Efficient Decomposition Research Articles

Removal of per- and polyfluoroalkyl substances from water by plasma treatment: Insights into structural effects and underlying mechanisms

Non-thermal plasma emerges as a promising technology for per- and polyfluoroalkyl substances (PFAS) decomposition due to its notable efficacy and environmentally friendly characteristics. In this study, we demonstrated the efficacy of a falling film dielectric barrier discharge (DBD) system for the removal of 10 PFAS, including perfluoroalkyl carboxylic acids (PFCAs), perfluoroalkyl sulfonic acids (PFSAs) and hexafluoropropylene oxide (HFPO) oligomer acids. Results showed that compounds with fluoroalkyl chain length>4 were effectively decomposed within 100 min, with long-chain PFAS demonstrating more pronounced removal performance than their short-chain analogues. The superior removal but low defluorination observed in HFPO oligomer acids could be ascribed to their ether-based structural features. The integration of experimental results with density functional theory (DFT) calculations revealed that the synergistic effects of various reactive species are pivotal to their efficient decomposition, with electrons, OH•, and NO2• playing essential roles. In contrast, the degradation of PFSAs was more dependent on electron attack than that of PFCAs and HFPO oligomer acids. Significantly, the most crucial degradation pathway for HFPO oligomer acids was the cleavage of ether CO, whether through radical or electron attack. Furthermore, the demonstrated effective removal in various water matrices showed the potential of the plasma system for removing PFAS in complex aquatic environments. This study provided mechanistic insights into PFAS degradation behavior in plasma processes, and it underscored the vital influence of molecular structures on degradability, thereby contributing to the further development and regulation of plasma-based technologies for treating PFAS in water.

Enhanced watershed model evaluation incorporating hydrologic signatures and consistency within efficient surrogate multi-objective optimization

This paper presents a new framework for calibrating computationally expensive watershed models with multi-objective optimization methods and hydrological consistency analysis. The analysis evaluates different algorithms' efficiencies for finding watershed model calibration solutions within a limited budget. Two surrogate multi-objective algorithms GOMORS and ParEGO are compared to five evolutionary algorithms without surrogates on two watershed models. We test the algorithms’ performance with two multi-objective formulations (i.e., threshold-based flow separation and decomposition of the Nash-Sutcliffe Efficiency (NSE)). Results indicate that the surrogate-based GOMORS is the most computationally efficient overall. We also propose a framework to select among the calibration solutions obtained from multi-objective optimization using different hydrologic signatures. GOMORS is assessed for its ability to identify hydrologically acceptable calibrations. The decomposition of NSE is the most effective calibration formulation in terms of hydraulic consistency analysis. In addition, hydrologic signatures could be used effectively to filter non-dominated solutions obtained from multi-objective optimization.

Highly efficient micropollutant decomposition by ultrathin amorphous cobalt-iron oxide nanosheets in peroxymonosulfate-mediated membrane-confined catalysis

Applications of advanced oxidation processes (AOPs) in water treatment require addressing technological challenges such as developing low-cost techniques for nanocatalyst synthesis, overcoming mass transfer limitations, and enhancing the yield of reactive oxygen species (ROS). This study employs a simple sodium borohydride (NaBH4)-based reduction technique for synthesizing ultrathin amorphous cobalt-iron oxide nanosheets (A/Co3-Fe ONS) to activate peroxymonosulfate (PMS). These nanosheets were found to outperform crystalline nanosheets due to their abundant reactive sites, oxygen vacancies, and capability to produce ROS through O–O and S–O bond cleavage. Due to the nanoconfinement effect, converting A/Co3-Fe ONS into a lamellar membrane significantly enhances reactivity and efficacy (1290 times) compared to batch PMS-mediated AOP reactors. Quenching experiments, solid-state and solution-based electron paramagnetic resonance (EPR) spectroscopy facilitated delineation of the reaction mechanisms involving both radical and nonradical pathways. Finally, the A/CoFeOx membrane achieved efficient removal (>95 %) of various organic micropollutants (OMPs), ultrafast destruction (318 ms), and excellent stability (48 h) through redox-recycling facilitated by the redox-potential difference and oxygen vacancies. This strategy offers a low-temperature cost-effective alternative and may be considered for scale-up in water treatment.

