Degradation Rate Research Articles

Contribution of individual phospholipase A2 enzymes to the cleavage of oxidized phospholipids in human blood plasma‡.

Phospholipids containing oxidized esterified PUFA residues (OxPLs) are increasingly recognized for multiple biological activities and causative involvement in disease pathogenesis. Pharmacokinetics of these compounds in blood plasma is essentially not studied. Human plasma contains both genuine phospholipases A2 (PAF-AH (also called Lp-PLA2) and sPLA2) and multifunctional enzymes capable of removing sn-2 residues in native and oxidized PLs (LCAT, PRDX6). The goal of this study was to compare relative activities of different PLA2 enzymes by analyzing cleavage of OxPAPC and OxPAPE by diluted plasma in the presence of enzyme inhibitors. We have found that human plasma demonstrated high total PLA2 activity against oxidized PCs and PEs. PAF-AH/Lp-PLA2 played a dominant role in LysoPC and LysoPE production as compared to other enzymes. Molecular species of OxPAPC and OxPAPE could be divided into 3 groups according to their degradation rate and sensitivity to PAF-AH/Lp-PLA2 inhibitor darapladib. Oxidatively truncated species were most rapidly metabolized in the presence of plasma; this process was strongly inhibited by darapladib. The rate of degradation of full-length OxPLs depended on the degree of oxygenation. Species containing 1 to 3 oxygen atoms were relatively stable to degradation in plasma, while OxPLs containing > 3 extra oxygens were degraded but at significantly slower rate than truncated species. In contrast to truncated species, degradation of full-length OxPLs with > 3 extra oxygens were only minimally inhibited by darapladib. These data provide further insights into the mechanisms regulating circulating levels of OxPLs and lipid mediators generated by PLA2 cleavage of OxPLs, namely oxylipins and LysoPC.

Role of silane compatibilization on cellulose nanofiber reinforced poly (lactic acid) (PLA) composites with superior mechanical properties, thermal stability, and tunable degradation rates.

Poly (lactic acid) (PLA) is a widely produced bio-based polymer known for its biodegradability and renewability, but its brittleness, low heat resistance, and weak mechanical properties limit its broader use. To address these challenges, TEMPO-oxidized cellulose nanofibers (TOCNF) were extracted from dissolving pulp using TEMPO oxidation and high-pressure homogenization. These TOCNF were modified with silane to reduce hydrophilicity and improve compatibility with PLA. The resulting silane modified TOCNF (S-TOCNF) were incorporated into PLA via solution casting to form S-TOCNF/PLA composite. Characterized by X-ray diffraction (XRD), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA) showed that S-TOCNF improved crystallization, compatibility, and enhanced the composite's mechanical properties. At 3 % S-TOCNF content, the S-TOCNF/PLA composites developed in this study achieve a balanced enhancement in mechanical properties, the tensile strength increased by 35.78 %, elongation at break by 66.25 %, and modulus by 25.99 % compared to pure PLA. Thermal stability improved, with decomposition temperature rising to 340 °C, while maintaining over 50 % light transmittance. Additionally, the degradation rate could be controlled by varying S-TOCNF content. This study demonstrates the potential of S-TOCNF to significantly enhance the mechanical, thermal, and degradation properties of PLA-based composites.

Injectable enzyme-crosslinking antioxidant hydrogel for stem cells protection and application in skeletal muscle regeneration

Repair of large and irregular skeletal muscle defects by cell therapy has been one of the major challenges in tissue engineering and regenerative medicine because of some major hurdles including stem cell death, function decline rapidly, and low retention in situ. Commercially available hydrogels for encapsulating stem cells are usually not suitable for uses in deep and irregular defects due to the limitations of crosslinking approaches as well as that of antioxidant properties. In this work, an injectable and self-healing hydrogel was developed, which is composed of caffeic acid grafted-gelatin molecules cross-linked through laccase catalysis reaction. Mechanical properties, swelling and degradation rates, cell compatibility, ROS-scavenging ability, and anti-senescence potentials of the hydrogels were characterized and investigated with varying caffeic acid contents. Result showed that the hydrogels hold features of strong capacity of scavenging reactive oxygen species, appropriated mechanical modulus falling in the range of that for bone marrow, and relative low oxygen microenvironment, which enabled the hydrogels to reduce the senescence of bone marrow-derived mesenchymal stem cells (BMSCs) and preserved their stemness. When applied to a mouse model of large and deep skeletal muscle defects, the hydrogel encapsulation increased BMSC retention in situ, improved the cell viability, and differentiation function, promoting myofiber regeneration, vascularization, and M2 macrophage polarization. In conclusion, this study highlights the superior ability of the hydrogel to preserve BMSCs’ stemness and enhance their therapeutic potential, offering a promising strategy for BMSCs protection and application to the repair of deep and large skeletal muscle defects in situ.

