An Integrated Electrochemical System for Synergistic Cathodic Nitrate Reduction and Anodic Sulfite Oxidation.

Electrochemical reduction of nitrate has broad application prospects. However, in traditional electrochemical reduction of nitrate, the low value of oxygen produced by the anodic oxygen evolution reaction and the high overpotential limit its application. Seeking a more valuable and faster anodic reaction to form a cathode-anode integrated system with nitrate reaction can effectively accelerate the reaction rate of the cathode and anode, and improve the utilization of electrical energy. Sulfite, as a pollutant after wet desulfurization, has faster reaction kinetics in its oxidation reaction compared to the oxygen evolution reaction. Therefore, this study proposes an integrated cathodic nitrate reduction and anodic sulfite oxidation system. The effect of operating parameters (cathode potential, initial NO3--N concentration, and initial SO32--S concentration) on the integrated system was studied. Under the optimal operating parameters, the nitrate reduction rate in the integrated system reached 93.26% within 1 h, and the sulfite oxidation rate reached 94.64%. Compared with the nitrate reduction rate (91.26%) and sulfite oxidation rate (53.33%) in the separate system, the integrated system had a significant synergistic effect. This work provides a reference for solving nitrate and sulfite pollution, and promotes the application and development of electrochemical cathode-anode integrated technology.

Optimization of Congo red dye adsorption from wastewater by a modified commercial zeolite catalyst using response surface modeling approach.

In the present work, Zeolite A was modified by using hexadecyltrimethylammonium bromide (HDTMABr) for adsorption of the Congo red (CR) dye from synthetic aqueous solutions. The Modified Zeolite A (MZA) was characterized by XRD, SEM, and FTIR. The influence of solution pH (in the 4-12 range), ionic strength (0.1-1 M), contact time (180 min), initial CR concentration (20-60 mg/L), temperature (24-36 °C), and an adsorbent dose (1-3 g m/L) on the % dye removal and adsorbent capacity were studied. A combined effect of the initial CR concentration and temperature on the CR removal % by MZA was also studied by applying response surface methodology (RSM). Experimental values were in a good agreement with those predicated by a second-order quartic model. A maximum of 99.24% dye removal and adsorbent capacity of 21.11 mg/g was achieved under the following conditions: pH = 7, initial CR concentration = 60 mg/L, temperature = 24 °C, ionic strength = 0.1 M, adsorbent dose = 3 g/L and 90 min contact time. The equilibrium data were subjected to the Langmuir, Freundlich and Temkin isotherms, with the latter providing the best fit while kinetic adsorption studies were conducted by applying three models. The results indicated that the removal process was best described by the pseudo-second-order model. The present study demonstrates that modified MZA can be utilized for the highly efficient CR dye removal.

Improved Resolution of 4-Chloromandelic Acid and the Effect of Chlorine Interactions Using (R)-(+)-Benzyl-1-Phenylethylamine as a Resolving Agent.

In order to avoid the disadvantage of commonly used resolving agent 1-phenylethylamine (hereafter: PEA), which is soluble in water, (R)-(+)-benzyl-1-phenylethylamine ((R)-(+)-BPA) was used to resolve 4-chloromandelic acid (4-ClMA) in this study. The optimal resolution conditions were determined: absolute ethanol as a solvent, the molar ratio of 4-ClMA to (R)-(+)-BPA as 1:1, the filtration temperature as 15 °C, and the amount of solvent as 1.6 mL/1 mmol 4-ClMA. Thermophysical properties, such as melting point, heat of fusion, and solubility, exhibited significant differences between the less and more soluble salts. The single crystals for the pair of diastereomeric salts were cultivated and their crystal structures were examined thoroughly. In addition to commonly observed interactions like hydrogen bonding and CH/π interactions. The chlorine…chlorine interaction was observed in the less soluble salt presenting as Cl…Cl between adjacent hydrogen network columns, while the Cl/π interaction was observed in the more soluble salt. It was found that halogen interactions played an important role in chiral recognition of 4-ClMA by (R)-(+)-BPA.

Crystallization of Esomeprazole Magnesium Water/Butanol Solvate.

