Circumventing bottlenecks in H2O2 photosynthesis over carbon nitride with iodine redox chemistry and electric field effects.

Artificial photosynthesis using carbon nitride (g-C3N4) holds a great promise for sustainable and cost-effective H2O2 production, but the high carrier recombination rate impedes its efficiency. To tackle this challenge, we propose an innovative method involving multispecies iodine mediators (I-/I3-) intercalation through a pre-photo-oxidation process using potassium iodide (suspected deteriorated "KI") within the g-C3N4 framework. Moreover, we introduce an external electric field by incorporating cationic methyl viologen ions to establish an auxiliary electron transfer channel. Such a unique design drastically improves the separation of photo-generated carriers, achieving an impressive H2O2 production rate of 46.40 mmol g-1 h-1 under visible light irradiation, surpassing the most visible-light H2O2-producing systems. Combining various advanced characterization techniques elucidates the inner photocatalytic mechanism, and the application potential of this photocatalytic system is validated with various simulation scenarios. This work presents a significative strategy for preparing and applying highly efficient g-C3N4-based catalysts in photochemical H2O2 production.

Buffer-free ozone-ferrate(VI) systems for enhanced oxidation of electron-deficient contaminants: Synergistic enhancement effects, systematic toxicity assessment, and practical applications.

The combination of ozone (O3) and ferrate (Fe(VI)) oxidation technology demonstrates substantial potential for practical applications, though it has been underreported, resulting in gaps in comprehensive activity assessments and thorough exploration of its mechanisms. This study reveals that the previous use of a borate buffer solution obscured certain synergistic reactions between O3 and Fe(VI), causing a reduction of activity by ∼40 % when oxidizing the electron-deficient pollutant atrazine. Consequently, we reassessed the activity and mechanisms using a buffer-salt-free O3/Fe(VI) system. Our findings showed that the hydroxyl radical (·OH) served as the predominant active species, responsible for an impressive 95.9 % of the oxidation activity against electron-deficient pollutants. Additional experiments demonstrated that the rapid production of neglected and really important superoxide radicals (·O2-) could facilitate the decomposition of O3 to generate ·OH and accelerate the reduction of Fe(VI) to Fe(V), reactivating O3 to produce ·OH anew. Intriguingly, as the reaction progressed, the initially depleted Fe(VI) was partially regenerated, stabilizing at over 50 %, highlighting the significant potential of this combined system. Moreover, this combined system could achieve a high mineralization efficiency of 80.4 % in treating actual coking wastewater, complemented by extensive toxicity assessments using Escherichia coli, wheat seeds, and zebrafish embryos, showcasing its robust application potential. This study revisits and amends previous research on the O3/Fe(VI) system, providing new insights into its activity and synergistic mechanisms. Such a combined technology has potential for the treatment of difficult-to-degrade industrial wastewater.

Direct Electron Transfer-Driven Nontoxic Oligomeric Deposition of Sulfonamide Antibiotics onto Carbon Materials for In Situ Water Remediation.

The rising in situ chemical oxidation (ISCO) technologies based on polymerization reactions have advanced the removal of emerging contaminants in the aquatic environment. However, despite their promise, uncertainties persist regarding their effectiveness in eliminating structurally complex contaminants, such as sulfonamide antibiotics (SAs). This study elucidated that oligomerization, rather than mineralization, predominantly governs the removal of SAs in the carbon materials/periodate system. The amine groups in SAs played a crucial role in forming organic radicals and subsequent coupling reactions due to their high f- index and low bond orders. Moreover, the study highlighted the robust adhesion of oligomers to the catalyst surface, facilitated by enhanced van der Waals forces and hydrophobic interactions. Importantly, plant and animal toxicity assessments confirmed the nontoxic nature of oligomers deposited on the carbon material surface, affirming the efficacy of carbon material-based ISCO in treating contaminated surface water and groundwater. Additionally, a novel classification approach, Δlog k, was proposed to differentiate SAs based on their kinetic control steps, providing deeper insights into the quantitative structure-activity relationship (QSAR) and facilitating the selection of optimal descriptors during the oligomerization processes. Overall, these insights significantly enhance our understanding of SAs removal via oligomerization and demonstrate the superiority of C-ISCO based on polymerization in water decontamination.

