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Solving the integrated problem of long-term planning and short-term scheduling in a large-scale refinery-petrochemical complex has been a big challenge over the past years. The mixed-integer nonlinear programming model is usually intractable due to the vast binary variables which increase the computational expenses. Therefore, a data-driven approach is proposed based on the idea of predicting the final objective with given integer variables. A convolutional neural
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Liquid–liquid mixing, including homogeneous and heterogeneous mixing, widely exists in the chemical industry. How to quantitatively characterize the mixing performance is important for reactor assessment and development. As a convenient and direct method for mixing characterization, the chemical probe method uses some special test reactions to characterize the mixing results. Here, the working principle and selection requirements of this method are introduced, and some common chemical probe systems for homogeneous and heterogeneous mixing processes are reviewed. The characteristics and applications of these systems are illustrated. Finally, the development of the new system is proposed.
Most current biotechnology industries are based on batch or fed-batch fermentation processes, which often show low productivity and high production costs compared to chemical processes. To increase the economic competitiveness of biological processes, continuous fermentation technologies are being developed that offer significant advantages in comparison with batch/fed-batch fermentation processes, including: (1) removal of potential substrates and product inhibition, (2) prolonging the microbial exponential growth phase and enhancing productivity, and (3) avoiding repeated fermentation preparation and lowering operation and installation costs. However, several key challenges should be addressed for the industrial application of continuous fermentation processes, including (1) contamination of the fermentation system, (2) degeneration of strains, and (3) relatively low product titer. In this study, we reviewed and discussed metabolic engineering and synthetic biology strategies to address these issues.
With the increasing development of digital devices and electric vehicles, high energy-density rechargeable batteries are strongly required. As one of the most promising anode materials with an ultrahigh specific capacity and extremely low electrode potential, lithium metal is greatly considered an ideal candidate for next-generation battery systems. Nevertheless, limited Coulombic efficiency and potential safety risks severely hinder the practical applications of lithium metal batteries due to the inevitable growth of lithium dendrites and poor interface stability. Tremendous efforts have been explored to address these challenges, mainly focusing on the design of novel electrolytes. Here, we provide an overview of the recent developments of localized high-concentration electrolytes in lithium metal batteries. Firstly, the solvation structures and physicochemical properties of localized high-concentration electrolytes are analyzed. Then, the developments of localized high-concentration electrolytes to suppress the formation of dendritic lithium, broaden the voltage window of electrolytes, enhance safety, and render low-temperature operation for robust lithium metal batteries are discussed. Lastly, the remaining challenges and further possible research directions for localized high-concentration electrolytes are outlined, which can promisingly render the practical applications of lithium metal batteries.
Lignin is the largest natural aromatic biopolymer, but usually treated as industrial biomass waste. The development of lignin/polymer biocomposites can promote the high value utilization of lignin and the greening of polymers. However, the weak interfacial interaction between industrial lignin and polymer induces poor compatibility and serious agglomeration in polymer owing to the strong intermolecular force of lignin. As such, it is extremely difficult to prepare high performance lignin/polymer biocomposites. Recently, we proposed the strategy of in situ construction of interfacial dynamic bonds in lignin/polymer composites. By taking advantage of the abundant oxygen-containing polar groups of lignin, we inserted dynamic bonding connection such as hydrogen bonds and coordination bonds into the interphase between lignin and the polymer matrix to improve the interfacial interactions. Meanwhile, the natural amphiphilic structure characteristics of lignin were utilized to construct the hierarchical nanophase separation structure in lignin/polymer composites. The persistent problems of poor dispersity and interfacial compatibility of lignin in the polymer matrix were effectively solved. The lignin-modified polymer composites achieved simultaneously enhanced strength and toughness. This concise review systematically summarized the recent research progress of our group toward building high-performance lignin/polymer biocomposites through the design of interfacial dynamic bonds (hydrogen bonds, coordination bonds, and dynamic covalent bonds) between lignin and different polymer systems (polar plastics, rubber, polyurethane, hydrogels, and other polymers). Finally, the future development direction, main challenges, and potential solutions of lignin application in polymers were presented.
