Degradation Rate Research Articles

A review on green waste composting, role of additives and composting methods for process acceleration.

Effective disposal of green waste has been a challenging task faced by urban bodies for a long time. Composting can be an effective method to manage green waste by recovering nutrients that can be used as organic manure. However, there are some limitations to green waste composting, such as a low degradation rate and the requirement for high manpower and space. Many researchers have studied ways to minimize the limitations of green waste composting through different approaches. These include the use of co-composting materials, inoculating agents, and process modifications such as multi-stage composting. In this review, we systematically summarized the physicochemical characteristics of green waste and green waste compost, optimum ratios of additives, and process modifications during the composting of green waste reported in various articles. This review is helpful for early-career researchers and individuals new to the field of green waste composting by providing them with key concepts and recent developments in the field. The study suggests that the sustainable selection of additives or methods for composting green waste should depend on resource availability, climatic conditions, and the characterization of the feedstock.

Preparation and Evaluation of Poloxamer/Carbopol In-Situ Gel Loaded with Quercetin: In-Vitro Drug Release and Cell Viability Study.

Periodontitis is a severe chronic inflammatory disease, whose traditional systemic antimicrobial therapy faces great limitations. In-situ gels provide an effective solution as an emerging local drug delivery system. In this study, the novel thermosensitive poloxamer/carbopol in-situ gels loaded with 20μmol/L quercetin for the treatment of periodontitis were prepared by cold method. Thirteen batches of in-situ gels based on two independent factors (X1: poloxamer 407 and X2: carbopol 934P) were designed and optimized by the statistical method of central composite design (CCD). The transparency, pH, injectability, viscosity, gelation temperature, gelation time, elasticity modulus, degradation rate and in-vitro drug release studies of the batches were evaluated, and the percentage of drug release in the first hour, the time required for 90% drug release, gelation temperature, and gelation time were selected as dependent variables. These two independent factors significantly affected the four dependent variables (p < 0.05). The optimization result displayed that the optimized concentration of poloxamer 407 was 20.84% (w/v), and carbopol 934P was 0.5% (w/v). The optimized formulation showed a clear appearance (++), acceptable injectability (Pass), viscosity(151,798mPas), gelation temperature (36°C), gelation time (213s), preferable cell viability and cell proliferation, conformed to first-order release kinetics, and had a significant antibacterial effect. The article demonstrates the great potential of the quercetin in-situ gel as an effective treatment for periodontitis.

Flat biofilms extrusion of poly(lactic acid)/poly(butylene adipate‐co‐terephthalate) grafted with glycidyl methacrylate blends: Toward ecological packaging for sustainability

AbstractBlends of poly(lactic acid) (PLA)/poly(butylene adipate‐co‐terephthalate) grafted with glycidyl methacrylate (PBAT‐g‐GMA) were developed to produce flat and flexible biofilms through extrusion. The PLA/PBAT‐g‐GMA (90%/10%, 80%/20%, 70%/30%, and 60%/40% by mass) blends were processed in the internal mixer, injection molded, and manufactured into flat films. The optimal composition to produce flexible biofilms was PLA/PBAT‐g‐GMA (60/40%), as it demonstrated a decrease in elastic modulus of 53.2% and a significant gain in elongation at a break of 4923% about pure PLA. The incorporation of 40% PBAT‐g‐GMA in PLA increased the torque (Z) by 208%, while the melt flow index (MFI) decreased by 51.57%, compared to PLA. Additionally, the degradation rate (Rz) and molar mass loss (Rm) during processing were minimized, indicating that 40% PBAT‐g‐GMA enhanced stability of the PLA matrix. Fourier transform infrared spectroscopy indicated interactions between the GMA of PBAT‐g‐GMA and PLA, justifying the increase in viscosity and elongation at break. The PLA/PBAT‐g‐GMA (60/40%) composition showed a transmittance in the range of 20%–48% (400–800 nm) and an oxygen gas permeability of 1.56 × 10−5 cm3 STP/cm−2 h bar, indicating its potential for applications in packaging with optical barrier properties. Scanning electron microscopy (SEM) revealed ligaments in the interfacial region between PLA and PBAT‐g‐GMA, confirming the good performance in elongation at break. The results presented are essential for the plastics processing sector, aiming to develop eco‐friendly packaging.

