Separation Of Materials Research Articles

Thermal diffusity in copper benzene-1,3,5-tricarboxylate–reduced graphite oxide mechanical composites

Metal organic frameworks (MOFs) and particularly copper benzene-1,3,5-tricarboxylate (HKUST-1) are excellent materials for gas storage (e.g., CH4, N2, H2 adsorption) and gas separation. In this work, reduced graphene oxide (RGO)–HKUST-1 mechanical mixtures were studied in order to reveal the effect of RGO content on the pressure tolerance of the texture and heat conductivity. HKUST-1 was obtained by two different synthesis routes. Air-dried MOF and RGO were thoroughly mixed prior to the compression. Powder XRD and Raman spectroscopy were used to characterize the response of the crystal structure, while low-temperature nitrogen adsorption was used the follow the adsorption properties of the pellets. Finally, the "flash" heat pulse method was used to assess the thermal properties. The gas adsorption isotherms revealed that the adsorption capacity decreases when RGO is added. Based on Raman and XRD results, we found that the synthesis route has an effect on multiple scales. We experimentally confirmed that evaluation of the thermal diffusivity requires a model more complex than the simple Fourier equation, due to the inherent heterogeneous structure of the material. A good approximation of the Fourier coefficient of thermal diffusivity was obtained using the parameters of the Guyer–Krumhansl equation. The heat pulse experiments also revealed possible size-dependent behavior.

Preparation of polystyrene and silane-modified nano-silica superhydrophobic and superoleophilic three-dimensional composite fiber membranes for efficient oil absorption and oil-water separation

Oily solid waste and wastewater are two kinds of contaminants that seriously endanger the environment and the general public. Recently, superhydrophobic and superoleophilic materials have attracted extensive attention owing to their exceptional oil-water separation capabilities. In this study, we demonstrated a simple, low-cost, and high-economic efficiency method to prepare nanosilica (SiO2) from dye diatomite filter aid waste (DDW) and silanize it with octadecyltrichlorosilane (OTS) to form hydrophobic nanosilica (hSiO2) by solution impregnation. Polystyrene/hydrophobic nanosilica (PS/hSiO2) composite fiber membranes with a rough surface and low surface energy were prepared by electrospinning. The prepared PS/hSiO2 water contact angle can reach 166.6°, showing superhydrophobicity and excellent adsorption capacity for various common oils. The maximum oil absorption capacity for transformer oil can reach 136.4 g/g. Importantly, the oil absorption process of the nanocomposite is selective, fast, and efficient, and it can be used for the purification of oil-contaminated water. In addition, it also demonstrates remarkable durability and stability in strong acid and alkali solutions. This strategy of making oil-water separation materials from solid waste may offer a straightforward, cost-effective, and environmentally sustainable option for the treatment of solid waste, industrial oil wastewater treatment, and marine oil spill cleanup.

Recent progress of cotton fabric based on bio‐inspired modification for oil/water separation

AbstractWith the continuous development of the industry, oil spill accidents occur frequently. Oil/water separation materials are considered to be a major choice for the treatment of oily wastewater due to their flexible operation and low cost. Cotton fabrics are low‐cost and environmentally friendly, which are used as substrates to prepare oil/water separation materials with quite competitive in the market. A large number of oil/water separation cotton fabrics with excellent properties have been frequently reported in recent decades. On the other hand, since the service life of these oil/water separation cotton fabrics is closely related to the thin layer covered on the surface, so in order to improve the practical applicability, substances such as dopamine and plant polyphenols that improve the adhesion of the thin layer to the surface of the material are introduced into the preparation process of these materials. On this basis, the research progress of super‐hydrophobic cotton fabrics, super‐hydrophilic/underwater super‐oleophobic cotton fabrics, super durable oil/water separation cotton fabrics and intelligent response to oil/water separation fabric in recent years are reviewed, as well as their applications in the field of oil/water separation.

κ‐Carrageenan/poly(sodium styrenesulfonate‐co‐acrylic acid) macroporous anionic monoliths: Dye adsorption and oil–water separation properties

Abstractκ‐Carrageenan (κC) is a widely used food hydrogel, but its use as an environmental adsorption separation material still needs to be further developed. Herein, a novel macroporous anionic monolith was synthesized by the oil‐in‐water high internal phase emulsion template method. The monolith was obtained by the continuous phase polymerization of sodium styrenesulfonate (NaSS) and acrylic acid (AA), in which κC was introduced to form a semi‐interpenetrating network structure to improve its overall performance. The results showed that the mechanical strength of the monolith increased with κC content. Because of the use of two strong hydrophilic monomers, NaSS and AA, the porous monolith proved to be superoleophobic underwater. In addition, the porous materials had a strong cationic dye adsorption capacity (2455 mg/g for malachite green, 1180 mg/g for methylene blue) and a fast removal rate, good reusability, and oil–water separation. This work highlights their potential application value in the purification of complex water environments.