Hydrothermal and catalytic stability of UIO-66 MOFs with defective structures are critical aspects to be considered in their catalytic applications, especially under the conditions involving water, moisture and/or heat. Here, we report a facile strategy to introduce the macromolecular acid group to UIO-66 to improve the stability of the resulting UIO-66−PhSO3H MOF in aqueous phase catalysis. In detail, UIO-66−PhSO3H was obtained by grafting benzenesulfonic acid on the surface of the pristine UIO-66 to introduce the hydrophobicity, as well as the Brønsted acidity, then assessed using catalytic hydrolysis of cyclohexyl acetate (to cyclohexanol) in water. The introduction of hydrophobic molecules to UIO-66 could prevent the material from being attacked by hydroxyl polar molecules effectively, explaining its good structural stability during catalysis. UIO-66−PhSO3H promoted the conversion of cyclohexyl acetate at ca. 87%, and its activity and textural properties were basically intact after the cyclic stability tests. The facile modification strategy can improve the hydrothermal stability of UIO-66 significantly, which can expand its catalytic applications in aqueous systems.
Three kinds of Ce-based catalysts (CePO4, CeVO4, Ce2(SO4)3) were synthesized and used for the selective catalytic reduction (SCR) of NO by NH3. NH3-SCR performances were conducted in the temperature range of 80 to 400 °C. The catalytic efficiencies of the three catalysts are as follow: CePO4 > CeVO4 > Ce2(SO4)3, which is in agreement with their abilities of NH3 adsorption capacities. The highest NO conversion rate of CePO4 could reach about 95%, and the catalyst had more than 90% NO conversion rate between 260 and 320 °C. The effect of PO43–, VO43– and SO42– on NH3-SCR performances of Ce-based catalysts was systematically investigated by the X-ray photoelectron spectroscopy analysis, NH3 temperature programmed desorption, H2 temperature programmed reduction and field emission scanning electron microscopy tests. The key factors that can enhance the SCR are the existence of Ce4+, large NH3 adsorption capacity, high and early H2 consumptions, and suitable microstructures for gas adsorption. Finally, CePO4 and CeVO4 catalysts also exhibited relatively strong tolerance of SO2, and the upward trend about 8% was detected due to the sulfation enhancement by SO2 for Ce2(SO4)3.
In this paper, Cu-doped Bi2WO6 was synthesized via a solvothermal method and applied it in photocatalytic N2 immobilization. Characterization results showed the presence of a small amount of metallic Bi in the photocatalyst, indicating that the synthesized photocatalyst is actually Bi/Cu-Bi2WO6 composite. The doped Cu had a valence state of +2 and most likely substituted the position of Bi3+. The introduced Cu did not affect the metallic Bi content, but mainly influenced the energy band structure of Bi2WO6. The band gap was slightly narrowed, the conduction band was elevated, and the work function was reduced. The reduced work function improved the transfer and separation of charge carriers, which mainly caused the increased photoactivity. The optimized NH3 generation rates of Bi/Cu-Bi2WO6 reached 624 and 243 μmol·L–1·g–1·h–1 under simulated solar and visible light, and these values were approximately 2.8 and 5.9 times higher those of Bi/Bi2WO6, respectively. This research provides a method for improving the photocatalytic N2 fixation and may provide more information on the design and preparation of heteroatom-doped semiconductor photocatalysts for N2-to-NH3 conversion.
Similar to Sn, Pb located at the same group (IVA) in the periodic table of elements, can also catalyze propane dehydrogenation to propene, while a fast deactivation can be observed. To enhance the stability, the traditional carrier Al2O3 with a small amount, was introduced into Pb/SiO2 catalyst in this study. It has been proved that Al2O3 can inhibit the reduction of PbO, and weaken the agglomeration and loss of Pb species due to its enhanced interaction with Pb species. As a result, 3Al15Pb/SiO2 catalyst exhibits a much higher stability up to more than 150 h. In addition, a simple schematic diagram of the change of surface species on the catalyst surface after Al2O3 addition was also proposed.
Transition metal phosphides have been extensively studied for catalytic applications in water splitting. Herein, we report an in situ phosphorization of zeolitic imidazole frameworks (ZIF-67) to generate amorphous cobalt phosphide/ZIF-67 heterojunction on a self-supporting copper foam (CF) substrate with excellent performance for hydrogen evolution reaction (HER). The needle-leaf like copper hydroxide was anchored on CF surface, which acted as implantation to grow ZIF-67. The intermediate product was phosphorized to obtain final electrocatalyst (CoP/Cu2O@CF) with uniform particle size, exhibiting a rhombic dodecahedron structure with wrinkles on the surface. The electrochemical measurement proved that CoP/Cu2O@CF catalyst exhibited excellent HER activity and long-term stability in 1.0 mol·L–1 KOH solution. The overpotential was only 62 mV with the Tafel slope of 83 mV·dec–1 at a current density of 10 mA·cm–2, with a large electrochemical active surface area. It also showed competitive performance at large current which indicated the potential application to industrial water electrolysis to produce hydrogen. First-principle calculations illustrated that benefit from the construction of CoP/ZIF-67 heterojunction, the d-band center of CoP downshifted after bonding with ZIF-67 and the Gibbs free energy (ΔGH*) changed from –0.18 to –0.11 eV, confirming both decrease in overpotential and excellent HER activity. This work illustrates the efficient HER activity of CoP/Cu2O@CF catalyst, which will act as a potential candidate for precious metal electrocatalysts.