Effect of Fiber Cross-Sectional and Surface Properties on the Degradation of Biobased Polymers.

Biobased polymers such as polylactic acid (PLA) and polybutylene succinate (PBS) break down naturally under certain environmental conditions. The efficiency of degradation can be linked directly to fiber surface properties, which influence polymer accessibility. Here, the degradation of PLA and PBS fibers with six different cross-sections was investigated. The fibers were aged by hydrolysis and UV exposure in an accelerated weathering test, followed by an ISO 20200 laboratory-scale disintegration test with non-aged fibers as controls. The polymers were analyzed by differential scanning calorimetry, Fourier transform infrared spectroscopy, and gel permeation chromatography, comparing the polymer granulate, virgin fibers, and UV-exposed fibers. It was found that the molecular mass and crystallinity of PBS changed more than PLA during spinning. Several PLA samples were completely degraded, whereas all the PBS samples remained intact. Furthermore, surface openings appeared on the PLA fibers during weathering, suggesting greater sensitivity to UV exposure and hydrolysis than PBS. A clear correlation between the fiber surface area and the degradation rate was observed for all samples, but the correlation was positive for PLA and negative for PBS. The slower degradation of PBS fibers with a larger surface area may reflect the ability of PBS to preserve itself by further crystallization during degradation processes at temperatures higher than the glass transition point. The data clearly show that the analysis of single degradation mechanisms is insufficient to predict the behavior of material under real-world conditions, where different degradation mechanisms may work in parallel or consecutively, and may show interdependencies.

Preparation of vanadium-titanium magnetite tailings/quartz sand monolithic composite and photocatalytic degradation of rhodamine B

This study focused on the preparation, characterization and photocatalytic performance of a monolithic composite made from vanadium-titanium magnetite tailings and quartz sand. Rhodamine B was used as a pollutant model and the photocatalytic degradation of rhodamine B by the prepared composites was investigated. The results indicated that the composite could effectively degraded Rhodamine B, achieving a degradation rate of 98 % within 20 min under optimal conditions. Investigations on the degradation mechanism revealed that dissolved oxygen, superoxide radicals, and the sensitization of Rhodamine B are crucial to the photocatalytic degradation process of Rhodamine B. These results suggest potential benefits for the comprehensive utilization of vanadium titanomagnetite tailings.

Electrochemical activation of periodate with graphite electrodes for degradation of high concentrations of thiocyanogen (SCN−) in mineral processing tail liquid

Cyanide has been widely used in gold extraction due to its cost-effectiveness, high selectivity and recovery. Regrettably, its wide application also leads to the presence of a large amount of thiocyanogen (SCN−) in the tail liquid of mineral processing plants, which affects the quality of the effluent water, and thus poses a threat to the ecological environment and human health. This paper investigates the degradation of high concentration of SCN− in water using electrochemical oxidation/periodate (E-GP/PI) system. A degradation rate of 90.25 % of SCN− was achieved by optimising various operating parameters. The effects of organic matter and typical heavy metal ion concentrations on the degradation of SCN− were investigated, and it was found that Cu2+ was able to promote the degradation of SCN− through the formation of stable complexes with SCN−, which enhanced the degradation rate to 96.48 %. However, the presence of Octadecyltrimethylammonium bromide (OTAB) and butylxanthin hindered the degradation process, where 500 mg/L of OTAB reduced the degradation rate of SCN− to 80.88 %, while 100 mg/L of butylxanthin reduced the degradation rate to 78.66 %. On this basis, experiments were carried out using real wastewater samples and SCN− degradation efficiencies of about 90 % were obtained. Afterwards, through electron paramagnetic resonance analysis, free radical burst, ion chromatograph and other research techniques, IO3 and O2– were obtained as the main drivers of SCN− degradation and SCN− degradation pathways were elucidated. Finally, the E-GP/PI system was shown to be effective in reducing the ecotoxicity of SCN− by increasing the 24-h LC50 from 12.5 % to 48.5 % in a toxicity test with daphnia. This study provides a new idea for the green and efficient treatment of SCN− rich beneficiation tail liquid.