Use calcium silicate filler to improve the properties of sago starch based degradable plastic

<p>The addition of fillers or additives to improve the mechanical properties of degradable plastics such as sago starch has gained the interest of researchers, scientists, and academicians. This research aims to investigate the addition of calcium silicate as an additive filler on the properties of a sago starch-based degradable plastic. The calcium silicate fillers used were 2, 4, 6, and 8% by weight starch, and the gelatinization process temperature used was 70, 80, and 90 ℃. The properties of these plastics were analyzed in terms of their strength, chemical composition, thermal stability, water absorption, and degradation rate. The optimum mechanical characteristics included a tensile strength of 28.04 MPa, 32.55 MPa of elongation at the break, and 70.02% of Young's modulus obtained with the addition of 8% calcium silicate and a gelatinization temperature of 90 ℃. Fourier Transform Infrared (FTIR) showed that there were O-H, C-H, and C = O groups that existed at wave numbers of 3795.91 cm<sup>-1</sup>, 2927.94 cm<sup>-1</sup>, and 1433.11–1616.35 cm<sup>-1</sup>; moreover, these groups are hydrophilic, which bind water, so they can be degraded by the microbial activity in the soil. Differential Scanning Calorimetry (DSC) showed that the degradable plastic had a thermogram peak at 271.38 ℃; additionally an endothermic peak occurred at 309.30 ℃. The maximum swelling value was 64.05% at 2% calcium silicate and a gelatinization temperature of 70 ℃. The addition of calcium silicate made the plastic more water-resistant. The degradation rate of the degradable plastic ranged from 12–15 days and conformed to the American Standard Testing and Materials (ASTM) D-20.96 (maximum 180 days of decomposition for degradable plastic).</p>

A combined strategy of brain neuroprotection and endogenous neuroregeneration for enhanced intracerebral hemorrhage treatment via an injectable biomimetic hydrogel with efficient ROS scavenging and therapeutics delivery

Intracerebral hemorrhage (ICH) is a subtype of stroke that leads to severe functional impairments and poses a significant global health burden. Current clinical treatments often have limited efficacy, resulting in unsatisfactory outcomes. Herein, we report a combined strategy of brain neuroprotection and endogenous neuroregeneration for enhanced ICH treatment via an injectable biomimetic hydrogel with efficient reactive oxygen species (ROS) scavenging and therapeutics delivery. The hydrogel is mainly composed of thiolated gelatin (G-SH) and thiolated hyaluronan (HA-SH) to biomimetic extracellular matrix, in which the thiols act not only as crosslinkers through a thiol-ene click reaction, but also as ROS scavenger. By adjusting the ratio of G-SH to HA-SH, the hydrogel is optimized in terms of gelation time, modulus, degradation rate, microstructure, ROS scavenging ability, and compatibility with cells, tissues, and blood. In vitro, the hydrogel demonstrates the ability to scavenge intracellular ROS and modulate macrophage polarization through the JAK2/STAT3 signaling pathway. When encapsulated with insulin-like growth factor 1 (IGF-1), it further promotes the proliferation, migration, and differentiation of neural stem cells (NSCs) and enhances endothelial cell angiogenesis. In vivo, notably, the hydrogel encapsulated with chondroitinase ABC (ChABC) and IGF-1 effectively scavenges tissue ROS, regulates the activation and polarization of microglia/macrophages, providing neuroprotection. It also reduces glial scarring while facilitating the proliferation and migration of endogenous NSCs and promotes angiogenesis, all contributing to neuroregeneration. These combined effects lead to enhanced neuronal and myelin repair, resulting in improved cognitive and motor functions. Overall, this combined strategy of neuroprotection and neuroregeneration is a promising approach for enhanced ICH treatment.