Mathematical Programming-Driven Daily Berth Planning in Xiamen Port

In this paper, we introduce the daily berth planning problem for Xiamen Hai-Tian Container Terminal (XHCT) at the Port of Xiamen, China, and propose the development and implementation of a berth planning system. The aim of the berth planning problem is to optimize daily berth plans by considering various decisions, including berth allocation, quay crane assignment, fairway traffic control, and berthing safety requirements. Among these decisions, the berthing safety requirement is a novel but practical problem in berth allocation that concerns the resource allocation related to berthing safety and interrelation with other decisions. A mathematical programming-driven methodological framework is designed with a 0-1 integer linear programming model for problem formulation and a highly efficient decomposition heuristic algorithm for solving the problem. This framework establishes the core for the berth planning system. The adoption of the berth planning system contributes to the increase of container throughput and berth capacity by transforming the planning process of XHCT. Moreover, the mathematical programming-driven daily berth planning informs further intelligent operations development in the Port of Xiamen and other container ports. History: This paper was refereed. Funding: This research was supported by the National Natural Science Foundation of China [Grants 72394360, 72394362, 72025103, 71831008, 72361137001, 72071173, and 72371221].

Efficient Decomposition of Perfluoroalkyl Substances by Low Concentration Indole: New Insights into the Molecular Mechanisms

Efficient Decomposition of Perfluoroalkyl Substances by Low Concentration Indole: New Insights into the Molecular Mechanisms

Measurement and decomposition of profit efficiency under alternative definitions in nonparametric models

Measurement and decomposition of profit efficiency under alternative definitions in nonparametric models

Deposition of vertical carbon nanostructures by microwave plasma source on nickel and alumina

Vertical carbon nanostructures on metal and ceramic substrates are deposited successfully using planar microwave plasma source at frequency of 2.45 GHz. The PECVD (Plasma Enhanced Chemical Vapor Deposition) with microwave surface wave discharge is applied because it produces a dense plasma providing efficient decomposition of the methane and creation of a large number of reactive particles which results in lower substrate temperature for graphene deposition compared to CVD method. Optimization of the gas mixture of H2, Ar and CH4, and the gas pressure in the chamber results in a homogeneous graphene structures deposition on the substrates of Ni-foil, Ni-foam and alumina ceramics at substrate temperatures ∼600 °C. The plasma parameters of surface wave discharge such as gas temperature, electron temperature and density are obtained by measuring OH-band and Ar-lines using optical emission spectroscopy. The morphology of the vertical carbon structures is obtained using SEM analysis and the characteristics of the graphene layers were determined by Raman spectroscopy.

Effects of an efficient straw decomposition system mediated by Stropharia rugosoannulata on soil properties and microbial communities in forestland

Cultivation of Stropharia rugosoannulata with straw in forestland is effective for straw biodegradation and can prevent the waste of straw resources and environmental pollution and generate economic benefits. However, there is a lack of systematic evaluation of spent mushroom substrate (SMS) input into forestland, such as soil properties and microbial succession. In this experiment, 0 (CK), 10 (SA), 20 (SB), 30 (SC), 40 (SD), and 50 (SE) kg/m2 straw were used to cultivate S. rugosoannulata, and two soil layers (0–10 cm, 10–20 cm) of the cultivated forestland were analyzed. The results indicated that SMS significantly promoted nutrient accumulation in forestland. The bacterial alpha diversity in the SC treatment group was greater than that in the control and gradually decreased to the control level with interannual changes, while the trend of fungal alpha diversity was opposite to that of bacterial alpha diversity. Furthermore, the SC treatment group positively affected soil nitrogen metabolism-related microorganisms for two consecutive years and significantly promoted tree growth. Habitat niche breadth and null model analysis revealed that bacterial communities were more sensitive than fungal communities after SMS input. Linear mixed model (LMM) analysis revealed that SMS supplementation significantly positively affected bacteria (Gammaproteobacteria and Bacteroidota) and significantly negatively affected fungi (Coniochaetales). The constructed fungal-bacterial co-occurrence networks exhibited modularity, and the five types of bacteria were significantly correlated with soil organic matter (SOM), soil organic carbon (SOC), available potassium (AK), available phosphorus (AAP) and available nitrogen (AN) levels. The structural equation model (SEM) showed that bacterial diversity responded more to changes in soil nutrients than did fungal diversity. Overall, 30 kg/m2 of straw decomposition and 2 years of continuous cultivation were beneficial to soil health. This study provides new insights into the rational decomposition of straw and maintenance of forestland ecological balance by S. rugosoannulata.

Boosting N2O Catalytic Decomposition by the Synergistic Effect of Multiple Elements in Cobalt-Based High-Entropy Oxides.

