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In this study, we have utilized theoretical calculations to predict the reaction active sites of naproxen when reacting with radicals and to further study the thermodynamics and kinetics of the reactions with ·OH and SO4-·. The evidence, derived from the average local ionization energy and electrostatic potential, points to the naphthalene ring as the preferred site of attack, especially for the C2, C6, C9, and C10 sites. The changes in Gibbs free energy and enthalpy of the reactions initiated by ·OH and SO4-· ranged between -19.6 kcal/mol - 26.3 kcal/mol and -22.3 kcal/mol -18.5 kcal/mol, respectively. More in-depth investigation revealed that RA2 pathway for ·OH exhibited the lowest free energy of activation, suggesting this reaction is more inclined to proceed. The second-order rate constant results indicate the ·OH attacking reaction is faster than reactions initiated by SO4·-, yet controlled by diffusion. The consistency between theoretical findings and experimental data underscores the validity of this computational method for our study.
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Radical Hidroxilo , Naproxeno , Sulfatos , Termodinámica , Naproxeno/química , Cinética , Radical Hidroxilo/química , Sulfatos/química , Agua/química , Modelos QuímicosRESUMEN
It is still a challenge to construct single-atom level reduction and oxidation sites in single-component photocatalyst by manipulating coordination configuration for photocatalytic water splitting. Herein, the atomically dispersed asymmetric configuration of six-coordinated Co-S2O4 (two exposed S atoms, two OH groups, and two CoâOâZn bonds) suspending on ZnIn2S4 nanosheets verified by combining experimental analysis with theoretical calculation, is applied into photocatalytic water splitting. The Co-S2O4 site immobilized by Vs acts as oxidation sites to guide electrons transferring to neighboring independent S atom, achieving efficient separation of reduction and oxidation sites. It is worth mentioning that stabilized Co-S2O4 configuration show dynamic structure evolution to highly active Co-S1O4 configuration (one exposed S atom, one OH group, and three CoâOâZn bonds) in reaction, which lowers energy barrier of transition state for H2O activization. Ultimately, the optimized photocatalyst exhibits excellent photocatalytic activity for water splitting (H2: 80.13 µmol g-1 h-1, O2: 37.81 µmol g-1 h-1) and outstanding stability than that of multicomponent photocatalysts due to dynamic and reversible evolution between stable Co-S2O4 configuration and active Co-S1O4 configuration. This work demonstrates new cognitions on immobilized strategy through vacancy inducing, manipulating coordination configuration, and dynamic evolution mechanism of single-atom level catalytic site in photocatalytic water splitting.
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Microalgae photobioreactor (PBR) is a kind of efficient wastewater treatment system for nitrogen removal. However, there is still an urgent need for process optimization of PBR. Especially, the synergistic effect and optimization of light and flow state poses a challenge. In this study, the computational fluid dynamics is employed for simulating the optimization of the number and length of the internal baffles, as well as the aeration rate of PBR, which in turn leads to the optimal growth of microalgae and efficient nitrogen removal. After optimization, the Light/Dark cycle of the reactor B is shortened by 51.6 %, and the biomass increases from 0.06 g/L to 3.94 g/L. In addition, the removal rate of NH4+-N increased by 106.0 % to 1.56 mg L-1 h-1. This work provides a feasible method for optimizing the design and operational parameters of PBR aiming the engineering application.
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Photocatalytic synthesis based on the oxygen reduction reaction (ORR) has shown great promise for H2O2 production. However, the low activity and selectivity of 2e- ORR result in a fairly low efficiency of H2O2 production. Herein, we propose a strategy to enhance the proton-coupled electron transfer (PCET) process in covalent organic frameworks (COFs), thereby significantly boosting H2O2 photosynthesis. We demonstrated that the construction of a hydrogen-bonding network, achieved by anchoring the H3PO4 molecular network on COF nanochannels, can greatly improve both proton conductivity and photogenerated charge separation efficiency of COFs. Thus, COF@H3PO4 exhibited superior photocatalytic performance in generating H2O2 without sacrificial agents, with a solar-to-chemical conversion efficiency as high as 0.69%. Results indicated that a much more localized spatial distribution of energy band charge density on COF@H3PO4 led to efficient charge separation, and the small energy barrier of the rate-limiting step from *OOH to H2O2 endowed COF@H3PO4 with higher 2e- ORR selectivity.