The molecular structure of esomeprazole magnesium derivative in the solid-state is reported for the first time, along with a simplified crystallization pathway. The structure was determined using the single crystal X-ray diffraction technique to reveal the bonding relationships between esomeprazole heteroatoms and magnesium. The esomeprazole crystallization process was carried out in 1-butanol and water was utilized as anti-solvent. The product proved to be esomeprazole magnesium tetrahydrate with two 1-butanol molecules that crystallized in P63 space group, in a hexagonal unit cell. Complete characterization of a sample after drying was conducted by the use of powder X-ray diffraction (PXRD), ¹H-nuclear magnetic resonance (NMR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), infrared spectroscopy (IR), and dynamic vapor sorption (DVS). Investigation by ¹H-NMR and TGA has shown that the solvent content in the dried sample consists of two water molecules and 0.3 butanol molecules per esomeprazole magnesium molecule. This is different from the single crystal X-ray diffraction results and can be attributed to the loss of some water and 1-butanol molecules stabilized by intermolecular interactions. The title compound, after drying, is a true solvate in terms of water; conversely, 1-butanol fills the voids of the crystal lattice in non-stoichiometric amounts.

Formation and Transformation Behavior of Sodium Dehydroacetate Hydrates.

The effect of various controlling factors on the polymorphic outcome of sodium dehydroacetate crystallization was investigated in this study. Cooling crystallization experiments of sodium dehydroacetate in water were conducted at different concentrations. The results revealed that the rate of supersaturation generation played a key role in the formation of the hydrates. At a high supersaturation generation rate, a new sodium dehydroacetate dihydrate needle form was obtained; on the contrary, a sodium dehydroacetate plate monohydrate was formed at a low supersaturation generation rate. Furthermore, the characterization and transformation behavior of these two hydrated forms were investigated with the combined use of microscopy, powder X-ray diffraction (PXRD), Raman spectroscopy, Fourier transform infrared (FTIR), thermal gravimetric analysis (TGA), scanning electron microscopy (SEM) and dynamic vapor sorption (DVS). It was found that the new needle crystals were dihydrated and hollow, and they eventually transformed into sodium dehydroacetate monohydrate. In addition, the mechanism of formation of sodium dehydroacetate hydrates was discussed, and a process growth model of hollow crystals in cooling crystallization was proposed.

Crystal structure of (R)-N-benzyl-1-phenylethanaminium (R)-4-chloro-mandelate.

The absolute configuration of the title mol-ecular salt, C15H18N(+)·C8H6ClO3 (-), has been confirmed by resonant scattering. In the (R)-N-benzyl-1-phenyl-ethyl-ammonium cation, the phenyl rings are inclined to one another by 44.65 (7)°. In the crystal, the (R)-4-chloro-mandelate anions are linked via O-H⋯O hydrogen bonds and bridged by N-H⋯O hydrogen bonds involving the cations, forming chains along [010]. There are C-H⋯O hydrogen bonds present within the chains, which are linked via C-H⋯π inter-actions and a short Cl⋯Cl inter-action [3.193 (1) Å] forming a three-dimensional framework. The structure was refined as a two-component inversion twin giving a Flack parameter of 0.05 (4).

Green Synthesis of pH-Responsive Metal-Organic Frameworks for Delivery of Diclofenac Sodium.

The current study developed a drug delivery system through the green chemistry-based synthesis of a biologically friendly metal-organic framework (bio-MOF) called Asp-Cu, which included copper ions and the environmentally friendly molecule L(+)-aspartic acid (Asp). For the first time, diclofenac sodium (DS) was loaded onto the synthesized bio-MOF simultaneously. The system's efficiency was then improved by encapsulating it with sodium alginate (SA). FT-IR, SEM, BET, TGA, and XRD analyses confirmed that DS@Cu-ASP was successfully synthesized. DS@Asp-Cu was found to release the total load within 2 h when used with simulated stomach media. This challenge was overcome by coating DS@Cu-ASP with SA (SA@DS@Cu-ASP). SA@DS@Cu-ASP displayed limited drug release at pH 1.2, and a higher percentage of the drug was released at pH 6.8 and 7.4 due to the pH-responsive nature of SA. In vitro cytotoxicity screening showed that SA@DS@Cu-ASP could be an appropriate biocompatible carrier with >90% cell viability. The on-command drug carrier was observed to be more applicable biocompatible with lower toxicity, as well as adequate loading properties and responsiveness, indicating its applicability as a feasible drug carrier with controlled release.