Nitrous oxide (N2O) has a detrimental impact on the greenhouse effect, and its efficient catalytic decomposition at low temperatures remains challenging. Herein, the cobalt-based high-entropy oxide with a spinel-type structure (Co-HEO) is successfully fabricated via a facile coprecipitation method for N2O catalytic decomposition. The obtained Co-HEO catalyst displays more remarkable catalytic performance and higher thermal stability compared with single and binary Co-based oxides, as the temperature of 90% N2O decomposition (T90) is 356 °C. A series of characterization results reveal that the synergistic effect of multiple elements enhances the reducibility and augments oxygen vacancy in the high-entropy system, thus boosting the activity of the Co-HEO catalyst. Moreover, density functional theory (DFT) calculations and the temperature-programmed surface reaction (TPSR) with isotope labeling demonstrate that N2O decomposition on the Co-HEO catalyst follows the Langmuir-Hinshelwood (L-H) mechanism with the promotion of abundant oxygen vacancies. This work provides a fundamental understanding of the synergistic catalytic effect in N2O decomposition and paves the way for the novel environmental catalytic applications of HEO.

Electron Redistribution in Iridium-Iron Dual-Metal-Atom Active Sites Enables Synergistic Enhancement for H2O2 Decomposition.

Developing efficient heterogeneous H2O2 decomposition catalysts under neutral conditions is of great importance in many fields such as clinical therapy, sewage treatment, and semiconductor manufacturing but still suffers from low intrinsic activity and ambiguous mechanism understanding. Herein, we constructed activated carbon supported with an Ir-Fe dual-metal-atom active sites catalyst (IrFe-AC) by using a facile method based on a pulsed laser. The electron redistribution in Ir-Fe dual-metal-atom active sites leads to the formation of double reductive metal active sites, which can strengthen the metal-H2O2 interaction and boost the H2O2 decomposition performance of Ir-Fe dual-metal-atom active sites. Ir-Fe dual-metal-atom active sites show a high second-order reaction rate constant of 3.53 × 106 M-1·min-1, which is ∼106 times higher than that of Fe3O4. IrFe-AC is effective in removing excess intracellular reactive oxygen species, protecting DNA, and reducing inflammation under oxidative stress, indicating its therapeutic potential against oxidative stress-related diseases. This study could advance the mechanism understanding of H2O2 decomposition by heterogeneous catalysts and provide guidance for the rational design of high-performance catalysts for H2O2 decomposition.

Efficient Direct Decomposition of NO over La0.8A0.2NiO3 (A=K, Ba, Y) Catalysts under Microwave Irradiation

Efficient Direct Decomposition of NO over La0.8A0.2NiO3 (A=K, Ba, Y) Catalysts under Microwave Irradiation

Superior visible-light absorbing Ag@ZnO nanorods hybrid photocatalyst for efficient decomposition of commercial pharmaceuticals tetracycline and amoxicillin

This work assesses the role of the noble metal silver in the visible-light sensitization of UV-active ZnO by introducing a localized plasmonic resonance effect and enhancing the spatial charge carrier separation. We herein synthesize ZnO nanorods via a solvothermal approach, yielding nanorods of length and diameter 1.356 ± 0.619 μm and 120.56 ± 25.09 nm, respectively. Silver nanoparticles are reduced on the surface of ZnO nanorods via the photodeposition route. XRD spectra reveal a high crystallinity and wurtzite-type structure for ZnO with new peaks for cubic phase Ag upon Ag-loading. The diffraction peaks shift upon Ag modification, indicating partial incorporation of Ag into the ZnO lattice. Further, upon Ag-decoration, a slight increase in dislocation density and micro strain is obtained, which could suppress the recombination rate of charge carriers. The DRS spectra reveal a band gap contraction of materials from 3.19 to 2.98 eV with increasing Ag density. The PL spectra confirmed that the optimum Ag concentration of 3 wt% is proficient in harvesting visible light towards high photocatalytic degradation efficiencies of tetracycline (92.1 %) and amoxicillin (76.4 %) in 90 min as compared to 49.4 % and 38 % over pristine ZnO nanorods. TOC studies reveal only partial mineralization of ∼42.7 % (tetracycline) and ∼31.3 % (amoxicillin) due to the formation of reaction intermediates identified by HR-MS chromatograms. In addition, degradation pathways are proposed through the fragments at different m/z ratios.

Immobilization of recombinant Trametes versicolor aflatoxin B1-degrading enzyme (TV-AFB1D) with montmorillonite for absorption and in situ degradation of aflatoxin B1.

