Qingdao, China. Lower salinity promoted BPA photodegradation, while higher salinity has an inhibitory effect, suggesting slower degradation in seawater compared to ultrapure water. Triplet-excited dissolved organic matter (3DOM*) was identified as the primary mediator of BPA degradation, with additional contributions from hydroxyl radicals (•OH), singlet oxygen (1O2), and halogen radicals (HRS). Alepocephalidae aquaculture water exhibited the fastest degradation rate, likely due to its high DOM and nitrate/nitrite (NO3-/NO2-) content, which are sources of 3DOM* and •OH. A positive correlation existed between NO3-/NO2- concentration and the BPA degradation rate. Ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) analysis identified the primary BPA photodegradation products, formed mainly through oxidative degradation, hydroxyl substitution, nitration, and chlorination pathways. Elucidating these photodegradation mechanisms provides valuable insights into the environmental fate and potential ecological risks of BPA in aquaculture environments. This knowledge can inform strategies for marine environmental protection and the development of sustainable practices.

GO/Bi2O2CO3/NiWO4 with Z-scheme heterojunction: efficiently enhanced degradation of organic pollutants under visible light and DFT studies

A ternary composite of GO/Bi2O2CO3/NiWO4 (GBCNWO) was prepared via an in-situ of Bi2O2CO3 onto the surface of NiWO4 and Bi2O2CO3/ NiWO4 being warped by GO, which was thereafter untilled as catalyst in photodegradation of organic pollutants. The microstructure, and optical properties of all the prepared samples were characterized using various techniques such as XRD, FT-IR, SEM, TEM, TG-DTG, XPS, UV-Vis, ESR, and N2-adsorption. Amongst the studied samples, GBNWO possessed the largest specific surface area, which would efficiently afford much more spaces for the exposing of active sites. Results of UV-vis and XPS suggested that GBNWO was more efficient for the adsorption and conversion of visible light, and photocurrent conduction through graphite carbon ring could lessen the recombination rate of photoelectrons and holes. Also, the minor arc radius of GBCNWO unveiled its lowest photoresistors among the composites, indicating that the GBNWO structured with GO, Bi2O2CO3 and NiWO4 has synergistic catalysis in the photodegradation. Importantly, 95.15% of degradation rate was observed under the optimized conditions (pH=7, catalyst weight of 30mg, 40mg/L of MB, 25oC). Additionally, the degradation rate of various substrates followed the order: MB (99.34%) > ciprofloxacin (97.28%) > RHB (97.01%) > indole (27.47%) > phenol (9.47%). The quenching experiment and ESR test suggested that three kinds of active species (•OH, •O2− and h+) can be photogenerated during visible light radiation. Among them, •O2− was confirmed as the key species during the photocatalytic process, which could be adduced that the existence of oxygen vacancies made the receiving photoelectrons to reduce O2, forming the superoxide radical. Finally, a Z-scheme mechanism about the production of active radicals was proposed, which was also validated by DFT calculations.

Fabrication and optimization of bioelectrochemical system using tetracycline-degrading bacterial strains for antibiotic wastewater treatment

In this study, a microbial fuel cell was constructed using Raoultella sp. XY-1 to efficiently degrade tetracycline (TC) and assess the effectiveness of the electrochemical system. The degradation rate reached 83.2 ± 1.8 % during the 7-day period, in which the system contained 30 mg/L TC, and the degradation pathway and intermediates were identified. Low concentrations of TC enhanced anodic biofilm power production, while high concentrations of TC decreased the electrochemical activity of the biofilm, extracellular polymeric substances, and enzymatic activities associated with electron transfer. Introducing electrogenic bacteria improved power generation efficiency. A three-strain hybrid system was fabricated using Castellaniella sp. A3, Castellaniella sp. A5 and Raoultella sp. XY-1, leading to the enhanced TC degradation rate of 90.4 % and the increased maximum output voltage from 200 to 265 mV. This study presents a strategy utilizing tetracycline-degrading bacteria as bioanodes for TC removal, while incorporating electrogenic bacteria to enhance electricity generation.

Effect of different pectin sources and structures on the stability of cyanidin-3-O-glucoside (C3G)

The physicochemical properties of cyanidin-3-O-glucoside (C3G) were investigated after binding with pectin from different sources (apple and peach) and fractions (water-soluble fraction (WSF), chelator soluble fraction (CSF) and sodium carbonate soluble fraction (NSF)). Apple WSF and peach CSF were high esterification degree pectin (DE) (63.23% and 55.66%). CSF of both AP and PP was abundant in HG and exhibited a much more linear structure than WSF and NSF. The maximum binding percentage was obtained at pH 2.0 for apple pectin (AP) (46%∼50%) and at pH 3.5 for peach pectin (PP) (50%∼54%). Binding with both pectins increased the color stability of C3G at pH 2.0. High DE pectin increased C3G light stability by reducing the degradation rate (0.03 h-1) compared to C3G alone (0.05 h-1). All the pectins reduced the thermal degradation rate of C3G, thus exhibiting a protective effect. A negative correlation was found between the relative RG I area and the particle size of the pectin-C3G complexes. Pectin played a leading role in the ζ-potential change.

Transformation of antibiotics to non-toxic and non-bactericidal products by laccases ensure the safety of Stropharia rugosoannulata

The substantial use of antibiotics contributes to the spread and evolution of antibiotic resistance, posing potential risks to food production systems, including mushroom production. In this study, the potential risk of antibiotics to Stropharia rugosoannulata, the third most productive straw-rotting mushroom in China, was assessed, and the underlying mechanisms were investigated. Tetracycline exposure at environmentally relevant concentrations (<500 μg/L) did not influence the growth of S. rugosoannulata mycelia, while high concentrations of tetracycline (>500 mg/L) slightly inhibited its growth. Biodegradation was identified as the main antibiotic removal mechanism in S. rugosoannulata, with a degradation rate reaching 98.31 % at 200 mg/L tetracycline. High antibiotic removal efficiency was observed with secreted proteins of S. rugosoannulata, showing removal efficiency in the order of tetracyclines > sulfadiazines > quinolones. Antibiotic degradation products lost the ability to inhibit the growth of Escherichia coli, and tetracycline degradation products could not confer a growth advantage to antibiotic-resistant strains. Two laccases, SrLAC1 and SrLAC9, responsible for antibiotic degradation were identified based on proteomic analysis. Eleven antibiotics from tetracyclines, sulfonamides, and quinolones families could be transformed by these two laccases with degradation rates of 95.54–99.95 %, 54.43–100 %, and 5.68–57.12 %, respectively. The biosafety of the antibiotic degradation products was evaluated using the Toxicity Estimation Software Tool (TEST), revealing a decreased toxicity or no toxic effect. None of the S. rugosoannulata fruiting bodies from seven provinces in China contained detectable antibiotic-resistance genes (ARGs). This study demonstrated that S. rugosoannulata can degrade antibiotics into non-toxic and non-bactericidal products that do not accelerate the spread of antibiotic resistance, ensuring the safety of S. rugosoannulata production.