Simple synthesis of K/P co-doped graphitic carbon nitride to enhance photocatalytic performance under simulated solar irradiation

The doping or co-doping of graphitic carbon nitride (g-C3N4) with other elements is a useful modification technique that overcomes the disadvantages of the base material and enhances its photocatalytic performance. In this study, K and P were successfully incorporated into g-C3N4 using a one-step, single-precursor (K2HPO4) synthesis method. The incorporation of K and P was confirmed using energy-dispersive X-ray spectrometry and wavelength-dispersive X-ray fluorescence spectrometry. Oxytetracycline (OTC) degradation rates were compared with and without elemental doping and with variation in the precursor content. In contrast to the low OTC degradation rate exhibited by pristine g-C3N4 (29.52 ± 0.03%), incorporating K and P into g-C3N4 greatly improved OTC degradation, with the sample produced using 100 mg of the precursor K2HPO4 (KPCN-100) achieving the highest degradation rate (99.43 ± 0.53%). The effects of the co-dopants K and P on the optical, photoelectrochemical properties, and band position of g-C3N4 were also investigated. Scavenging and N2 purging tests confirmed that reactive species, including O2•- (87.25%) and 1O2 (56.53%), played an important role in the degradation of OTC. In addition, several experimental parameters, including the presence of co-existing ions and humic acid, the pH level, the initial OTC concentration, and the photocatalyst dosage, were varied to better understand the photodegradation mechanisms at work within the KPCN-100 system. The stability of KPCN-100 and the toxicity assessment of the OTC intermediate were also conducted to evaluate their potential for environmental applications. Overall, this study demonstrates a simple synthesis method for the elemental co-doping of g-C3N4, offering an effective photocatalytic strategy that can greatly enhance the efficiency of OTC degradation.

SnO2 and Sn0.95M0.05O2 [M=Fe, Co and Cu] thin films: synthesis, characterization and photocatalytic activity

On discussed the relationship between the nature of dopant (Cu, Co, Fe)-SnO2 and their structural, morphological, optical, electrical, and photocatalysts characteristics. We prepared the films on glass substrates using the spray pyrolysis technique. Detailed analysis by X-ray diffraction (XRD) revealed that all obtained thin films crystallized in a rutile tetragonal structure. A homogeneous and compact surface with an important dimension of grains was revealed by observation (SEM) for the doped films. The transmittance spectra results indicated that the layers are dependent on the doping nature and that the doping leads to a broadening of the calculated bandgap. Lastly, the Seebeck coefficient rises from │76│for undoped SnO2 to │110│for Co-doping, │133│for Cu-doping, and declines with Fe- doping (│71│µV/K). While the concentration of carriers decreases by 1.96×10¹⁹, 9.80×10¹⁸, and 6. 66×10¹⁸ cm-³ for SnO2, Sn0.95Co0.05O2, and Sn0.95 Cu 0.05O2 thin films, respectively, and increased for Fe doping (6.17 ×10¹⁹ cm-³). These electrical properties indicated that the resistivity is affected by the nature of the doping. For the photocatalytic tests, the best performance was observed for samples Sn0.90Fe0.05 O2 (45% rate of degradation).