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Functionalized biochars are crucial for simultaneous soil remediation and safe agricultural production. However, a comprehensive understanding of the remediation mechanism and crop safety is imperative. In this work, the all-in-one biochars loaded with a Bacillus aryabhattai (B10) were developed via physisorption (BBC) and sodium alginate embedding (EBC) for simultaneous toxic As and Cd stabilization in soil. The bacteria-loaded biochar composites significantly decreased exchangeable As and Cd fractions in co-contaminated soil, with enhanced residual fractions. Heavy metal bioavailability analysis showed a maximum CaCl2-As concentration decline of 63.51% and a CaCl2-Cd decline of 50.96%. At a 3% dosage of composite, rhizosphere soil showed improved organic matter, cation exchange capacity, and enzyme activity. The aboveground portion of water spinach grown in pots was edible, with final As and Cd contents (0.347 and 0.075 mg·kg⻹, respectively) meeting food safety standards. Microbial analysis revealed the composite's influence on the rhizosphere microbial community, favoring beneficial bacteria and reducing plant pathogenic fungi. Additionally, it increased functional microorganisms with heavy metal-resistant genes, limiting metal migration in plants and favoring its growth. Our research highlights an effective strategy for simultaneous As and Cd immobilization in soil and inhibition of heavy metal accumulation in vegetables.
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Arsénico , Bacillus , Ipomoea , Metales Pesados , Contaminantes del Suelo , Cadmio/toxicidad , Cadmio/análisis , Arsénico/análisis , Cloruro de Calcio , Metales Pesados/análisis , Carbón Orgánico/farmacología , Suelo , Bacterias , Contaminantes del Suelo/análisisRESUMEN
Conventional microalgal-bacterial consortia have limited capacity to treat low-C/N wastewater due to carbon limitation and single nitrogen (N) removal mode. In this work, indigenous synergetic microalgal-bacterial consortia with high N removal performance and bidirectional interaction were successful in treating rare earth tailing wastewaters with low-C/N. Ammonia removal reached 0.89 mg N L-1 h-1, 1.84-fold more efficient than a common microalgal-bacterial system. Metagenomics-based metabolic reconstruction revealed bidirectional microalgal-bacterial interactions. The presence of microalgae increased the abundance of bacterial N-related genes by 1.5- to 57-fold. Similarly, the presence of bacteria increased the abundance of microalgal N assimilation by 2.5- to 15.8-fold. Furthermore, nine bacterial species were isolated, and the bidirectional promotion of N removal by the microalgal-bacterial system was verified. The mechanism of microalgal N assimilation enhanced by indole-3-acetic acid was revealed. In addition, the bidirectional mode of the system ensured the scavenging of toxic byproducts from nitrate metabolism to maintain the stability of the system. Collectively, the bidirectional enhancement system of synergetic microalgae-bacteria was established as an effective N removal strategy to broaden the stable application of this system for the effective treatment of low C/N ratio wastewater.
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Microalgas , Aguas Residuales , Microalgas/metabolismo , Desnitrificación , Nitrógeno/metabolismo , Bacterias/metabolismo , BiomasaRESUMEN
The long-standing crisis of soil salinization and alkalization poses a significant challenge to global agricultural development. High soil salinity-alkalinity, water dispersion, and nutrient loss present major hurdles to soil improvement. Novel environmentally friendly gels have demonstrated excellent water retention and slow-release capabilities in agricultural enhancement. However, their application for improving saline-alkali soil is both scarce and competitive. This study proposes a new strategy for regulating saline-alkali soil using gel-coated controlled-release soil modifiers (CWR-SRMs), where radical-polymerized gels are embedded on the surface of composite gel beads through spray coating. Characterization and performance analysis reveal that the three-dimensional spatial network structure rich in hydrophilic groups exhibits good thermal stability (first-stage weight loss temperature of 257.7 °C in thermogravimetric analysis) and encapsulation efficiency for fulvic acidpotassium (FA-K), which can enhance soil quality in saline-alkali environments. The molecular chain relaxation under saline-alkali conditions promotes a synergistic effect of swelling and slow release, endowing it with qualifications as a water reservoir, Ca2+ source unit, and slow-release body. The results of a 6 weeks incubation experiment on 0-20 cm saline-alkaline soil with different application gradients showed that the gradient content had a significant effect on the soil improvement effect. Specifically, the T2 (the dosage accounted for 1 % of soil mass) treatment significantly increases water retention (30 % ~ 90 %), and nutrient levels (30 % ~ 50 %), while significantly decreasing soil sodium colloid content (30 % ~ 60 %) and soil pH (10 % ~ 15 %). Furthermore, PCA analysis indicates that the addition of 1 % CWR-SRMs as amendments can significantly adjust the negative aspects of soil salinity and alkalinity. This highlights the excellent applicability of CWR-SRMs in improving saline-alkali agricultural ecosystems, demonstrating the potential value of novel environmentally friendly gels as an alternative solution for soil challenges persistently affected by adverse salinity and alkalinity.
