Mesoporous Molecular Sieves Research Articles

Heteroatom Sr doped MCM-41 molecular sieve for VOC adsorption: Study of the surface functionalization and adsorption performance

Volatile organic compounds (VOCs) are recognized as greater adverse effects on both environment and human health, and adsorption is a simple and effective method. Ordered mesoporous MCM-41 molecular sieve were functionalized with heteroatom Sr to change the pore size and surface property by one-step hydrothermal method and adsorption performance for toluene (C7H8) and formaldehyde (CH2O) were investigated. It is found that Sr doped MCM-41 achieves high static adsorption capacities of 534 mg/g for C7H8 and 388 mg/g for CH2O. The dynamic adsorption of C7H8 follows the Langmuir model over Sr doped and undoped MCM-41 under different process conditions, but the dynamic adsorption capacity is only 21 ∼ 99 mg/g. Sr doped MCM-41 maintains a typical pore structure of MCM-41, with some Sr entering the skeleton to form Sr-O-Si bonds. Sr-M−130 has 857 m2/g of SBET and 0.86 cm3/g of Vtotal, but high hydrothermal temperature (150 °C) causes the sintering of MCM-41 structure. Sr doping decreases surface acidity of MCM-41 and increases surface hydroxyl groups (Si-OH). The kinetic diameter and polarity of the adsorbate cause differences in adsorption performance of Sr doped or undoped MCM-41, meaning that the adsorption behavior of non-polar C7H8 mainly depends on surface area and micropore volume while that of polar CH2O is related to the number of ultra-micropore (<1 nm) and forms chemical adsorption of C = O with Si-OH by hydrogen bonds.

Humidity-resistant hydrogen sensors based on rare-earth-doped tin dioxide nanofibers with hydrophobic mesoporous silica sieve encapsulation

Air humidity is a major factor that degrades the performance and long-term stability of metal-oxide-semiconductor (MOS) based gas sensors. In this work, we propose an encapsulation strategy by coating a mesoporous silica molecular sieve (SBA-15) on rare earth doped tin oxide (RE-SnO2) nanofibers for humidity-resistant hydrogen detection. In this design, the hydrophobic SBA-15 sieve layer effectively blocks the water molecules without affecting hydrogen diffusion, while the RE dopant greatly improves the responsivity and lowers down the operating temperature of the sensors, As a result, the Er-SnO2/SBA-15 and Tb-SnO2/SBA-15 sensors respectively show the maximum response values of 27.71 and 33.68 (to 10 ppm hydrogen at 280 °C, 4.67 and 5.67 times that of the bare SnO2 ones, respectively), short response/recovery time (< 1.0s / < 1.0s), as well as a low limit of detection for hydrogen (200 ppb) and a good gas selectivity. Under the protection of the SBA-15 sieve layer, the response retention of the sensors is significantly improved when the humidity increases from 25% to 85% RH (Er-doping, from 38.8% to 60.0%; Tb-doping, form 25.6% to 57.8%). Besides, further analysis on enhancement mechanism of response indicates that the SBA-15 coating contribute about 1/3 of the response enhancements via its own hydrogen physical adsorption capacity and the induced oxygen vacancies during the calcination processes.

Morin loaded mesoporous molecular sieves as novel devices to the potential treatment of tumor pathologies.

