Formate Research Articles

Effects of Heterogeneous Mixing of Imidazolium-Based Ionic Liquids with Alcohols on Complex Formation of Ni(II) Ion.

Understanding the complex formation of metal ions in room-temperature ionic liquids (ILs) is essential for the application of ILs in solvent extraction. Nevertheless, the research on metal complex formation in ILs lags behind other applications. The complex formation equilibria may be influenced by specific interactions among the metal ion, ligand molecule, and IL cation and anion. In the present investigation, the complex formation of Ni2+ with ethanol (EtOH) and methanol (MeOH) molecules in ILs, 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide ([CNmim][TFSA], where N represents the alkyl chain lengths of 2 and 8) was discussed in terms of the microscopic interactions among alcohol molecules, [CNmim]+ and [TFSA]-, and the mesoscopic mixing states of alcohols in [CNmim][TFSA], with N = 2-12. The microscopic interaction of alcohol molecules with the imidazolium ring H atoms in the ILs was evaluated by using ATR-IR and 1H and 13C NMR spectroscopies. The self-hydrogen bonding of alcohol molecules was clarified from the O-H stretching vibration of alcohol molecules. MeOH molecules can be more strongly hydrogen-bonded with themselves than EtOH molecules due to the less steric hindrance and the weaker dispersion force of MeOH with the IL cation's alkyl chain. In fact, small-angle neutron scattering (SANS) experiments revealed the more heterogeneous mixing of MeOH with the ILs by the self-hydrogen bonding among MeOH molecules than EtOH. The longer the IL cation's alkyl chain, the more the MeOH clusters significantly form. In contrast, the formation of EtOH clusters becomes weaker with elongating the alkyl chain. Ultraviolet (UV)-visible spectroscopic measurements on Ni2+-[CNmim][TFSA]-alcohol solutions with N = 2 and 8 revealed that di-, tetra-, and hexa-alcohol-Ni2+ complexes are formed in both the ILs. With N = 2, the stabilities of Ni2+-EtOH and Ni2+-MeOH complexes are comparable in the IL. However, with N = 8, the complexes are more stable in the EtOH solutions than in the MeOH solutions. This is because the less heterogeneous mixing of EtOH molecules with the IL results in the larger enthalpic contribution in the complex formation, as shown by the thermodynamic parameters estimated by the van't Hoff plots on the stability constants at several temperatures.

Molecular Insights into the Quenching Mechanism of the Triplet Excited State of Rose Bengal through Oxidative and Reductive Organic Compounds.

In oxygenated aquatic environments, the predominant scavenging of the triplet excited state of chromophoric dissolved organic matter (3CDOM*) involves dissolved ground-state oxygen, diverting attention away from the scavenging mechanisms of 3CDOM* mediated through specific organic compounds. Previous studies demonstrated that model 3CDOM* exhibited quantum yields (i.e., 1-56%) in the formation of radical ions, resulting from the competition between physical and chemical quenching through a common exciplex intermediate. Physical quenching was rationalized through the reverse intersystem crossing of the exciplex, followed by back electron transfer, yielding ground-state reactants. Despite this, direct experimental evidence for exciplex involvement has been elusive, owing to detection challenges. Herein, employing density functional theory (DFT) and time-dependent DFT specifically for excited state surrogate CDOM and organic scavengers, we unveil, for the first time, the underlying mechanisms responsible for the quenching of Rose Bengal through oxidative and reductive scavengers. Our computational findings provide evidence for the involvement of exciplexes during the quenching process of the excited triplet state of Rose Bengal, highlighting the impact of electronic coupling between Rose Bengal and quenchers on the quantum yield for radical ion formation.

Theoretical justification for obtaining new nanomaterials by taking into account the influence of three main factors

By generalizing and transferring the results of the Marcus theory for homogeneous reactions to heterogeneous, Dogonadze and Kuznetsov created a quantum-mechanical theory of electrode reactions for ionic melts, the methodological principles of which allow more adequately evaluating the results of certain experimental methods of obtaining new substances with given properties. Such methods include high-temperature electrochemical synthesis (HES), the implementation of which is complicated by the lack of precise understanding of the mechanism of multi-electron processes of reduction of various ionic forms of refractory metals and nonmetals in ionic melts, including those containing molybdate and tungstate ions, both constantly and simultaneously.