The composite electrode of CoNiSx and Ti3C2Tx MXene was successfully prepared using a one-step hydrothermal method under the in-situ doping of the cobalt element. The effects of in-situ doping of the cobalt element on the micromorphology and electrochemical performance of the electrodes were investigated. After in-situ doping of the cobalt element, NiS with a needle-like structure was converted into a CoNiSx with petal-like structure. The petal-like CoNiSx with a rough surface was very dense and evenly wrapped on the surface and interlamination of Ti3C2Tx, which helped increase the specific surface area and pore volume of the electrode. Under the identical test conditions, CoNiSx@Ti3C2Tx had a higher specific capacitance and capacitance retention than NiS@Ti3C2Tx. This result indicated that the in-situ doping of the cobalt element promoted the electrochemical performance of the electrode. The energy density of the CoNiSx@Ti3C2Tx/nickel foam (NF)//activated carbon (AC)/NF asymmetric supercapacitor device was 59.20 Wh·kg–1 at a power density of 826.73 W·kg–1, which was much higher than that of NiS@Ti3C2Tx/NF//AC/NF. Three CoNiSx@Ti3C2Tx/NF//AC/NF in series were able to illuminate the light emitting diode lamp for about 10 min, which was higher than the 5 min of three NiS@Ti3C2Tx/NF//AC/NF in series under the same condition. The CoNiSx@Ti3C2Tx/NF//AC/NF with high energy density had better application potential in energy storage than the NiS@Ti3C2Tx/NF//AC/NF.
Membrane technology is ideal for removing aqueous humic acid, but humic acid deposits cause membrane fouling, a significant challenge that limits its application. Herein, this work proposed an alternative approach to the controllably magnetically induced magneto-hybrid polyoxometalate (magneto-HPOM) nanocomposite migration toward the polyethersulfone (PES) membrane surface under a magnetic field to enhance the self-cleaning and antifouling functionalities of the membrane. Before incorporating magneto-HPOM nanocomposite into the PES casting solution, functionalized magnetite nanoparticles (F-MNP) were first coated with HPOM photocatalyst to fabricate a magneto-HPOM-PES membrane. It was shown that the apparent impacts of this novel magneto-HPOM-PES membrane on the hydrophilic behavior and photocatalytic properties of the magneto-HPOM nanocomposite improve the hydrophilicity, separation performance, antifouling and self-cleaning properties of the membrane compared with neat PES membrane. Furthermore, after exposure to ultraviolet light, the magneto-HPOM-PES membrane can be recovered after three cycles with a flux recovery ratio of 107.95%, 100.06%, and 95.56%, which is attributed to the temporal super hydrophilicity effect. Meanwhile, the magneto-HPOM-PES membrane could efficiently maintain 100% humic acid rejection for the first and second cycles and 99.81% for the third cycle. This study revealed a novel approach to fabricating membranes with high antifouling and self-cleaning properties for water treatment.
Electromagnetic interference pollution has raised urgent demand for the development of electromagnetic interference shielding materials. Transition metal carbides (MXenes) with excellent conductivity have shown great potential in electromagnetic interference (EMI) shielding materials, while the poor mechanical strength, flexibility, and structural stability greatly limit their further applications. Here, cellulose nanofibers and sodium alginate are incorporated with MXene nanosheets as flexible matrices to construct strong and flexible mussel-like layered MXene/Cellulose nanofiber/Sodium Alginate composite films, and nickel ions are further introduced to induce metal coordination crosslinking of alginate units. Benefited from the dual-crosslinked network structure of hydrogen bonding and metal coordination, the tensile strength, Young’s modulus, and toughness of the MXene/cellulose nanofiber/nickel alginate composite film are significantly increased. After subsequent reduction by ascorbic acid, excess nickel ions are reduced to nickel nanoparticles and uniformly dispersed within the highly conductive composite film, which further improved its hysteresis loss effect toward the incident electromagnetic waves. Consequently, the MXene/cellulose nanofiber/nickel alginate-Ni composite film presents a considerably enhanced electromagnetic interference shielding effectiveness (47.17 dB) at a very low thickness of 29 μm. This study proposes a feasible dual-crosslinking and subsequent reduction strategy to synergistically enhance the mechanical properties and electromagnetic interference shielding performance of MXene-based composite materials.
