Polyethylenimine Research Articles

Polyethyleneimine Modified Two-Dimensional GO/MXene Composite Membranes with Enhanced Mg2+/Li+ Separation Performance for Salt Lake Brine.

As global demand for renewable energy and electric vehicles increases, the need for lithium has surged significantly. Extracting lithium from salt lake brine has become a cutting-edge technology in lithium resource production. In this study, two-dimensional (2D) GO/MXene composite membranes were fabricated using pressure-assisted filtration with a polyethyleneimine (PEI) coating, resulting in positively charged PEI-GO/MXene membranes. These innovative membranes, taking advantage of the synergistic effects of interlayer channel sieving and the Donnan effect, demonstrated excellent performance in Mg2+/Li+ separation with a mass ratio of 20 (Mg2+ rejection = 85.3%, Li+ rejection = 16.7%, SLi,Mg = 5.7) in simulated saline lake brine. Testing on actual salt lake brine in Tibet, China, confirmed the composite membrane's potential for effective Mg2+/Li+ separation. In the actual brine test with high concentration, Mg2+/Li+ after membrane separation is 2.2, which indicates that the membrane can significantly reduce the concentration of Mg2+ in the brine. Additionally, the PEI-GO/MXene composite membrane demonstrated strong anti-swelling properties and effective divalent ion rejection. This research presents an innovative approach to advance the development of 2D membranes for the selective removal of Mg2+ and Li+ from salt lake brine.

Polyethylenimine-assisted preparation of Zr-MOF/GO membranes for radionuclide separation

In this study, a zirconium-metal organic framework/graphene oxide (UiO-66-NH2/GO) nanofiltration membrane has been prepared with the assistance of branched polyethyleneimine (PEI). This PEI-assisted method facilitates a more uniform dispersion of UiO-66-NH2 within the GO membrane, thereby enhancing the structural stability of the membrane during membrane separation. The as-prepared membrane has exhibited excellent performance in removing radioactive strontium ions, which is a trending research field in nuclear wastewater treatment. A comprehensive investigation into the separation mechanism of the PEI-UiO-66-NH2/GO membrane has revealed a synergistic effect involving size exclusion and electrostatic repulsion. Furthermore, the PEI-UiO-66-NH2/GO membrane has consistently achieved high strontium rejection across a wide range of strontium concentrations, pH levels, and even in the presence of other interfering ions. More significantly, the membrane has demonstrated remarkably enhanced capacity for selectively separating binary mixtures of cesium and strontium, offering practical relevance. Our results have indicated that the PEI-UiO-66-NH2/GO membrane holds considerable promise for the separation of strontium ions.

Cross-linked copolyimide-P84/CAU-10-H/branched polyethyleneimine membranes for organic solvent nanofiltration

The advancement of organic solvent nanofiltration (OSN) is often hindered by the inherent trade-off between permeance and rejection. In this study, we present a novel nanocomposite mixed matrix membrane (MMM) fabricated by integrating a compatible metal–organic framework (CAU-10-H) into a co-polyimide (P84) matrix. The resulting P84/CAU-10-H membrane was cross-linked using branched polyethyleneimine (PEI) to produce a P84/CAU-10-H/PEI MMM with robust resistance to harsh organic solvents, making it suitable for OSN applications. The integration of CAU-10-H, PEI, and P84 significantly enhanced the OSN performance, improving sieving efficiency and reducing fouling tendencies. The fabricated membrane exhibited outstanding permeance across various solvents, with values of 42.4, 45.4, 24.5, and 27.1 LMH/bar for methanol, acetone, N-methyl-2-pyrrolidone (NMP), and dimethyl sulfoxide (DMSO), respectively. Besides, the P84/CAU-10-H/PEI MMM demonstrated excellent rejection (Brilliant yellow (BY) > 90 %, Congo red (CR), Methyl blue (MB), Evans blue (EB), and Alcian blue (AB) > 99 %, respectively). In a 96-hour long-term test, the membrane demonstrated excellent stability and anti-fouling properties. This study presents a facile and viable approach for designing and constructing novel OSN MMMs.

PEI-Engineered Lipid@PLGA Hybrid Nanoparticles for Multimodal Delivery of Antigens and Immune Adjuvants to the Respiratory Mucosa.