Low-Energy Electron Interactions with Methyl-p-benzoquinone: A Study of Negative Ion Formation.

Methyl-p-benzoquinone (MpBQ, CH3C6H3(=O)2) is a prototypical molecule in the study of quinones, which are compounds of relevance in biology and several redox reactions. Understanding the electron attachment properties of MpBQ and its ability to form anions is crucial in elucidating its role in these reactions. In this study, we investigate electron attachment to MpBQ employing a crossed electron-molecular beam experiment in the electron energy range of approximately 0 to 12 eV, as well as theoretical approaches using quantum chemical and electron scattering calculations. Six anionic species were identified: C7H6O2 -, C7H5O2 -, C6H5O-, C4HO-, C2H2 -, and O-. The parent anion is formed most efficiently, with large cross sections, through two resonances at electron energies between 1 and 2 eV. Potential reaction pathways for all negative ions observed are explored, and the experimental appearance energies are compared with calculated thermochemical thresholds. Although exhibiting similar electron attachment properties to pBQ, MpBQ's additional methyl group introduces entirely new dissociative reactions, while quenching others, underscoring its distinctive chemical behavior.

Mineralogy of Zinc and Lead Metallurgical Slags in Terms of Their Impact on the Environment: A Review

This paper presents the results of a study of the mineralogical and chemical composition of zinc and lead metallurgical slags. These slags contain numerous elements, including toxic metals, which form conglomerates or multiphase intergrowths. The phase composition of slags is one of the main factors that determine their behaviour in weathering environments, that is, their ability to release metals when exposed to atmospheric factors. In this paper, the release of elements from slags and their mobility in a hypergenic environment is determined based on the results of leachability tests and on geochemical modelling, thus assessing the environmental impact of landfilled slags. The elements released from slags in the largest quantities are zinc and lead. Zn is leached out over a long period of time. It was found that after 12 years, the concentration of Zn in the eluate exceeds by 40 times the permissible value of 200 mg/kg for hazardous waste. The degree of leaching of lead from slags as a function of time (after 12 years), despite its significant solubility in water, is much lower than the degree of leaching of zinc. The most mobile phase components of slags in the studied hypergenic environment are the lead phases (anglesite and galena) and, to a lesser extent, the zinc phases (sphalerite and willemite). Anglesite and galena in almost the entire Eh-pH range, along with admixtures of elements, decompose into ionic forms: PbCl42−, Pb2+, and PbOH+. Sphalerite in the soil and water environment (oxidizing and acidic conditions) will decompose into the mobile ionic form Zn2+. Willemite, which is resistant to weathering, will undergo similar decomposition. It can therefore be assumed that the carriers of toxic metals are primarily lead sulphides and sulphates, zinc sulphides, and, less frequently, zinc, lead, and iron oxides.

Removal of Heavy Metals from Wastewaters and Other Aqueous Streams by Pressure-Driven Membrane Technologies: An Outlook on Reverse Osmosis, Nanofiltration, Ultrafiltration and Microfiltration Potential from a Bibliometric Analysis.

A bibliometric study to analyze the scientific documents released until 2024 in the database Scopus related to the use of pressure-driven membrane technologies (microfiltration, ultrafiltration, nanofiltration and reverse osmosis) for heavy metal removal was conducted. The work aimed to assess the primary quantitative attributes of the research in this field during the specified period. A total of 2205 documents were identified, and the corresponding analysis indicated an exponential growth in the number of publications over time. The contribution of the three most productive countries (China, India and USA) accounts for more than 47.1% of the total number of publications, with Chinese institutions appearing as the most productive ones. Environmental Science was the most frequent knowledge category (51.9% contribution), followed by Chemistry and Chemical Engineering. The relative frequency of the keywords and a complete bibliometric network analysis allowed the conclusion that the low-pressure technologies (microfiltration and ultrafiltration) have been more deeply investigated than the high-pressure technologies (nanofiltration and reverse osmosis). Although porous low-pressure membranes are not adequate for the removal of dissolved heavy metals in ionic forms, the incorporation of embedded adsorbents within the membrane structure and the use of auxiliary chemicals to form metallic complexes or micelles that can be retained by this type of membrane are promising approaches. High-pressure membranes can achieve rejection percentages above 90% (99% in the case of reverse osmosis), but they imply lower permeate productivity and higher costs due to the required pressure gradients.