In this paper, graphene oxide quantum dots with amino groups (NH2-GOQDs) were tailored to the surface of a thin-film composite (TFC) membrane surface for optimizing forward osmosis (FO) membrane performance using the amide coupling reaction. The results jointly demonstrated hydrophilicity and surface roughness of the membrane enhanced after grafting NH2-GOQDs, leading to the optimized affinity and the contact area between the membrane and water molecules. Therefore, grafting of the membrane with a concentration of 100 ppm (TFC-100) exhibited excellent permeability performance (58.32 L·m–2·h–1) compared with TFC membrane (16.94 L·m–2·h–1). In the evaluation of static antibacterial properties of membranes, TFC-100 membrane destroyed the cell morphology of Escherichia coli (E. coli) and reduced the degree of bacterial adsorption. In the dynamic biofouling experiment, TFC-100 membrane showed a lower flux decline than TFC membrane. After the physical cleaning, the flux of TFC-100 membrane could recover to 96% of the initial flux, which was notably better than that of TFC membrane (63%). Additionally, the extended Derjaguin–Landau–Verwey–Overbeek analysis of the affinity between pollutants and membrane surface verified that NH2-GOQDs alleviates E. coli contamination of membrane. This work highlights the potential applications of NH2-GOQDs for optimizing permeability and biofouling mitigation of FO membranes.
Various hydrophilic poly(ethylene-co-vinyl alcohol) (EVOH) were used herein to precisely control the structure and hydrodynamic properties of polysulfone (PSF) membranes. Particularly, to prepare pristine PSF and PSF/EVOH blends with increasing vinyl alcohol (VOH: 73%, 68%, 56%), the non-solvent-induced phase separation (NIPS) technique was used. Polyethylene glycol was used as a compatibilizer and as a porogen in N,N-dimethylacetamide. Rheological and ultrasonic separation kinetic measurements were also carried out to develop an ultrafiltration membrane mechanism. The extracted membrane properties and filtration capabilities were systematically compared to the proposed mechanism. Accordingly, the addition of EVOH led to an increase in the rheology of the dopes. The resulting membranes exhibited a microporous structure, while the finger-like structures became more evident with increasing VOH content. The PSF/EVOH behavior was changed from immediate to delayed segregation due to a change in the hydrodynamic kinetics. Interestingly, the PSF/EVOH32 membranes showed high hydrophilicity and achieved a pure water permeability of 264 L·m–2·h–1·bar–1, which was higher than that of pure PSF membranes (171 L·m–2·h–1·bar–1). In addition, PSF/EVOH32 rejected bovine serum albumin at a high rate (> 90%) and achieved a significant restoration of permeability. Finally, from the thermodynamic and hydrodynamic results, valuable insights into the selection of hydrophilic copolymers were provided to tailor the membrane structure while improving both the permeability and antifouling performance.
In this work, the influence of the initial chemical potential gradient, stirring speed, and polymer type on sulfamethoxazole (SMX) crystal growth kinetics was systematically investigated through density functional theory (DFT) calculations, experimental measurements and the two-step chemical potential gradient model. To investigate the influence of different conditions on the thermodynamic driving force of SMX crystal growth, SMX solubilities in different polymer solutions were studied. Four model polymers effectively improved SMX solubility. It was further found that polyvinylpyrrolidone (PVP) and hydroxypropyl methyl cellulose (HPMC) played a crucial role in inhibiting SMX crystal growth. However, polyethylene glycol (PEG) promoted SMX crystal growth. The effect of the polymer on the crystal growth mechanisms of SMX was further analyzed by the two-step chemical potential gradient model. In the system containing PEG 6000, crystal growth is dominated by the surface reaction. However, in the system containing PEG 20000, crystal growth is dominated by both the surface reaction and diffusion. In addition, DFT calculations results showed that HPMC and PVP could form strong and stable binding energies with SMX, indicating that PVP and HPMC had the potential ability to inhibit SMX crystal growth.