Aflatoxin B1 is a highly carcinogenic and teratogenic substance mainly produced by toxin-producing strains such as Aspergillus flavus and Aspergillus parasitic. The efficient decomposition of aflatoxin is an important means to reduce its harm to humans and livestock. In this study, Trametes versicolor aflatoxin B1-degrading enzyme (TV-AFB1D) was recombinantly expressed in Bacillus subtilis (B. subtilis) 168. MMT-CTAB-AFB1D complex was prepared by the immobilization of TV-AFB1D and montmorillonite (MMT) by cross-linking glutaraldehyde. The results indicated that TV-AFB1D could recombinantly express in engineered B. subtilis 168 with a size of approximately 77kDa. The immobilization efficiency of MMT-CTAB-AFB1D reached 98.63% when the concentration of glutaraldehyde was 5% (v/v). The relative activity of TV-AFB1D decreased to 72.36% after reusing for 10 times. The content of AFB1 in MMT-CTAB-AFB1D-AFB1 decreased to 1.1µg/g from the initial 5.6µg/g after incubation at 50°C for 6h. The amount of 80.4% AFB1 in the MMT-CTAB-AFB1D-AFB1 complex was degraded by in situ catalytic degradation. Thus, the strategy of combining adsorption and in situ degradation could effectively reduce the content of AFB1 residue in the MMT-CTAB-AFB1D complex.

Efficient Photocatalytic Decomposition of Acid Blue 25 Dye using Facilely Synthesized Magnesium Aluminate Nanoparticles

Efficient Photocatalytic Decomposition of Acid Blue 25 Dye using Facilely Synthesized Magnesium Aluminate Nanoparticles

Highly efficient photocatalytic decomposition of triazophos using novel In2O3/WO3 nanocomposites with oxygen defects and S-Scheme heterojunctions

Confronted with the substantial environmental threat posed by organophosphorus pesticides, the urgency to develop reliable and efficient mitigation strategies is paramount. Photocatalytic technology, which catalyzes the generation of potent oxidizing radicals, emerges as a promising solution. In this study, we have successfully synthesized In2O3/WO3 (IO/WO) nanocomposites, endowed with oxygen defects and S-scheme heterojunctions, exhibiting exceptional photocatalytic degradation activity and mineralization efficiency. Notably, the WO material synthesized in this study is blue in color, unlike the traditional yellow color of WO, indicating a rich presence of oxygen defects. The 60-IO/WO nanocomposite, containing 60 % IO, achieved superior photocatalytic degradation, reducing triazophos pesticide from 100 % to 21.29 % within 60 min, outperforming the individual materials IO (56.97 %) and WO (48.02 %). This nanocomposite also exhibited remarkable corrosion resistance across multiple cycles, showcasing significantly enhanced stability compared to the individual IO and WO materials. Electron paramagnetic resonance (EPR) spectroscopy confirmed the presence of oxygen defects in the blue WO, while both EPR and theoretical calculations substantiated the formation of the S-scheme heterojunction in the 60-IO/WO nanocomposite. The new nanocomposite's excellent photocatalytic degradation activity is influenced by various factors such as differing surface areas, composite amounts, photocurrent responses, and resistances, all of which impact the degradation performance of triazophos. Compared to traditional photocatalytic materials, the IO/WO nanocomposite demonstrates a significant edge in photocatalytic efficiency and chemical stability, offering considerable potential for environmental remediation, especially in the degradation of organophosphorus pesticides.

Binary Ce-doped-ZnO/rGO composite as excellent photocatalyst for bromothymol blue dye degradation

Organic contaminants pose a grave danger to both the surroundings and public health, which emphasizes the urgent need for efficient decomposition techniques. Building a composite and adding a cocatalyst can both enhance the transfer of photogenerated electrons, which are useful strategies to increase photocatalytic efficiency. This study sought to synthesize cerium–doped ZnO–rGO nanoparticles with varying concentrations of Ce for visible–light photocatalytic degradation of bromothymol blue dye in water. The synthesized photocatalysts were characterized using transmission electron microscopy, x–ray diffraction, ultraviolet–visible spectrophotometry, energy dispersive spectroscopy, and scanning electron microscopy. The results disclosed that the photoactivity of the 0.6% Ce–ZnO–rGO was the highest and degraded 92% of bromothymol blue dye under visible light within 180 min (k = 1.072 ×10–2 min–1) compared to the pristine ZnO which only degraded the dye by about 22% (k = 1.15 ×10−3 min−1). The band gap of the pure ZnO was estimated to be 3.09 eV and that of the best performing composite (0.6% Ce) to be 2.81 eV which we suggest are responsible for the improved photodegradation. The pseudo–first–order photocatalytic kinetic has a strong correlation value of 0.99. The Ce–ZnO–rGO composites offer a lot of potential for cleaning the environment.

