Dimeric Rh Complexes Supported by a Bridging Phosphido/Bis(Phosphine) PPP Ligand

Rh complexes of a tridentate PPP ligand bearing 1,2-pyrrolediyl linkers have been prepared, including examples with the central P donor being either a phosphine or a phosphide. Three bimetallic Rh complexes containing the diamandoid Rh2P2 core (P = phosphido) have been structurally and spectroscopically characterized. The Rh-Rh interaction in these three dimers was examined by way of structural comparisons and DFT investigations.

A Single Component, Single Layer Flexile Foam Evaporator with the Higher Efficiency for Water Generation

One of the greenest and promising ways to solve the problem of freshwater crisis is surface solar steam generation from seawater. A great number of photothermal materials with multi-component and multi-layered delicate yet complex structures often suffer from either low evaporation rate or high energy loss. Here, this work presents a single component foam evaporator with steam generation rate of up to 4.32 kg m-2 h-1 under 1 sun irradiation. The evaporator is constructed from an aniline oligomer as a single light-absorbing component, covalent linked with polyethylene glycol to form a monolithic polymer foam. Floating on the seawater, the foam has absorbance of 99.5% over the entire solar spectral range and low thermal conductivity (0.0077 W K-1m-1) that effectively retains heat in the material and at the interface. After 3 months of continuous outdoor natural sunlight irradiation, the evaporator maintains a stable and durable evaporation rate. Moreover, the materials have good mechanical properties (7.48 MPa young's modulus and 57.38% elongation at break) and excellent chemical resistance in 10 common organic solvents and aqueous solutions of pH = 1 to 14. This study provides a new system and strategy for desalination, steam power generation, treatment of polluted water and sewage, etc.

Activation of periodate by biocarbon-supported multiple modified nanoscale iron for the degradation of bisphenol A in high-temperature aqueous solution

As reported, the persistent toxic and harmful pollutant bisphenol A (BPA) from industrial emissions has been consistently found in aquatic environments inhabited by humans. Periodate (PI)-based advanced oxidation processes (AOPs) have been employed to degrade BPA, although activating PI proves more challenging compared to other oxidants. A novel nano iron metal catalyst, sulfided nanoscale iron-nickel bimetallic nanoparticle supported on biocarbon (S-(nFe0-Ni)/BC) was synthesized and utilized to activate PI for the removal of BPA. The morphology, structure, and composition of S-(nFe0-Ni)/BC were characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy-energy dispersive spectrometer (SEM-EDS), and fourier-transform infrared spectrum (FTIR). The catalyst demonstrates an excellent ability to activate PI, achieving a BPA removal efficacy of 86.4%, accompanied by a 33% reduction in total organic carbon (TOC) in the {S-(nFe0-Ni)/BC}/PI system. BPA degradation exhibited a significant change at the 5-min mark. In the first stage (0-5 min), nonlinear dynamic fitting research, combined with scavenging experiments, unveiled the competitive degradation of pollutants primarily driven by iodate radical ( IO 3 · ), singlet oxygen1 O 2 , and hydroxyl radical ( · OH ). The competitive dynamics aligned with the ExpAssoc model. The contribution rates of different active species during the second stage (5-120 min) were calculated. The contributions of main species to BPA removal follow the order of IO 3 · >1 O 2 > · OH throughout the entire process. The influence of various parameters, such as the dosage of S-(nFe0-Ni)/BC, initial PI concentration, BPA concentration, pH, temperature, and the presence of coexisting anions, was also examined. Finally, a plausible reaction mechanism in the system is proposed, suggesting that the {S-(nFe0-Ni)/BC}/PI system involves a heterogeneous synergistic reaction occurring primarily on the surface of S-(nFe0-Ni)/BC. Therefore, this study proposes a promising approach for PI-based AOPs to degrade organic pollutants, aiming to mitigate the irreversible harm caused by such pollutants to organisms and the environment.