Antigen delivery via respiratory mucosal surfaces is an interesting needle-free option for vaccination. Nonetheless, it demands for the design of especially tailored formulations. Here, lipid/poly(lactic-co-glycolic) acid (PLGA) hybrid nanoparticles (hNPs) for the combined delivery of an antigen, ovalbumin (Ova), and an adjuvant, synthetic unmethylated cytosine-phosphate-guanine oligodeoxynucleotide (CpG) motifs, is developed. A panel of Ova/CpG-loaded lipid@PLGA hNPs with tunable size and surface is attained by exploiting two lipid moieties, 1,2 distearoil-sn-glycero-3-phosphoethanolamine-poly(ethylene glycol) (DSPE-PEG) and monophosphoryl lipid A (MPLA), with or without polyethyleneimine (PEI). It is gained insights on the lipid@PLGA hNPs through a combination of techniques to analytically determine the specific moiety on the surface, the spatial distribution of the components and the internal structure of the nanoplatforms. The collected results suggest that PEI plays a role of paramount importance not only in promoting in vitro antigen escape from lysosomes and enhancing antigen cross-presentation, but also in determining the arrangement of the moieties in the final architecture of the hNPs. Though multicomponent PEI-engineered lipid@PLGA hNPs turn out as a viable strategy for delivery of antigens and adjuvant to the respiratory mucosa, tunable nanoparticle features are achievable only through the optimal selection of the components and their relative amounts.

Fabrication of charged and zwitterionic nanofiltration membranes and anti-adhesion analysis using quartz crystal microbalance with dissipation and atomic force microscopy

Three nanofiltration (NF) membranes (positive charge, negative charge and near charge neutrality) were fabricated to investigate the anti-adhesion mechanism. Among them, the NF membrane with positive charge was synthesized through an electrophilic substitution reaction between the amino group of polyethyleneimine (PEI) and the chloromethyl groups of chloromethyl polysulfone (CMPSf) on a supporting polysulfone (PSf)/CMPSf blend membrane. The NF membrane with negative charge was fabricated through polycondensation using 1, 3, 5-benzenetricarbonyl trichloride (TMC) as a reactive monomer on the positive charge NF membrane. Subsequently, the near charge neutral zwitterion NF membrane (ZNF) was prepared by grafting 3-((2-aminoethyl) dimethylammonio) propane-1-sulfonate (sulfobetaine) (ADSS) onto the negative charge NF membrane. The anti-adhesion behaviors of the NF membranes during the dye selective separation were analyzed by Atomic force microscopy (AFM) and quartz crystal microbalance with dissipation (QCM-D). The results demonstrated that the near charge neutral ZNF membrane displayed a higher dyes rejection (>94.4 %) and higher flux recovery rates (>88.1 %) than charged NF membranes. Meanwhile, the near charge neutral ZNF membrane demonstrated the lowest amounts of dye deposition compared with charged NF membranes, such as reactive blue 4 (R4) for 509.9 ng/cm2, basic blue 24 (BB 24) for 269.0 ng/cm2, rhodamine B (RB) for 197.4 ng/cm2). Additionally, the near charge neutral ZNF membrane with the thicker hydration layer (121.7 nm) displayed weaker interaction forces (−4.8 nN to −7.4 nN) with the dyes than the charged membranes (−10.4 nN to −28.6 nN). Finally, an anti-adhesion mechanism involved charged shielding effect and hydration layer formation was proposed. These observations provide comprehensive insights into the anti-adhesion mechanism of ZNF membrane.

Self-assembled ROS-triggered Bletilla striata polysaccharide-releasing hydrogel dressing for inflammation-regulation and enhanced tissue-healing