Morin is an antioxidant and anticancer flavonoid, extracted from natural sources, that may exert beneficial effects for several pathologies. Despite this, the administration of morin represents a challenge due to its low aqueous solubility. Mesoporous silica materials have emerged as biocompatible tools for drug delivery, as their pore size can be modulated for maximum surface area to volume ratio. In this contribution, we evaluate the ability of iron-modified mesoporous materials, for morin loading and controlled delivery. The SBA-15 and MCM-41 sieves were synthesized and modified with iron (metal content 4.02 and 6.27 % wt, respectivily). Characterization by transmission electron microscopy, XRD and UV-Vis revealed adequate pore size and agglomerates of very small metallic nanospecies (nanoclusters), without larger iron oxide nanoparticles. FT-IR spectra confirmed the presence of silanol groups in the solid hosts, which can interact with different groups present in morin molecules. SBA-15 materials were more efficient in terms of morin loading capacity (LC) due to their larger pore diameter. LC was more than 35% for SBA-15 materials when adsorptions studies were carried out with 9mg of drug. Antioxidant activity were assayed by using DPPH test. Free iron materials presented a significate improvement as antioxidants after morin incorporation, reaching a scavenging activity of almost a 90%. On the other hand, in iron modified mesoporous materials, the presence of morin did not affect the scavenging activity. The results could be related with the formation of a complex between the flavonoid and the iron. Finally, biosafety studies using normal epithelial cells revealed that neither the loaded nor the unloaded materials exerted toxicity, even at doses of 1mg/ml. These findings expand knowledge about mesoporous materials as suitable carriers of flavonoids with the aim of improving therapies for a wide range of pathologies.

Mesoporous molecular sieve confined phase change materials with high absorption, enhanced thermal conductivity, and cooling energy charging/discharging capacity

Mesoporous molecular sieve confined phase change materials with high absorption, enhanced thermal conductivity, and cooling energy charging/discharging capacity

Ruthenium supported on silicate and aluminosilicate mesoporous materials applied to selective sugar hydrogenation: Xylose to xylitol

A series of ruthenium-based catalysts supported on a set of silicate and aluminosilicate mesoporous molecular sieves was synthesized and tested in xylose hydrogenation. The materials were characterized in terms of morphology, textural properties, acidity, as well as ruthenium loading, dispersion, and oxidation state. In general, the aluminosilicates-based catalysts displayed a higher activity compared to their respective silicate supports, which can be ascribed to a higher Ru content and dispersion, enhanced by a higher acidity. The most active synthesized catalyst (Ru/Al-MCM-4) displayed an improved performance compared to a commercial Ru/C catalyst due to a better xylitol selectivity. Two modelling approaches were implemented to describe the kinetic rate. The first model was based on the hypothesis that xylose molecules and hydrogen are adsorbed in different active sites on the catalyst surface, while the second model supposes the formation of an intermediate on the catalyst surface that reacts to form xylitol. Both models gave a very good description of the experimental data.

On the effect of hafnium loading and location in mesoporous silica on the activity of catalysts in oxidation of dibenzothiophene

Oxidation of thiophenes to sulfones (easily extracted from fuel) is of crucial importance in petrochemical and automotive industry. The rational design and synthesis of stable catalysts of this process still remains one of the biggest challenges. In this work, a series of HfSBA-15 mesoporous materials with different hafnium content (3, 5 or 10 wt.%) has been prepared and studied in the liquid phase oxidation of dibenzothiophene (DBT) with H2O2. The activity of HfSBA-15 samples prepared by one-pot method was compared to that of Hf/SBA-15 synthesized by impregnation and that of HfMCF type of silica. It has been shown that hafnium loading and its location in the silica structure (framework and/or extra-framework positions) affect the efficiency of DBT oxidation. Moreover, the reaction conditions (i.e. oxidation temperature, reaction time, oxidant/sulfur ratio and catalyst amount) were optimized to achieve maximum conversion of dibenzothiophene (99 %). The location of hafnium species in SBA-15 and MCF materials was influenced by the loading of the metal and the type of silica structure (determined by the preparation method). Hafnium located in the framework of SBA-15 promoted generation of a higher number of active Lewis acid sites (LAS) and higher activity in oxidation of dibenzothiophene compared to extra-framework HfO2 species anchored in HfMCF material. It indicates that the location (framework vs extra-framework) and formation of isolated Hf4+ species are decisive for high activity of hafnium-doped mesoporous molecular sieves. This finding opens up a pathway for the development of highly efficient, stable and relatively cheap solid acid catalyst for oxidation of thiophenes to sulfones.