COF-anchored design of nanoporous graphene membranes for ultrafast and selective organic separation

Nanoporous graphene has attracted extensive attention as a type of disruptive membrane materials for organic separation. However, the fabrication of an ideal graphene membrane with high permeability and selectivity remains challenging due to the inevitable non-selective defects. Here, a strategy based on synergetic effect of graphene membranes and covalent organic framework (COF) nanounits is developed. Atomically thin nanoporous graphene provides high solvent flux and stability. To prevent the leakage from inevitable non-selective pores in graphene without sacrificing flux, porous COF nanounits are directly anchored at the defective sites. The fabricated membranes exhibit record-high solvent flux of 49.81 L m−2 h−1 (1–2 orders of magnitude higher than that of state-of-the-art membranes), and relatively low reverse solute flux of 1.69 g m−2 h−1 in organic solvent forward osmosis (OSFO) process. The strategy we proposed gives dramatic impetus to the development of OSFO and other membrane separation processes.

Rapid, Massive, and Green Synthesis of Polyoxometalate-Based Metal-Organic Frameworks to Fabricate POMOF/PAN Nanofiber Membranes for Selective Filtration of Cationic Dyes.

Developing high-efficiency membrane materials for the rapid removal of organic dyes is crucial but remains a challenge. Polyoxometalates (POMs) clusters with anionic structures are promising candidates for the removal of cationic dyes via electrostatic interactions. However, their shortcomings, such as their solubility and inability to be mass-produced, hinder their application in water pollution treatment. Here, we propose a simple and green strategy utilizing the room temperature stirring method to mass produce nanoscale polyoxometalate-based metal-organic frameworks (POMOFs) with porous rhomboid-shaped dodecahedral and hexagonal prism structures. The products were labeled as POMOF1 (POMOF-PW12) and POMOF2 (POMOF-PMo12). Subsequently, a series of x wt% POMOF1/PAN (x = 0, 3, 5, and 10) nanofiber membranes (NFMs) were prepared using electrospinning technology, where polyacrylonitrile (PAN) acts as a "glue" molecule facilitating the bonding of POMOF1 nanoparticles. The as-prepared samples were comprehensively characterized and exhibited obvious water stability, as well as rapid selective adsorption filtration performance towards cationic dyes. The 5 wt% POMOF1/PAN NFM possessed the highest removal efficiency of 96.7% for RhB, 95.8% for MB, and 86.4% for CV dyes, which realized the selective separation over 95% of positively charged dyes from the mixed solution. The adsorption mechanism was explained using FT-IR, SEM, Zeta potential, and adsorption kinetics model, which proved that separation was determined via electrostatic interaction, hydrogen bonding, and π-π interactions. Moreover, the POMOF1/PAN membrane presented an outstanding recoverable and stable removal rate after four cycles. This study provides a new direction for the systematic design and manufacture of membrane separation materials with outstanding properties for contaminant removal.

Room-temperature fabrication of fluorinated covalent organic polymer @ Attapulgite composite for in-syringe membrane solid-phase extraction and analysis of domoic acid in aquatic products

A novel fluorinated covalent organic polymer @ attapulgite composite (F-COP@ATP) was prepared at room temperature for in-syringe membrane solid-phase extraction (SM-SPE) of domoic acid (DA) in aquatic products. Natural ore ATP has the advantages of low cost, good mechanical strength and abundant hydroxyl group on its surface, and in-situ modified F-COP layer can provide abundant adsorption sites. F-COP@ATP combining the advantages of F-COP and ATP, becomes an ideal adsorbent for DA extracting. Moreover, a high-throughput sample preparation strategy was carried out by using the F-COP@ATP membrane as syringe filter and assembling syringes with a ten-channel injection pump. In addition, the experimental factors were optimized, such as pH of extract, amount of adsorbent, velocity of extraction and desorption, type and volume of desorption solvent. The DA analytical method was established by SM-SPE-HPLC/tandem mass spectrometry. The method had a wide linear range with low limit of detection (0.344 ng/kg) and low limit of quantification (1.14 ng/kg). F-COP@ATP membrane can be reused more than five times. The method realized the analysis of DA in scallop and razor clam samples, which shows its application prospect in practical analysis. This study provided an efficient, low-energy and mild idea for preparing other reusable natural mineral ATP-based composite materials for separation and enrichment, which reduces the experimental cost and is closer to environmental protection and green chemistry to a certain extent.