The antimicrobial and pro-healing properties remain critical clinical objectives for skin wound management. However, the escalating problem of antibiotic overuse and the corresponding rise in bacterial resistance necessitates an urgent shift towards an antibiotic-free approach to antibacterial treatment. The quest for antimicrobial efficacy while accelerating wound healing without antibiotic treatment have emerged as innovative strategies in skin wound treatment. Here, a dual-function hydrogel with antimicrobial and enhanced tissue-healing properties was developed by utilizing cyclodextrin, ferrocene, polyethyleneimine (PEI), and Bletilla striata polysaccharide (BSP), through multiple non-covalent interactions, which can intelligently release BSP by recognizing the wound inflammatory microenvironment through the cyclodextrin-ferrocene unit. Moreover, the porosity (65 % - 85 %), Young's modulus (400 KPa - 140 KPa), and DPPH scavenge rate (18 % - 40 %) of the hydrogel are modulated by varying the BSP content. The hydrogel exhibits outstanding antibacterial properties (98.3 % reduction of Escherichia coli observed after exposure to HTFC@BSP-20 for 24 h) and favorable biocompatibility. Furthermore, in a rat full-thickness skin wound model, the dual-function hydrogel significantly accelerates wound healing, increased CD31 expression promotes vascular regeneration, reduced TNF-α express and inhibited the inflammation. This multifunctional ROS responsive hydrogel provides a new perspective for antibiotics-free treatment of skin injuries.

Comparative study: High performance polymers of polyphenylene sulfide and polyethylenimine using Taguchi-Topsis optimization approaches

The role of high-performance thermoplastic products is increasing in the present days because of its excellent physical and mechanical properties and also capable of withstanding critical loads and temperatures. In this study, an attempt was made to improve the mechanical and physical properties of two polymers PPS (Polyphenylene Sulfide) and PEI (Polyethylenimine) by addition of glass fiber as a reinforcement fiber. The glass fiber (GF) content considered as 40 wt% for both the polymers. Injection molding method was used for fabrication of PPS and PEI samples. After fabrication, mechanical tests such as tensile, impact and dimensional shrinkage (%) of samples were calculated. Taguchi and Topsis analysis techniques were applied for evaluation of major influencing parameters and determining the best experiment to be performed on the machine. After conducting the test, PPS polymer exhibited better mechanical strength values and lower shrinkage (%) compared to PEI. The best input parameters kept on the machine were observed to be gate way type, temperature and pressure. The conditions of gate way type 2, temperature 320°C, and a pressure of 100 bar are obtained as the best input parameters to be fixed on the machine for achieving higher values of mechanical strength and lower dimensional shrinkage for both PPS and PEI polymers. Out of these two polymers, PPS exhibited better mechanical and physical properties combining with GF. This polymer can extend its usage as a high-performance polymer for various industrial applications.

Addressing small-scale temperature swing adsorption challenges using intensified fluidised bed technology for carbon capture process development

Polyethylenimine (PEI)-based adsorbents exhibit high CO2 capacities, making them potential candidates for mitigating unavoidable industrial CO2 emissions. However, desorption of CO2 from PEI, and from adsorbents in general, has received far less attention in the literature than adsorption. Whilst Temperature Swing Adsorption (TSA) is simple to conceptualise, it is difficult to implement in small-scale experiments in practice. Here we study the desorption characteristics of a commercial branched PEI adsorbent in a small-scale swirling fluidised bed reactor (TORBED) to improve the small-scale heat transfer rates. Our experimental results show that higher desorption temperatures, higher gas flow rates, and higher CO2 concentrations during adsorption can improve the desorption efficiency (defined as the amount of CO2 removed as a fraction of the initial amount adsorbed). In terms of kinetics, we found that the fractional order kinetic model provided the best fit to the PEI adsorbent, implying that this adsorbent involves multiple simultaneous molecular interactions, physisorption processes, and chemisorption processes, that cannot be described by simpler pseudo 1st or 2nd order models. Desorption rates in the TORBED in this study were 1 order of magnitude faster than fluidised beds, and 2–3 orders of magnitude faster than packed beds.

Capping-grafting synergistic strategy for the preparation of high-performance Mg2+/Li+ separation nanofiltration membranes