Nanominerals Packaged in pH‐Responsive Alginate Microcapsules Exhibit Selective Delivery in Small Intestine and Enhanced Absorption and Bioavailability

AbstractMineral supplementation is crucial for human nutrition to facilitate appropriate growth, disease prevention, and improved reproductive health. The conventional forms of mineral supplementation involve an ionic form of elements mixed with biomolecules; however, suffer from unfavorable reactions under an acidic environment of stomach, ROS generation, and poor absorption in the small intestine. To address this, nanominerals (NMs) of six essential mineral elements are synthesized and packed in pH‐responsive microcapsule. Each NMs is coated with biomolecules that are known to rapidly absorb through the intestinal epithelium. Microcapsules are found intact at acidic pH (pH: 2.0–6.5); however, selectively release NMs at pH ≥7.0. The in vitro study demonstrates that the mixture of NMs and microcapsules is biocompatible and exhibits excellent ROS scavenging ability at physiological pH. Oral administration of NMs‐loaded microcapsules to rats shows enhanced levels of minerals, vitamin B12, hemoglobin, and total antioxidant activity in blood. The liver, kidneys, and spleen show enhanced expression of Cu/Zn‐SOD and Mn‐SOD enzymes due to high absorption and bioavailability of ZnO, Cu2O, and MnO2 NMs through the intestine. Thus, the pH‐responsive microcapsules hold promise to effectively stealth the encapsulated nutrient materials from the acidic environment of stomach and precisely deliver them to small intestine.

In-silico antibacterial activity of piperazinyl-based copper(II) metallo-organic pharmacophores

The piperazinyl-based Cu(II)-Schiff base complex {[Cu(HL1′)(N3)]2∙(ClO4)2·4H2O} (1) [HL1′ is the Zwitter ionic form of (E)-2-((2-piperazin-1-ylethylimino)methyl)phenol] was synthesized and characterized by spectroscopic and single crystal X-ray diffraction studies. The X-ray single crystal structure analysis shows that the asymmetric unit of 1 contains a four-coordinate discrete complex cation, [Cu(HL1′)(N3)]+ (1a), with a perchlorate anion and a lattice water molecule. Two square planar units of 1a are dimerized by weak Cu···N intermolecular interaction, forming [Cu(HL1′)(N3)]2 2+ (1′a). DFT and TD-DFT calculations of the monomeric cationic unit, [Cu(HL1′)(N3)]+ (1a) were performed. In-silico antibacterial activities of HL1 as well as monomeric and dimeric cationic units 1a and 1'a, respectively, were performed and study shows that 1a (EC50 0.30 μM) and 1′a (EC50 0.06 μM) may be treated as antibacterial drugs after in-vivo analysis and clinical testing.

Formation of ions under the action of cosmic rays in humid air

The processes of ion formation in humid tropospheric air under the action of cosmic rays are considered. In this case, positive and negative cluster ions appear. For this analysis, a kinetic model was developed that includes 55 components and 161 reactions. The calculation was carried out using the KINET software package. It is shown that the ionization of air by cosmic rays at altitudes of 5–35 km leads to the formation of plasma consisting mainly of NH4+⋅NH3⋅H2O, H+⋅(H2O)4 and O2−⋅(H2O)2 ions. The maximum concentrations of ions under conditions of minimum magnetic rigidity are observed at altitudes from 10 to 18 km. These results differ sharply from the calculation results obtained for the dry air model.