2D/2D heterojunctions for rapid and self-cleaning removal of antibiotics via visible light-assisted peroxymonosulfate activation: Efficiency, synergistic effects, and applications.

Developing eco-friendly and efficient technologies for treating antibiotic wastewater is crucial. Traditional methods face challenges in incomplete removal, high costs, and secondary pollution. Heterogeneous peroxymonosulfate (PMS) activation assisted by visible light shows promise, but suitable activators remain a huge challenge. Here, we synthesized cost-effective carbon nitride/bismuth bromide oxide (CN/BiOBr) heterojunctions. Such a heterojunction achieved rapid PMS activation, achieving over 90.00% tetracycline (TC) removal only within 1 min (kobs of 2.23 min-1), surpassing previous systems by nearly 1-2 orders of magnitude and even remarkably superior to the popular single-atom catalysts. The system exhibited self-cleaning properties, maintaining activity after 8 cycles and stability across a wide pH range (3.01 to 9.03). Quenching experiments and theoretical calculations elucidated the exclusive •O2- species involvement and removal pathways. Eco-toxicity assessment and total organic carbon results confirmed simultaneous degradation, detoxification, and mineralization. This system also showed excellent resistance to environmental factors, e.g., coexisting anions, varying pH, and water sources, and demonstrated potential in coking and medical wastewater purification. This study presents a novel technique for rapidly decontaminating antibiotic wastewater through visible light-assisted PMS activation and introduces innovative bionic catalytic oxidation combining light and darkness for practical applications.

Embedding electronic perpetual motion into single-atom catalysts for persistent Fenton-like reactions.

In our quest to leverage the capabilities of the emerging single-atom catalysts (SACs) for wastewater purification, we confronted fundamental challenges related to electron scarcity and instability. Through meticulous theoretical calculations, we identified optimal placements for nitrogen vacancies (Nv) and iron (Fe) single-atom sites, uncovering a dual-site approach that significantly amplified visible-light absorption and charge transfer dynamics. Informed by these computational insights, we cleverly integrated Nv into the catalyst design to boost electron density around iron atoms, yielding a potent and flexible photoactivator for benign peracetic acid. This exceptional catalyst exhibited remarkable stability and effectively degraded various organic contaminants over 20 cycles with self-cleaning properties. Specifically, the Nv sites captured electrons, enabling their swift transfer to adjacent Fe sites under visible light irradiation. This mechanism accelerated the reduction of the formed "peracetic acid-catalyst" intermediate. Theoretical calculations were used to elucidate the synergistic interplay of dual mechanisms, illuminating increased adsorption and activation of reactive molecules. Furthermore, electron reduction pathways on the conduction band were elaborately explored, unveiling the production of reactive species that enhanced photocatalytic processes. A six-flux model and associated parameters were also applied to precisely optimize the photocatalytic process, providing invaluable insights for future photocatalyst design. Overall, this study offers a molecule-level insight into the rational design of robust SACs in a photo-Fenton-like system, with promising implications for wastewater treatment and other high-value applications.

pH-Driven Efficacy of the Ferrate(VI)-Peracetic Acid System in Swift Sulfonamide Antibiotic Degradation: A Deep Dive into Active Species Evolution and Mechanistic Insights.

In the realm of wastewater treatment, the power of ferrate (Fe(VI)) and peracetic acid (PAA) as oxidants stands out. But their combined might is where the enhancement truly lies. Their collaborative effect intensifies, but the underlying mechanics, especially across varying pH levels and pollutant types, still lurks in obscurity. Our study delved into the sophisticated oxidation interplay among Fe(VI)-PAA, Fe(VI)-H2O2, and standalone Fe(VI) systems. Notably, at a pH of 9.0, boasting a kinetic constant of ∼0.127 M-1·s-1, the Fe(VI)-PAA system annihilated the pollutant sulfamethoxazole, outpacing its counterparts by a staggering 48.73-fold when compared to the Fe(VI)-H2O2 system and 105.58-fold when using Fe(VI) individually. The behavior of active species─such as the dynamic •OH radicals and high-valent iron species (Fe(IV)/Fe(V))─shifted with pH variations, leading to distinct degradation pathways. Our detailed exploration pinpoints the behaviors of certain species across pH levels from 3.0 to 9.0. In more acidic environments, the •OH species proved indispensable for the system's reactivity. Conversely, as the pH inclined, degradation was increasingly steered by high-valent iron species. This intensive probe demystifies Fe(VI) interactions, deepening our understanding of the capabilities of the Fe(VI)-centered system and guiding us toward cleaner water solutions. Importantly, pH value, often underappreciated, holds the reins in organic wastewater decontamination. Embracing this key player is vital as we strategize for more expansive systems in upcoming ventures.