Persistent Toughness and Heat Triggered Plasticization in Polylactide Modified with Poly(ethylene oxide)-block-poly(butylene oxide).

Poly(lactide) (PLA) is a promising biodegradable polymer with potential applications in single-use packaging. However, its use is limited by brittleness, and its biodegradability is restricted to industrial compost conditions due in part to an elevated glass transition temperature (Tg). We previously showed that addition of a poly(ethylene-oxide)-block-poly(butylene oxide) diblock copolymer (PEO-PBO) forms macrophase-separated rubbery domains in PLA that can impart significant toughness at only 5 wt %. This work demonstrates that PEO-PBO/PLA blends exhibit substantial toughness for at least nine months, beyond the average lifetime of single-use packaging, even amidst oxidative degradation of PEO-PBO into oligomeric products. Due to the glassy nature of the PLA matrix, these degradation products are confined to macrophase-separated domains, and the blend morphology is preserved. However, modest thermal annealing (∼60 °C) causes these domains to rapidly reduce in area fraction and size from migration and solubilization of the PEO-PBO degradation products into PLA, which plasticizes PLA and reduces the blend Tg. As a result, aged PEO-PBO/PLA blends degrade in just under half the time of similarly aged neat PLA when submerged in artificial seawater at 50 °C. This surprising combination of properties addresses two of PLA's most significant limitations with a single additive by (1) toughening the PLA during its useful lifetime and then (2) accelerating its degradation rate by heat-triggered plasticization when exposed to elevated temperatures at end-of-life, such as those of industrial (or even home) compost.

Fabrication of In Situ-Cross-Linked N-Succinyl Chitosan/Oxidized Alginate Hydrogel-Loaded Ascorbic Acid and Biphasic Calcium Phosphate for Bone Tissue Engineering.

Bone tissue engineering is a promising technology being studied globally to become an effective and sustainable method to treat the problems of damaged or diseased bones. In this work, we developed an in situ cross-linking hydrogel system that combined N-succinyl chitosan (NSC) and oxidized alginate (OA) at varying mixing ratios through Schiff base cross-linking. The hydrogel system also contains biphasic calcium phosphate (BCP) and ascorbic acid (AA), which could enhance biological characteristics and accelerate bone repair. The hydrogels' properties were examined through physicochemical tests such as scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR), x-ray diffraction (XRD), pore size and porosity measurement, swelling ratio, degradation rate, AA release study, as well as cytocompatibility, including live/dead and cytotoxicity assays. The results revealed that the supplementation of AA and BCP components can affect the physico-mechanical properties of the hydrogel system. However, they exhibited noncytotoxic properties. Overall, the results demonstrated that the hydrogel composed of 3% (w/v) NSC and 3% (w/v) OA (NSC: OA volume ratio is 8:2) loaded with 40% (w/w) BCP and 0.3 mg/mL AA has the potential for bone regeneration.

In-vitro investigation of chitosan/polyvinyl alcohol/TiO2 composite membranes for wound regeneration

Bacterial infections significantly delay the physiological wound healing process and can cause further damage to the wound region. In the current work, we aim to design titanium dioxide nanoparticles (TiO2 NPs) incorporated with chitosan (Chi) and poly(vinyl alcohol) (PVA) film using the casting method and to study their potential for faster wound healing. The prepared TiO2 NPs were analyzed for physicochemical properties, and TEM results showed an average particle size of 39.6nm. The nanocomposite films were scrutinized by FTIR, XRD, and TGA analyses. The effective incorporation of the nanoparticles and their uniform dispersion within the Chi/PVA matrix was confirmed through SEM analysis. The composite films exhibited excellent hydrophilic properties (64.3º), along with favorable swelling and degradation rates, and mechanical properties similar to native skin tissue, ensuring comfortable interaction with wound beds. The better hemocompatibility, with an erythrocyte lysis percentage of 3.52%, further supports the wound healing properties of these films. Additionally, composite films possess excellent antibacterial activity against wound pathogens such as B. subtilis and E.coli. Furthermore, an in vitro wound closure rate of 92.3% at 48 hours was observed for the TiO2 incorporated film (CPT3) using fibroblast HIH3T3 cells. The results suggest that it could be a promising biomaterial for wound healing application.