Carboxylate Pseudo-Halide-Assisted crystallization and antioxidant strategy for stable wide bandgap tin perovskite photovoltaics

The facile oxidation of Sn2+ to Sn4+ and uncontrolled crystal growth are significant challenges in the development of wide-bandgap (WBG) tin perovskite solar cells (TPSCs), affecting their performance and stability. This study introduces three strategically synthesized carboxylate pseudo-halides—3,3-diphenylpropylammonium trifluoroacetate (D-TFA), 3,3-diphenylpropylammonium acetate (D-Ac), and 3,3-diphenylpropylammonium formate (D-Fo), —as additives to mitigate Sn2+/Sn4+ oxidation in WBG TPSCs. These pseudo-halides coordinate with Sn2+, reducing electron density at the carboxylate carbon and forming robust bonds with SnI2(DMSO)3, thus impeding Sn2+ oxidation through oxygen adsorption. Among them, the formate ion (Fo-) in D-Fo exhibited the most significant deshielded peak, indicating the strongest coordination with Sn2+ and superior antioxidation effects by reducing reactivity with ambient oxygen. These interactions, along with 3,3-diphenylpropylammonium (DPA+), aid in controlling crystal growth, enhancing the formation of highly crystalline thin films, and improving overall stability. Consequently, D-Fo-assisted WBG tin perovskites demonstrated strong suppression of phase segregation under prolonged illumination of the air mass 1.5 spectrum, retaining 90 % of their initial characteristics. Ultimately, the D-Fo-enhanced WBG TPSC achieved an exemplary power conversion efficiency of 10.69 % with minimal hysteresis, surpassing the control cell’s 7.43 %. Furthermore, the unencapsulated D-Fo device maintained nearly 87 % of its initial performance after 960 h under ambient conditions.

Remediation of water containing lead(II) using (3-iminodiacetic acid) propyltriethoxysilane graphene oxide

A novel chelating adsorbent based on (3-iminodiacetic acid) propyltriethoxysilane graphene oxide (IAT-GO) has been developed, showing exceptional promise for capturing lead. IAT-GO is made by combining a high-surface-area graphene oxide with a specially designed chelating ligand, which can selectively and efficiently remove lead. The synthesis of IAT-GO involves a two-step progression. In the first step, covalent bonds form between graphene oxide and (3-aminopropyl)-triethoxysilane (AT) through hydrolysis, condensation, and epoxide ring opening reactions. In the second step, nucleophilic substitution reactions occur between the primary amines and chloroacetic acid (CAA). A comprehensive suite of characterization techniques, including XPS, UV–Vis, XRD, Raman, FTIR, TEM, and SEM, provides detailed insights into the IAT-GO adsorbent's chemical composition and physical form, elucidating its intricate structure and morphology. Optimizing the experimental conditions for using the adsorbent material to remove Pb(II) ions from contaminated water revealed a maximum adsorption capacity of 124.0 mg/g at pH 5 and 30 min. The IAT-GO displays high selectivity for Pb(II) in a mixture of six metal ions containing 100 ppm of each one. Moreover, the IAT-GO shows 100% removal of Pb(II) for concentrations lower than 50 ppm. The excellent fit of the experimental data with the Langmuir adsorption isotherm and pseudo-second-order kinetic models (R2 > 99%) indicates that Pb(II) ion uptake onto the IAT-GO surface occurs via the monolayer formation of mercury ions. IAT-GO demonstrates exceptional potential as an innovative adsorbent for lead-contaminated water. Nitric acid (0.4 M) effectively regenerates the material, while its reusability remains impressive even after five cycles (> 97% removal efficiency). Therefore, this study highlights the development of a groundbreaking material, IAT-GO, with exceptional potential for remediating lead-contaminated water. Its high efficiency, selectivity, reusability, and cost-effectiveness make it a promising candidate for real-world applications.

Unraveling the Potential of Vitamin B3-Derived Salts with a Salicylate Anion as Dermal Active Agents for Acne Treatment.

