Diagnostic value of one-step nucleic acid amplification for sentinel lymph node metastasis in cytokeratin 19-positive tumors: evidence from bioinformatics and meta-analysis.

Background: The status of the sentinel lymph nodes (SLNs) was an important prognostic factor in varies cancers. A one-step nucleic acid amplification (OSNA) assay, a molecular-based whole-node analysis method based on CK19 mRNA copy number, was developed to diagnose lymph node metastases. We aimed to evaluate the value of OSNA for the diagnosis of sentinel lymph node metastasis in CK19 positive cancers. CK19 mRNA and protein expression for pan-caner analysis were obtained from TCGA and the Human protein atlas database. Methods: Two researchers independently searched the PubMed, Cochrane Library and Web of Science databases for qualified articles published before December 1, 2023. A meta-analysis was performed using MetaDisc and STATA. Risk bias and quality assessments of the included studies were evaluated, and a subgroup analysis was performed. Ten cancer types were found to be CK19 positively expressed and 7 of 10 had been reported to use OSNA for SLN detection. Results: After literature review, there were 61 articles included in the meta-analysis, which consisted of 7115 patients with 18007 sentinel lymph nodes. The pooled sensitivity and specificity of OSNA were 0.87 and 0.95 in overall patients. Moreover, we found the background CK19 expression in normal tissue affected the diagnostic accuracy of OSNA. In breast cancer, we performed subgroup analysis. OSNA exhibited to be a stable method across different population groups and various medical centers. In addition, when 250 copies/µl was chosen as the cutoff point of CK19 mRNA, there were a relatively higher sensitivity and AUC in detecting SLN micro-metastasis than 5000 copies/µl. Discussion: OSNA can predict the occurrence of SLN metastasis accurately in CK19 positive cancers, especially in breast cancer, colorectal cancer, lung cancer, gastric cancer and endometrial cancer. Our study warrants future studies investigating the clinical application of OSNA in pancreatic, ovarian and bladder cancers.

Synergistic etching of nickel foam by Fe3+ and Cl- ions to synthesize nickel-iron-layered double hydroxide nanolayers with abundant oxygen vacancies for superior urea oxidation.

Urea electrolysis is an appealing topic for hydrogen production due to its ability to extract hydrogen at a lower potential. However, it is plagued by sluggish kinetics and noble-metal catalyst requirements. Herein, we developed nickel-iron-layered double hydroxide (NiFe-LDH) nanolayers with abundant oxygen vacancies (OV) via synergistically etching nickel foam with Fe3+ and Cl- ions, enabling the efficient conversion of urea into H2 and N2. The synthesized OV-NiFe-LDH exhibits a lower potential (1.30 vs. reversible hydrogen electrode, RHE) for achieving 10 mA cm-2 in the urea oxidation reaction (UOR), surpassing most recently reported Ni-based electrodes. OV provides favorable conductivity and a large surface area, which results in a 4.1-fold in electron transport and a 5.1-fold increase in catalyst reactive sites. Density Functional Theory (DFT) calculations indicate that OV can lower the adsorption energy of urea, and enhance the bonding strength of *CONHNH, giving rise to improved UOR. This study provides a viable path toward economical and efficient production of high-purity hydrogen.

Enhanced nitrogen removal via partial nitrification/denitrification coupled Anammox using three stage anoxic/oxic biofilm process with intermittent aeration.