Spherical Crystallization Based on Liquid-Liquid Phase Separation in a Reverse Antisolvent Crystallization Process.

Vanillin crystals undergo needle-like morphology that results in poor flowability, crystal breakage, and low packing density. The spherical crystallization technology can produce particles with improved flowability and stability. A reverse antisolvent crystallization based on liquid-liquid phase separation is proposed in this work to produce vanillin spherical agglomerates. Hansen Solubility Parameters are applied to explain the liquid-liquid phase separation (LLPS) phenomenon. The Pixact Crystallization Monitoring system is applied to in-situ monitor the whole process. A six-step spherical crystallization mechanism is revealed based on the recorded photos, including the generation of oil droplets, nucleation inside oil droplets, the coalescence and split of oil droplets, crystal growth and agglomeration, breakage of oil droplets, and attrition of agglomerates. Different working conditions are tested to explore the best operation parameters and a frequency-conversion stirring strategy is proposed to improve the production of spherical crystals.

Applications, challenges and prospects of superabsorbent polymers based on cellulose derived from lignocellulosic biomass.

The synthetic superabsorbent polymers (SAPs) market is experiencing significant growth, with applications spanning agriculture, healthcare, and civil engineering, projected to increase from $9.0 billion USD in 2019 to $12.9 billion USD by 2024. Despite this positive trend, challenges such as fluctuating raw material costs and lower biodegradability of fossil fuel-based SAPs could impede further expansion. In contrast, cellulose and its derivatives present a sustainable alternative due to their renewable, biodegradable, and abundant characteristics. Lignocellulosic biomass (LCB), rich in cellulose and lignin, shows promise as a source for eco-friendly superabsorbent polymer (SAP) production. This review discusses the applications, challenges, and future prospects of SAPs derived from lignocellulosic resources, focusing on the cellulose extraction process through fractionation and various modification and crosslinking techniques. The review underscores the potential of cellulose-based SAPs to meet environmental and market needs, offering a viable path forward in the quest for more sustainable materials.

New metal-organic framework coated sodium alginate for the delivery of curcumin as a sustainable drug delivery and cancer therapy system.

The utilization of biocompatible drug delivery systems with extended drug release capabilities is highly advantageous in cancer therapy, as they can mitigate adverse effects. To establish such a biocompatible system with prolonged drug release behavior, researchers developed an innovative drug carrier. In this study, a sustainable approach was employed to synthesize a new zinc-based metal-organic framework (Zn-MOF) through the reaction between synthesized Schiff base ligands and zinc ions. Comprehensive analyses, including FT-IR, XRD, SEM, BET surface area, and TGA techniques, were employed to thoroughly characterize the frameworks. Following comprehensive characterization, curcumin (CUR) was loaded onto the Zn-MOF, resulting in CUR entrapment efficiency and loading capacity of 79.23 % and 26.11 %, respectively. In vitro evaluations of CUR release from CUR@MOF exhibited controlled release patterns, releasing 78.9 % and 50.0 % of CUR at pH 5.0 and pH 7.4, respectively. To mitigate initial burst release, a coating of the biopolymer sodium alginate (SA) was applied to CUR@Zn-MOF. In vitro CUR release tests indicated that SA/CUR@Zn-MOF outperformed pristine CUR@Zn-MOF. The release of CUR conformed to the Korsmeyer-Peppas model, displaying non-Fickian diffusion. Furthermore, an in vitro cytotoxicity study clearly demonstrated the potent anti-tumor activity of the synthesized CUR@Zn-MOF attributed to its controlled release of CUR. This led to the induction of apoptotic effects and cell death across HeLa, HEK293, and SH-SY5Y cell lines. These findings strongly suggest that the developed pH-sensitive carriers hold remarkable potential as targeted vehicles for drug delivery in cancer therapy.

Mathematical modeling and experimental breakthrough curves of carbon dioxide adsorption on metal organic framework CPM-5.

