N-methyl-2-pyrrolidone Research Articles

One‐Step Nickel‐Catalyzed Synthesis of Alpha‐Arylidene and Gamma Hydroxy‐Substituted N‐Methyl‐2‐Pyrrolidones

AbstractThis study describes a method to synthesize compounds with an arylidene group at the alpha position of N‐methyl‐2‐pyrrolidone (NMP) and an alcohol group at the gamma position in a single‐step reaction using NMP and aldehyde. The highest yields were obtained with Ni(glyme)Cl2 as a nickel catalyst and tert‐butyl hydroperoxide as the oxidant, and various aryl aldehydes reacted under optimal conditions to yield the target compounds.

Bifunctional low molecular weight polyacrylic acid as aqueous binder and coating agent enables high performance LiMn2O4 cathode for lithium-ion batteries

LiMn2O4 is considered to be a promising cathode material for lithium-ion batteries due to its decent energy density, low price and environmental benignity. However, the problems of Mn dissolution, migration and deposition during the cycle, seriously affect its lifespan, especially at high temperature. In this study, we developed a strategy by which we killed two birds with one stone. A low molecular weight polyacrylic acid (PAA) mixed with sodium carboxymethyl cellulose (CMC) is applied as binder and coating agent for cathode particles at the same time. The conventional and environmental unfriendly polyvinylidene difluoride (PVDF)-N-methylpyrrolidone (NMP) system is replaced by the cheap and green aqueous binder with improved adhesive effect. Furthermore, the binder-based surface coating layer not only alleviates the side reaction between the electrolyte and the cathode particles, but also chelates the dissolved Mn2+ by the large amount of carboxyl groups in PAA molecules and so prevents the following migration and deposition of Mn2+. In the button half-cell with low molecular weight PAA based binder, the capacity retention reaches 94.1 % after 1000 cycles at room temperature and 92.0 % after 200 cycles at 60 degrees centigrade. Meanwhile, 18650-type cylindrical cells were prepared with this binder, which shows a great high temperature storage performance. After the cell was held at 60 degrees centigrade for 25 days at full charged state, the internal resistance increased by only 1.25mΩ, the voltage decreased by only 0.1 V, the residual capacity retention and recovery capacity retention reaches 85.6 % and 92.2 %. This work shows the great potential of the aqueous binder in dealing with the problem of Mn dissolution during the cycling of manganese-based cathode materials for lithium-ion batteries.

Improving the cycling performance of lithium-air batteries using a nitrite salt electrolyte

Lithium nitrate (LiNO3) has been used as the electrolyte salt for Lithium-air battery (LAB), both to protect the lithium metal anode and to generate NO2− anions that function as the redox mediator (RM) reducing the charging voltage. However, this RM effect minimally improves cycling performance because only a low NO2− concentration is produced. Instead, the use of lithium nitrite (LiNO2) as the supporting electrolyte salt can overcome this limitation. In this study, 1 M solutions of LiNO3 or LiNO2 in tetraethylene glycol dimethyl ether (TEGDME) or N-methyl-2-pyrrolidone (NMP) were prepared as LAB electrolytes. Walden plots of these electrolytes established a higher degree of dissociation in the NMP having a greater dielectric constant, thus enhancing ionic conductivity. Electrochemical impedance spectroscopy determined that an LAB cell incorporating the LiNO2/NMP electrolyte exhibited reduced diffusion resistance during discharge-charge cycling as a consequence of the enhanced RM effect of NO2− anions. Microscopic observation and pore distribution analysis of cathodes confirmed that the clogging of pores was minimized with the LiNO2/NMP electrolyte. As a result, the LAB cell using this electrolyte extended the cycle performance, more than doubling the cycle life. LiNO2 is considered to be an effective alternative for electrolyte salt for LAB.

Nitrocellulose for Prolonged Permeation of Levofloxacin HCl-Salicylic Acid In Situ Gel.