Pre-capturing organics in municipal wastewater for biogas production, combined with Anammox-based nitrogen removal process, improves the sustainability of sewage treatment. Thus, enhancing nitrogen removal via Anammox in mainstream wastewater treatment becomes very crucial. In present study, a three-stage anoxic/oxic (AO) biofilm process with intermittent aeration was designed to strengthen partial nitrification/denitrification coupling Anammox (PNA/PDA) in treatment of low C/N wastewater, which contained chemical oxygen demand (COD) of 79.8 mg/L and total inorganic nitrogen (TIN) of 58.9 mg/L. With a hydraulic retention time of 8.0 h, the process successfully reduced TIN to 10.6 mg/L, achieving a nitrogen removal efficiency of 83.3 %. The 1st anoxic zone accounted for 32.0 % TIN removal, with 10.3 % by denitrification and 21.7 % by PDA, meanwhile, the 2nd and 3rd anoxic zones contributed 19.4 % and 4.5 % of TIN removal, primarily achieved through PDA (including endogenous PD coupling Anammox). The 1st and 2nd intermittent zones accounted for 27.2 % and 17.0 % of TIN removal, respectively, with 13.7 %-21.3 % by PNA and 3.2 %-5.3 % by PDA. Although this process did not pursue nitrite accumulation in any zone (< 1.5 mg-N/L), PNA and PDA accounted for 35.1 % and 52.1 % of TIN removal, respectively. Only 0.21 % of removed TIN was released as nitrous oxide. The AnAOB of Candidatus Brocadia was enriched in each zone, with a relative abundance of 0.66 %-2.29 %. In intermittent zones, NOB had been partially suppressed (AOB/NOB = 0.73-0.88), mainly due to intermittent aeration and effective nitrite utilization by AnAOB since its population size was much greater than NOB. Present study indicated that the three-stage AO biofilm process with intermittent aeration could enhance nitrogen removal via PNA and PDA with a low N2O emission factor.

Synergistic catalysis of TiO2/WO3 photoanode and Sb-SnO2 electrode with highly efficient ClO• generation for urine treatment.

Urine is the major source of nitrogen pollutants in domestic sewage and is a neglected source of H2. Although ClO• is used to overcome the poor selectivity and slow kinetics of urea decomposition, the generation of ClO• suffers from the inefficient formation reaction of HO• and reactive chlorine species (RCS). In this study, a synergistic catalytic method based on TiO2/WO3 photoanode and Sb-SnO2 electrode efficiently producing ClO• is proposed for urine treatment. The critical design is that TiO2/WO3 photoanode and Sb-SnO2 electrode that generate HO• and RCS, respectively, are assembled in a confined space through face-to-face (TiO2/WO3//Sb-SnO2), which effectively strengthens the direct reaction of HO• and RCS. Furthermore, a Si solar panel as rear photovoltaic cell (Si PVC) is placed behind TiO2/WO3//Sb-SnO2 to fully use sunlight and provide the driving force of charge separation. The composite photoanode (TiO2/WO3//Sb-SnO2 @Si PVC) has a ClO• generation rate of 260% compared with the back-to-bake assembly way. In addition, the electrons transfer to the NiFe LDH@Cu NWs/CF cathode for rapid H2 production by the constructed photoelectric catalytic (PEC) cell without applied external biasing potential, in which the H2 production yield reaches 84.55 µmol h-1 with 25% improvement of the urine denitrification rate. The superior performance and long-term stability of PEC cell provide an effective and promising method for denitrification and H2 generation.

Therapeutic utility of human umbilical cord-derived mesenchymal stem cells-based approaches in pulmonary diseases: Recent advancements and prospects.

Pulmonary diseases across all ages threaten millions of people and have emerged as one of the major public health issues worldwide. For diverse disease conditions, the currently available approaches are focused on alleviating clinical symptoms and delaying disease progression but have not shown significant therapeutic effects in patients with lung diseases. Human umbilical cord-derived mesenchymal stem cells (UC-MSCs) isolated from the human UC have the capacity for self-renewal and multilineage differentiation. Moreover, in recent years, these cells have been demonstrated to have unique advantages in the treatment of lung diseases. We searched the Public Clinical Trial Database and found 55 clinical trials involving UC-MSC therapy for pulmonary diseases, including coronavirus disease 2019, acute respiratory distress syndrome, bronchopulmonary dysplasia, chronic obstructive pulmonary disease, and pulmonary fibrosis. In this review, we summarize the characteristics of these registered clinical trials and relevant published results and explore in depth the challenges and opportunitiesfaced in clinical application. Moreover, the underlying molecular mechanisms involved in UC-MSC-based therapy for pulmonary diseases are also analyzed in depth. In brief, this comprehensive review and detailed analysis of these clinical trials can be expected to provide a scientific reference for future large-scale clinical application.