Ionization-modified beetle structure for enhanced demulsification and anti-clogging performances

Superwetting materials are considered to have great potential for oil–water separation in water purification, food processing, petrochemical production, etc. However, weak demulsification performance and clogging are the key challenges in most practical applications. Here, we successfully prepared a charged beetle structure copper foam (SPCS-CF) with a surface composed of superhydrophilic charged carbon nanotubes and superhydrophobic SiO2 bumps, which can apply electrostatic force and wetting driving force to obtain higher demulsification and anti-clogging performances than conventional superhydrophilic materials. These two forces can cause the charged surfactant and the oil to move towards the charged carbon nanotubes and superhydrophobic SiO2 surfaces, respectively, resulting in charge heterogeneity and severe deformation of droplets, thereby enhancing the demulsification performance of SPCS-CF. Therefore, SPCS-CF can separate various oil-in-water emulsions with high separation efficiency (over 99.2 %) and high permeation flux (27,734.0 L m-2 h−1). Furthermore, superhydrophobic SiO2 prevents oil droplets from accumulating in pores and causing clogging by aggregating them on the skeleton. Therefore, this charged beetle structure provides a new perspective for developing advanced materials for demulsification and separation in the petroleum industry and water purification fields.

Dicationic imidazole ionic liquid stationary phase for preservative detection and its application under mixed mode of HILIC/RPLC/IEC

BackgroundFood safety has always been a great concern, and the detection of additives is vital to ensuring food safety. Therefore, there is a necessity to develop a method that can quickly and efficiently separate and detect additives in food. High performance liquid chromatography is widely used in the analysis and testing of food additives. Ionic liquids have attracted wide attention in the preparation of high performance liquid chromatography stationary phases owing to their high stability, low vapor pressure and adjustable structure. ResultsWe developed a novel dicationic imidazole ionic liquid stationary phase for the simultaneous determination of organic preservatives (sodium benzoate, potassium sorbate) and inorganic preservatives (nitrate and nitrite) in foodstuffs under mixed-mode chromatography. The method had the advantages of easy operation, high reproducibility, good linearity and precision. In the detection of these four preservatives, the limit of detection ≤0.4740 mg⋅L−1 and the limit of quantification ≤1.5800 mg⋅L−1. The intra-day and inter-day precision were less than 4.02%, and the recovery rate was 95.90∼100.19 %. At the same time, we also characterized the stationary phase, explored the mechanism and evaluated the chromatographic performance. The stationary phase was able to operate under the mixed mode of reversed phase/hydrophilic interaction/ion exchange chromatography, and it was capable of separating hydrophilic substances, hydrophobic substances, acids, and inorganic anionic substances with good separation efficiency and had high column efficiency. SignificanceIn summary, the stationary phase has a promising application in the routine analysis of organic and inorganic preservatives in food. In addition, the stationary phase has good separation ability for hydrophilic, hydrophobic, ionic substances and complex samples, making it a prospective material for chromatographic separation.

Heat and water recovery from gaseous stream using a flat-sheet ceramic membrane as a transport membrane condenser

Ceramic-membrane technology has been employed to recover waste heat and vapor from moist gases. In addition to the hydrophilicity, pore size, and porosity of separation materials, a membrane condenser can achieve a high recovery rate. In this study, a transport membrane condenser (TMC) was successfully constructed using a flat-sheet ceramic membrane (FCM) with a large pore size of 45.54 μm. The membrane characteristics, including the mean pore size, pore size distribution, and porosity, were investigated to determine their recovery mechanism. Their water and heat fluxes, recovery rates, and thermal resistance were compared under several experimental conditions. The inlet conditions significantly affect the TMC recovery performance. Higher recovery fluxes were obtained at lower water temperatures, higher gas temperatures, and higher gas flow rates. However, when the Reynolds number of water increased, the heat flux increased rapidly, and the recovered water decreased slightly. The highest TMC water recovery rate was 84.1%. In addition, to further analyze the separation mechanisms, a two-dimensional model was developed using ANSYS Fluent code. The simulation results were compared with the experimental data to verify the accuracy of the numerical method. The comparison results showed a high degree of consistency.