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Endophytes can assist crops in adapting to high temperatures and drought conditions, thereby reducing agricultural losses. However, the mechanism through which endophytes regulate crop resistance to high temperatures and drought stress remains unclear, and concerns regarding safety and stability exist with active endophytes. Thus, heat-treated endophytic bacteria LSE01 (HTB) were employed as a novel microbial fertilizer to investigate their effects on plant adaptation to high temperatures and drought conditions. The results indicated that the diameter and weight of tomatoes treated with HTB under stress conditions increased by 23.04% and 71.15%, respectively, compared to the control. Tomato yield did not significantly decrease compared to non-stress conditions. Additionally, the contents of vitamin C, soluble sugars, and proteins treated with HTB increased by 18.81%, 11.54%, and 99.75%, respectively. Mechanistic research revealed that HTB treatment enhances tomato's stress resistance by elevating photosynthetic pigment and proline contents, enhancing antioxidant enzyme activities, and reducing the accumulation of MDA. Molecular biology research demonstrates that HTB treatment upregulates the expression of drought-resistant genes (GA2ox7, USP1, SlNAC3, SlNAC4), leading to modifications in stomatal conductance, plant morphology, photosynthetic intensity, and antioxidant enzyme synthesis to facilitate adaptation to dry conditions. Furthermore, the upregulation of the heat-resistant gene (SlCathB2-2) can increases the thickness of tomato cell walls, rendering them less vulnerable to heat stress. In summary, HTB endows tomatoes with the ability to adapt to high temperatures and drought conditions, providing new opportunities for sustainable agriculture.
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Endófitos , Salicilatos , Solanum lycopersicum , Endófitos/fisiología , Estrés Fisiológico , Antioxidantes , Sequías , TemperaturaRESUMEN
Direct photocatalytic reduction of toxic formaldehyde (HCHO) in value-added chemicals and fuels is promising because that not only abates the environmental pollution, but also solves the energy shortage. Herein, self-supported MoO2 and MoO3 nanoparticles growing on Mo meshes were comparatively applied to the photocatalytic conversion of HCHO. Under UV-visble lights, MoO2 reduces HCHO in methanol (CH3OH) while MoO3 oxidizes HCHO in carbon oxide and water. Their contrary photocatalytic capacities were revealed. Compared with MoO3, the lower work function of MoO2 enables an electron-rich interface, realizing a complete reduction of 30 ppm HCHO to CH3OH in 30 min. Theoretical calculations clarify that a large number of delocalized electrons on MoO2 attracts HCHO molecule and activates its CO bond, facilitating subsequent hydrogenation and reduction of HCHO to CH3OH. As for MoO3, the wider bandgap and higher potential of valence band govern the photocatalytic oxidation of HCHO.