Polyethyleneimine (PEI) nanofiltration (NF) membranes demonstrate remarkable effectiveness in separating lithium and magnesium from salt lakes, attributed to their positively charged surface. However, undesired permeability resulting from densely cross-linked structures limits the further industrial applications and development of PEI NF membranes. Herein, a high permeable Mg2+/Li+ separation NF membrane with stronger internal and surface positive charge was fabricated using 1-Aminopyridinium iodide (1-AI) for the first time through a capping-grafting synergistic strategy. On the one hand, the monoamine character of 1-AI can realize the end-capping (EC) effect on the acyl chloride monomers in the interfacial polymerization process, which can contribute to a reduction in the cross-linking degree of the membrane. On the other hand, 1-AI with a quaternary ammonium group as the surface grafting (SG) agent can significantly improve the surface positive charge property of the membrane. The synergistic effect of capping-grafting not only rendered the membrane looser and effectively enhanced the surface positive charge of the membrane, but also increased the depth of grafting modification, leading to a notable rise in the internal positive charge of the membrane. After the capping-grafting treatment, the water permeance of the PEI-EC/SG membrane reached 19.8 L·m−2·h−1·bar−1, approximately 4.5 times that of the original PEI membrane, while keeping an ideal MgCl2 rejection rate (97.1%) and exhibiting good Mg2+/Li+ selectivity (27.7). This work demonstrates the advantages of the capping-grafting synergistic method in regulating membrane structure for improving permeability as well as the surface and internal charge properties of the membrane for enhancing ion selectivity.

Enhancing virus inhibition in track-etched membranes through surface modification with silver nanoparticles and curcumin

The present work reports on the use of silver nanoparticles (AgNPs) and curcumin immobilized on the surface of microfiltration track-etched membranes (mTMs) as antiviral filtration materials. AgNPs were synthesized through the direct reduction of silver nitrate by sodium borohydride in the presence of a stabilizing agent. The synthesized nanoparticles and curcumin were immobilized on polyethyleneimine (PEI)-modified mTMs through a static sorption process. TEM, SEM, UV–vis. spectroscopy and luminescence measurements revealed a uniform distribution of AgNPs and confirmed the presence of curcumin on the membrane surface. The resulting TM-PEI-AgNPs-PVP and TM-PEI-Curcumin hybrid membranes were employed for the filtration of HSV-1, VSV, IAV, and EMCV viruses. While both membrane types exhibited insignificant inhibition for the latter two, they achieved 95 and 99 % inhibition for HSV-1 and VSV, respectively. These findings suggest that hybrid membranes with immobilized AgNPs and curcumin can have potential as antiviral filtration materials.

A Reconfigurable Proangiogenic Hydrogel Patch Enabling Minimally Invasive Drug Delivery.

Hydrogel is widely used for the sustained delivery of bioactive molecules that can treat various injuries, diseases, and tissue defects. However, inserting hydrogel implants without disrupting their functionality and microstructure often requires a large incision, leading to potential complications, such as infection, scarring, and pain. The gel implant is often manually rolled and inserted through a catheter for a minimally invasive delivery. However, success heavily depends on the user's skills, which can inadvertently damage the implant. To address this issue, we developed a reconfigurable hydrogel patch that can self-fold into a small tube and unfold spontaneously after implantation through a catheter. The hydrogel path was assembled by layering a drug-releasing poly(ethylene glycol) diacrylate (PEGDA) hydrogel sheet onto a PEGDA and polyethylenimine (PEI) hydrogel sheet, which rapidly swells and degrades homogeneously at controlled rates. The dynamics of the self-folding and unfolding process could be controlled by differences in the expansion ratio and elastic modulus between the two gel layers according to a mathematical model that closely matched experimental results. The unfolding process triggered a sustained release of the protein cargo. Specifically, the reconfigurable gel loaded with angiopoietin 1 significantly enhanced neovascularization, nearly doubling the vascular density compared to the control group following implantation through a tube with 15% smaller diameter than the original shape of the gel patch. This gel biopatch will be broadly useful for the minimally invasive delivery of a wide array of therapeutic molecules, potentially enhancing therapeutic outcomes.

Experimental study on EOR potential of P(AM/NVP) based gel in ultra-high temperature reservoirs