This study is focused on the utilization of naturally occurring salicylic acid and nicotinamide (vitamin B3) in the development of novel sustainable Active Pharmaceutical Ingredients (APIs) with significant potential for treating acne vulgaris. The study highlights how the chemical structure of the cation significantly influences surface activity, lipophilicity, and solubility in aqueous media. Furthermore, the new ionic forms of APIs, the synthesis of which was assessed with Green Chemistry metrics, exhibited very good antibacterial properties against common pathogens that contribute to the development of acne, resulting in remarkable enhancement of biological activity ranging from 200 to as much as 2000 times when compared to salicylic acid alone. The molecular docking studies also revealed the excellent anti-inflammatory activity of N-alkylnicotinamide salicylates comparable to commonly used drugs (indomethacin, ibuprofen, and acetylsalicylic acid) and were even characterized by better IC50 values than common anti-inflammatory drugs in some cases. The derivative, featuring a decyl substituent in the pyridinium ring of nicotinamide, exhibited efficacy against Cutibacterium acnes while displaying favorable water solubility and improved wettability on hydrophobic surfaces, marking it as particularly promising. To investigate the impact of the APIs on the biosphere, the EC50 parameter was determined against a model representative of crustaceans─Artemia franciscana. The majority of compounds (with the exception of the salt containing the dodecyl substituent) could be classified as "Relatively Harmless" or "Practically Nontoxic", indicating their potential low environmental impact, which is essential in the context of modern drug development.

Controlling curcumin/acrylic polymer interactions for tailored delivery systems

In this work, we investigate the interaction between curcumin and biocompatible polymethacrylates (methyl, ethyl, and n-butyl side groups). Blend samples were produced using the salt leaching technique to increase the contact area in the ionic medium with pH 2.0, 5.0, 7.4, and 8.0. Using curcumin photoluminescence (PL) spectra to determine release profiles, we found a 6-fold higher quantity and a 3-fold higher release ratio for poly(n-butyl methacrylate) (PnBMA). Changes in the ionic form of curcumin were observed with PL blue shift and decrease in the characteristic time, from ca. 435 min at pH 2.0 and 5.0 to 192 min at pH 7.4 for PnBMA. The relative importance of curcumin interactions with the side and main polymer chains could be determined by interpreting the release profiles. With curcumin interaction controlled by pH and the length of the polymer side chain, one may envisage tailored drug delivery systems focusing on prolonged release.

Investigation of the Activity and Stability of Manganese-Based Electrocatalysts for the Electrochemical Oxidation of Water and Small Organic Molecules in Acidic Electrolyte

Water electrolysis is a crucial process for hydrogen production, providing a clean and sustainable method for H2 production. Iridium-based catalysts are particularly effective in promoting the oxygen evolution reaction (OER) that takes place at the anode of electrolyzers. The unique properties of iridium make it well-suited for this purpose, but its high cost becomes a bottleneck in making water electrolysis economically viable on a large scale. Manganese-based electrocatalysts have emerged as promising candidates for the OER, mainly due to their earth abundance, low toxicity, and activity. It has been shown that manganese oxide can operate stably in acid, in a restricted potential window, where the formation of permanganate ions is avoided. Thus, for practical application, the stability must be improved, so a larger potential window can be employed. To address this challenge, some approaches have emerged from combining a catalytically active, but instable oxide, with the one that is stable, but inactive for the OER. In the presentation, we will show the results of activity, stability, and faradaic efficiency (FE) for O2 formation for water electro-oxidation on manganese oxide, and on manganese oxide combined with antimony, tin, titanium, niobium, and silicon oxide. The faradaic efficiencies, determined via EC-MS (Electrochemistry coupled to mass spectrometry) measurements revealed that manganese antimonate and pure manganese oxide have the highest values for O2 formation, with the former presenting higher stability at high overpotentials. We will discuss the obtained trends in stability and FEs for the other synthesized oxides. Additionally, for these two most efficient electrocatalysts, EC-MS measurements were conducted for the electrochemical oxidation of some small organic molecules, such as formic acid, methanol, ethanol, and ethylene glycol (electrochemical reforming for H2 production). The results showed that the selectivity for the electro-oxidation of water and/or of the organic molecule (monitoring the formation of CO2) strongly depends on the catalyst composition and on the number of carbon atoms of the molecule. We will further discuss, in the presentation, the factors that govern the selectivity and stability for each case. The obtained results of this study may be helpful for developing more efficient, selective and, mainly, more stable earth-abundant electrocatalysts for electrolyzers.