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Anode materials with excellent properties have become the key to develop sodium-ion hybrid capacitors (SIHCs) that combine the advantages of both batteries and capacitors. Amorphous modulation is an effective strategy to realize high energy/power density in SIHCs. Herein, atomically amorphous Nb-O/N clusters with asymmetric coordination are in situ created in N-doped hollow carbon shells (Nb-O/N@C). The amorphous clusters with asymmetric Nb-O3/N1 configurations have abundant charge density and low diffusion energy barriers, which effectively modulate the charge transport paths and improve the reaction kinetics. The clusters are also enriched with unsaturated vacancy defects and isotropic ion-transport channels, and their atomic disordering exhibits high structural stress buffering, which are strong impetuses for realizing bulk-phase-indifferent ion storage and enhancing the storage properties of the composite. Based on these features, Nb-O/N@C achieves notably improved sodium-ion storage properties (reversible capacity of 240.1 mAh g-1 at 10.0 A g-1 after 8000 cycles), and has great potential for SIHCs (230 Wh Kg-1 at 4001.5 W Kg-1). This study sheds new light on developing high-performance electrodes for sodium-ion batteries and SIHCs by designing amorphous clusters and asymmetric coordination.
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Extreme fast charging of Ampere-hour (Ah)-scale electrochemical energy storage devices targeting charging times of less than 10 minutes are desired to increase widespread adoption. However, this metric is difficult to achieve in conventional Li-ion batteries due to their inherent reaction mechanism and safety hazards at high current densities. In this work, we report 1 Ah soft-package potassium-ion hybrid supercapacitors (PIHCs), which combine the merits of high-energy density of battery-type negative electrodes and high-power density of capacitor-type positive electrodes. The PIHC consists of a defect-rich, high specific surface area N-doped carbon nanotube-based positive electrode, MnO quantum dots inlaid spacing-expanded carbon nanotube-based negative electrode, carbonate-based non-aqueous electrolyte, and a binder- and current collector-free cell design. Through the optimization of the cell configuration, electrodes, and electrolyte, the full cells (1 Ah) exhibit a cell voltage up to 4.8 V, high full-cell level specific energy of 140 Wh kg-1 (based on the whole mass of device) with a full charge of 6 minutes. An 88% capacity retention after 200 cycles at 10 C (10 A) and a voltage retention of 99% at 25 ± 1 °C are also demonstrated.
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Photocatalytic CO2 reduction has been regarded as an ideal method to simulate photosynthesis for achieving carbon neutralization. However, poor charge transfer efficiency limits its development. Herein, an efficient Co/CoP@C catalyst was prepared with compact contact of Co and CoP layer by using MOF as precursor. At the interface of Co/CoP, the difference in functionality between the two phases may result in uneven distribution of electrons, thus forming a self-driven space-chare region. In this region, spontaneous electron transfer is guaranteed, thus facilitating the effective separation of photogenerated carriers as well as boosting the utilization of solar energy. Furthermore, the electron density of active site Co in CoP is increased and more active sites are exposed, which promotes the adsorption and activation of CO2 molecules. Together with suitable redox potential, low energy barrier for *COOH formation and easy desorption of CO, the reduction rate of CO2 catalyzed by Co/CoP@C is 4 times higher than that of CoP@C.
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Sodium-ion batteries (SIBs) as economic candidates have received considerable attention for large-scale energy storage applications. However, crystalline metal compounds with specific transport routes and rigid structures restrict their practical applications. Herein, the atomically dispersed N-rich amorphous WN clusters confined in the carbon nanosheets (WN/CNSs) are reported. Through advanced tests and calculations, the structural advantages, reaction mechanisms, and kinetic behaviors of the clusters are systematically analyzed. Compared with the crystalline W2 N with low theoretical capacity (only 209.3 mAh g-1 ), the amorphous WN clusters have the advantages of atomic disorders and non-grain boundaries and can afford abundant active sites (unsaturated dangling bonds) and isotropic charge transfer channels, which can be further enhanced by the N-rich characteristics and high electronegativity of the clusters. The encapsulation of CNSs has high conductivity and structural stability, which promotes electron transfer and effectively buffers volume expansions. As a SIB anode, the reversible capacity of WN/CNSs reaches 421.2 mAh g-1 at 0.1 A g-1 . Even at 20 A g-1 , the reversible capacity of 170.7 mAh g-1 is maintained after 8000 cycles. This study focuses on the advantages of amorphous nitrides, which have important guiding significance for the design of atomic clusters for high-performance metal ion batteries.