Polymer gel has been widely used in high water cut reservoirs for enhanced oil recovery (EOR), while its effectiveness is often curtailed in ultra-high temperature reservoirs for the indeterminate stability. In the present work, the ultra-high temperature resistant gel was constructed with P(AM/NVP) as the main agent, hydroquinone and Polyethylenimine (PEI) as the crosslinking agent, and the EOR potential of P(AM/NVP) based gel is studied at 150 °C, including injectivity, plugging property, and oil increasing performance. The experimental results indicated that the base solution of P(AM/NVP) based gel could establish resistance factor of 17.5–182.5, the plugging rate of the gel exceeded 96%, and the breakthrough pressure gradient ranged from 17.99 MPa/m to 46.54 MPa/m in matrix cores. For fractured cores, the plugging ratio surpassed 95%, and the breakthrough pressure gradient decreased to 9.56 MPa/m ∼24.32 MPa/m. Moreover, within a permeability ratio of 5.90–28.75, the water cut could be decreased from 98.0%–100.0%–50.9%–65.81%, with an increase in oil recovery of 20.10%–44.30%. In addition, NMR experiment verified the gel blocking channeling channel and expand the sweeping efficiency of chase water flooding. This study's findings showed that P(AM/NVP) based gel has excellent EOR potential in ultra-high temperature reservoirs.

Potential applications of PEI loaded graphene oxide quantum dots in safe and efficient DNA delivery

In order to improve the safety and efficacy of gene delivery using polyethyleneimine (PEI), this work focused on developing PEI quantum dots and incorporating them onto graphene to improve gene loading capacity. The successful creation of graphene-polyethyleneimine quantum dots (GPQDs) was confirmed through fluorescence emission spectrum and infrared spectroscopy. Both polyethyleneimine quantum dots (PQDs) and GPQDs exhibited blue fluorescence when excited between 310 and 430 nm, indicating that they retained the fluorescence characteristics of broad excitation and narrow emission. Furthermore, GPQDs displayed smaller particle sizes, increased hydrophilicity, and better dispersibility compared to PQDs. GPQDs were able to efficiently load DNA with lower cytotoxicity than PQDs and PEI. The enhanced fluorescence properties of GPQDs allowed for the observation that GPQDs/DNA complexes were effectively internalized by cells with higher uptake efficiency than PEI/DNA and PQDs/DNA complexes. The study demonstrated that GPQDs/DNA complexes successfully transfected 293T and HeLa cells, with GPQDs prepared using PEI25k showing improved cell uptake and transfection efficiency compared to those prepared with PEI10k. Overall, the findings suggest that GPQDs are a more effective and safer gene delivery vector than PEI, with promising potential for future gene delivery applications.

High-Performance Crown Ether-Modified Membranes for Selective Lithium Recovery from High Na+ and Mg2+ Brines Using Electrodialysis

The challenge of efficiently extracting Li+ from brines with high Na+ or Mg2+ concentrations has led to extensive research on developing highly selective separation membranes for electrodialysis. Various studies have demonstrated that nanofiltration membranes or adsorbents modified with crown ethers (CEs) such as 2-OH-12-crown-4-ether (12CE), 2-OH-18-crown-6-ether (18CE), and 2-OH-15-crown-5-ether (15CE) show selectivity for Li+ in brines. This study aims to develop high-performance cation exchange membranes (CEMs) using CEs to enhance Li+ selectivity and to compare the performance of various CE-modified membranes for selective electrodialysis. The novel CEM (CR671) was modified with 12CE, 18CE, and 15CE to identify the optimal CE for efficient Li+ recovery during brine electrodialysis. The modification process included polydopamine (PDA) treatment and the deposition of polyethyleneimine (PEI) complexes with the different CEs via hydrogen bonding. Interfacial polymerization with 1,3,5-benzenetricarbonyl trichloride-crosslinked PEI was used to create specific channels for Li+ transport within the modified membranes (12CE/CR671, 15CE/CR671, and 18CE/CR671). The successful application of CE coatings and Li+ selectivity of the modified membranes were verified through Fourier-transform infrared spectroscopy, zeta-potential measurements, and electrochemical impedance spectroscopy. Bench-scale electrodialysis tests showed significant improvements in permselectivity and Li+ flux for all three modified membranes. In brines with high Na+ and Mg2+ concentrations, the 15CE/CR671 membrane demonstrated more significant improvements in permselectivity compared to the 12CE/CR671 (3.3-fold and 1.7-fold) and the 18CE/CR671 (2.4-fold and 2.6-fold) membranes at current densities of 2.3 mA/cm2 and 2.2 mA/cm2, respectively. At higher current densities of 14.7 mA/cm2 in Mg2+-rich brine and 15.9 mA/cm2 in Na+-rich brine, the 15CE/CR671 membrane showed greater improvements in Li+ flux, approximately 2.1-fold and 2.3-fold, and 3.2-fold and 3.4-fold compared to the 12CE/CR671 and 18CE/CR671 membranes. This study underscores the superior performance of 15CE-modified membranes for efficient Li+ recovery with low energy demand and offers valuable insights for advancing electrodialysis processes in challenging brine environments.