Long non-coding RNA Linc00657 up-regulates Skp2 to promote the progression of cervical cancer through lipid reprogramming and regulation of immune microenvironment.

More and more evidence shows that long non-coding RNA (lncRNA) plays an important role in the biological behavior of many kinds of malignant tumors, but the specific function of lncRNA Linc00657 in cervical cancer is still unknown. The purpose of this study is to explore the effect of Linc00657 on the malignant progression of cervical cancer and its potential mechanism. In two kinds of cervical cancer cell lines and normal cervical epithelial cells, qRT-PCR showed increased expression of Linc00657 in cervical cancer cells. Through MTT, clone formation test, flow cytometry, wound healing test and Transwell test, it has been found that overexpression of Linc00657 could promote the proliferation,migration and invasion of cervical cancer cells，and inhibit apoptosis. Through the StarBase database, it was found that there may be a mutual regulatory relationship between Linc00657 and Skp2, and Skp2 may be the downstream target of Linc00657. QRT-PCR detection confirmed that the expression of Skp2 was increased in cervical cancer cells with overexpression of Linc00657. TIMER2 database found that Skp2 was associated with lipid metabolic enzymes and immune cell infiltration. It was found that Linc00657 knockdown inhibited tumor growth and metastasis and inhibited the expression of Skp2 in vivo. In short, our research shows that Linc00657 has carcinogenic properties in cervical cancer, and LINC00657 promotes the occurrence of cervical cancer by up-regulating the expression of Skp2. We predict that Linc00657/mir30s/Skp2 axis plays a role in the malignant progression of cervical cancer. In addition, Skp2 may participate in cancer immune response and promote lymph node metastasis of cervical cancer through lipid reprogramming. These findings also provide promising targets for the diagnosis and treatment of cervical cancer.

Predation preference for extracellular polysaccharides by paramecia and rotifers may have accelerated the decline of membrane biofilm hydraulic resistance.

The hydraulic resistance of biofilm layer on membranes impacts the filtration resistance significantly. The effect of predation by two model microfauna (i.e., paramecia and rotifers) on the hydraulic resistance, structure, extracellular polymeric substance (EPS), and bacterial community of biofilms developed on supporting materials (i.e., nylon mesh) was evaluated in this study. Long-term experiments demonstrated that predation could alter biofilm compositions and accelerated the decline of hydraulic resistance by increasing biofilm heterogeneity and deformation. Importantly, predation preference of paramecia and rotifers on biofilm components were further investigated for the first time by tracking the fluorescence change in the predator bodies after exposure to the stained biofilms. Results indicated that after 12-hour's incubation, the ratio of extracellular α-polysaccharides (α-PS) to proteins (PN) within the bodies of paramecia and rotifers increased to 2.6 and 3.9, respectively, which was 0.76 in the original biofilms. The ratios of α-PS/live cells within paramecia and rotifers increased to 1.42 and 1.64 from 0.81 in the original biofilms. The ratio of live/dead cells in the predator bodies, however, changed slightly compared to the original biofilms. These results clearly and directly evidenced that both paramecia and rotifers could feed on biofilm EPS and cells, but having a significant preference for PS over PN and cells. Since extracellular PS is recognized as a primary biofilm adhesion agent, the preference for PS could better explain why predation had accelerated the disintegration and hydraulic resistance decline of mesh biofilms.

Assessing the quality and making appropriate use of historical negative control data: A report of the International Workshop on Genotoxicity Testing (IWGT).