Engineered selective biotoxin‐binding hydrogels for toxin sequestration

AbstractThe development of synthetic selective membranes that separate materials of similar sizes, charges, and/or polarities remains a difficult challenge, and looking towards biology provides inspiration for new designs. In this work, a series of cholera toxin binding peptides (CTBPs) are identified, spanning a range of binding inhibitions, and integrated into chemically cross‐linked cholera toxin binding gels (CTBGs) via thiol‐Michael polycondensation reactions. All gels demonstrate rheological profiles consistent with elastic solids. The CTBGs are probed via small‐angle neutron scattering and exhibit a correlation length, ξ, smaller than most proteins (1.3–2.5 nm). Thus, an effective entropic mesh is formed to block non‐targeted proteins. However, the CTBGs have a dynamic mesh size, Ξ, that is larger than cholera toxin (CT) to allow the transport of target proteins. The CTBGs with the highest binding inhibitions both show high selectivity and permeation of CT, rejecting all other tested proteins. In total, two new highly selective CTBGs are synthesized and validated for use in cholera toxin remediation. Together, this platform demonstrates the wide applicability of selectively‐diffusive materials for difficult separations.

Breakthrough applications of porous organic materials for membrane-based CO2 separation: a review.

Over the last decades, porous organic materials (POMs) have been extensively employed in various industrial approaches including gas separation, catalysis and energy production due to possessing indisputable advantages like great surface area, high permeability, controllable pore size, appropriate functionalization and excellent processability compared to traditional substances like zeolites, Alumina and polymers. This review presents the recent breakthroughs in the multifunctional POMs for potential use in the membrane-based CO2 separation. Some examples of highly-selective membranes using multifunctional POMs are described. Moreover, various classifications of POMs following with their advantages and disadvantages in CO2 separation processes are explained. Apart from reviewing the state-of-the-art POMs in CO2 separation, the challenges/limitations of POMs with tailored structures for reasonable application are discussed.

Electrochemical properties of Sr-doped La2-xSrxCe2O7-δ hydrogen separation membrane

The prominence of hydrogen energy has brought membrane separation technology to forefront attention. La2Ce2O7, possessing a fluorite structure, exhibits notable stability in both H2O and CO2, rendering it a prospective material for membrane separation. The impact of Sr doping on the electrochemical characteristics of La2Ce2O7 was systematically investigated. The findings indicate that a minor addition of Sr2+ through doping enhances the electrical conductivity, with the most significant improvement observed in La2-xSrxCe2O7-δ (x = 0, 0.05, 0.15, 0.30) when doped by 0.05. Elevated temperature and increased hydrogen partial pressure on the feed side enhance hydrogen permeability. Hydrogen permeation is predominantly governed by bulk diffusion when the membrane thickness exceeds 0.59 mm, while for thicknesses below 0.49 mm, the process is influenced by both surface and bulk diffusion. Moreover, the doped La2Ce2O7 exhibit commendable stability in H2O and CO2 environments. Consequently, La2Ce2O7 emerges as a promising candidate for ceramic hydrogen separation membranes.

Adsorption and Diffusion Properties of Functionalized MOFs for CO2 Capture: A Combination of Molecular Dynamics Simulation and Density Functional Theory Calculation.

The capture of carbon dioxide (CO2) from fuel gases is a significant method to solve the global warming problem. Metal-organic frameworks (MOFs) are considered to be promising porous materials and have shown great potential for CO2 adsorption and separation applications. However, the adsorption and diffusion mechanisms of CO2 in functionalized MOFs from the perspective of binding energies are still not clear. Actually, the adsorption and diffusion mechanisms can be revealed more intuitively by the binding energies of CO2 with the functionalized MOFs. In this work, a combination of molecular dynamics simulation and density functional theory calculation was performed to study CO2 adsorption and diffusion mechanisms in five different functionalized isoreticular MOFs (IRMOF-1 through -5), considering the influence of functionalized linkers on the adsorption capacity of functionalized MOFs. The results show that the CO2 uptake is determined by two elements: the binding energy and porosity of MOFs. The porosity of the MOFs plays a dominant role in IRMOF-5, resulting in the lowest level of CO2 uptake. The potential of mean force (PMF) of CO2 is strongest at the CO2/functionalized MOFs interface, which is consistent with the maximum CO2 density distribution at the interface. IRMOF-3 with the functionalized linker -NH2 shows the highest CO2 uptake due to the higher porosity and binding energy. Although IRMOF-5 with the functionalized linker -OC5H11 exhibits the lowest diffusivity of CO2 and the highest binding energy, it shows the lowest CO2 uptake. Accordingly, among the five simulated functionalized MOFs, IRMOF-3 is an excellent CO2 adsorbent and IRMOF-5 can be used to separate CO2 from other gases, which will be helpful for the designing of CO2 capture devices. This work will contribute to the design and screening of materials for CO2 adsorption and separation in practical applications.