Dual contrasting ability of NaGd0.7Eu0.3F4 nanocrystals tuned by their hydrophilic coating mode

This work introduces non-covalent hydrophilic coating of NaGd0.7Eu0.3F4 nanocrystals by polylysine (PL) and polyethyleneimine (PEI) for MRI and fluorescent imaging purposes. PL- and PEI-stabilized nanocrystals exhibit high colloidal stability, cell internalization, fluorescent contrasting of nuclei and cytoplasm, low cytotoxicity, and relaxivity (r1= 0.17 dm3 mmol–1 s–1 and r1 = 0.23 dm3 mmol–1 s–1).

Magnetic graphene oxide grafted boronic acid-decorated metal-organic frameworks for selective enrichment of cis-diol-containing nucleosides

In this study, a novel magnetic graphene oxide grafted boronic acid-decorated metal-organic frameworks (Fe3O4@GO@BA-MOF) composite was developed for the selective enrichment of cis-diol-containing nucleosides. It is noteworthy that the amino-functionalized Fe3O4 was prepared by polyethyleneimine (PEI) as modifier, resulting in excellent durability and stability of magnetic nanoparticles under different environment, as well as introducing rich active functional groups for post-modification. GO with large surface area and abundant multi-active group was covalently bonded on amino-rich Fe3O4 as interlayer to facilitate the growth of BA-MOF with high boronic acid grafting density for selective capture of nucleosides. Due to the multi-interactions, especially the boronate affinity as well as the synergistic effect, the Fe3O4@GO@BA-MOF composite exhibited superior selectivity and adsorption capacity to nucleosides. Under the optimal conditions, an efficient magnetic solid-phase extraction-high-performance liquid chromatography technique was established using Fe3O4@GO@BA-MOF composite for the purpose of extracting and detecting nucleosides in urine, with recoveries ranging from 90.69 % to 110.36 %, relative standard deviations below 8.5 % and detection limits ranging from 0.004 to 0.010 μg mL−1. This study offers a new approach for preparation of high grafting density of boronic acid-decorated magnetic MOF, which is promising in selective enrichment of cis-diol-containing compounds in biological analysis.

Efficient removal of Pb(II) and Cd(II) from water by polyethyleneimine-amidated sepiolite-sodium alginate composite microspheres: Characterization and mechanistic analysis

In order to improve the physicochemical properties of heavy metal adsorbents, researchers developed a novel composite microsphere material (SEI) by incorporating Sepiolite (Sep) and cross-linked polyethyleneimine (PEI) with sodium alginate (SA) as a carrier. The stability of the SEI under normal use conditions was high by thermogravimetric analysis, and COOH, OH, and NH2 functional groups were detected by FTIR, which were confirmed to be involved in adsorption. It was found that the adsorption rate of SEI on Pb(II) and Cd(II) obeyed a pseudo-second-order kinetic model, while the adsorption pattern was closely related to the Langmuir equation. Notably, the maximum adsorption capacity of SEI for Pb(II) and Cd(II) was 1099.93 mg/g and 112.89 mg/g, respectively, at 30 °C. In addition, thermodynamic analyses showed that the adsorption process was spontaneous, with entropy increase along with heat absorption. After six adsorption and desorption cycles, the removal of Pb(II) and Cd(II) by SEI remained above 90 %. These findings suggest that SEI is a promising and environmentally friendly material for the removal of Pb(II) and Cd(II).