Historical negative control data (HCD) have played an increasingly important role in interpreting the results of genotoxicity tests. In particular, Organisation for Economic Co-operation and Development (OECD) genetic toxicology test guidelines recommend comparing responses produced by exposure to test substances with the distribution of HCD as one of three criteria for evaluating and interpreting study results (referred to herein as "Criterion C"). Because of the potential for inconsistency in how HCD are acquired, maintained, described, and used to interpret genotoxicity testing results, a workgroup of the International Workshops for Genotoxicity Testing was convened to provide recommendations on this crucial topic. The workgroup used example data sets from four in vivo tests, the Pig-a gene mutation assay, the erythrocyte-based micronucleus test, the transgenic rodent gene mutation assay, and the in vivo alkaline comet assay to illustrate how the quality of HCD can be evaluated. In addition, recommendations are offered on appropriate methods for evaluating HCD distributions. Recommendations of the workgroup are: When concurrent negative control data fulfill study acceptability criteria, they represent the most important comparator for judging whether a particular test substance induced a genotoxic effect. HCD can provide useful context for interpreting study results, but this requires supporting evidence that (i) HCD were generated appropriately, and (ii) their quality has been assessed and deemed sufficiently high for this purpose. HCD should be visualized before any study comparisons take place; graph(s) that show the degree to which HCD are stable over time are particularly useful. Qualitative and semi-quantitative assessments of HCD should also be supplemented with quantitative evaluations. Key factors in the assessment of HCD include: (i) the stability of HCD over time, and (ii) the degree to which inter-study variation explains the total variability observed. When animal-to-animal variation is the predominant source of variability, the relationship between responses in the study and an HCD-derived interval or upper bounds value (i.e., OECD Criterion C) can be used with a strong degree of confidence in contextualizing a particular study's results. When inter-study variation is the major source of variability, comparisons between study data and the HCD bounds are less useful, and consequentially, less emphasis should be placed on using HCD to contextualize a particular study's results. The workgroup findings add additional support for the use of HCD for data interpretation; but relative to most current OECD test guidelines, we recommend a more flexible application that takes into consideration HCD quality. The workgroup considered only commonly used in vivo tests, but it anticipates that the same principles will apply to other genotoxicity tests, including many in vitro tests.

Nitrogen-containing wastewater fuel cells for total nitrogen removal and energy recovery based on Cl•/ClO• oxidation of ammonia nitrogen.

The excess nitrogen discharge into water bodies has resulted in extensive water pollution and human health risks, which has become a critical global issue. Moreover, nitrogenous wastewater contains considerable chemical energy contributed by organic pollutants and nitrogenous compounds. Therefore, the treatment of various kinds of nitrogen-containing wastewater for nitrogen removal and energy recovery is of significance. Biological methode and advanced oxidation processes (AOPs) are the main methods for nitrogen removal. However, biological treatment is easily inhibited by high-salinity, high ammonia nitrogen (NH3-N/NH4+-N), nitrite and toxic organics in wastewater, which limits its application. AOPs mainly induce in situ generation of highly reactive species, such as hydroxyl radical (HO•), sulfate radical (SO4•-) and chlorine radicals (Cl•, ClO•, Cl2•-), for nitrogen removal. Nevertheless, HO• shows low reactivity and N2 selectivity towards NH3-N/NH4+-N oxidation, and SO4•- also demonstrates unsatisfactory NH3-N/NH4+-N removal. It has been shown that Cl•/ClO• can efficiently remove NH3-N/NH4+-N with high N2 selectivity. The generation of Cl•/ClO• can be triggered by various techniques, among which the PEC technique shows great potential due to its higher efficiency for Cl•/ClO• generation and eco-friendly approach for pollutants degradation and energy recovery by utilizing solar energy. Cl•/ClO• oxidation of NH3-N/NH4+-N and nitrate nitrogen (NO3--N) reduction can be strengthened through the design of photoanode and cathode materials, respectively. Coupling with this two pathways, an exhaustive total nitrogen (TN) removal system is designed for complete TN removal. When introducing the mechanism into photocatalytic fuel cells (PFCs), the concept of nitrogen-containing wastewater fuel cells (NFCs) is proposed to treat several typical types of nitrogen-containing wastewater, achieving high-efficiency TN removal, organics degradation, toxic chlorate control, and energy recovery simultaneously. Recent research progress in this field is reviewed, summarized and discussed, and in-depth perspectives are proposed, providing new ideas for the resource treatment of nitrogen-containing wastewater.

Ni doped amorphous FeOOH layer as ultrafast hole transfer channel for enhanced PEC performance of BiVO4.