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Traditional methods cannot efficiently recover Cu from Cu(II)-EDTA wastewater and encounter the formation of secondary contaminants. In this study, an ozone/percarbonate (O3/SPC) process was proposed to efficiently decomplex Cu(II)-EDTA and simultaneously recover Cu. The results demonstrate that the O3/SPC process achieves 100% recovery of Cu with the corresponding kobs value of 0.103 min-1 compared with the typical â¢OH-based O3/H2O2 process (81.2%, 0.042 min-1). The carbonate radical anion (CO3â¢-) is generated from the O3/SPC process and carries out the targeted attack of amino groups of Cu(II)-EDTA for decarboxylation and deamination processes, resulting in successive cleavage of Cu-O and Cu-N bonds. In comparison, the â¢OH-based O3/H2O2 process is predominantly responsible for the breakage of Cu-O bonds via decarboxylation and formic acid removal. Moreover, the released Cu(II) can be transformed into stable copper precipitates by employing an endogenous precipitant (CO32-), accompanied by toxic-free byproducts in the O3/SPC process. More importantly, the O3/SPC process exhibits excellent metal recovery in the treatment of real copper electroplating wastewater and other metal-EDTA complexes. This study provides a promising technology and opens a new avenue for the efficient decomplexation of metal-organic complexes with simultaneous recovery of valuable metal resources.
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Complejos de Coordinación , Ozono , Contaminantes Químicos del Agua , Aguas Residuales , Cobre , Ácido Edético/química , Peróxido de Hidrógeno , Oxidación-Reducción , Carbonatos , Contaminantes Químicos del Agua/químicaRESUMEN
Rare earth element tailings (REEs) wastewater, which has the characteristics of high ammonia nitrogen (NH4+-N) and low COD. It can cause eutrophication and biotoxicity in water which is produced in high volumes, requiring treatment before final disposal. Microalgae-Bacteria symbiotic (MBS) system can be applied in REEs wastewater, but its low extent of nitrogen removal and instability limit its application. By adding biodegradable carrier as both carbon source and carrier, the system can be stabilized and the efficiency can be improved. In this work, the extent of NH4+-N removal reached 100% within 24 h in a MBS system after adding loofah under optimal conditions, and the removal rate reached 127.6 mg NH4+-N·L-1·d-1. In addition, the carbon release from loofah in 3 d reached 408.7 mg/L, which could be used as a carbon source to support denitrification. During 90 d of operation of the MBS system loaded with loofah, the effluent NH4+-N was less than 15 mg/L. At phylum level, Proteobacteria were dominant which accounted for 78.2%. Functional gene analysis showed that enhancement of microalgae assimilation was the main factor affecting NH4+-N removal. This work expands our understanding of the enhanced role of carbon-based carriers in the denitrification of REEs wastewater.
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Luffa , Microalgas , Aguas Residuales , Desnitrificación , Microalgas/genética , Nitrógeno/análisis , Reactores Biológicos , Bacterias/genética , CarbonoRESUMEN
Copper and zinc are toxic heavy metals in soils that require development of feasible strategies for remediation of contaminated soils around the mine areas. In this study, the processing conditions and mechanisms of immobilization and bioleaching for remediation of highly contaminated soils with heavy metals are investigated. Soil remediation is carried out using a bioleaching-immobilization bipolar method. The results show that LSE03 bacteria provide efficient leaching result and immobilization on Cu2+ and Zn2+. Among the bacterial metabolites, cis, cis-muconic acid and isovaleric acid play major roles in the bioleaching process. The bacterial extracellular polymeric substances are rich in a variety of organic acids that show a significant decrease in content after the adsorption process, indicating that all of these substances are involved in the binding of heavy metals. Characterization of the endophytes and immobilizing agents with FTIR, TEM-mapping, and XPS techniques reveal the ability of both bacteria and composites to adsorb Cu-Zn as well as the main functional groups of -OH, -COOH, -PO43-, and -NH. According to the heavy metals species analyses, competitive adsorption experiments, and bioleaching desorption experiments, it is planned to carry out the bipolar remediation of contaminated soil through immobilization followed by bioleaching process. After bipolar remediation processing, 97.923% and 96.387% of available Cu and Zn are respectively removed. Soils fertility significantly increases in all cases. Our study provides a green, practical, and environmentally friendly treatment method for soils contaminated with high concentrations of heavy metals.