This paper focuses on the integrated problem of long-term planning and short-term scheduling in a large-scale refinery-petrochemical complex, and considers the overall manufacturing process from the upstream refinery to the downstream petrochemical site. Different time scales are incorporated from the planning and scheduling subproblems. At the end of each discrete time period, additional constraints are imposed to ensure material balance between different time scales. Discrete time representation is applied to the planning subproblem, while continuous time is applied to the scheduling of ethylene cracking and polymerization processes in the petrochemical site. An enterprise-wide mathematical model is formulated through mixed integer nonlinear programming. To solve the problem efficiently, a heuristic algorithm combined with a convolutional neural network (CNN), is proposed. Binary variables are used as the CNN input, leading to the integration of a data-driven approach and classical optimization by which a heuristic algorithm is established. The results do not only illustrate the detailed operations in a refinery and petrochemical complex under planning and scheduling, but also confirm the high efficiency of the proposed algorithm for solving large-scale problems.
Iron oxychloride (FeOCl) is a unique layered material with tunable electronic properties. The conventional synthetic route of chemical vapor transition involves a thermodynamics-driven gas–solid interfacial reaction which often generates macroscopic crystals with stable facets. In this study, through analyzing the effects of the synthetic parameters on the FeOCl synthesis, we discovered the dominant contribution of the α-Fe2O3 precursors on the chemical property of the FeOCl product, and subsequently developed a highly-controllable synthetic route of tailoring the FeOCl structures into small sizes and exposed high-energy facets via a facile and scalable mechanical-chemical approach. The synthesized products could be systematically tuned by the ball-milling conditions of the α-Fe2O3 precursors. With increased milling time, the FeOCl crystallites demonstrated reduced sizes and more exposed (110) facets. Intriguingly, these small-sized FeOCl catalysts exhibited much faster Fenton-like kinetics than the pristine macroscopic FeOCl materials. Specifically, FeOCl catalysts with a 12-hour milling time showed nearly 39 times higher efficiency toward phenol degradation than the pristine FeOCl. The structure-reactivity relationship was further elucidated using the combinatory analysis via density functional theory calculation, electron paramagnetic resonance and radical quenching probe experiments. This work provides a rationale for tailoring the surface structures of FeOCl crystallites for potential applications in environmental catalysis.
The current SARS-CoV-2 pandemic has resulted in the widespread use of personal protective equipment, particularly face masks. However, the use of commercial disposable face masks puts great pressure on the environment. In this study, nano-copper ions assembled cotton fabric used in face masks to impart antibacterial activity has been discussed. To produce the nanocomposite, the cotton fabric was modified by sodium chloroacetate after its mercerization, and assembled with bactericidal nano-copper ions (about 10.61 mg·g–1) through electrostatic adsorption. It demonstrated excellent antibacterial activity against Staphylococcus aureus and Escherichia coli because the gaps between fibers in the cotton fabric allow the nano-copper ions to be fully released. Moreover, the antibacterial efficiency was maintained even after 50 washing cycles. Furthermore, the face mask constructed with this novel nanocomposite upper layer exhibited a high particle filtration efficiency (96.08% ± 0.91%) without compromising the air permeability (28.9 min·L–1). This green, economical, facile, and scalable process of depositing nano-copper ions onto modified cotton fibric has great potential to reduce disease transmission, resource consumption, and environmental impact of waste, while also expanding the range of protective fabrics.
Herein, polyethersulfone (PES) and sulfonated polysulfone (SPSf) blend membranes were prepared with addition of sulfonated polyethersulfone (SPES) as a hydrophilic polymer and adipic acid as a porogen via non-solvent induced phase separation method for effective fractionation of dyes based on the influence of steric hindrance and charge effect. Raman spectroscopy and molecular dynamic simulation modeling confirmed that hydrogen bonds between PES, SPSf, SPES, and adipic acid were crucial to membrane formation and spatial arrangement. Further addition of hydrophilic SPES resulted in a membrane with reduced pore size and molecular weight cut-off as well as amplified negative charge and pure water permeance. During separation, the blend membranes exhibited higher rejection rates for nine types of small molecular weight (269.3–800 Da) dyes than for neutral polyethylene glycol molecules (200–1000 Da). This was attributed to the size effect and the synergistic effect between steric hindrance and charge repulsion. Notably, the synergistic impact decreased with dye molecular weight, while greater membrane negative charge enhanced small molecular dye rejection. Ideal operational stability and anti-fouling performance were best observed in M2 (PES/SPSf/SPES, 3.1 wt %). Summarily, this study demonstrates that SPES with –SO3‒ functional groups can be applied to control the microstructure and separation of membranes.