Bismuth vanadate (BiVO4), as the potential and prospective photocatalyst, has been limited by the issue of poor separation and transfer of charge carrier for photoelectrocatalytic (PEC) water oxidation. Here, a significant increase of surface injection efficiency for BiVO4 is realized by the rationally designed Ni doped FeOOH (Ni:FeOOH) layer growing on BiVO4 photoanode (Ni:FeOOH/BiVO4), in which doped Ni2+ can induce partial-charge of FeOOH to serve as ultrafast transfer channel for hole transfer and transportation at the semiconductor/electrolyte interface. In addition, the Ni:FeOOH/BiVO4 shows the ηsurface value of 81.6 %, which is 3.28-fold and 1.47-fold of BiVO4 and FeOOH/BiVO4, respectively. The photocurrent density of Ni:FeOOH/BiVO4 is 4.21 mA cm-2 at 1.23 V vs. RHE, with the onset potential cathodically shifting 237 mV over BiVO4 and a long-term stability for suppressing surface charge recombination. The UPS and UV-Vis spectra have confirmed the type-II band alignment between Ni:FeOOH and BiVO4 for promoting carrier transfer. This facile and effective spin-coating method could deposit oxygen evolution catalysts (OECs) availably onto photoanodes with enhanced PEC water splitting.

Quinoline is more genotoxic than 4-methylquinoline in hiHeps cells and rodent liver.

Environmental pollutants, such as quinoline (QN) and 4-methylquinoline (4-MeQ), may be genotoxic and carcinogenic. Earlier studies, including in vitro genotoxicity tests, indicated that 4-MeQ is more mutagenic than QN. However, we hypothesized that the methyl group of 4-MeQ favors detoxication over bioactivation, and this factor may be overlooked in in vitro tests that do not incorporate supplementation with cofactors for enzymes that catalyze conjugation reactions. We used human induced hepatocyte cells (hiHeps), which express such enzymes, and compared the genotoxicity of 4-MeQ and QN. We also carried out an in vivo micronucleus (MN) test in rat liver, since 4-MeQ is not genotoxic in rodent bone marrow. In the Ames test and the Tk gene mutation assay, with rat S9 activation, 4-MeQ was more mutagenic than QN. However, QN induced significantly higher MN frequencies in hiHeps and rat liver than did 4-MeQ. Furthermore, QN upregulated genotoxicity marker genes much more than did 4-MeQ. We also investigated the roles of two important detoxication enzymes, UDP-glucuronosyltransferases (UGTs) and cytosolic sulfotransferases (SULTs). When hiHeps were preincubated with hesperetin (UGT inhibitor) and 2,6-dichloro-4-nitrophenol (SULT inhibitor), MN frequencies were elevated approximately 1.5-fold for 4-MeQ, whereas no significant effects were seen for QN. This study shows that QN is more genotoxic than 4-MeQ, when the roles of SULTs and UGTs in detoxication are considered and our results may improve understanding the structure-activity relationships of quinoline derivatives.

Unconventional Substitution for BiVO4 to Enhance Photoelectrocatalytic Performance by Accelerating Polaron Hopping.

Bismuth vanadate (BiVO4) as a fascinating semiconductor for photoelectrocatalytic (PEC) water oxidation with suitable band gap (Eg) has been limited by the issue of poor separation and transportation of charge carriers. Herein, we propose an unconventional substitution of V5+ sites by Ti4+ in BiVO4 (Ti:BiVO4) for the similar ionic radii and accelerated polaron hopping. Ti:BiVO4 increased the photocurrent density 1.90 times up to 2.51 mA cm-2 at 1.23 V vs RHE and increased the charge carrier density 1.81 times to 5.86 × 1018 cm-3. Compared with bare BiVO4, Ti:BiVO4 improves the bulk separation efficiency to 88.3% at 1.23 V vs RHE. The DFT calculations have illustrated that Ti-doping modification could decrease the polaron hopping energy barrier, narrow the Eg, and decrease the overpotential of the oxygen evolution reaction (OER) concurrently. With further spin-coated FeOOH cocatalyst, the photoanode has a photocurrent density of 3.99 mA cm-2 at 1.23 V vs RHE. The excellent PEC performance of FeOOH/Ti:BiVO4 is attributed to the synergistic effect of the FeOOH layer and Ti doping, which could promote charge carrier separation and transfer by expediting polaron migration.