Preparation of thermoresponsive & enzymatically crosslinkable gelatin-gellan gum bioink: A protein-polysaccharide hydrogel for 3D bioprinting of complex soft tissues.

Developing superior bioinks presents several challenges in achieving ideal properties such as biocompatibility, viscosity, degradation rates & mechanical properties which are required to make functional tissue constructs. Various attempts have been made to prepare excellent bioink compositions that are suitable to address the above challenges. Herein, a versatile combination of gelatin (GL) - gellan gum (GG) bioink was successfully formulated & the bioink 7.5GL/2GG was found to be ideal for printing complex and highly intricate structures with excellent shape fidelity. Two different crosslinkers namely transglutaminase (TG) and calcium chloride (CaCl2) were utilized for crosslinking. The rheological properties of GL/GG bioink indicated that TG and dual (TG + CaCl2) crosslinked constructs had storage modulus equivalent to the that of native skin. Direct and indirect cytotoxicity assays revealed that the developed constructs were cytocompatible as well as hemocompatible. The 3D bioprinted GL/GG constructs crosslinked with only TG showed better cell viability, proliferation, cell spreading and wound healing efficiency in vitro compared to dual crosslinked constructs. In conclusion, TG crosslinking of 7.5GL/2GG bioink was ideal for bioprinting of skin tissue constructs for regenerative medicine applications. By altering the concentrations & printing conditions, this bioink may be tuned for other soft tissue engineering applications.

Validation of a post-processing methodology to readjust the voltage of a high-temperature PEM fuel cell according to the atmospheric pressure on a 2753h aging test at different constant currents

During an aging test of a high temperature proton exchange membrane fuel cell (HT-PEMFC) without exhaust pressure control loop, the anode and cathode pressures are dependent on variations in gas flow and atmospheric pressure. The voltage degradation rate is then impacted by atmospheric pressure variations. To extract the aging rate independently of the pressure, a possible solution is to estimate the voltage variation at a given pressure change. In this work, this voltage/pressure sensitivity was estimated in post-processing, by fitting regression planes (on measured voltage data) in the three dimensions: voltage, pressure, and time. It was applied on an aging test of 2753 h at 160 °C, at ambient pressure and at different constant currents (0.2, 0.4, and 0.6 A/cm2) which was carried out on an Advent Technologies Inc. PBI MEA of 45 cm2 active surface. The impact of varying atmospheric pressure on the calculation of degradation rates is then discussed and compared with another method developed in a previous work. It was found that a variation of 6 mV (2.4 % of initial voltage) at 1 A/cm2 during an aging test can be attributed to pressure variation alone, and not to cell degradation. Furthermore, it was observed that the voltage/pressure sensitivity is different depending on the period analyzed, at identical operating conditions (which would indicate that the dependence on pressure varies during aging). Indeed, at 0.2 A/cm2, the voltage response to a variation in pressure was quantified at approximately 50 μV/mbar and 80 μV/mbar at the start and end of life respectively. This method could therefore be used as an on-line diagnostic tool to monitor the fuel cell state of health.

Functions of unique middle loop and C-terminal tail in GnT-III activity and secretion.

N-Glycan branching modulates the diversity of protein functions. β1,4-N-acetylglucosaminyltransferase III (GnT-III or MGAT3) produces a unique GlcNAc branch, "bisecting GlcNAc", in N-glycans, and is involved in Alzheimer's disease and cancer. However, the 3D structure and catalytic mechanism of GnT-III are unclear. According to AlphaFold-based structure prediction, GnT-III likely contains two putative disordered segments, a long middle loop (Loop) and a C-terminal tail (Tail). We hypothesized that these segments play important roles in regulating the activity or intracellular behaviors of GnT-III. We expressed wild-type GnT-III (GnT-III-WT), GnT-III-Loop- and -Tail-deletion mutants in cells. Their in vitro catalytic activity and glycan biosynthesis in cells were examined using high-performance liquid chromatography, UDP-Glo glycosyltransferase assays, and glycomic analysis. Subcellular localization of WT and GnT-III mutants was investigated by immunostaining, and degradation rate and secretion were also examined. The Loop-deletion mutant had higher in vitro and in cellulo activity than GnT-III-WT, indicating that Loop suppresses catalytic activity. In contrast, the Tail-deletion mutant showed weaker activity, increased ER localization, and faster degradation than GnT-III-WT, indicating that Tail is required for proper folding. In addition, deletion of Loop led to aberrant shedding of GnT-III, indicating that Loop contains the cleavage site or regulates GnT-III shedding. Loop and Tail of GnT-III play important roles in catalytic activity, folding and shedding. Our results provide further understanding of the catalysis and shedding mechanisms of GnT-III and can help in the development of methods for modifying the levels of bisecting GlcNAc on glycoproteins and in cells.