Boosting Efficient Alkaline Hydrogen Evolution Reaction of CoFe-Layered Double Hydroxides Nanosheets via Co-Coordination Mechanism of W-Doping and Oxygen Defect Engineering

While surface defects and heteroatom doping exhibit promising potential in augmenting the electrocatalytic hydrogen evolution reaction (HER), their performance remains unable to rival that of the costly Pt-based catalysts. Yet, the concurrent modification of catalysts by integrating both approaches stands as a promising strategy to effectively address the aforementioned limitation. In this work, tungsten dopants are introduced into self-supported CoFe-layered double hydroxides (LDH) on nickel foam using a hydrothermal method, and oxygen vacancies (Ov) are further introduced through calcination. The analysis results demonstrated that tungsten doping reduces the Ov formation energy of CoFeW-LDH. The Ov acted as oxophilic sites, facilitating water adsorption and dissociation, and reducing the barrier for cleaving HO─H bonds from 0.64 to 0.14 eV. Additionally, Ov regulated the electronic structure of CoFeW-LDH to endow optimized hydrogen binding ability on tungsten atoms, thereby accelerating alkaline Volmer and Heyrovsky reaction kinetics. Specifically, the abundance of Ov induced a transition of tungsten from a six-coordinated to highly active four-coordinated structure, which becomes the active site for HER. Consequently, an ultra-low overpotential of 41 mV at 10 mA cm-2 , and a low Tafel slope of 35 mV dec-1 are achieved. These findings offer crucial insights for the design of efficient HER electrocatalysts.

Construct Robust Epitaxial Growth of (101) Textured Zinc Metal Anode for Long Life and High Capacity in Mild Aqueous Zinc-Ion Batteries

Aqueous zinc-metal batteries are considered to have the potential for energy storage due to their high safety and low cost. However, the practical applications of zinc batteries are limited by dendrite growth and side reactions. Epitaxial growth is considered an effective method for stabilizing Zn anode, especially for manipulating the (002) plane of deposited zinc. However, (002) texture zinc is difficult to achieve stable cycle at high capacity due to its large lattice distortion and uneven electric field distribution. Here, a novel zinc anode with highly (101) texture (denoted as (101)-Zn) is constructed. Due to unique directional guidance and strong bonding effect, (101)-Zn can achieve dense vertical electroepitaxy in near-neutral electrolytes. In addition, the low grain boundary area inhibits the occurrence of side reactions. The resultant (101)-Zn symmetric cells exhibit excellent stability over 5300 h (4 mA cm-2 for 2 mAh cm-2 ) and 330 h (15 mA cm-2 for 10 mAh cm-2 ). Meanwhile, the cycle life of Zn//MnO2 full cell is meaningfully improved over 1000 cycles.

Unraveling the molecular mechanisms of selenite reduction: transcriptomic analysis of Bacillus reveals the key role of sulfur assimilation

Selenite biotransformation by microorganisms is an effective detoxification and assimilation process. However, current knowledge of the molecular mechanisms of selenite reduction remains circumscribed. Here, the reduction of Se(IV) by a highly selenite-resistant Bacillus sp. SL (up to 50 mM) was systematically analyzed, and the molecular mechanisms of selenite reduction were investigated. Remarkably, 10 mM selenite was entirely transformed by the strain SL within 20 h, demonstrating a faster conversion rate compared to other microorganisms. Furthermore, glutathione (GSH) and exopolysaccharides (EPS) changes were also monitored during the process. Transcriptomic analysis revealed that the genes of ferredoxin-sulfite oxidoreductase (6.82) and sulfate adenylyltransferase (6.32) were significantly upregulated, indicating that the sulfur assimilation pathway is the primary reducing pathway involved in selenite reduction by strain SL. Moreover, key genes associated with NAD(P)/FAD-dependent oxidoreductases and thioredoxin were significantly upregulated. The reduction of Se(IV) was mediated by multiple pathways in strain SL. To our knowledge, this is the initial report to identify the involvement of sulfur assimilation pathway in selenite reduction for bacillus, which is rare in aerobic bacteria.