It is essential to capture carbon dioxide from flue gas because it is considered one of the main causes of global warming. Several materials and different methods have been reported for CO2 capturing including adsorption onto zeolites and porous membranes, as well as absorption in amine solutions. All such methods require high energy input and high cost. A new class of porous materials called Metal Organic Frameworks (MOFs) exhibited excellent performance in extracting carbon dioxide from a gas mixture. In this study, the breakthrough curves for the adsorption of carbon dioxide on CPM-5 (crystalline porous materials) were obtained experimentally and theoretically using a laboratory-scale fixed-bed column at different experimental conditions such as feed flow rate, adsorption temperature, and feed concentration. It was found that the CPM-5 has a dynamic CO2 adsorption capacity of 11.9 wt % (2.7 mmol/g) (corresponding to 8 mL/min, 298 K, and 25% v/v CO2). The tested CPM-5 showed an outstanding adsorption equilibrium capacity (e.g., 2.3 mmol/g (10.2 wt %) at 298 K) compared to other adsorbents, which can be considered as an attractive adsorbent for separation of CO2 from flue gas.

Cubic magnetically guided nanoaggregates for inhalable drug delivery: in vitro magnetic aerosol deposition study.

The present work describes the in vitro aerosol deposition and enhanced deaggregation behavior of superparamagnetic iron oxide nanoaggregates (SPIONs). SPIONs were surface-coated with amine functionalized polyrotaxane and were proposed as a carrier for inhalation dry powders. Polyrotaxane is primarily composed of beta cyclodextrin rings which are spontaneously threaded on the block copolymer, poly(propylene glycol) bis(2-aminopropylether). Variable concentrations of surface coating polymers showed controlled manipulation of the crystal size and morphology. Magnetic nanoaggregates fabricated with low concentration of polyrotaxane showed cubic crystal morphology. However, these nanoaggregates exhibited rhombic dodecahedron crystal structure upon increasing the coating polymer concentration. In comparison to the spherical uncoated magnetic nanoparticles, cubic phase magnetic nanoaggregates demonstrated an enhanced in vitro aerosol deposition using magnetic field alignment. This enhancement can be accomplished at low inhalation flow rates (15 and 30 L/min). However, transformation to the cubic crystal structure was observed to be associated with a reduction in the powder geometric standard deviation. Using a mathematical modeling approach, we noted significant enhancement in the deaggregation behavior of inhalation dry powders; that can be achieved with small amounts of magnetic nanoaggregates. Aggregates of cubic nanoparticles showed promise for targeted pulmonary deposition of anticancer drugs.

Modeling and simulation of smart magnetic self-assembled nanomicelle trajectories in an internal thoracic artery flow for breast cancer therapy.

Magnetic drug targeting (MDT) is one of the most modern techniques in cancer therapy for its ability to reduce the side effects of chemotherapy experienced by systemic drug administration. In this study, a comprehensive mathematical model has been developed to predict the drug particle trajectories of anticancer dasatinib magnetic nanomicelles (DAS-MNM) released in an internal thoracic artery (ITA) blood flow for breast cancer therapy using an external magnetic field. Several factors are investigated in regard to the efficiency of MDT through the ITA, including magnetic field strength (MFS), relative magnetic permeability, magnet size, drug particle size, and initial position of drug particle. The drug particle trajectory results confirmed the successful MDT using an external magnetic field with a capture efficiency of more than 90%. This was achieved by employing a wide range of particle sizes of DAS-MNM close to the external magnetic field source at the arterial wall than in other positions. Moreover, the results showed that the number of trapped particles increased with increasing both MFS and drug particle diameter within the target tissue, while the drug particle permeability did not have a considerable effect on the particle retention. In addition, for achieving a successful drug/cargo delivery through the arteries, the magnetic field, the particle size, and the initial release locations should be adjusted simultaneously. The present work offers insights into the critical factors in MDT with a significant impact on breast cancer therapy, tissue engineering, and regenerative medicine. Magnetic drug targeting model of anticancer dasatinib magnetic nanomicelles (DAS-MNM) released in an internal thoracic artery blood flow for breast cancer therapy.

Overcoming the Hydrophobic Nature of Zinc Phenylacetate Through Co-Crystallization with Isonicotinamide.