Facile, Controllable, and Ultrathin NiFe-LDH In Situ Grown on a Ni Foam by Ultrasonic Self-Etching for Highly Efficient Urine Conversion.

As the primary source of nitrogen pollutants in domestic sewage, urine is also an alternative for H2 production via electrochemical processes. However, it suffers from sluggish kinetics and noble-metal catalyst requirement. Here, we report a non-precious ultrathin NiFe-layered double hydroxide catalyst for the remarkable conversion of urea into N2 and H2, which is in situ grown on a Ni foam via ultrasonic self-etching in Fe3+/ethylene glycol (EG). EG regulates the etching rate of Fe3+, resulting in an ultrathin nanosheet structure with the aid of ultrasonication. This structure dramatically promotes the dehydrogenation process via decreasing the nanolayer thickness from 120 to 3.4 nm and leads to a 4.8-fold increase in the generation of active sites. It exhibits record urea oxidation kinetics (390.8 mA·cm-2 at 1.5 V vs RHE) with excellent stability (120 h), which is 11.8 times better than that of commercial Pt/C catalyst (33.1 mA·cm-2). Tests with real urine at 20 mA cm-2 achieve 74% total nitrogen removal and 2853 µmol·h-1 of H2 production. This study provides an attractive landscape for producing H2 by consuming urine biowastes.

Type-II Heterojunction CdIn2S4/BiVO4 Coupling with CQDs to Improve PEC Water Splitting Performance Synergistically.

Bismuth vanadate (BiVO4) has been considered as a promising photoelectrocatalytic (PEC) semiconductor, but suffers from severe hole recombination, attributed to the short hole-diffusion length and the low carrier mobility. Herein, a type-II heterojunction CdIn2S4/BiVO4 is designed to improve the photocurrent density from 1.22 (pristine BiVO4) to 2.68 mA cm-2 at 1.23 V vs the reversible hydrogen electrode (RHE), accelerating the bulk separation of photogenerated carriers by the built-in field from the matched energy band. With the introduction of CQDs, CQDs/CdIn2S4/BiVO4 increases the photocurrent density to 4.84 mA cm-2, enhancing the light absorption and cathodically shifting its onset potential, due to the synergetic effect of the heterojunction and CQDs. Compared with BiVO4, CQDs/CdIn2S4/BiVO4 promotes the bulk separation efficiency to 94.6% and the surface injection efficiency to 72.2%. Additionally, spin-coating of FeOOH on CQDs/CdIn2S4/BiVO4 could further improve the PEC performance and keep a long stability for water splitting. The density function theory (DFT) calculations illustrated that the type-II heterojunction CdIn2S4/BiVO4 could decrease the oxygen evolution reaction (OER) overpotential and accelerate bulk charge separation for the built-in field of the aligned band structure.

LncRNA SCAMP1 disrupts the balance between miR-26a-5p and ZEB2 to promote osteosarcoma cell viability and invasion.

Osteosarcoma often occurs in children and adolescents and affects their health. The survival rate of osteosarcoma patients is unsatisfactory due to the lack of early detection and metastasis development and drug resistance. Hence, dissection of molecular insight into osteosarcoma initiation and progression is pivotal to provide the new therapeutic strategy. In recent years, long noncoding RNAs (lncRNAs) have burst into stage in osteosarcoma development and malignant behaviors. LncRNA SCAMP1 has been discovered to play an essential role in carcinogenesis and progression. However, the mechanisms of lncRNA SCAMP1-involved tumorigenesis have not been reported in human osteosarcoma. In this study, we utilized multiple cellular biological approaches to determine the function of lncRNA SCAMP1 in osteosarcoma cells. Moreover, we performed several molecular biological approaches to define the mechanism by which lncRNA SCAMP1 regulated cell viability and invasion in osteosarcoma. We dissected that lncRNA SCAMP1 promoted progression of osteosarcoma via modulation of miR-26a-5p/ZEB2 axis. In conclusion, targeting lncRNA SCAMP1 and its downstream targets, miR-26a-5p and ZEB2, might be a useful approach for osteosarcoma therapy.