Orientated construction of visible-light-assisted peroxymonosulfate activation system for antibiotic removal: Significant enhancing effect of Cl.

Antibiotic contaminants can migrate over long distances in the water, thus possibly causing severe detriment to the environment and even potential harm to human health. Heterogeneous activation of peroxymonosulfate (PMS) assisted by visible light is an emerging and promising technology for the purification of such wastewater. This study designed an ultra-efficient and stable PMS activator (FeCN) to restore the typical antibiotic-polluted water under harsh conditions. About 90.94% of sulfamethoxazole (SMX) was degraded in 35 min in the constructed FeCN+PMS/vis system, and the reaction rate constant was nearly 50-fold higher than direct photocatalysis. Electron spin resonance, quenching experiments, LC/MS technique, eco-toxicity assessment, and density functional theory validated that the SMX removal was dominated by the attack of h+, •O2- and 1O2 on the active atoms of SMX molecules with high Fukui index, presenting as a simultaneous degradation and detoxification process. Such a visible-light-assisted PMS activation system also had good resistance to the environmental water bodies and a broad spectrum in the degradation of various pollutants. In particular, Cl- (50 mM) could significantly accelerate the removal of SMX with a 32.6-fold increase in catalytic activity, and the mineralization efficiency could reach 56.6% under identical conditions. Moreover, this Cl- containing system excluded the degradation products of disinfection by-products, and such a system was also versatile for different contaminants. This work demonstrates the feasibility of the FeCN+PMS/vis system for the remediation of antibiotic-contaminated wastewater in the presence and absence of Cl-, and also highlights their great potential in WWTPs.

Convolver Design and Convolve-Accumulate Unit Design for Low-Power Edge Computing.

Convolution operations have a significant influence on the overall performance of a convolutional neural network, especially in edge-computing hardware design. In this paper, we propose a low-power signed convolver hardware architecture that is well suited for low-power edge computing. The basic idea of the proposed convolver design is to combine all multipliers' final additions and their corresponding adder tree to form a partial product matrix (PPM) and then to use the reduction tree algorithm to reduce this PPM. As a result, compared with the state-of-the-art approach, our convolver design not only saves a lot of carry propagation adders but also saves one clock cycle per convolution operation. Moreover, the proposed convolver design can be adapted for different dataflows (including input stationary dataflow, weight stationary dataflow, and output stationary dataflow). According to dataflows, two types of convolve-accumulate units are proposed to perform the accumulation of convolution results. The results show that, compared with the state-of-the-art approach, the proposed convolver design can save 15.6% power consumption. Furthermore, compared with the state-of-the-art approach, on average, the proposed convolve-accumulate units can reduce 15.7% power consumption.

Prognostic value of 18F-FDG PET/MR imaging biomarkers in oesophageal squamous cell carcinoma.

PURPOSE: To correlate the clinical stage and prognosis of oesophageal squamous cell carcinoma (SCC) using the imaging biomarkers from integrated positron emission tomography (PET)/magnetic resonance imaging (MRI). METHODS: In total, 54 consecutive patients with oesophageal SCC who receive PET/MRI scan were recruited before treatment. The imaging biomarkers used were the mean and minimal apparent diffusion coefficients (ADCmean and ADCmin), standardized uptake value (SUV), metabolic tumour volume (MTV), and total lesion glycolysis (TLG) of tumours. The correlation between each imaging biomarker and survival was investigated using the Cox proportional hazards model. RESULTS: ADCmean was negatively correlated with SUVmax (r = -0.414, P =  0.025). ADCmin was negatively correlated with SUVmax (r = -0.423, P =  0.001) and SUVpeak (r = -0.402, P =  0.003), and was significantly lower in M1 than in M0 tumours (829.6 vs. 1069.8, P = 0.005). MTV was significantly higher in T3 + (P <  0.001), N1 + (P = 0.014) and TNM stage III + (P <  0.001) tumours. TLG was significantly higher in T3 + (P <  0.001), N1 + (P <  0.001), M1 (P =  0.045) and TNM stage III + (P <  0.001) tumours. The MTV/ADCmin ratio exhibited the highest area under the receiver operating characteristic curve (AUROC) for predicting M1 and advanced TNM stage tumours. Multivariate analysis for progression-free survival (PFS) and overall survival (OS) showed that a larger MTV/ADCmin was associated with a shorter PFS and OS (P = 0.024 and 0.046, respectively). CONCLUSION: The imaging biomarkers in integrated PET/MRI may predict clinical stage and survival in patients with oesophageal SCC.