Zinc phenylacetate (Zn-PA), a substitute for sodium phenylacetate as an ammonia-scavenging drug is hydrophobic, which poses problems for drug dissolution and solubility. We were able to co-crystallize the zinc phenylacetate with isonicotinamide (INAM) and produce a novel crystalline compound (Zn-PA-INAM). The single crystal of this new crystal was obtained, and its structure is reported here for the first time. Zn-PA-INAM was characterized computationally by ab initio, Hirshfeld calculations, CLP-PIXEL lattice energy calculation, and BFDH morphology analysis, and experimentally by PXRD, Sc-XRD, FTIR, DSC, and TGA analyses. Structural and vibrational analyses showed a major modification in intermolecular interaction of Zn-PA-INAM compared to Zn-PA. The dispersion-based pi-stacking in Zn-PA is replaced by coulomb-polarization effect of hydrogen bonds. As a result, Zn-PA-INAM is hydrophilic, improving the wettability and powder dissolution of the target compound in an aqueous solution. Morphology analysis revealed, unlike Zn-PA, Zn-PA-INAM has polar groups exposed on its prominent crystalline faces, reducing the hydrophobicity of the crystal. The shift in average water droplet contact angle from 128.1° (Zn-PA) to 27.1° (Zn-PA-INAM) is strong evidence of a marked decrease in hydrophobicity of the target compound. Finally, HPLC was used to obtain the dissolution profile and solubility of Zn-PA-INAM compared to Zn-PA.

A comparison of nitrogen removal systems through cost-coupled life cycle assessment and energy efficiency analysis.

The global water crisis reflects the necessity of exploring the best approaches for the water supply. Therefore, for the first time, the current study compares nitrogen removal systems (NRSs) from life cycle assessment (LCA), economic, kinetic, thermodynamic, and synergistic perspectives. The assessed systems were sequential batch reactor (SBR), oxic/anoxic (OA), and oxic/anaerobic/oxic (OAO) bioreactors. Among all, the SBR configuration showed the best efficiency (98.74 %) for nitrogen removal. The environmental impacts notably presented by marine + freshwater ecotoxicity (53.76 %), and climate change categories (16.39 %), significantly because of metal emissions. Non-renewable sources supplied 95 % of total energy demand. The operation of NRSs showed the most impact on human health (63.67 %) through CH4 and CO2 emissions. The total costs significantly belonged to the construction (<86.37 %) > amortization> operation. The influent COD illustrated the most role in environmental burdens (16.44 %) based on the sensitivity analysis. The removal reaction was endothermic, physical, non-spontaneous, and followed a pseudo-second-order kinetic model (R2 > 0.98). The chemical exergy provided the major portion of the total calculated exergy (83 %). The exergetic efficiency of the system was 69 %, which was predominantly supplied by biogas (∼50.75 %). Accordingly, this study can present a stepwise guideline for further related investigations.

The green synthesis and applications of biological metal-organic frameworks for targeted drug delivery and tumor treatments.

Biological metal-organic frameworks (bio-MOFs) constitute a growing subclass of MOFs composed of metals and bio-ligands derived from biology, such as nucleobases, peptides, saccharides, and amino acids. Bio-ligands are more abundant than other traditional organic ligands, providing multiple coordination sites for MOFs. However, bio-MOFs are typically prepared using hazardous or harmful solvents or reagents, as well as laborious processes that do not conform to environmentally friendly standards. To improve biocompatibility and biosafety, eco-friendly synthesis and functionalization techniques should be employed with mild conditions and safer materials, aiming to reduce or avoid the use of toxic and hazardous chemical agents. Recently, bio-MOF applications have gained importance in some research areas, including imaging, tumor therapy, and targeted drug delivery, owing to their flexibility, low steric hindrances, low toxicity, remarkable biocompatibility, surface property refining, and degradability. This has led to an exponential increase in research on these materials. This paper provides a comprehensive review of updated strategies for the synthesis of environmentally friendly bio-MOFs, as well as an examination of the current progress and accomplishments in green-synthesized bio-MOFs for drug delivery aims and tumor treatments. In conclusion, we consider the challenges of applying bio-MOFs for biomedical applications and clarify the possible research orientation that can lead to highly efficient therapeutic outcomes.

Acid-free extraction of valuable metal elements from spent lithium-ion batteries using waste copperas.