Enhanced bioremediation of bensulfuron-methyl contaminated soil by Hansschlegelia zhihuaiae S113: metabolic pathways and bacterial community structure

Bensulfuron-methyl (BSM), a widely used herbicide, can persist in soil and damag sensitive crops. Microbial degradation, supplemented with exogenous additives, provides an effective strategy to enhance BSM breakdown. Hansschlegelia zhihuaiae S113 has been shown to efficiently degrade this sulfonylurea herbicide. However, depending solely on a single strain for degradation proves inefficient and unlikely to achieve ideal remediation in practical applications. This study assessed the impact of various carbon sources on the degradation efficiency of S113 in BSM-polluted soil. Among these, glucose was the most effective, achieving a 98.7% degradation rate after 9 d of inoculation. In addition, seven intermediates were detected during BSM degradation in soil through the cleavage of the phenyl ring ester bond, the pyrimidine rings, and urea bridge peptide bond, among other pathways. 2-amino-4,6-dimethoxy pyrimidine (ADMP), and 2-(aminosulfonylmethyl)-methyl benzoate(MSMB) were the primary intermediates. These metabolites were less toxic to maize, sorghum, and bacteria than the BSM. Community structure analysis indicated that variations in exogenous carbon sources and environmental pollutants significantly improved the ecological functions of soil microbial communities, enhancing pollutant degradation. Addition of carbon sources notably affected soil microbial community structure, modifying metabolic activities and interaction patterns. Specifically, glucose substantially increased the richness and diversity of soil bacterial communities. These findings offer valuable insights for field remediation practices and contributed to the development of more robuste soil pollution management strategies.

Degradation of dioxins in chelated municipal solid waste incineration fly ash by low-temperature pyrolysis

In this study, low-temperature pyrolysis is applied to raw and chelated municipal solid waste incinerator fly ash to degrade and remove PCDD/F (polychlorinated dibenzo-p-dioxins, and dibenzofurans) and corresponding I-TEQs (international toxic equivalents), respectively. Additionally, PCDD/F degradation pathways are identified based on PCDD/F signatures. From the analysis of the average signal intensity of dioxin isomers in thermally treated fly ashes, the PCDD/F degradation rate was between 89.97 and 99.80 %, and the I-TEQs removal rate was 98.96 and 99.90% across all samples compared to untreated raw fly ash. The chelating agent EDTA enhanced the thermal degradation of PCDD/F, but the addition of Na2HPO4 in chelated fly ash as an inhibitor promoted PCDD/F regeneration. Further, there is a variable output of dioxins and corresponding I-TEQs under different temperatures and reaction times; however, longer reaction duration and higher temperatures proved highly effective. The overall toxicity of all thermally tested fly ashes was lesser than the permissible value of 50 ng I-TEQ/kg for resource utilization and observed in the range of 1.84 ± 0.15 to 19.45 ± 0.89 ng I-TEQ/kg. The investigation of the PCDD and PCDF signatures suggests that thermal destruction was a major pathway of degradation by breakage of the C-O bond, compared to dechlorination as observed by a high percentage contribution of HpCDD/F and OCDD/F congeners in thermally treated fly ashes. Low-temperature pyrolysis is an auspicious disposal technology that requires additional studies for large-scale applications.

Microalgae-bacterial consortiums for enhanced degradation of nonylphenol: Biodegradability and kinetic analysis

The widespread use of non-ionic surfactant nonylphenol (NP) has led to significant water pollution, posing a threat to both ecological stability and human health. However, the efficient biodegradation method and system of NP-biodegradation remain complex scientific challenges. In this study, we isolated and characterized three Pseudomonas sp. strains SW-1 (Scenedesmus quadricauda-associated), ZL-2 (Ankistrodesmus acicularis-associated), XQ-3 (Chlorella vulgaris-associated), and one NP-degrading Cupriavidus sp. strain EB-4, which exhibited the ability to utilize NP as the sole carbon source. Furthermore, four consortiums of microalgae-bacterial, S. quadricauda and SW-1 (S-SW), A. acicularis and ZL-2 (A-ZL), C. vulgaris and XQ-3 (C-XQ), S. quadricauda and EB-4 (S-EB), were constructed to investigate their biodegradability and kinetic characteristics of NP degradation from water. The consortiums showed higher degradation efficiency compared to individual microalgae or bacteria. The C-XQ consortium exhibited the highest degradation rate, removing over 94% of NP within just seven days. The first-order model with the following order of degradation rate by consortiums was C-XQ (0.3960 d−1) > S-SW (0.3506 d−1) > A-ZL (0.1968 d−1) > S-EB (0.1776 d−1). Compared with the results of our previous study, the interaction between microalgae and bacteria is not a simple additive relationship. Our findings highlight the potential of an algal-bacterial consortium for the remediation of NP-contaminated environments.