Role of Ammonia in Aerosol Liquid Water, pH, and Secondary Inorganic Aerosols Formation at an Ammonia-rich City in Changzhou

Ammonia （NH3） is an important alkaline reactive nitrogen, which, as a precursor of fine particulate matter, raises public health issues. In this study, online NH3, SO2, NO2, PM2.5, and its water-soluble inorganic ions were detected to deduce the influence of NH3 on aerosol liquid water content （AWC） and aerosol pH, including the formation of water-soluble secondary ions in PM2.5 in winter in Changzhou, an ammonia-rich city in the Yangtze River Delta area in winter. The results showed that NH4+ mainly existed in the form of NH4NO3 and （NH4）2SO4, and the remaining NH4+ existed as NH4Cl. Owing to the NH3-NH4+ buffer system, the aerosol pH values were found at 4.2 ± 0.4, which was positively correlated with the NH3 content. The aerosol pH value variation narrowed with the increase in PM2.5 concentration and tended to be between 4 to 5. AWC increased exponentially with the increase in humidity and SNA content, among which NH4NO3, （NH4）2SO4, and NH4Cl contributed 58.5%, 18.4%, and 8.3%, respectively, due to their hygroscopicity. Aerosol pH, AWC, and NH3-NH4+ conversion promoted the gas-to-particle conversion of SO2 and NO2. In Changzhou, rich NH3-NH4+ were found to maintain relatively high pH values, push up AWC, and promote the heterogeneous reaction of SO2, whereas NO3- generation was dominated by a homogeneous reaction, which was accelerated by NH3. According to the simulation results, relatively noticeable changes in aerosol pH and AWC could be found by the reduction of up to 30% of NH3.

Mechanistic Insights on the Formation of a Carbodiimide Ion from Urea in La2O2NCN Synthesis Based on the "Proanion" Strategy.

This study affords mechanistic insights into the formation mechanism of carbodiimide ions (NCN2-) from urea during the synthesis of La2O2NCN by employing the "proanion" strategy without using NH3 gas. It is a safer, cost-effective, and environmentally friendly approach. Urea, acting as a proanion, decomposes upon heating, facilitating conversion to NCN2-. This work meticulously examines the phase transitions and identifies intermediate species formed during the reaction using in situ X-ray diffraction, Fourier transform infrared spectroscopy, and thermogravimetric-differential thermal analysis-mass spectrometry. The findings present a detailed mechanism in which urea initially decomposes at 140 °C, releasing HNCO, which reacts with La(OH)3 to immobilize NCO- species on the surface of La(OH)3. As the temperature reaches approximately 400 °C, these NCO- anions transform into NCN2- anions by releasing CO2 gas, resulting in the formation of an amorphous phase rich in NCN2-. Following further heating to 600 °C, La2O2NCN crystallizes, enhancing its crystallinity as the temperature increases. These findings elucidate the formation mechanism of La2O2NCN, introduce the "proanion method" for the alternative synthesis of metal (oxy)carbodiimides, and expand their potential for applications as functional materials.

Analysis of the Substituent Distribution in Carboxymethyl-1,4-glucans on Different Structural Levels—An Ongoing Challenge

Carboxymethylglucans (CMGs) are widely used semisynthetic polyelectrolytes, e.g., for pharmaceuticals. They are produced in heterogeneous processes on activated starch granules or cellulose fibers. In contrast to neutral ether derivatives, a lower DS in the range, commonly between 0.6 and 1.2, is sufficient to achieve the water solubility of CM cellulose. The high proportion of unsubstituted domains, which could aggregate and therefore only swell and form gel particles but do not dissolve, places higher demands on the statistical distribution of the substituents. The knowledge of regioselectivity, essential for the interpretation of higher structural-level data, can be obtained by various methods, preferentially by CE/UV after hydrolysis. To study the distribution of substituents at the polymer level by mass spectrometric (MS) analysis, partial random depolymerization is required. Due to the ionic character and acid functionality, all the attempts of the direct depolymerization of CMG and further sample preparation suffered from bias, side reactions, and multiple ion formation in MS. Finally, the transformation of CMGs to the corresponding hydroxyethylglucans (HEGs) by the reduction of the esterified carboxy groups with LiAlH4 opened the window for quantitative oligomer MS analysis. While the CM amyloses were reduced quantitatively, the transformation of the CMC was only about 60% but without the formation of mixed CM/HE ethers.