A large amount of hazardous spent lithium-ion batteries (LIBs) is produced every year. Recovery of valuable metals from spent LIBs is significant to achieve environmental protection and alleviate resource shortages. In this study, a green and facile process for recovery of valuable metals from spent LIBs by waste copperas was proposed. The effects of heat treatment parameters on recovery efficiency of valuable metals and the redox mechanism were studied systematically through phase transformation behavior and valence transition. At low temperature (≤460 °C), copperas reacted with lithium on the outer layer of LIBs preferentially, but the reduction of transition metals was limited. As the temperature rose to 460-700 °C, the extraction efficiency of valuable metals was greatly enhanced due to the generation of SO2, and the gas-solid reaction proceeded much fast than the solid-solid reaction. In the final stage (≥700 °C), the main reactions were the thermal decomposition of soluble sulfates and the combination of decomposed oxides with Fe2O3 to form insoluble spinel. Under the optimum roasting conditions, i.e., at a copperas/LIBs mass ratio of 4.5, and a roasting temperature of 650 °C and roasting time of 120 min, the leaching efficiencies of Li, Ni, Co and Mn were 99.94%, 99.2%, 99.5% and 99.65%, respectively. The results showed that valuable metals can be selectively and efficiently extracted from the complex cathode materials by water leaching. This study used waste copperas as an aid to recover metals and provided an alternative technical route for green recycling of spent LIBs.

Resolution of sertraline with (R)-mandelic acid: chiral discrimination mechanism study.

The chiral discrimination mechanism in the resolution of sertraline with mandelic acid was investigated by examining the weak intermolecular interactions (such as hydrogen bond, CH/π, and van der Waals interactions) and molecular packing difference in crystal structures of the resulting diastereomeric salts. A new one-dimensional chain-like hydrogen-bonding network and unique supramolecular packing mode are disclosed. The investigation demonstrated that stable hydrogen-bonding pattern, herringbone-like arrangement of aromatic rings, and planar boundary surface in the hydrophobic region are the three most important structural characteristics expected in less soluble diastereomeric salts. The existence and magnitude of hydrogen bond, CH/π interaction, and van der Waals interaction related to three characteristic structures, determine the stability of diastereomeric salt. The hydrogen bond is not necessarily the dominant factor while the synergy and optimization of all weak intermolecular interactions attribute to the chiral recognition.

Resolution of 2-chloromandelic acid with (R)-(+)-N-benzyl-1-phenylethylamine: chiral discrimination mechanism.

During the resolution of 2-chloromandelic acid with (R)-(+)-N-benzyl-1-phenylethylamine, the crystals of the less soluble salt were grown, and their structure were determined and presented. The chiral discrimination mechanism was investigated by examining the weak intermolecular interactions (such as hydrogen bond, CH/π, and van der Waals interactions) and molecular packing mode in crystal structure of the less soluble diastereomeric salt. A one-dimensional double-chain hydrogen-bonding network and a "lock-and-key" supramolecular packing mode are disclosed. The investigation demonstrates that hydrophobic layers with corrugated surfaces can fit into the grooves of one another to realize a compact packing, when the molecular structure of resolving agent is much larger than that of the racemate. This "lock-and-key" assembly is recognized to be another characteristic of molecular packing contributing to the chiral discrimination, in addition to the well-known sandwich-like packing by hydrophobic layers with planar boundary surfaces.

Chromatographic resolution and isotherm determination of (R,S)-mandelic acid on Chiralcel-OD column.

Resolution of racemic mandelic acid ((R,S)-MA) and numerical determination of binary competitive isotherm of (R,S)-MA on Chiralcel-OD column have been investigated in this study. The effects of the alcohol modifier and acidic additive in the mobile phase on the retention and enantioseparation of (R,S)-MA were studied at first. The inverse method was then used to determine the competitive isotherm parameters of (R,S)-MA by minimizing the sum of square deviations of the model predictions from the measured elution profiles. The results indicate that the mobile phase with 85% hexane/15% isopropanol/0.3% trifluoroacetic acid mixture gives the best resolution of (R,S)-MA and competitive-modified Langmuir isotherm provides the more accurate sorption mechanism of (R,S)-MA on the cellulose tris(3,5-dimethylphenylcarbamate) chiral stationary phase.