Target Development towards First Production of High-Molar- Activity 44gSc and 47Sc by Mass Separation at CERN-MEDICIS.

The radionuclides 43Sc, 44g/mSc, and 47Sc can be produced cost-effectively in sufficient yield for medical research and applications by irradiating natTi and natV target materials with protons. Maximizing the production yield of the therapeutic 47Sc in the highest cross section energy range of 24-70 MeV results in the co-production of long-lived, high-γ-ray-energy 46Sc and 48Sc contaminants if one does not use enriched target materials. Mass separation can be used to obtain high molar activity and isotopically pure Sc radionuclides from natural target materials; however, suitable operational conditions to obtain relevant activity released from irradiated natTi and natV have not yet been established at CERN-MEDICIS and ISOLDE. The objective of this work was to develop target units for the production, release, and purification of Sc radionuclides by mass separation as well as to investigate target materials for the mass separation that are compatible with high-yield Sc radionuclide production in the 9-70 MeV proton energy range. In this study, the in-target production yield obtained at MEDICIS with 1.4 GeV protons is compared with the production yield that can be reached with commercially available cyclotrons. The thick-target materials were irradiated at MEDICIS and comprised of metallic natTi, natV metallic foils, and natTiC pellets. The produced radionuclides were subsequently released, ionized, and extracted from various target and ion source units and mass separated. Mono-atomic Sc laser and molecule ionization with forced-electron-beam-induced arc-discharge ion sources were investigated. Sc radionuclide production in thick natTi and natV targets at MEDICIS is equivalent to low- to medium-energy cyclotron-irradiated targets at medically relevant yields, furthermore benefiting from the mass separation possibility. A two-step laser resonance ionization scheme was used to obtain mono-atomic Sc ion beams. Sc radionuclide release from irradiated target units most effectively could be promoted by volatile scandium fluoride formation. Thus, isotopically pure 44g/mSc, 46Sc, and 47Sc were obtained as mono-atomic and molecular ScF 2+ ion beams and collected for the first time at CERN-MEDICIS. Among all the investigated target materials, natTiC is the most suitable target material for Sc mass separation as molecular halide beams, due to high possible operating temperatures and sustained release.

Effect of composite membrane flux behavior on oily wastewater treatment: Predicting and optimizing based response surface methodology and AI

The use of inorganic-organic composite membranes or mixed matrix membranes in membrane technology has gained worldwide recognition as a reliable method for producing drinkable water and effectively treating and purifying wastewater. This study aimed to create a model using response surface methodology (RSM) and artificial neural network (ANN) that can accurately predict and optimize the flux behavior of a membrane made of a polymeric-ceramic composite material for oil-water separation. In addition, as mentioned earlier, the optimization of the factor has been achieved through the use of RSM to establish the most optimal mode for the oil-water separation process. The findings of the RSM analysis show that the projected R2 value of 0.9764 closely matches the Adjusted R2 value of 0.9789, indicating a strong agreement between the two. Furthermore, the ANN modeling exhibited significant agreement with the actual data. The ANN model achieved a high level of performance, with an R-squared value of 0.9998 and a mean squared error (MSE) of 2.57E-03. The results were obtained by employing a model structure comprising two concealed layers, with the initial concealed layer comprising 3 neurons and the subsequent concealed layer comprising 10 neurons. The RSM was tweaked to find that the best flow mode happened when the oil emulsion level was 107.117 mg/L, the transmembrane pressure (TP) was 134.219 kPa, and the time period was 12.836 s.