Superefficient non-radical degradation of benzo[a]pyrene in soil by Fe-biochar composites activating persulfate

Efficient decomposition of organic pollutants in complex soil environments through non-radical pathways is vital but challenging. Herein, biochar supported nZVI (nZVI@BC800) fabricated by carbothermal reduction method was prepared for persulfate activation, exhibiting ultrafast degradation efficiency of benzo[a]pyrene of 71.80 % within 5 min with excellent adaptability to wide pH range of 3.0–9.0 and high anti-interference capacity to coexisting substances in soil. In nZVI@BC800/persulfate system, non-radical pathways including singlet oxygen (1O2) and electron transfer made dominant contributions to benzo[a]pyrene degradation. 1O2 could be produced not only by the reaction between C = O on BC800 and persulfate, but also via the transformation of O2∙- and ∙OH. On the other hand, biochar as an electron shuttle could accelerate electron transfer from benzo[a]pyrene to persulfate adsorbed on the catalyst. Additionally, possible degradation pathways of benzo[a]pyrene in nZVI@BC800/persulfate system were inferred through GC–MS and DFT calculations. Furthermore, the system could modulate the soil microbial community to further improve plant stress resistance. Therefore, this study provided a promising strategy via developing carbon-supported iron catalyst for carrying out persulfate-based non-radical pathways to remediate organic-polluted soil.

Measurement and decomposition of environmental efficiency in the power industry based on multi-hierarchy meta-frontier BAM model

The improvement of the environmental efficiency in the power industry is crucial in promoting energy conservation and emission reduction to achieve sustainable development. This study constructs a multi-hierarchy meta-frontier BAM model to measure environmental efficiency considering technological and regional heterogeneity. Using this model, we measure and decompose the environmental efficiency of the power industry in 30 Chinese provinces during 2008–2020. The main results are as follows. (1) Beijing and four other provinces have the highest environmental efficiency among the high-technology group, while Jiangsu and Hainan have the highest environmental efficiency among the medium-technology and low-technology groups, respectively. There are significant differences in environmental efficiency among provinces within each technology group. (2) Regional and technical inefficiencies in the high-technology and medium-technology groups are the main factors influencing inefficiency. However, the inefficiency of the low-technology group is 0.36, while technical inefficiency is 0.34. (3) The environmental efficiency of all three technical groups has improved as a result of technological progress. Environmental efficiency improvement is the largest in the high-technology group but only by 1%. This study extends conventional approaches of environmental efficiency assessment and enhances the comprehension of the operation of the power industry in various Chinese provinces. The research outcomes provide insights for formulating more precise and effective strategies towards the sustainable evolution of China's power sector.

Image Super-Resolution via Efficient Transformer Embedding Frequency Decomposition With Restart.

Recently, transformer-based backbones show superior performance over the convolutional counterparts in computer vision. Due to quadratic complexity with respect to the token number in global attention, local attention is always adopted in low-level image processing with linear complexity. However, the limited receptive field is harmful to the performance. In this paper, motivated by Octave convolution, we propose a transformer-based single image super-resolution (SISR) model, which explicitly embeds dynamic frequency decomposition into the standard local transformer. All the frequency components are continuously updated and re-assigned via intra-scale attention and inter-scale interaction, respectively. Specifically, the attention in low resolution is enough for low-frequency features, which not only increases the receptive field, but also decreases the complexity. Compared with the standard local transformer, the proposed FDRTran layer simultaneously decreases FLOPs and parameters. By contrast, Octave convolution only decreases FLOPs of the standard convolution, but keeps the parameter number unchanged. In addition, the restart mechanism is proposed for every a few frequency updates, which first fuses the low and high frequency, then decomposes the features again. In this way, the features can be decomposed in multiple viewpoints by learnable parameters, which avoids the risk of early saturation for frequency representation. Furthermore, based on the FDRTran layer with restart mechanism, the proposed FDRNet is the first transformer backbone for SISR which discusses the Octave design. Sufficient experiments show our model reaches state-of-the-art performance on 6 synthetic and real datasets. The code and the models are available at https://github.com/catnip1029/FDRNet.

α-MnO2 catalysts with efficient ozone-catalyzed decomposition under high humidity conditions

α-MnO₂ catalysts with efficient ozone-catalyzed decomposition under high humidity conditions