Biodegradable electrospinning superhydrophilic nanofiber membranes for ultrafast oil-water separation

Although membrane technology has attracted considerable attention for oily wastewater treatment, the plastic waste generated from discarded membranes presents an immediate challenge for achieving eco-friendly separation. We designed on-demand biodegradable superhydrophilic membranes composed of polylactic acid nanofibers in conjunction with polyethylene oxide hydrogels using electrospinning technology for ultrafast purification of oily water. Our results showed that the use of the polyethylene oxide hydrogels increased the number of hydrogen bonds formed between the membrane surface and water molecules by 357.6%. This converted hydrophobic membranes into superhydrophilic ones, which prevented membrane fouling and accelerated emulsion penetration through the membranes. The oil-in-water emulsion permeance of our newly designed nanofiber membranes increased by 61.9 times (2.1 × 104 liters per square meter per hour per bar) with separation efficiency >99.6%, which was superior to state-of-the-art membranes. Moreover, the formation of hydrogen bonds was found to accelerate polylactic acid biodegradation into lactic acid by over 30%, offering a promising approach for waste membrane treatment.

Spatial distribution and temporal trend of organochlorine pesticides in Chinese surface soil

Although organochlorine pesticides (OCPs) in the Stockholm Convention List were banned for a period of time, the residue of OCPs in environment was still detected recently. Therefore, the continuous environmental monitoring was necessary and important for the deep understanding on the temporal trend of environmental fate of OCPs. In this study, the national scale surface soil samples in 26 provinces of China in 2012 were collected, and 28 OCPs were analyzed. The mean concentrations (ng/g dw) of Σhexachlorocyclohexanes (HCHs), Σdichlorodiphenyltrichloroethane (DDTs), hexachlorobenzene (HCB), and hexachlorobutadiene (HCBD) were 2.47 ± 5.4, 4.29 ± 8.28, 3.33 ± 7.68, and 0.041 ± 0.097, respectively. The correlations between OCPs concentrations with temperature, latitude, and longitude were conducted for the deep study of the spatial distribution pattern of OCPs. It was found that HCHs, HCB, and HCBD are positively correlated with latitude and longitude; however, the correlations were not significant. HCHs followed the secondary distribution pattern, and DDTs followed both the primary and/or secondary distribution patterns. Except for HCB, other OCPs showed a gradual downward trend from 2005 to 2012, indicating the effectiveness of the phase-out of OCPs. In summary, the results of the study provided new insight into the related studies, which will help us to better understand the long-term environmental fate of OCPs on large scales.

Key Roles of Interfacial OH- ion Distribution on Proton Coupled Electron Transfer Kinetics Toward Urea Oxidation Reaction

Enhancing alkaline urea oxidation reaction (UOR) activity is essential to upgrade renewable electrolysis systems. As a core step of UOR, proton-coupled electron transfer (PCET) determines the overall performance, and accelerating its kinetic remains a challenge. In this work, a newly raised electrocatalyst of NiCoMoCuO_x H_y with derived multi-metal co-doping (oxy)hydroxide species during electrochemical oxidation states is reported, which ensures considerable alkaline UOR activity (10/500 mA cm^-2 at 1.32/1.52 V vs RHE, respectively). Impressively, comprehensive studies elucidate the correlation between the electrode-electrolyte interfacial microenvironment and the electrocatalytic urea oxidation behavior. Specifically, NiCoMoCuO_x H_y featured with dendritic nanostructure creates a strengthened electric field distribution. This structural factor prompts the local OH^- enrichment in electrical double layer (EDL), so that the dehydrogenative oxidation of the catalyst is directly reinforced to facilitate the subsequent PCET kinetics of nucleophilic urea, resulting in high UOR performance. In practical utilization, NiCoMoCuO_x H_y -driven UOR coupled cathodic hydrogen evolution reaction (HER) and carbon dioxide reduction reaction (CO₂ RR), and harvested high value-added products of H₂ and C₂ H₄ , respectively. This work clarifies a novel mechanism to improve electrocatalytic UOR performance through structure-induced interfacial microenvironment modulation.

Simultaneous determination of fourteen pharmaceuticals in sewage sludge using online solid-phase extraction-liquid chromatography-tandem mass spectrometry combined with accelerated solvent extraction

An online solid-phase extraction (SPE) liquid chromatography tandem mass spectrometry method (HPLC-MS/MS) combined with accelerated solvent extraction (ASE) was developed for simultaneous determination of 14 pharmaceuticals in sludge. In the online SPE procedures, ultrapure water with no additives was used as the loading solvent. In addition, low molecular weight targets such as atenolol were difficult to retain on SPE column after acetone was added to the washing solvent. The response signal of analytes can be greatly improved by adding 0.2% formic acid to the mobile phase. Under the optimized conditions, the recoveries of all the analytes ranged between 75.1 and 112%. Moreover, the limit of detections ranged from 1.8 to 7.9 ug/kg. The precision of analytical data was determined with relative standard deviation (RSD) ≤ 4.87%. This method was successfully applied to determine the concentration of pharmaceuticals in sludge.