By using a two-step hydrothermal method and trithiocyanuric acid (TTCA), 2,4,6-trihydrazino-1,3,5-triazine (THT), and Fe3O4 as raw materials, a spherical magnetic adsorbent polymer (TTCA/THT@Fe3O4) was synthesized to achieve the efficient removal of Cr(VI) from wastewater. Under optimal adsorption conditions, the maximum adsorption capacity of TTCA/THT@Fe3O4 for Cr(VI) can reach 1340 mg∙g‒1. Notably, the removal efficiency can approach 98.9%, even at the lower concentration of 20 mg∙L‒1 Cr(VI). For actual wastewater containing Cr(VI), the Cr(VI) concentration was reduced from 25.8 to 0.4 mg∙L‒1, a remarkable 20% lower than the current industry discharge standard value. A mechanism for the high adsorption performance of Cr(VI) on TTCA/THT@Fe3O4 was investigated using Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and density functional theory. It can be plausibly attributed to the formation of Cr/N and Cr/S coordination bonds. Additionally, surface electrostatic adsorption, reduction effects, and the spherical polymer structure increase the contact area with Cr(VI), maximizing adsorption. The synergistic effect of adsorption and reduction enhances the adsorption performance of TTCA/THT@Fe3O4 for Cr(VI) and total chromium in water. The resultant polymer has a simple preparation process, excellent adsorption performance, easy magnetic separation, and promising application for actual wastewater.
Herein, Cu–Al bimetallic oxide was synthesized and mixed with mesoporous silica spheres via a simple hydrothermal method. The prepared sample was then analyzed and employed to activate potassium peroxydisulfate for bisphenol A removal. Based on the results of X-ray diffraction, scanning electron microscopy, and energy dispersion spectroscopy, Cu–Al bimetallic oxide was determined as CuO-Al2O3, and mesoporous silica spheres were found around the these particles. At 30 min, a bisphenol A degradation level of 90% was achieved, and it remained at over 60% after five consecutive cycles, indicating the catalyst’s superior capacity and stability. In terms of removal performance, the radical pathway (including
With increasing emphasis on green chemistry, biomass-based materials have attracted increased attention regarding the development of highly efficient functional materials. Herein, a new pore-rich cellulose nanofibril aerogel is utilized as a substrate to integrate highly conductive polypyrrole and active nanoflower-like nickel-cobalt layered double hydroxide through in situ chemical polymerization and electrodeposition. This ternary composite can act as an effective self-supported electrode for the electrocatalytic oxidation of glucose. With the synergistic effect of three heterogeneous components, the electrode achieves outstanding glucose sensing performance, including a high sensitivity (851.4 µA·mmol−1·L·cm−2), a short response time (2.2 s), a wide linear range (two stages: 0.001−8.145 and 8.145−35.500 mmol·L−1), strong immunity to interference, outstanding intraelectrode and interelectrode reproducibility, a favorable toxicity resistance (Cl‒), and a good long-term stability (maintaining 86.0% of the original value after 30 d). These data are superior to those of some traditional glucose sensors using nonbiomass substrates. When determining the blood glucose level of a human serum, this electrode realizes a high recovery rate of 97.07%–98.89%, validating the potential for high-performance blood glucose sensing.
MgCl2–NaCl–KCl salts mixture shows great potential as a high-temperature (> 700 °C) thermal energy storage material in next-generation concentrated solar power plants. Adding Mg into molten MgCl2–NaCl–KCl salt as a corrosion inhibitor is one of the most effective and cost-effective methods to mitigate the molten salt corrosion of commercial Fe–Cr–Ni alloys. However, it is found in this work that both stainless steel 310 and Incoloy 800H samples were severely corroded after 500 h immersion test at 700 °C when the alloy samples directly contacted with the over-added Mg in the liquid form. The corrosion attack is different from the classical impurity-driven corrosion in molten chloride salts found in previous work. Microscopic analysis indicates that Ni preferentially leaches out of alloy matrix due to the tendency to form MgNi2/Mg2Ni compounds. The Ni-depletion leads to the formation of a porous corrosion layer on both alloys, with the thickness around 204 µm (stainless steel 310) and 1300 µm (Incoloy 800H), respectively. These results suggest that direct contact of liquid Mg with Ni-containing alloys should be avoided during using Mg as a corrosion inhibitor for MgCl2–NaCl–KCl or other chlorides for high temperature heat storage and transfer.