Evaluation of swelling and degradation rates in crumb rubber modified bituminous binders

Evaluation of swelling and degradation rates in crumb rubber modified bituminous binders

Versatile electrospun cobalt-doped carbon films for rapid antibiotic degradation.

This study presents a novel approach to water contamination remediation by developing cobalt-doped carbon nanofiber films using electrospun ZIF-67 precursors, aiming to degrade tetracycline hydrochloride (TCH) and other antibiotics. This method uniquely combines the advantages of metal-organic frameworks (MOFs) and electrospinning to enhance catalytic performance, demonstrating significant innovation in environmental catalysis. The research systematically evaluated the impact of various factors on the catalytic activity of carbonized PAN@ZIF-67 films (CPZF), including carbonization temperature, ZIF-67 content, and PMS dosage. Notably, the CPZF catalyst with 11% ZIF-67 content (named as CPZF-11%) achieved an impressive 99.7% degradation of TCH within just 10 min under visible light and PMS activation, highlighting its superior catalytic efficiency. The study revealed that CPZF-11% exhibited excellent stability and recyclability, maintaining near 100% degradation rates even after six cycles. This catalytic performance is attributed to the synergistic effect of photogenerated electrons and PMS activation, leading to the formation of reactive oxygen species (ROS) such as sulfate radicals and singlet oxygen. The research further elucidated the degradation pathways and intermediate products through quenching experiments and electron paramagnetic resonance (EPR) analysis. The findings demonstrate the broad applicability of CPZF/Vis/PMS in various water matrices, including tap water and wastewater, underscoring its potential for real-world applications in wastewater treatment. This innovative integration of MOFs and electrospinning offers a promising strategy for developing efficient, recyclable, and high-performance catalysts for environmental remediation.

ASSEMBLY COUPLING TECHNOLOGY OF MICROLENS ARRAY AND OPTICAL FIBER BUNDLE

Continuous improvements in high-resolution infrared remote sensing imaging technology have led to important applications in various fields; however, the low filling rate of optical fiber and degradation of the focal ratio of the image end remain problems that restrict further development. The coupling technology of the microlens array and optical fiber bundle assembly is the key to solving these problems. In this work, we studied the coupling technology of microlens array and optical fiber bundle assembly. Specifically, six degrees-of-freedom coupling assembly and infrared radiation energy measurement subsystems were built, and based on this a high-precision mechanical alignment coupling efficiency measurement system was designed. After kinematic analysis, it was found that the maximum positioning error was within the allowable error range, making the system suitable for the requirements of precision assembly. Finally, the alignment coupling efficiency of the system was tested, and the results showed that the coupling efficiency reached 92.65%, which was only 6.01% lower than the assumed theoretical value and affirmed the feasibility of the system design for improving the performance of optical fiber image transmission systems.

Photocatalytic activity of zinc oxide nanorods incorporated graphitic carbon nitride catalyst