Construction of bilayer cellulose-based aerogel with salt-resistant design for efficient solar desalination and wastewater purification

Solar-driven interfacial evaporation (SDIE) technology, which utilizes green and renewable solar energy to produce clean water, has shown great potential in alleviating global water scarcity. However, practical applications still face numerous challenges, including salt crystallization precipitation and accumulation, low energy utilization, and complex preparation processes. Hence, We designed a vertically ordered porous bilayer aerogel based on nanofibrillated cellulose (NFC)/polyethyleneimine (PEI) with excellent salt resistance, light absorption and local thermal effects to achieve efficient solar steam generation. Specifically, the photothermal conversion layer (PCL) at the top had excellent light absorption and photothermal conversion efficiency by introducing graphene oxide (GO) as a highly efficient photothermal material. The water transport layer (WTL) at the bottom ensured a stable water supply to the evaporation layer by virtue of the vertical water transfer path and inherent hydrophilicity, and effectively prevented formation of salts in the evaporation area. In addition, the designed aerogel had a low thermal conductivity, which achieved effective thermal insulation and further enhanced the localized heating effect. This superhydrophilic bilayer aerogel achieved a high evaporation rate of 1.9596 kg m−2 h−1 and an energy conversion efficiency of 92.28% under one solar irradiation. It is noteworthy that evaporation process exhibited excellent stability during 8 h of continuous evaporation in 20 wt% brine and no salt accumulation was observed on the evaporated surface. In addition, the bilayer aerogel demonstrated excellent long-term stability and self-cleaning. Meanwhile, its excellent anti-contamination and wastewater treatment capabilities give SDIE technology a stable and continuous operation in practical applications, thus demonstrating significant application potential.

Improving the performance of glucose oxidase biofuel cell by methyl red and chitosan composite electrodes

This research aims to improve the output power of self-pumping glucose enzymatic biofuel cell (EBFC) and modifying the anode. Adding a fixed ratio of methyl red-chitosan (MR-CS) can effectively improve the EBFC efficiency and stability. In addition, chitosan can be obtained from discarded crustacean fishery waste objects such as shrimp and oysters, are also significant to the use of environmentally friendly materials. The catalyst was immobilized on pyrenecarboxaldehyde (PCA), polyethyleneimine (PEI) and multi-wall carbon nanotubes (MWCNT) and combined with glucose oxidase (GOx). Finally, the [PCA/GOx]/PEI/Nafion solution/MWCNT/[MR-CS] catalyst was immobilized on the carbon cloth. Experimental analysis was progressed under the preparation of enzyme-supported electrode to observe the feasibility of the anode electrode. Experiment including Fourier transform infrared spectroscopy (FTIR) to analyze the distribution of functional groups after modification of the carbon cloth electrode, and through the comparison of the ultraviolet–visible spectrometer (UV–Vis), it can be known that the concentration ratio of [MR-CS] is 1:5, the glucose oxidase load can be maximized. Electrochemical analysis (Cyclic Voltammetry, CV) measures the activity of the maximum reaction of the anode material and the corresponding redox peak, and scanning electron microscope (SEM) observes the surface morphology of the modified electrode. Self-pumping glucose enzymatic biofuel cell module was assembled and examined, the results showed that the maximum output power density (MPD) was 2.64 mW/cm2.

Advancing Phosphorus Recovery from Phosphogypsum Leachate with Solvent-Activated Nanofiltration Membrane

Phosphogypsum leachate is a phosphorus-rich wastewater posing a significant threat to the aquatic environment. The phosphorus in the leachate can be recovered via nanofiltration by allowing permeation of phosphorus while rejecting multivalent cations. However, the existing nanofiltration membranes face a significant challenge in addressing the inherent trade-off between the permeation of phosphorus and the rejection of multivalent cations, limiting the phosphorus recovery rate. Herein, solvent activation following interfacial polymerization between branched polyethyleneimine (PEI) and trimethyl chloride (TMC) was employed to simultaneously enhance the positive charge and enlarge its pore size. The MgCl2 rejection of the membrane increased from 93.7 ± 0.4% to 97.2 ± 0.3% and permeation also increased from 4.4 ± 0.1 L/(bar.m2.h) to 9.1 ± 0.4 L/(bar.m2.h) after activation, breaking the trade-off between rejection and permeation. Besides, in a mixture containing phosphorus and Mg2+, the activated membrane demonstrates a P/Mg2+ selectivity that is 6 times of the membrane before treatment, and surpassing the commercial and state-of-the-art membranes. Due to its high permeation and ideal P/Mg selectivity, the activated nanofiltration membrane has great potential for phosphorus recovery from phosphogypsum leachate.