Currently, the application of solvent exchange-induced in situ gel is underway for drug delivery to the body target site. Nitrocellulose was attempted in this research as the matrix-forming agent in solvent exchange-induced in situ gel for acne and periodontitis treatments. The gel incorporated a combination of 1% w/w levofloxacin HCl and 2% w/w salicylic acid as the active compounds. In order to facilitate formulation development, the study explored the matrix-forming behavior of different concentrations of nitrocellulose in N-methyl pyrrolidone (NMP). Consequently, their physicochemical properties and matrix-forming behavior, as well as antimicrobial and anti-inflammatory activities, were evaluated using the agar cup diffusion method and thermal inhibition of protein denaturation in the egg albumin technique, respectively. All prepared formulations presented as clear solutions with Newtonian flow. Their contact angles on agarose gel were higher than on a glass slide due to matrix formation upon exposure to the aqueous phase of agarose, with an angle of less than 60° indicating good spreadability. Nitrocellulose concentrations exceeding 20% initiated stable opaque matrix formation upon contact with phosphate buffer pH 6.8. The high hardness and remaining force of the transformed gel indicated their robustness after solvent exchange. Fluorescence tracking using sodium fluorescein and Nile red confirmed the retardation of NMP and water diffusion by the nitrocellulose matrix. From the Franz cell permeation study, these drugs could permeate through neonate porcine skin and tissue of porcine buccal from the nitrocellulose in situ forming gel. Their accumulation in these tissues might enable the inhibition of the invading bacterial pathogens. The developed in situ gels effectively inhibited Staphylococcus aureus, Staphylococcus epidermidis, Propionibacterium acnes, and Porphyromonas gingivalis. Furthermore, the formulations demonstrated an anti-inflammatory effect. The low viscosity of LvSa25Nc makes it appropriate for injectable treatments targeting periodontitis, while the higher viscosity of LvSa40Nc renders it appropriate for topical applications in acne treatment. Therefore, the nitrocellulose in situ gel loaded with combined levofloxacin HCl and salicylic acid emerges as a promising dosage form for treating acne and periodontitis.

Preparation and characterization of injectable in-situ forming gel based on lipid liquid crystal for one month delivery of aripiprazole: In-vitro and in-vivo evaluations in rats

The present study developed a one-month sustained-release formulation of aripiprazole, used for the treatment of schizophrenia and bipolar disorder, based on lipid liquid crystal (LLC) using phosphatidylcholine (PC) and N-methyl-2-pyrrolidone (NMP) solvent with sorbitan monooleate (SMO) or derivative glycerol oleate (glycerol monooleate (GMO), glycerol di-oleate (GDO), and glycerol trioleate (GTO)). The best formulation was selected based on the minimum initial burst release and the highest release of aripiprazole during the 30-day period. So, the formulations containing GMO and SMO exhibited the best initial slow release, while the other two formulations showed a burst release within 24 h. Furthermore, the GMO formulation did not release the drug completely during the 30-day study period, and the formulation containing GTO released the drug completely in less than a month. Therefore, the two formulations containing SMO and GDO were selected for further tests. The prepared liquid crystals had a hexagonal structure, indicating the creation of a suitable formulation structure with slow and controlled release. The area under the curve for the LLC-SMO formulation was higher than for other formulations, supporting the sustained release of aripiprazole and improving the long-term bioavailability of the drug. Moreover, this formulation was found to be safe and did not cause any damage to the skin at the injection site or vital organs such as the spleen, kidney, brain, heart, and liver. Hence, it can be considered a suitable option for developing an extended-release LLC formulation of aripiprazole.

NMP limits silver particle size to solve deposited film breakup problems

Metal based electroreflective devices (MERDs) have gained wide attention in recent years in the fields of smart windows and automotive glass due to their excellent photo-thermal modulation capability in the visible and near-infrared wavelength bands due to their high reflectivity. However, the high porosity due to the island-like growth of silver particles makes the devices susceptible to electrodeposited film breakage during prolonged energization or bleaching. This will seriously affect the effectiveness and stability of the device. In this paper, it is shown that the problem of Ag electrodeposition film fragmentation can be effectively overcome by replacing dimethyl sulfoxide solvent by N-methylpyrrolidone (NMP). The optical constants during film deposition were tested by the spectroscopic ellipsometry technique, and the porosity was calculated (reduced by 21.6%). The results show that MERDs with NMP as the solvent have more and more dispersed silver deposition sites, which leads to lower porosity of the silver deposited film during the deposition process. In addition, the lower turn-on voltage, greater contrast, longer memory effect, and greater coloring efficiency reveal that they are more promising for energy-saving applications.