Background: Photocatalysts are user-friendly and serve as compatible materials for degrading industrial dye pollutants. This study utilizes zinc oxide/graphitic carbon nitride (ZnO/g-C3N4) nanocomposites against degrading methylene blue (MB). Methods: The hydrothermal method assisted sonication technique was used to fabricate the ZnO/g-C3N4 composite with varying ratios of ZnO/g-C3N4 (1:0.25, 1:0.50, 1:1). The synthesized materials have undergone various sophisticated techniques for finding their physiochemical properties and have been utilized for photodegradation activities. Significant Findings: The characterized results exhibit that the nanoflakes of g-C3N4 were covered with nanorods of zinc oxide when observed through scanning electron microscopy (SEM). Furthermore, the X-ray diffraction (XRD) studies demonstrate that the ZnO/g-C3N4 material was successfully synthesized. The X-ray photoelectron spectra (XPS) and Fourier-transform infrared (FTIR) spectra revealed the present oxidation states and chemical bonding of the materials. The photocatalytic activity results demonstrated that the concentration of ZnO molar ratio in varying g-C3N4 significantly affected the decomposition performance. The ZnO/g-C3N4 (1:0.50) presented a higher rate of degradation, reaching 92% at 120 minutes under UV light and 65% at 240 minutes under visible light irradiation. This could be explained by the mechanism that follows the separation of charge carriers, thereby producing hydroxyl radicals for the effective degradation of MB pollutants.

Rapid Fabrication of Polyvinyl Alcohol Hydrogel Foams With Encapsulated Mesenchymal Stem Cells for Chronic Wound Treatment.

Chronic wounds present a major healthcare challenge around the world, and significant hurdles remain in their effective treatment due to limitations in accessible treatment options. Mesenchymal stem cells (MSCs) with multifunctional differentiation and modulatory properties have been delivered to chronic wounds to enhance closure but have limited engraftment when delivered without a scaffold. In this study, hybrid porous hydrogel foams composed of modified polyvinyl alcohol and gelatin were developed that are suitable for rapid and facile MSC encapsulation, fully degradable, and supportive of wound healing. Rapid fabrication and encapsulation within porous foams was achieved using a cytocompatible gas blowing process. The hybrid hydrogels have tunable degradation rates based on chemistry, with complete mass loss achieved within 2-6 weeks, which is compatible with chronic wound closure rates. High encapsulated A375 epithelial cell and MSC viability with maintained cell functionality over 2 weeks reveals the potential of these hydrogels to serve as cell delivery systems for chronic wound treatment. An exvivo porcine skin wound model demonstrated enhanced healing after application of cell-laden hydrogel foams. Overall, hybrid hydrogel foams with encapsulated therapeutic cells have the capacity for robust wound healing and are a promising platform for chronic wound dressings.

Selective Generation of Hydroxyl and Sulfate Radicals under Electric Field Regulation for Micropollutants Degradation: Mechanism and Structure-Activity Relationship

Peroxymonosulfate (PMS) activation generates potent reactive oxygen species (ROS) such as sulfate radical (SO4·–) and hydroxyl radical (·OH), which play a key role in organic pollutant degradation. However, controlling the generation of these free radicals remains challenging. In this study, various metal (Co, Ni, and Cu)-doped nitrogen carbon compounds (NCs) were synthesized, and their performance in PMS activation under electric field regulation was explored to modulate ROS production for selective pollutant degradation. Bisphenol A (BPA), a readily degradable compound, and ibuprofen (IBU), a recalcitrant pollutant, were chosen as model pollutants to assess degradation efficiency. All catalysts achieved over 95% BPA removal without the electric field, but the application of an electric field significantly accelerated BPA degradation, achieving complete removal within 3min. In contrast, IBU degradation showed significant variation depending on the catalyst used and the electric field intensity, with Cu-NC demonstrating the highest performance, enhancing the degradation rate by 3.78-fold. Mechanistic studies revealed that the electric field altered the electron density on the catalyst surface, shifting ROS production from SO4·– to ·OH in Co-NC systems. The findings could provide valuable insights into PMS activation under electric field regulation, offering a novel strategy for enhancing micropollutant removal through controlled ROS generation.

Synergistic and efficient photocatalytic degradation of rhodamine B and tetracycline in wastewater based on novel S-scheme heterojunction phosphotungstic Acid@MIL-101(Cr).