Rapid Conversion of Co2+ to Co3+ by Introducing Oxygen Vacancies in Co3O4 Nanowire Anodes for Nitrogen Removal with Highly Efficient H2 Recovery in Urine Treatment.

Urine is a nitrogenous waste biomass but can be used as an appealing alternative substrate for H2 recovery. However, urine electrolysis suffers from sluggish kinetics and requires alkaline condition. Herein, we report a novel system to decompose urine to H2 and N2 under neutral conditions mediated by Cl• using oxygen-vacancy-rich Co3O4 nanowire (Ov-Co3O4) anodes and CuO nanowire cathodes. The Co2+/Co3+ cycle in Co3O4 activates Cl- in urine to Cl•, which rapidly and selectively converts urea into N2. Thus, electron transfer is boosted for H2 production, eliminating the kinetic limitations. The shuttle of Co2+ to Co3+ is the key step for Cl• yield, which is accelerated due to the introduction of Ov. Electrochemical analysis shows that Ov induces positive charge on the Co center; therefore, Co2+ loses electrons more efficiently to form Co3+. H2 production in this system reaches 716 µmol h-1, which is 320% that of non-radical-mediated urine electrolysis. The utilization of Ov-Co3O4 further enhances H2 generation, which is 490 and 210% those of noble Pt and RuO2, respectively. Moreover, urine is effectively degraded in 90 min with the total nitrogen removal of 95.4%, and N2 is the final product. This work provides new insights for efficient and low-cost recovery of H2 and urine remediation.

Novel Denitrification Fuel Cell for Energy Recovery of Nitrate-N and TN Removal Based on NH4+ Generation on a CNW@CF Cathode.

NO3- is an undesirable environmental pollutant that causes eutrophication in aquatic ecosystems, and its pollution is difficult to eliminate because it is easily converted into NH4+ instead of N2. Additionally, it is a high-energy substance. Herein, we propose a novel denitrification fuel cell to realize the chemical energy recovery of NO3- and simultaneous conversion of total nitrogen (TN) into N2 based on the outstanding ability of NH4+ generation on a three-dimensional copper nanowire (CNW)-modified copper foam (CF) cathode (CNW@CF). The basic steps are as follows: direct and highly selective reduction of NO3- to NH4+ rather than to N2 on the CNW@CF cathode, on which negative NO3- ions can be easily adsorbed due to their double-electron layer structure and active hydrogen ([H]) can be generated due to a large number of catalytic active sites exposed on CNWs. Then, NH4+ is selectively oxidized to N2 by the strong oxidation of chlorine free radicals (Cl•), which originate from the reaction of chlorine ions (Cl-) by photogenerated holes (h+) and hydroxyl radicals (OH•) under irradiation. Then, the electrons from the oxidation on the photoanode is transferred to the cathode to form a closed loop for external power generation. Owing to the continuous redox loop, NO3- completely reduces to N2, and the released chemical energy is converted into electrical energy. The results indicate that 99.9% of NO3- can be removed in 90 min, and the highest yield of electrical power density reaches 0.973 mW cm-2, of which the nitrate reduction rates on the CNW@CF cathode is 79 and 71 times higher than those on the Pt and CF cathodes, respectively. This study presents a novel and robust energy recycling concept for treating nitrate-rich wastewater.

Treatment of hazardous organic amine wastewater and simultaneous electricity generation using photocatalytic fuel cell based on TiO2/WO3 photoanode and Cu nanowires cathode.