Fabricating Planar Perovskite Solar Cells through a Greener Approach.

High-quality perovskite thin films are typically produced via solvent engineering, which results in efficient perovskite solar cells (PSCs). Nevertheless, the use of hazardous solvents like precursor solvents (N-Methyl-2-pyrrolidone (NMP), dimethyl sulfoxide (DMSO), dimethylformamide (DMF), gamma-butyrolactone (GBL)) and antisolvents (chlorobenzene (CB), dibutyl ether (DEE), diethyl ether (Et2O), etc.) is crucial to the preparation of perovskite solutions and the control of perovskite thin film crystallization. The consumption of hazardous solvents poses an imminent threat to both the health of manufacturers and the environment. Consequently, before PSCs are commercialized, the current concerns about the toxicity of solvents must be addressed. In this study, we fabricated highly efficient planar PSCs using a novel, environmentally friendly method. Initially, we employed a greener solvent engineering approach that substituted the hazardous precursor solvents with an environmentally friendly solvent called triethyl phosphate (TEP). In the following stage, we fabricated perovskite thin films without the use of an antisolvent by employing a two-step procedure. Of all the greener techniques used to fabricate PSCs, the FTO/SnO2/MAFAPbI3/spiro-OMeTAD planar device configuration yielded the highest PCE of 20.98%. Therefore, this work addresses the toxicity of the solvents used in the perovskite film fabrication procedure and provides a promising universal method for producing PSCs with high efficiency. The aforementioned environmentally friendly approach might allow for PSC fabrication on an industrial scale in the future under sustainable conditions.

Impact of N-Methyl-2-pyrrolidone Erosion on Surface Functional Groups and Pore Evolution in Coals of Different Ranks.

In low-permeability coal reservoirs, utilizing the organic solvent N-methyl-2-pyrrolidone (NMP) has emerged as an effective approach to improving the coal pore structure and enhancing coalbed methane productivity. However, the exact mechanisms of how solvent erosion alters functional groups and develops pores remain incompletely understood. This study utilized Fourier transform infrared spectroscopy and low-field nuclear magnetic resonance to assess the impact of NMP on the functional groups and pore structures of lignite, bituminous coal, and anthracite. The results indicate that a 6 h treatment with NMP led to an increased proportion of oxygen-containing functional groups in all coal samples, accompanied by a decrease in hydroxyls and aliphatic hydrocarbons. The aromaticity of the coal samples was enhanced to varying degrees, most notably for lignite. In terms of pore modification, the porosity of lignite and bituminous coal increased by 84.82 and 43.56%, while anthracite experienced a porosity increase of 3.04%, indicating a diminished effectiveness of NMP as the coal rank increased. These findings suggest that NMP selectively dissolves specific organic molecules in coals, thereby enhancing pore connectivity and promoting a transition from micro- to meso- and macropores. These findings highlight the potential of NMP in enhancing coalbed methane production and advance our understanding of the mechanisms behind solvent erosion.

Green synthesis of positive electrodes for high performance structural batteries - A study on graphene additives

Carbon fibres (CF) have the potential to serve as versatile and multifunctional conductive electrodes within the concept of “structural batteries”. These batteries possess the unique ability to both store electrical energy and bear mechanical loads without requiring extra current collectors. However, numerous challenges remain on the path to commercializing structural batteries. One significant challenge lies in the fabrication process of CF-based cathode composites, including the poor adhesion of active materials to the CF surface and the use of hazardous organic solvents, such as N-methyl pyrrolidone (NMP) through traditional blade coating. In this study, we present a sustainable fabrication approach, using electrophoretic deposition (EPD) to construct positive electrode composites with lithium iron phosphate (LiFePO4) and graphene nanosheets. Especially, ethanol was used as a green solvent replacing NMP to minimize the environmental impact. Meanwhile, the influence of different types of graphene additives (three kinds of graphene nanoplatelets (GNP), four kinds of reduced graphene oxide (rGO) and one home-made graphene) to the relative battery performance were evaluated under a systematic comparative analysis. Among the tested graphene additives, LFP/rGO2 based positive electrode exhibits a desirable specific capacity of 126.2 mAhg−1, maintaining over 93% retention even under the demanding conditions of 2C over 500 cycles.