To efficiently treat rhodamine B (RhB) and tetracycline (TC) in wastewater, MIL-101(Cr) was prepared by hydrothermal method and encapsulated with phosphotungstic acid (H3PW12O40, abbreviated as PTA) to form an S-scheme heterojunction PTA@MIL-101(Cr)-x (P@M-x, x=50, 100, 150, 200). The experimental results showed that after 180min under visible light at pH 7, the degradation rates of RhB and TC were 97.81% and 99.9%, respectively. Meanwhile, the cycling experiments have showed that the P@M-100S-scheme heterojunction exhibits good stability. Density Functional Theory (DFT) calculations theoretically verified the experimental results and elucidated the electrons migrate to MIL-101(Cr) and hole enrichment on the PTA surface. It was also revealed that the P@M-x photocatalyst belongs to the S-scheme heterojunction. Moreover, •O2- and h+ had been identified as the main active constituents during the photocatalytic degradation process. The synergistic effect of MIL-101(Cr) and PTA enhances the visible light absorption of P@M-x S-scheme heterojunction, resulting in more efficient electron transfer ability and faster photoreaction rate, thereby improved its photocatalytic performance. This study provides a potential solution for addressing aromatic pollutants in water.

Fabrication of 2D/2D Bi2MoO6/Sx@g-C3N(4-y) type-II heterojunction photocatalyst for enhanced visible-light-mediated degradation of tetracycline in wastewater.

Aquatic biota and human health are seriously threatened by the dramatic rise in antibiotics in environmental matrices. In this regard, the present study aims to improve knowledge of the combined effects of heterojunction design and defect engineering on the photocatalytic degradation of pharmaceuticals in aqueous matrices. Advantageously, the positioning of the valence band (VB) and conduction band (CB) levels of Sx@g-C3N(4-y), being higher than those of Bi2MoO6, demonstrates the feasibility of forming a type-II heterojunction between these materials. Initially, S and N defects were inserted in S-doped g-C3N4 through an alkali-assisted calcination method (referred to as Sx@g-C3N(4-y)), as affirmed by the reduced concentrations of S and N in the end product. Thereafter, the Bi2MoO6/Sx@g-C3N(4-y) photocatalysts (referred to as BSxNy) were synthesized via a solvothermal method followed by calcination. Among the prepared samples, the integration of 10% Sx@g-C3N(4-y) with Bi2MoO6 (referred to as BSxNy (II)) demonstrated superior photocatalytic performance. Under optimal conditions, BSxNy (II) achieved a remarkable 92.4% degradation efficiency of tetracycline (TCL) in an aqueous solution after 60 min. The degradation rate of BSxNy (II) transcended that of pristine Sx@g-C3N(4-y) and Bi2MoO6 by 4.86 and 3.41 times, respectively. The higher number of active sites and the greater electron-hole pair separation are responsible for this improvement in the rate of TCL degradation. The photocatalyst also exhibited remarkable thermal/chemical stability and possessed reusability, as noted by 84% TCL degradation TCL up to 5 cycles. The radical scavenging experiment indicated O2˙- as the primary contributor towards TCL degradation, with h+ and ˙OH playing a secondary role. Additionally, a seed germination experiment used to measure phytotoxicity determined that the treated effluent was non-phytotoxic, making it suitable for irrigation.

Z-scheme BiOBr/WS2 heterojunction with integrated photocatalytic degradation and photothermal water evaporation for effective dye wastewater purification

The restoration of water resources and the optimization of solar energy use are critical challenges. In this study, hydrophilic BiOBr/WS2 Z-scheme heterojunctions were prepared using a series of reactions for solar interface water evaporation and photocatalytic degradation of RhB. WS2 nanoparticles were deposited on the surface of titanium mesh using a hydrothermal method, and BiOBr nanosheets were further modified on WS2 using a successive ionic layer adsorption reaction (SILAR) method and solvothermal method. The relatively broad absorption range of WS2 in the full spectrum resulted in enhanced light absorption and improved light utilization of BiOBr/WS2. The formation of Z-scheme heterojunction between BiOBr and WS2 improved the hydrophilicity of the material, enhanced the photocatalytic degradation of organic pollutants in BiOBr/WS2 composite materials, and improved the solar interface water evaporation performance. The degradation rate of RhB by BiOBr/WS2 could reach 95.6% under one solar irradiation, and the photothermal water evaporation rate could reach 1.81 kgꞏm-2ꞏh-1. This study solved the problem of dye enrichment on solar absorber and provided a new way to construct an efficient solar interfacial water evaporation-photocatalytic system to treat dye wastewater.