Synthesized CuO-PEI-JE with 3D open-cell structure as an efficient heterogeneous activator of peroxodisulfate for phenol degradation

The core of heterogeneous catalytic systems is to design high-performance heterogeneous catalysts. In the present study, CuO-PEI-JE was synthesized via in situ precipitation of CuO on the 3D structure of PEI-JE prepared by a cross-linking method. It possessed a macro-size and 3D open-cell structure, being easily separated and having super-performance for PDS activation. Compared to PDS alone (0.0017 min-1), the CuO-PEI-JE+PDS+NaHCO3 system increased the kobs (0.3526 min-1) by a factor of 207 with 100% phenol degradation within 20 min and 87% TOC removal at 30 min. It outperformed many other published heterogeneous persulfate systems in phenol degradation. Meanwhile, the developed system displayed a good anti-interference ability in the coexistence of anions or different water matrixes. After five successive cycles, the degradation rate still kept 100%, exhibiting the excellent reusability of CuO-PEI-JE. Furthermore, the preparation of CuO-PEI-JE had the advantages with moderate preparation conditions (60 °C) and readily available raw materials. The activation mechanism was mainly involved in the formation of active PDS and its further decomposition into ·OHads, SO4·-ads, O2·- and 1O2. Surface functional groups and phenol acted as electron donors for active PDS. Phenol was first degraded into hexadienedioic acid, then oxidized to propane diacid and oxalic acid, and finally mineralized into CO2 and H2O. This work provides a new strategy for preparing effective heterogeneous persulfate activators and has high potential for the treatment of phenol-containing wastewater.

Photocatalytic magnetic bimetallic ferrite synergistically activates ammonium persulfate for the efficient degradation of tetrachlorobisphenol A(TCBPA)

The presence of tetrachlorobisphenol A(TCBPA) in the environment is continually increasing, which has potential negative effects on human health. Therefore, it is important to develop new materials that can degrade these compounds using various modification techniques. Recently, the photocatalytic degradation of organic pollutants using peroxides has been widely used as the focus of several research studies. This study synthesized Zr-doped NiFe2O4 (Zr-NiFe2O4) metal complex materials using a co-precipitation method and applied them to catalyze the degradation of a typical halogenated bisphenol A pollutant using different phase-catalyzed peroxydisulfate (PS) compounds. The results showed that Zr-NiFe2O4 significantly enhances the nitrogen-active adaptive catalytic action between the reactive species and (NH4)2S2O8, exhibiting an excellent catalytic performance (99 %). The degradation rate could reach 90 % after 30 mins with the low concentration of TCBPA (20 mg•L–1). Furthermore, the degradation of TCBPA in the Zr-NiFe2O4/LED/(NH4)2S2O8 system occurred over a wide pH range of 3–11. The results of leaching metals were detected that the concentrations of the leached zirconium, nickel and iron ions declined to 0.018 mg•L−1. In addition, the tri-metal synergistic effect of Zr-NiFe2O4 not only significantly improved the TCBPA removal efficiency, but also enhanced the long-term stability of the composite material. Mechanistic studies revealed that ·OH and SO4·– were involved in the TCBPA degradation process with ·OH being the primary active species, and the possible degradation pathways were deduced using mass spectrometry. The on-line infrared test experiments showed the disappearance of the hydroxyl and double bond within approximately 120 seconds. Moreover, the magnetic properties of Zr-NiFe2O4 met the water recovery requirements, effectively reducing secondary pollution, and aligned with the practical needs for water treatment, providing data for the construction of efficient magnetic catalysts.