A low pollution surface pretreatment of PC‐ABS under acidic conditions

AbstractIn the present study, the low pollution acidic potassium permanganate system has been used in the study of its micro‐etching effect on polycarbonate‐acrylonitrile butadiene styrene (PC‐ABS). Prior to micro‐etching using a N methyl pyrrolidone (NMP)‐glycol butyl ether solution was used as the swelling system of PC‐ABS. Reasonable swelling conditions were determined, a 2‐min expansion period at a temperature of 35°C with an NMP concentration of 80%. After the swelling processes, the effects of the volume ratio of :, micro‐etching temperature, and micro‐etching duration on the PC‐ABS surface morphology, surface roughness, surface hydrophilicity, and peel strength, have been investigated. It was finally determined that the best micro‐etching effect could be obtained by reacting at : = 1:2 and a temperature of 60°C for 25 min. The surface of the PC‐ABS copolymers was characterized by x‐ray photoelectron spectroscopy, atomic force microscopy, and Fourier‐transform infrared spectroscopy. The results showed that the micro‐etching process changed the morphology of the PC‐ABS surface and generated cavities. In addition, the surface roughness increased from the initial Ra = 9.69 to Ra = 197 nm. Also, the water contact angle on the PC‐ABS surface decreased from 92.2° to 28.6°, and the peel strength increased to 0.98 kN/m.

Adsorption of chlorpyrifos in water using polyaniline/graphene oxide composites

Graphene oxide and polyaniline have some unique properties and are considered as new generation materials for various applications. One major application of these materials is the adsorption of pollutants. In this study, Graphene oxide was synthesized with different levels of oxidation by using the modified Hummers method. Polyaniline/graphene oxide composite was synthesized by in situ polymerization with GO loading at 10% and 50% and further the composite is casted inside a disposable syringe by using N-methyl-2-pyrrolidone (NMP) as a dispersing agent. An adsorption experiment was carried out for water containing pesticide chlorpyrifos. The produced materials were characterized by FTIR spectroscopy & and XRD. Morphology was studied by SEM images. The FTIR spectra shows the formation of functional groups like -OH, -COOH on graphene, which may increase the hydrophilicity and adsorption properties. FTIR spectra of the composite portrayed the formation of bonds between polyaniline and graphene oxide. XRD peaks were obtained corresponding to crystals of polyaniline and graphite sheets. The adsorption efficiency was determined by analysis of water samples before and after filtration by using GC-MS. The composite produced with 50% amount of GO showed optimum results for the removal of chlorpyrifos. However, the composite with 10% GO loading is showing very low efficiency for the removal of chlorpyrifos. The PANI/GO composite is a possible candidate for the treatment of river water polluted by agricultural pollutants.

Study on the Adsorption of Trace Water in N-Methyl-pyrrolidone Solvents by A-Type Molecular Sieves.