Nanozyme-Participated Biosensing of Pesticides and Cholinesterases: A Critical Review

To improve the output and quality of agricultural products, pesticides are globally utilized as an efficient tool to protect crops from insects. However, given that most pesticides used are difficult to decompose, they inevitably remain in agricultural products and are further enriched into food chains and ecosystems, posing great threats to human health and the environment. Thus, developing efficient methods and tools to monitor pesticide residues and related biomarkers (acetylcholinesterase and butylcholinesterase) became quite significant. With the advantages of excellent stability, tailorable catalytic performance, low cost, and easy mass production, nanomaterials with enzyme-like properties (nanozymes) are extensively utilized in fields ranging from biomedicine to environmental remediation. Especially, with the catalytic nature to offer amplified signals for highly sensitive detection, nanozymes were finding potential applications in the sensing of various analytes, including pesticides and their biomarkers. To highlight the progress in this field, here the sensing principles of pesticides and cholinesterases based on nanozyme catalysis are definitively summarized, and emerging detection methods and technologies with the participation of nanozymes are critically discussed. Importantly, typical examples are introduced to reveal the promising use of nanozymes. Also, some challenges in the field and future trends are proposed, with the hope of inspiring more efforts to advance nanozyme-involved sensors for pesticides and cholinesterases.

An improved ASM-GDA approach to evaluate the production kinetics of loosely bound and tightly bound extracellular polymeric substances in biological phosphorus removal process

This study established an extended activated sludge model no. 2 (ASM2) for providing a new recognition of the contributions of both loosely-bound EPS (LB-EPS) and tightly-bound EPS (TB-EPS) into phosphorus (P) removal by incorporating their formation and degradation processes during the anaerobic-aerobic cycle. For determining the best-fit values for the new model parameters (k _h,TB-EPS, k _h,LB-EPS, f _PP,TB-EPS, and f _PP,LB-EPS) in this extended ASM2, a novel and convenient gradient descent algorithm (GDA) based ASM (ASM-GDA) method was developed. Sensitivity analysis of f _PP,TB-EPS, f _PP,LB-EPS, k _h,TB-EPS, and k _h,LB-EPS on the model target outputs of S _PO4 , X _TB-EPS, X _LB-EPS, and X _PP proved the accuracy of the chosen parameters. Eight batch experiments conducted under different influential chemical oxygen demand (COD) and P conditions were quantitatively and qualitatively analyzed. Respectively, 9.37-9.64% and 4.17-4.29% of P removal by TB-EPS and LB-EPS were achieved. Self-Organizing Map (SOM) has shown its high performance for visualization and abstraction for exhibiting the high correlations of the influential COD/P concentrations and the P% removal by TB-EPS (and LB-EPS). Comprehensive analyses of the influences of influential COD and P concentration on the biological phosphorus removal process help us in successfully establishing the mechanism kinetics of production and degradation of P in a dynamic P biological-treatment model.

Bacterial Concentration Detection using a PCB-based Contactless Conductivity Sensor

Capacitively coupled contactless conductivity detection (C⁴D) is an improved approach to avoid the problems of labor-intensive, time-consuming and insufficient accuracy of plate count as well as the high-cost apparatus of flow cytometry (FCM) in bacterial counting. This article describes a novel electrode-integrated printed-circuit-board (PCB)-based C⁴D device, which supports the simple and safe exchange of capillaries and improves the sensitivity and repeatability of the contactless detection. Furthermore, no syringe pump is needed in the detection, it reduces the system size, and, more importantly, avoids the effect on the bacteria due to high pressure. The recovered bacteria after C⁴D detection at excitation of 25 Vpp and 60⁻120 kHz were analyzed by flow cytometry, and a survival rate higher than 96% was given. It was verified that C⁴D detection did not influence the bacterial viability. Moreover, bacteria concentrations from 10⁶ cells/mL to 10⁸ cells/mL were measured in a linear range, and relative standard deviation (RSD) is below 0.2%. In addition, the effects on bacteria and C⁴D from background solutions were discussed. In contrast to common methods used in most laboratories, this method may provide a simple solution to in situ detection of bacterial cultures.