3D-printed porous calcium silicate scaffolds with hydroxyapatite/graphene oxide hybrid coating for guided bone regeneration

Calcium silicate (CS) is a suitable bone repair material due to its bioactivity and biocompatibility. However, its rapid degradation rate and poor cell response affect the bone regeneration process. Surface modification of implants represents a potent strategy for enhancing the performance of biomaterials. Here, we present a novel method combining hydrothermal treatment and chemical grafting to tailor the surface morphology and composition of 3D-printed calcium silicate porous scaffolds. The resulting scaffold surface features hydroxyapatite (HA) nanosheets and graphene oxide (GO) sheet structures. Surface modification significantly reduced the degradation rate of CS scaffolds and decreased the Si ion concentration after PBS immersion, which was more conducive to cell survival. Our findings reveal that the CS/HA/GO scaffold exhibits superior biocompatibility and significantly enhances cell adhesion, proliferation, and osteogenic differentiation. In vivo studies demonstrate that the CS/HA/GO scaffold markedly promotes the regeneration of defective bone tissue. This work highlights the potential of HA and GO coatings on interconnected porous scaffolds to induce bone tissue regeneration, offering a promising strategy for orthopedic applications.

2D MXene nanosheet dispersed Mn, Ru NPs loaded Ti composite electrodes for electrocatalytic synergistic degradation of antibiotics in high-salt mariculture wastewater

In this study, a composite electrode based on etched TiO2 nanotube arrays and two-dimensional (2D) MXene nanosheets was successfully designed for efficient degradation of antibiotics in mariculture wastewater. The composite electrode effectively dispersed Mn and Ru nanoparticles (NPs) by introducing 2D MXene nanosheets as an intermediate layer, which significantly enhanced the catalytic performance. The bifunctional properties of Mn and Ru NPs in catalysis and the contribution of d-orbital electrons to the formation of metal‑hydrogen bonds were revealed in depth by analyzing the electron transfer mechanism at the electrodes. The experimental results demonstrated a synergistic catalytic effect between Mn and Ru bimetals and MXene, resulting in an effective increase in the degradation rate. Under the optimal conditions, the degradation rate of Tetracycline (TC) by Mn/Ru/MXene/Ti composite electrode could reach 90.69 % in 60 min. In addition, it still shows excellent stability after 45 days of air exposure, 10 cycling experiments, and 10,000 s of timed current testing. Mechanistic studies have demonstrated that anode hydroxyl radical (·OH), HClO, and cathode activated hydrogen atoms (H*) all play catalytic roles in the degradation process. The degradation pathways were analyzed using density-functional theory (DFT) calculations and liquid-liquid-mass spectrometry (LC-MS) techniques, with further experiments confirming that this degradation process effectively reduces the biotoxicity of intermediate products, improving the safety of wastewater discharge. Finally, we designed the reactor and calculated the energy consumption to verify the feasibility and economy of the system in practical applications. This research proposes a novel multi-metal co-catalysis and cathode and anode co-catalysis system for the efficient degradation of antibiotics in mariculture wastewater, with potential applications in the electrocatalytic degradation of antibiotics.