Organic amines are regarded as high toxic, refractory chemicals due to the great damage on human body, and ecosystem. The treatment of organic amine wastewater involves the removal of total nitrogen and toxic organics simultaneously, which is one of the biggest difficulties in wastewater treatment. In this study, hazardous organic amine wastewater was purified by a photocatalytic fuel cell (PFC) with efficient nitrogen removal and organic degradation, and its chemical energy was recovered simultaneously based on hydroxyl radical (HO·) and chlorine radical (Cl·) reaction in a novel TiO2/WO3 and 3D Cu nanowires modified Cu foam (CuNWs/CF) system. TiO2/WO3 heterojunction as photoanode provided rapid charge separation and good stability, and the composite of poly-Si enhanced the light harvest and charge transfer. HO· played critical role in degrading organic amines, while Cl· was responsible for selectively oxidizing amine group or NH4+ to N2. Besides, trace amount of NO2- and NO3- formed by over-oxidation was eliminated on CuNWs/CF cathode due to large specific surface area and fast charge transfer. Moderate Cl- concentration and initial pH had vital influence on strengthening Cl· and HO· generation in the system, and the optimal conditions were 50 mM NaCl and pH = 7. For methylamine, ethylamine and dimethylamine wastewater, the system showed total nitrogen removal efficiency of 94.93%, 91.81%, 93.10% and total organic carbon removal of 58.47%, 53.57%, and 56.71% within 2 h, respectively. Moreover, the corresponding maximum power densities of 2.49, 2.40, 2.27 mW cm-2 were also generated, respectively. The study proposes an efficient, sustainable method for the treatment of hazardous organic amine wastewater and simultaneous energy recovery.

Efficient Hydrogen Generation and Total Nitrogen Removal for Urine Treatment in a Neutral Solution Based on a Self-Driving Nano Photoelectrocatalytic System.

Urine is the main source of nitrogen pollution, while urea is a hydrogen-enriched carrier that has been ignored. Decomposition of urea to H2 and N2 is of great significance. Unfortunately, direct urea oxidation suffers from sluggish kinetics, and needs strong alkaline condition. Herein, we developed a self-driving nano photoelectrocatalytic (PEC) system to efficiently produce hydrogen and remove total nitrogen (TN) for urine treatment under neutral pH conditions. TiO2/WO3 nanosheets were used as photoanode to generate chlorine radicals (Cl•) to convert urea-nitrogen to N2, which can promote hydrogen generation, due to the kinetic advantage of Cl-/Cl• cyclic catalysis. Copper nanowire electrodes (Cu NWs/CF) were employed as the cathode to produce hydrogen and simultaneously eliminate the over-oxidized nitrate-nitrogen. The self-driving was achieved based on a self-bias photoanode, consisting of confronted TiO2/WO3 nanosheets and a rear Si photovoltaic cell (Si PVC). The experiment results showed that hydrogen generation with Cl• is 2.03 times higher than in urine treatment without Cl•, generating hydrogen at 66.71 µmol h-1. At the same time, this system achieved a decomposition rate of 98.33% for urea in 2 h, with a reaction rate constant of 0.0359 min-1. The removal rate of total nitrogen and total organic carbon (TOC) reached 75.3% and 48.4% in 2 h, respectively. This study proposes an efficient and potential urine treatment and energy recovery method in neutral solution.

High Yield of CO and Synchronous S Recovery from the Conversion of CO2 and H2S in Natural Gas Based on a Novel Electrochemical Reactor.

H2S and CO2 are the main impurities in raw natural gas, which needs to be purified before use. However, the comprehensive utilization of H2S and CO2 has been ignored. Herein, we proposed a fully resource-based method to convert toxic gas H2S and greenhouse gas CO2 synchronously into CO and elemental S by using a novel electrochemical reactor. The special designs include that, in the anodic chamber, H2S was oxidized rapidly to S based on the I-/I3- cyclic redox system to avoid anode passivation. On the other hand, in the cathodic chamber, CO2 was rapidly and selectively reduced to CO based on a porous carbon gas diffusion electrode (GDE) modified with polytetrafluoroethylene and cobalt phthalocyanine (CoPc). A high Faraday efficiency (>95%) toward CO was achieved due to the enhanced mass transfer of CO2 on the GDE and the presence of the selective CoPc catalyst. The maximum energy efficiency of the system was more than 72.41% with a current density of over 50 mA/cm2, which was 12.5 times higher than what was previously reported on the H2S treatment system. The yields of S and CO were 24.94 mg·cm-2·h-1 and 19.93 mL·cm-2·h-1, respectively. A model analysis determined that the operation cost of the synchronous utilization of H2S and CO2 method was slightly lower than that of the single utilization of H2S in the existing natural gas purification technology. Overall, this paper provides efficient and simultaneous conversion of H2S and CO2 into S and CO.