Quantitative proteomic analysis reveals the ethanologenic metabolism regulation of Ethanoligenens harbinense by exogenous ethanol addition

BACKGROUND

H₂-ethanol-coproducing bacteria, as primary fermenters, play important roles in the microbiome of bioreactors for bioenergy production from organic wastewater or solid wastes. Ethanoligenens harbinense YUAN-3 is an anaerobic ethanol-H₂-fermenting bacterium. Ethanol is one of the main end-products of strain YUAN-3 that influence its fermentative process. Until recently, the molecular mechanism of metabolic regulation in strain YUAN-3 during ethanol accumulation has still been unclear. This study aims to elucidate the metabolic regulation mechanisms in strain YUAN-3, which contributes to effectively shape the microbiome for biofuel and bioenergy production from waste stream.

RESULTS

This study reports that ethanol stress altered the distribution of end-product yields in the H₂-ethanol-coproducing Ethanoligenens harbinense strain YUAN-3. Decreasing trends of hydrogen yield from 1888.6 ± 45.8 to 837 ± 64.7 mL L^-1 and acetic acid yield from 1767.7 ± 45 to 160.6 ± 44.7 mg L^-1 were observed in strain YUAN-3 with increasing exogenous ethanol (0 mM-200 mM). However, the ethanol yield of strain YUAN-3 increased by 15.1%, 30.1%, and 27.4% in 50 mM, 100 mM, and 200 mM ethanol stress, respectively. The endogenous ethanol accounted for 96.1% (w/w) in liquid end-products when exogenous ethanol of 200 mM was added. The molar ratio of ethanol to acetic acid increased 14 times (exogenous ethanol of 200 mM) compared to the control. iTRAQ-based quantitative proteomic analysis indicated that 263 proteins of strain YUAN-3 were differentially expressed in 50 mM, 100 mM, and 200 mM of exogenous ethanol. These proteins are mainly involved in amino acid transport and metabolism, central carbon metabolism, and oxidative stress response.

CONCLUSION

These differentially expressed proteins play important roles in metabolic changes necessary for growth and survival of strain YUAN-3 during ethanol stress. The up-regulation of bifunctional acetaldehyde-CoA/alcohol dehydrogenase (ADHE) was the main reason why ethanol production was enhanced, while hydrogen gas and acetic acid yields declined in strain YUAN-3 during ethanol stress. This study also provides a new approach for the enhancement of ethanologenesis by H₂-ethanol-coproducing bacteria through exogenous ethanol addition.

Rapid in vivo lipid/carbohydrate quantification of single microalgal cell by Raman spectral imaging to reveal salinity-induced starch-to-lipid shift

BACKGROUND

Lipid/carbohydrate content and ratio are extremely important when engineering algal cells for liquid biofuel production. However, conventional methods for such determination and quantification are not only destructive and tedious, but also energy consuming and environment unfriendly. In this study, we first demonstrate that Raman spectroscopy is a clean, fast, and accurate method to simultaneously quantify the lipid/carbohydrate content and ratio in living microalgal cells.

RESULTS

The quantification results of both lipids and carbohydrates obtained by Raman spectroscopy showed a linear correspondence with that obtained by conventional methods, indicating Raman can provide a similar accuracy to conventional methods, with a significantly shorter detection time. Furthermore, the subcellular resolution of Raman spectroscopy enabled not only the concentration mapping of lipid/carbohydrate content in single living cells, but also the evaluation of standard deviation between the biomass accumulation levels of individual algal cells.

CONCLUSIONS

In this study, we first demonstrate that Raman spectroscopy can be used for starch quantification in addition to lipid quantification in algal cells. Due to the easiness and non-destructive nature of Raman spectroscopy, it makes a perfect tool for the further study of starch-lipid shift mechanism.