Excellent photocatalytic performance of PAA/Na2MoO4-Fe3+ hydrogel with Na2MoO4 as sacrificial agent for dye removal

Currently, the majority of photocatalytic materials primarily consist of insoluble semiconductors, whereas soluble semiconductor materials have limited applications in photocatalysis. In this study, it is proposed for the first time to use the soluble semiconductor sodium molybdate (Na2MoO4) as a sacrificial agent to fabricate a polyacrylic acid/sodium molybdate-Fe3+ hydrogel photocatalyst (PAA/Na2MoO4-Fe3+) through polymerization with Fe3+ ions and acrylic acid (AA) monomer. The hydrogel photocatalyst was thoroughly characterized and the results revealed that the presence of Na2MoO4 in ionic form within the hydrogel significantly enhanced its adsorption capacity for pollutant molecules. Additionally, Fe3+ ions coordinated with -COOH (L) groups on PAA to form [Fe(L)6]3+ ions, which acted as active sites of photocatalytic. Moreover, the PAA/Na2MoO4-Fe3+ hydrogel exhibited promising potential as a photocatalyst for the remove of dye pollutants (e.g. MB, MG, RhB and MO) from wastewater. Finally, we also explored and analyzed the photocatalytic mechanism of the hydrogel. It is noteworthy to conclude that the hydrogel possesses immense potential for the practical application of photocatalytic techniques in the treatment of dyes wastewater.

NiOx Passivation in Perovskite Solar Cells: From Surface Reactivity to Device Performance.

Nonstoichiometric nickel oxide (NiOx) is one of the very few metal oxides successfully used as hole extraction layer in p-i-n type perovskite solar cells (PSCs). Its favorable optoelectronic properties and facile large-scale preparation methods are potentially relevant for future commercialization of PSCs, though currently low operational stability of PSCs is reported when a NiOx hole extraction layer is used in direct contact with the perovskite absorber. Poorly understood degradation reactions at this interface are seen as cause for the inferior stability, and a variety of interface passivation approaches have been shown to be effective in improving the overall solar cell performance. To gain a better understanding of the processes happening at this interface, we systematically passivated specific defects on NiOx with three different categories of organic/inorganic compounds. The effects on NiOx and the perovskite (MAPbI3) deposited on top were investigated using X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and scanning electron microscopy (SEM). Here, we find that the perovskite's structural stability and film formation can be significantly affected by the passivation treatment of the NiOx surface. In combination with density functional theory (DFT) calculations, a likely origin of NiOx-perovskite degradation interactions is proposed. The surface passivated NiOx layers were incorporated into MAPbI3-based PSCs, and the influence on device performance and operational stability was investigated by current-voltage (J-V) characterization, impedance spectroscopy (IS), and open circuit voltage decay (OCVD) measurements. Interestingly, we find that a superior structural stability due to interface passivation must not relate to high operational stability. The discrepancy comes from the formation of excess ions at the interface, which negatively impacts all solar cell parameters.

The Deep Removal of Mercury in Contaminated Acid by Colloidal Agglomeration Materials M201

The high-temperature roasting/smelting process of copper and zinc concentrates will cause the mercury in the concentrate to evaporate into the flue gas, and most of the mercury in the flue gas will eventually enter the waste acid in its ionic form. A highly efficient mercury removal agent M201 with long carbon chains and loaded active functional groups can adsorb and disperse fine particles for mercury removal in the system. Through bridging, the linear structure is woven into a network to achieve large-scale capture and dispersion of fine particles and colloidal substances. The recommended operating conditions for developing mercury deep purification technology are as follows: M201 reagent concentration of 50 g/L, 6 mL/L added acid solution, room temperature, mixing time of 5 min, air flotation time of 10 min, ventilation rate of 0.1 L/min, H2SO4 concentration of 33.67 g/L, and the residual mercury content of 2 mg/L (the mercury content reaches 0.01 mg/L after two-stage mercury removal treatment). Meanwhile, the residual arsenic content is 21.9 mg/L. This study shows a better separation of arsenic and mercury and achieves one-step mercury removal.