N-Methyl-pyrrolidone (NMP) is an important coating solvent for the production of lithium batteries, and its water content will greatly affect the coating quality and energy density of lithium batteries, which needs to be reduced to 200 ppm. The current vacuum distillation technology suffers from high operating costs and high energy consumption, whereas the pervaporation technology only achieves solvent dehydration up to 99.5%. Therefore, it is of great significance to carry out the study of trace water removal from NMP solvents. In this paper, the A-type molecular sieve adsorption method was used to remove trace water from the NMP solvent, and the effects of molecular sieve type, particle size, adsorption temperature, feeding amount, and contact time on the dehydration performance of NMP system were first investigated. Adsorbed at 25 °C for 240 min at a feeding amount of 120 g/L, 3A molecular sieves were able to reduce the water content of the NMP solvent from 5000 to 140 ppm. Second, Langmuir and Freundlich equations were used to fit the static isothermal adsorption data, and the results showed a better correlation of the Langmuir equation. Then, the adsorption kinetics and diffusion mechanism were analyzed by the kinetic model and the Crank single-pore diffusion model. The R2 of the pseudo-first-order kinetic model was 0.9993, which was more suitable for describing the process of adsorption of water from the NMP solvent by 3A molecular sieves, and the effective diffusion coefficient De = 2.986 × 10-8 cm2/s was calculated for the Crank single-pore adsorption model, which proved water molecules on the 3A molecular sieve. The diffusion of water molecules on the inner surface of the pores is the controlling step of the adsorption process. Finally, the fixed-bed dynamic penetration curves were investigated to obtain the experimental data of fixed-bed adsorption, and the experimental data were fitted using the Thomas and Yoon-Nelson models, which showed that both models could describe the adsorption behavior of trace water in NMP solvents on 3A molecular sieves. This study provides a new idea for the removal of trace water in NMP systems, and a series of model fitting parameters provide basic data for industrial scale-up.

Potential Dependent Reorientation Controlling Activity of a Molecular Electrocatalyst.

The activity of molecular electrocatalysts depends on the interplay of electrolyte composition near the electrode surface, the composition and morphology of the electrode surface, and the electric field at the electrode-electrolyte interface. This interplay is challenging to study and often overlooked when assessing molecular catalyst activity. Here, we use surface specific vibrational sum frequency generation (VSFG) spectroscopy to study the solvent and potential dependent activation of Mo(bpy)(CO)4, a CO2 reduction catalyst, at a polycrystalline Au electrode. We find that the parent complex undergoes potential dependent reorientation at the electrode surface when a small amount of N-methyl-2-pyrrolidone (NMP) is present. This preactivates the complex, resulting in greater yields at less negative potentials, of the active electrocatalyst for CO2 reduction.

Facile and Nondestructive Transformation of Intrinsic Hydrophobic Behavior of a Carbon Nanotubes Sheet to Hydrophilic.

It is imperative to induce hydrophilicity in intrinsically hydrophobic carbon nanotubes (CNTs) without losing their superior properties for applications that specifically deal with aqueous media. A method for transforming a CNTs sheet from hydrophobic to hydrophilic by treatment with N-methyl-2-pyrrolidone (NMP) is explored. The NMP-treated CNT sheets are assessed based on complementing characterization, and it is concluded that the binding of NMP to a CNTs surface is through noncovalent interaction without the incorporation of defects in CNTs. The induced hydrophilicity in the CNTs sheet is stable for water exposure over a longer duration while it displays a semireversible nature upon heat treatment. The mechanical and electrical properties of the NMP-treated CNTs sheet revealed enhancement in the tensile strength from 221 to 421 MPa while maintaining a good electrical conductivity of ∼1.22 × 104 S/m because of the improved interfacial properties. The hydrophilic CNTs exhibited excellent adsorption capacity for methylene blue dye. The NMP-treated CNTs sheets demonstrated their suitability in flexible hybrid supercapacitor (FHSC) devices with improved electrochemical performance with enhancement in the capacitance from 5.4 to 7.6 F/g and a decrease in the equivalent series resistance from 53 to 34 Ω compared to pristine CNTs-based devices. These solid-state FHSC devices displayed excellent cyclic charge-discharge performance along with robust behavior over thousands of bending cycles without significant performance degradation. The excellent dye removal capability and superior electrochemical performance of the NMP-treated CNTs sheet is a consequence of their improved interface with aqueous media, which is governed by the hydrophilic nature of the CNTs sheet.