PET/MRI in pancreatic and periampullary cancer: correlating diffusion-weighted imaging, MR spectroscopy and glucose metabolic activity with clinical stage and prognosis.

PURPOSE: To correlate the clinical stage and prognosis of pancreatic or periampullary cancer with the imaging biomarkers on diffusion-weighted imaging, magnetic resonance spectroscopy and glucose metabolic activity derived from integrated PET/MRI. METHODS: This prospective study was approved by the institutional review board and informed consent was obtained. The study group comprised 60 consecutive patients with pancreatic or periampullary cancer who underwent PET/MRI before treatment. The imaging biomarkers were the minimal apparent diffusion coefficient (ADCmin), choline levels, standardized uptake values, metabolic tumour volume (MTV), and total lesion glycolysis (TLG) of the tumours. The relationships between these biomarkers and clinical TNM stage were evaluated using the Pearson test and the Mann-Whitney U test. The area under the receiver operating characteristic curve (AUROC) was used to evaluate accuracy. The correlation between the imaging biomarker and progression-free survival (PFS) was investigated using the Cox proportional hazards model. RESULTS: ADCmin was significantly lower in N1 and TNM stage 3+ tumours. Choline levels significantly higher in T4 tumours. TLG was significantly higher in T4, N1 and TNM stage 3+ tumours. MTV was significantly higher in T4, N1, M1, and TNM stage 3+ tumours (all P < 0.05). The MTV/ADCmin ratio exhibited the highest AUROC for predicting T4, N1, M1, and advanced TNM stages tumours, and was an independent predictor of PFS (P = 0.018) after adjustment for age, sex, tumour size and stage. CONCLUSION: The imaging biomarkers from integrated PET/MRI may predict clinical stage and PFS in patients with pancreatic or periampullary cancer.

Standardized uptake value and apparent diffusion coefficient of endometrial cancer evaluated with integrated whole-body PET/MR: Correlation with pathological prognostic factors.

PURPOSE: To evaluate the correlation between maximum standardized uptake value (SUVmax ) and minimum apparent diffusion coefficient (ADCmin ) of endometrial cancer derived from an integrated positron emission tomography / magnetic resonance (PET/MR) system and to determine their correlation with pathological prognostic factors. MATERIALS AND METHODS: This prospective study was approved by the Institutional Review Board of the hospital, and informed consent was obtained. Between April and December 2014, 47 consecutive patients with endometrial cancer were enrolled and underwent simultaneous PET/MR examinations before surgery. Thirty-six patients with measurable tumors on PET/MR were included for image analysis. Pearson's correlation coefficient was used to evaluate the correlation between SUVmax and ADCmin of the tumors. The Mann-Whitney U-test was utilized to evaluate relationships between these two imaging biomarkers and pathological prognostic factors. RESULTS: The mean SUVmax and ADCmin were 14.7 ± 7.1 and 0.48 ± 0.13 × 10(-3) mm(2) /s, respectively. A significant inverse correlation was found between SUVmax and ADCmin (r = -0.53; P = 0.001). SUVmax was significantly higher in tumors with advanced stage, deep myometrial invasion, cervical invasion, lymphovascular space involvement, and lymph node metastasis (P < 0.05). ADCmin was lower in tumors with higher grade, advanced stage, and cervical invasion (P < 0.05). The ratio of SUVmax to ADCmin was higher in tumors with higher grade, advanced stage, deep myometrial invasion, cervical invasion, lymphovascular space involvement, and lymph node metastasis (P < 0.05). CONCLUSION: SUVmax and ADCmin of endometrial cancer derived from integrated PET/MR are inversely correlated and are associated with pathological prognostic factors.