Measurement of Acrylamido Tertiary Butyl Sulfonate Polymer Retention on Limestone by Three Methods Under Varying Temperature and Oil Presence

Summary Polymer retention poses a significant challenge in polymer flooding applications, emphasizing the importance of accurately determining retention levels for successful project design. In carbonate reservoirs of the Middle East, where temperatures exceed 90°C, conducting adsorption tests under similar temperature conditions becomes crucial for the precise determination of adsorption values. The choice of analytical method potentially impacts the accuracy of retention measurements from effluent analysis. This study investigates the effect of temperature on the performance of a polymer, specifically its rheological behavior and retention. Rheological and polymer flooding experiments were carried out using an acrylamido tertiary butyl sulfonate (ATBS)-based polymer in formation water (167,114 ppm) at different temperatures (25°C, 60°C, and 90°C) with required oxygen control measures. Dynamic polymer retention was conducted in both the absence of oil (single-phase tests) and the presence of oil (two-phase tests). In addition, different analytical techniques were evaluated, including viscosity measurements, ultraviolet (UV)-visible spectroscopy, and total organic carbon-total nitrogen (TOC-TN) analysis, to determine the most accurate method for measuring the polymer concentration with the least associated uncertainty. Furthermore, the study investigates the effects of these uncertainties on the final dynamic polymer retention values by applying the propagation of error theory. The effluent polymer concentration was determined using viscosity correlation, UV spectrometry, and TOC-TN analysis, all of which were reliable methods with coefficient of determination (R2) values of ~0.99. The study analyzed the effects of flow through porous media and backpressure regulator on polymer degradation. The results showed that the degradation rates were around 2% for flow through porous media and 16% for mechanical degradation due to the backpressure regulator for all temperature conditions. For the effluent sample, the concentration of polymer was lower when using the viscosity method due to polymer degradation. However, the TOC-TN and UV methods were unaffected as they measured the TN and absorbance at a specific wavelength, respectively. Therefore, all viscosity results were corrected for polymer degradation effects in all tests. During the two-phase coreflooding experiment conducted at 25°C, the accuracy of the UV spectrometry and viscosity measurements was affected by the presence of oil, rendering these methods unsuitable. However, the TOC-TN measurements were able to determine effluent polymer concentration and, subsequently, the retention value. Moreover, the use of glycerin preflush to inhibit oil production during polymer injection in the two-phase studies showed that all three methods were appropriate. The error range was obtained using the propagation of error theory for all the methods. Accordingly, it was noted that the temperature did not affect the dynamic retention values in both single-phase and two-phase conditions. The findings of this study highlight that when adequate oxygen control measures are implemented, the temperature does not exhibit a statistically significant impact on the retention of the ATBS-based polymer under investigation. Furthermore, TOC-TN has been identified as the optimal analytical method due to its minimal uncertainties and ease of measuring polymer concentration under varying experimental conditions.

Photocatalyst for Antibiotics Degradation by In Situ Growth of Direct Z-Type Bi2S3/Bi4Ti3O12 Heterojunction.

Effective removal of antibiotics from aqueous solutions has emerged as a hot research topic in wastewater treatment. Photocatalytic degradation of antibiotics is one of the most effective methods to reduce ecological damage and environmental pollution. In this work, a novel photocatalyst consisting of Z-type heterojunction Bi2S3/Bi4Ti3O12 (BS/BTO) with visible light responses was prepared by an in situ growth method, and the obtained material was used for the degradation of tetracycline hydrochloride (TC). The best performing photocatalyst was BS/BTO-2, which exhibited high photocatalytic activity. The rates of TC degradation reached 97.9% within 40 min of illumination. The photocatalyst demonstrated a high stability and reproducibility even after 5 cycles. Electron spin resonance (EPR) tests and quenching experiments established that ·O2- and h+ were the main species responsible for the elimination of TC. On the basis of theoretical calculations and experimental data, a possible mechanism for the photocatalytic degradation of TC has been proposed. The heterojunction structure, which effectively increases the visible light absorption range and decreases the compounding efficiency of photogenerated electrons and holes, is principally responsible for the photocatalytic performance of BS/BTO. Additionally, liquid chromatography-mass spectrometry (LC-MS) was utilized to investigate the formation and degradation of reaction intermediates. The nontoxicity of the solution after tetracycline degradation was verified by cultivating wheat seeds. This work offers guidance for bismuth-based photocatalysts in the field of sustainable wastewater treatments.