A novel ex-situ method to fabricate pH-responsive material based on core-shell Fe3O4@SiO2 nanoparticles for multi-functional oil-water separation and efficient recycling

The ex-situ method is suitable for the preparation and practical engineering application of large-sized adsorption materials like sponges. pH-responsiveness can solve the post-treatment problem of oil-absorbing sponges. Here, a facile ex-situ method is proposed to construct large-sized multi-functional oil-water separation materials by adsorbing pH-responsive magnetic core-shell structured nanoparticles (MNP) onto different substrates including sponge, metal mesh, and sandpaper. The MNPs are prepared by chemical coating and surface modification. The sponge can achieve in-situ renewable oil-water separation through the "oil absorption - oil desorption" process under different pH values, and the oil droplets exhibit a segmented wiredrawing desorption process. The generated secondary oily wastewater can be further separated through modified metal mesh, which can treat oily wastewater with more complex situations such as oil-water-oil three-phase mixtures. The detached nanoparticles (NP) can be easily recycled and reused through magnets. This method can achieve a large-scale in-situ treatment renewable oil-water separation process that integrates wastewater purification, oil collection, and material regeneration, which is environmentally friendly, energy-saving, and suitable for engineering applications.

Efficient CO2 capture and separation in TpPa COFs: Synergies from functional groups and metal Li

Covalent organic frameworks (COFs) have emerged as promising materials for CO2 capture and separation owing to their exceptional structural stability. Herein, grand canonical Monte Carlo simulation (GCMC) and density functional theory (DFT) were used to first screen the most favorable functional group in the COFs consisting of 1,3,5-triformylphloroglucinol (Tp) and p-phenylenediamine (Pa) functionalized with –OH, –COOH, and –SO3H, respectively (TpPa-X). Subsequently, the H atoms of –SO3H, the best functional group, were replaced by Li atoms to form –SO3Li, revealing the synergies of functional group –SO3H and Li modification on selective CO2 capture. TpPa-OLi/COOLi were also constructed to confirmed the universality of this synergistic effect. The introduction of functional groups enhanced the CO2 capture and separation performances by creating a more suitable pore environment. The Li introduction increased the structural polarity and provided strong adsorption sites, further improving the selective CO2 capture performance. Notably, TpPa-SO3Li exhibited a remarkable CO2 adsorption capacity of 136.11 cm3 cm−3 with the CO2 over N2/CH4 selectivity of 264.22/164.38, respectively, at 298 K and 1.0 bar. Structural stabilities, pore characteristics, gas adsorption distribution, isothermal adsorption heat, and interactions were adopted to reveal the synergistic effect between functional groups and Li in enhancing CO2 capture and separation.

High-parameters experimental linear plasma device for fusion wall conditioning studies

In future, HELPD would provide valuable platform for investigating the issue in the W impurity control, towards the wall conditioning requirements in tokamak.The tungsten (W) impurity caused by sputtering of the first wall is considered as an issue influencing the plasma safe operation of EAST, ITER and other future fusion devices. As a supplement to the experiments on the tokamak, the linear plasma device (LPD) serves as an effective divertor simulator for the W impurity control research. This work presents the design and construction of High-parameters Experimental Linear Plasma Device (HELPD) in detail, including its layout and operation parameters. Besides the function of plasma exposure, the target sample could be exchanged in a separate material pretreatment vessel for wall conditioning, such as lithium coating and glow discharge cleaning (GDC) without breaking vacuum conditions. And the preliminary results show that the device could produce a steady state plasma of 1∼10 eV, and its flux could reach 1022 m−2s−1 with 10 kW helicon wave. In the future, HELPD would provide valuable platform for investigating the issue in the W impurity control，towards the wall conditioning requirements in tokamak.

Material Separation from Polyester/Cotton Blended Fabrics Using Hydrothermal Treatment.

The production of textile products is increasing annually, and most of them are disposed of after use without recycling. One of the reasons for the low recycling percentage of discarded textile products is the difficulty of recycling as a single material as these products are produced from a combination of two or more materials. Therefore, a technology to separate materials is necessary to improve the recycling percentage of textile products and to build a sustainable recycling industry. The aim of this study was to separate the most common combination of materials, such as cotton/polyester, in an environmentally friendly technique using hydrothermal treatment with only water. Herein, the optimal treatment conditions for blended fabrics in a high-pressure reactor were studied. Moreover, cotton could be separated by treating the fabrics at 220 to 230 °C for 10 min while maintaining the shape of the fabrics. Additionally, polyester showed a melting point, confirming that polyester could be separated without decomposition into monomers, unlike common chemical recycling. The strength of the separated cotton and the molecular weight of the polyester were evaluated, and a kinetic analysis of the changes due to the treatment was conducted. The activation energy obtained from the Arrhenius plot was 111.8 kJ/mol for PET, which was smaller than 142.6 kJ/mol for cotton. This indicates that the decrease in the molecular weight of PET is more likely to occur than the change in the strength of cotton, suggesting the possibility of separating the materials from the kinetic analysis.