Parameterization of the IEF PCM model for calculating solvation energies in N-methylpyrrolidone solution

ABSTRACT Theoretical modelling of N-methylpyrrolidone (NMP) solutions, using a polarisable continuum model (IEFPCM), has been carried out with the aim to find the optimal value of a model parameter, a so-called scaling factor (α) for NMP, which should afford an improved modelling of various N-methylpyrrolidone solutions. Our working protocol comprised evaluations of the Gibbs free energy for the dissociation reaction of a set of 22 acids, employing the B2PLYP-D2/6–311+G**//B3LYP/6–31+G* approach, which were then used to calculate the acidity indices by considering the solvation energy at various values of α within the IEFPCM model. The optimal value of α for the N-methylpyrrolidone solvent has been found to amount to 1.40.

The Comparison of Polyethersulfone (PES)/N-Methyl 2-Pyrrolidone (NMP) on the Fabrication of Hollow Fiber Membranes with Commercial Membranes for Applications Hemodialysis

The decrease in kidney function is caused by an increase in creatinine and urea levels in the blood; this is the cause of chronic kidney failure (GGK) in patients. Hemodialysis membrane technology is an alternative treatment for chronic renal failure by separating dissolved components in the blood, such as creatinine and urea, using dialysate fluid by passing through the membrane pores. Therefore, the characteristics of hemodialysis membranes become essential to meet the requirements of a dialyzer. This study aimed to compare the features of the resulting hemodialysis membrane with several commercial membranes. In this study, there were four kinds of commercial membranes used, namely F8HPS, FX80, LO PS 15, and Nipro Elisio 15-H, were compared with membrane products that have variations in the composition of polyethylene (PES) using N-methyl-2-pyrolidone (NMP) solvents are 22.5; 24; and 25%. The membrane manufacturing method uses nonsolvent-induced precipitation (NISP). The resulting hollow fiber membrane is characterized by surface morphology using a scanning electron microscope (SEM), functional groups (FT-IR), and tensile test analysis (DMA). The results showed that the composition of PES/NMP is 25%, close to the characteristics of Nipro Elisio 15-H.

Efficiency of NZ2114 on Superficial Pyoderma Infected with Staphylococcus pseudintermedius.

Staphylococcus pseudintermedius (S. pseudintermedius) is the main pathogen causing pyoderma of canines. With the emergence of drug-resistant bacteria, traditional antibiotic treatments are limited. As a potential antibacterial agent, NZ2114 was effective against S. pseudintermedius, including drug-resistant strains. Its bactericidal efficacy was superior to mupiroxacin, ofloxacin and lincomycin. To facilitate the transcutaneous delivery of NZ2114 for the treatment of superficial pyoderma, chemical permeation enhancers were added since water-soluble NZ2114 does not easily penetrate the skin lipid layer. Two different NZ2114 sprays were prepared by combining 1% Azone + 10% propylene glycol (PG) or 5% N-methylpyrrolidone (NMP) + 10% PG with NZ2114 after screening. The cumulative permeability of NZ2114 sprays were 244.149 and 405.245 μg/cm2 at 24 h with an in vitro percutaneous assay of mice skin, which showed a 244% and 405% increase in skin permeability than NZ2114, respectively. In addition, the efficacy of NZ2114 sprays in reducing skin bacteria colonisation was demonstrated in a mouse model of superficial pyoderma (24 mice, 3 mice/group) induced by S. pseudintermedius, and the 5% NMP + 10% PG + NZ2114 group had the best therapeutic effect compared to the other groups. This preparation did not cause any skin irritation, laying the foundation for the development of an effective and non-toxic topical product.

Al2O3 Thin Layer Formed inside Porous Membrane Using Spray Synthesis Method and Its Application

Aluminum oxide (Al2O3) films have been investigated for use in various applications, and numerous deposition techniques have been reported. The spray synthesis method has the advantage of forming a thin layer of crystal at low temperatures using the appropriate precursors. A precursor prepared by diluting Methylaluminoxane with N-methyl pyrrolidone was sprayed onto a porous membrane while varying conditions such as the substrate temperature, feeding speed, and spray amount. The solution penetrated the film during spray application, and the ultra-thin layers deposited on the side wall of the internal pores were observed using a cross-sectional transmission electron microscope (XTEM). The lattice image obtained using the TEM and the composition analysis conducted using a scanning TEM and an energy-dispersive X-ray spectroscope suggest that this thin layer is a layer of Al2O3. The formation of Al2O3 occurred at lower temperatures than in previous reports. This is a major advantage for applications with low-melting-point materials. The most suitable spraying conditions were determined based on the state of deposition on the surface and inside the membrane. These conditions were applied to a three-layer separator for lithium-ion batteries and their effect on thermal stability was investigated. Through heating experiments and XRD analysis, it was confirmed that the shrinkage and melting of the separator are suppressed by spraying. This process can be expected to have wide applications in low-melting-point materials such as polyolefin.