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Metales Pesados , Contaminantes del Suelo , Zinc/análisis , Cobre/química , Endófitos , Suelo/química , Metales Pesados/análisis , Compuestos Orgánicos , Hidroxiapatitas , Contaminantes del Suelo/análisisRESUMEN
Given the large amount of toxic Cr(VI) wastewater from various industries, it is urgent to take effective treatment measures. Adsorption has been regarded as highly desirable for Cr(VI) removal, but the effectiveness of most adsorbents is significantly dependent on pH value, in which precipitous performance drop and even structural collapse generally occur in strong acidic/alkaline aqueous. Thus, maintaining high adsorption performance and structural integrity over a wide pH range is challenging. To efficiently remove Cr(VI), we designed and prepared of an acid-base resistant metal-organic framework (MOF) Zr-BDPO, by introducing weak acid-base groups (-NH-, -N= and -OH) onto the ligand. Zr-BDPO achieved a maximum adsorption capacity of 555.6 mg·g-1 and retained skeletal structure at pH= 1-11. Interestingly, all these groups can generate conjugate acid-base pairs by means of H+ and OH- in the external solution and then form buffer layer. The removal of Cr(VI) at a broad range of pH values primarily via hydrogen bonds between -NH- and -OH, and the oxoanion species of Cr(VI) is unusual. This strategy that insulating high concentrations of acids and bases and relying on hydrogen bonds to capture Cr(VI) oxoanions provides a new perspective for actual Cr(VI) wastewater treatment.
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Estructuras Metalorgánicas , Contaminantes Químicos del Agua , Adsorción , Emparejamiento Base , Cromo/química , Enlace de Hidrógeno , Concentración de Iones de Hidrógeno , Cinética , Ligandos , Aguas Residuales , Contaminantes Químicos del Agua/químicaRESUMEN
Rational synthesis of metal-organic frameworks (MOFs) via structural and morphology engineering are fundamental for enhanced heavy metal removal. Beyond tuning intrinsic characteristics, it is essential to address inseparability and instability issues of MOFs to fulfill the practical applications. Herein, we successfully constructed macroscopic zeolitic imidazole frameworks-functionalized melamine sponge (MS@ZIFx, x represents the ultrasonication duration) using a facile dip-coating method. By varying ultrasonication duration, the morphology and structure of the loaded ZIF were modulated from leaf-shaped phase to hollow mixed phase to achieve the excellent adsorption performance. The optimized MS-ZIF10 exhibited significantly enhanced performance for Pb(II) and Cu(II) adsorption. Specifically, the MS-ZIF10 combined high adsorption capacities (624.8 and 588.6 mg g-1 for Pb(II) and Cu(II), respectively), rapid kinetics, excellent anti-interfering capability (e.g., cations, dissolved organic matters) with outstanding reusability (removal efficiency > 91.8 % after 10 cycles). The MS-ZIF10 presented satisfactory performance on Pb(II) and Cu(II) removal in various real water matrices. Fixed-bed experiments were performed to assess the practicality of MS-ZIF10, and 1821 bed volumes (BVs) and 1630 BVs of feeding streams containing Pb(II) and Cu(II) were effectively treated. This work proposed a novel paradigm for promoting the MOF's performance and simultaneously boosting MOF's application in actual heavy metal removal.
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Estructuras Metalorgánicas , Metales Pesados , Contaminantes Químicos del Agua , Zeolitas , Plomo , Contaminantes Químicos del Agua/química , Metales Pesados/química , Adsorción , Estructuras Metalorgánicas/química , Imidazoles , CinéticaRESUMEN
Limited by the electrostatic interaction, the oxidation reaction of cations at the anode and the reduction reaction of anions at the cathode in the electrocatalytic system nearly cannot be achieved. This study proposes a novel strategy to overcome electrostatic interaction via strong complexation, realizing the electrocatalytic reduction of cyanide (CN- ) at the cathode and then converting the generated reduction products into nitrogen (N2 ) at the anode. Theoretical calculations and experimental results confirm that the polarization of the transition metal oxide cathodes under the electric field causes the strong chemisorption between CN- and cathode, inducing the preferential enrichment of CN- to the cathode. CN- is hydrogenated by atomic hydrogen at the cathode to methylamine/ammonia, which are further oxidized into N2 by free chlorine derived from the anode. This paper provides a new idea for realizing the unconventional and unrealizable reactions in the electrocatalytic system.