Bioresorbable composites based on magnesium and hydroxyapatite for use in bone tissue engineering: focus on controlling and minimizing corrosion activity

A biodegradable matrix with a significant content of bioactive components can be applied for bone tissue replacement, including load-bearing applications in orthopedic surgery. The study outlines the optimized procedure for the production of bioresorbable magnesium-hydroxyapatite (Mg-HA) composites and their corrosion resistance properties. Composites were meticulously crafted by combining pure magnesium with microwave-synthesized hydroxyapatite nanopowder. Sintering occurred via spark plasma sintering technology (SPS). To align the degradation time of the resulting composites with bone remodeling, the corrosion resistance of SPS materials was enhanced through the application of plasma electrolytic oxidation (PEO) and polycaprolactone (PCL) spin-coating methods. The protective properties, morphology dynamics, and composition due to surface treatment and corrosion propagation were investigated using Electrochemical Impedance Spectroscopy (EIS), Potentiodynamic Polarization (PDP), hydrogen evolution tests, Scanning Electron Microscopy (SEM), Energy-dispersive X-ray (EDX) as well as X-ray diffraction (XRD) analysis. Analytics of the physicochemical properties data of the formed coatings indicate a significant improvement in protective characteristics and deceleration of the corrosive degradation of the samples. The application of polycaprolactone to the PEO coating leads to a decrease in the corrosion current compared to uncoated magnesium composites by more than three orders of magnitude: from 1 10-5 to 2 10-9 A cm-2. During long-term exposure of samples to 0.9 % NaCl solution, it was found that coating reduced the rate of corrosion degradation of samples from 1.5 to 80 times compared to an unprotected Mg-HA composite and sintered magnesium. Mg-HA composites treated with PEO exhibit potential application as bioactive and biodegradable materials for orthopedic implants and fixation devices.

Quickly UV-curing protective coating for cotton fabrics

In order to eliminate the numerous limitations in application of cotton fibers, we designed and made a protective coating that changes many features of these material (such as water repellency or reducing the rate of thermal degradation), but does not change its natural flexibility and macroscopic appearance. The coating we developed consists a UV-crosslinked polysiloxanes together with organophosphates. The coating preparation process takes only a few minutes and takes place easily at room temperature. Even a very subtle layer of such a coating makes the fabric highly hydrophobic, and with greater occupancy, it significantly slows down thermal degradation and reduces the flammability of fabrics. A very interesting phenomenon observed by us is also the fact that the thicker the coating layer, the worse hydrophobic properties have been observed. The resulting coating is resistant to washing with both clean water and water with detergents.

Assessing the Soil Infiltration Rate of Alpine Meadows Using the Electrolyte Tracer Method

ABSTRACTGrassland on the Qinghai‐Tibet Plateau is highly susceptible to climate change and human activities, and vegetation degradation can affect biodiversity and soil erosion. Soil infiltration is a crucial water flow process that determines the amount of runoff and water storage capacity, and it is of great importance in maintaining biodiversity. This research investigated the effects of vegetation degradation and soil rates on soil infiltration rate and processes using the electrolyte tracer method. This technique accurately calculated soil infiltration rate by tracking continuous changes in the solute concentration change process throughout the experimental period and did not require calibration. Findings indicate that vegetation type, root mass, soil water content and soil porosity significantly affect soil infiltration rate. In particular, root mass was found to have a negative effect on soil infiltration rate. Soil moisture content initially dominated soil infiltration, but subsequently, soil porosity became increasingly influential in affecting infiltration in degraded meadow. Soil infiltration capacity varied more with vegetation type than with surface runoff. Shrub meadows had the highest infiltration rate followed by normal alpine meadows and degraded meadows, indicating the importance of vegetation on soil infiltration. The research also shows that mixed shrub and meadow can improve the ecological environment by introducing a more complex root system and increasing the infiltration rate. The electrolyte tracer method was used as an alternative to other methods that can be used in different environments than the one studied in this research.