Performances Study of Polyvinylidene Fluoride (PVDF)/Waste Eggshell (WES) Mixed-Matrix Membrane for Copper Removal

The presence of heavy metals in water resources brings hazard to health and the environment considering that most of these cannot be degraded and may result in bioaccumulation in the food chain. This study investigated the applicability and efficiency of waste eggshells for the removal of Copper (Cu) heavy metal in aqueous solution. The mixed-matrix membrane with polyvinylidene fluoride (PVDF) as membrane material, N-Methyl-2-pyrrolidone (NMP) as solvent and waste eggshell as additive with ratio of (a) 15:85:0, (b) 14.9:85:0.1, (c) 14.7:85:0.3, (d) 14.5:85:0.5 and (e) 14:85:1 is fabricated using phase inversion method. Phase inversion is a well-studied immersion precipitation technique for membrane synthesis. Using this common method, polymer is dissolved in an organic solvent and the solution cast upon a glass surface with 0.40 knife gap. The resulting membrane morphologies were analysed by using Scanning Electron Microscopy (SEM) and the significant functional group of the resulting membranes were identified using Fourier Transform Infrared Spectroscopy (FTIR). The addition of waste eggshell to the casting solution improved the morphology and structure of the membrane significantly. The appearance of waste eggshell on membrane surface demonstrated in SEM and FTIR analysis. Furthermore, the result of the study showed that the waste eggshells as an adsorbent could remove Cu in an aqueous solution up to 99% with water permeability of 56.52 Lm-2h-1bar-1. Overall, the study demonstrated that the waste eggshell that is generally considered as wastes in large quantities could become an economically advantageous for Cu removal.

Investigation of the mechanism of solvothermal extraction of direct coal liquefaction residue by macromolecular models

Direct coal liquefaction residue (DCLR) is an industrial by-product from the direct coal liquefaction process. It has the unique characteristics of high carbon, high sulfur and high ash content, strong cohesiveness and low softening point, which makes DLCR a potential raw material. However, direct discharge of untreated DCLR can cause severe damage to environment and human body. Thus it is of great importance to utilize DCLR properly. In this study, solvothermal extraction of direct coal liquefaction residue (DCLR)was treated with N-methyl-2-pyrrolidone (NMP) and 1-methyl naphthalene (1-MN). In addition, molecular models of DCLR and two hypercoals (HPC: NMP-HPC, MN-HPC) were built to clarify the extraction mechanism, aiming to provide a technically feasible route to utilize DCLR and investigate the adaptation between extractant and raw materials. The structural parameters were obtained by means of industrial and elemental analysis, 13C NMR, XPS and FTIR. Subsequently, macromolecular structure models were constructed, with simulated molecular formulas C153H108N2O10S, C206H168N6O7 and C278H202N2O13S, respectively. After modifying the macromolecular models by Materials Studio for geometric optimization, annealing dynamics calculation, density simulation and analysis of chemical bonds and charge layout, these models reflected the macromolecular structural characteristics precisely. On the other hand, DCLR model underwent significant changes in functional groups, branched chain length and quantity pre and post solvothermal extraction, indicating that the thermal extraction process was mainly affected by swelling behavior and pyrolysis. Meanwhile the principles of the two extractants were also different.1-MN extraction was a heat-induced relaxation, while NMP extraction was heat & solvent-induced relaxation process. This study will be helpful in expanding the utilization of DCLR and understanding of mechanism of solvothermal extraction on the macromolecular level based on modeling.