Regulating electronic metal-support interaction (EMSI) via pore-confinement to enhance non-thermal plasma catalytic oxidation of toluene

The non-thermal plasma catalysis holds great promise for VOCs removal, and the development of catalysts with electronic metal-support interaction (EMSI) effect is beneficial for VOCs removal. In this study, we prepared three Mn@M catalysts with EMSI coordination structures by encapsulating MnOx particles within the mesoporous molecular sieve (MCM-41) with different pore size (2.9 nm, 4.4 nm, and 7.9 nm), and investigated the effect of pore size on EMSI and non-thermal plasma catalytic performance of Mn@M for toluene. Among three catalysts, Mn@M2 with an average pore size of 4.38 nm exhibited the strongest EMSI and superior redox capabilities, thus demonstrating the highest mineralization rate, carbon balance, and CO2 selectivity for plasma catalytic oxidation of toluene. The EMSI effect leads to the formation of electron-rich and electron-poor centers on the Si-O-Mn-O bond, facilitating the generation of reactive oxygen species and enhancing the oxygen cycle. In addition, the reaction degradation pathway was investigated using in situ DRIFTS and GC–MS. This study provides valuable insights for designing highly effective supported catalysts by pore confinement to degrade VOCs in adsorption-plasma catalysis system.

Synthesis and Application of Encapsulating Metal/Sulfonic Dual‐Acid Based Phosphotungstic Acid Ionic Liquids

AbstractIn recent years, ionic liquids have been widely used for industrial acid‐catalysis. The enhancements of the acidity and immobilization of ionic liquids have been drawing increasing attention from researchers. In this study, dual‐acid based phosphotungstic acid ionic liquids (PWILs) modified by a variety of metal ions (Fe3+, Cu2+, Al3+) and sulfonic acid group (−SO3) were synthesized. They were subsequently embeded into B‐SBA‐16 mesoporous molecular sieves with acidic sites to produce a plurality of encapsulating metal/sulfonic dual‐acid based phosphotungstic acid ionic liquids (MnPWIL/B‐SBA‐16s) composite catalysts. The structural properties, thermal stability, and encapsulation of the as‐fabricated composite catalysts were systematically investigated by FT‐IR, BET, SAXD, TEM, TG‐DSC and XPS. Moreover, the catalytic performances of the composite catalysts were evaluated using the ketalization of cyclohexanone with ethylene glycol as a model reaction. Among the different composite catalysts, Al0.50PWIL/B‐SBA‐16 showed the highest cyclohexanone conversion of 94.05 % and the maximum cyclohexanone glycol ketal yield of 83.45 %. Meanwhile, this catalyst still exhibited superior catalytic properties after five cycles of the catalytic reaction. These results demonstrate the high activity and durability of the novel ionic liquid composite catalyst.

Rapid Antibiotic Adsorption from Water Using MCM-41-Based Material

The contamination of antibiotics in the environment has raised serious concerns, impacting both human life and ecosystems. This has led to a growing focus on the development of cost-effective and environmentally friendly adsorbent materials. Mesoporous molecular sieve MCM-41, known for its strong adsorption capacity, low cost, and efficient regenerative properties, holds significant promise for addressing this issue. In this study, we investigated the adsorption behavior of demolded MCM-41 materials in relation to tetracycline, doxycycline, and levofloxacin at different temperatures and pH levels. Our experiments encompassed the adsorption of these three common antibiotics, revealing that a neutral or weakly acidic pH environment promoted adsorption, whereas alkaline conditions hindered it. Utilizing the equilibrium isotherm model, we determined the theoretical maximum adsorption capacities for tetracycline (TC), doxycycline (DOX), and levofloxacin (LFX) as 73.41, 144.83, and 33.67 mg g−1, respectively. These findings underscore the significant potential of MCM-41 in mitigating antibiotic wastewater contamination.

Functionalization of mesoporous Al-MCM-41 for indoor humidity control as building humidity conditioning material

This study sought to overcome the high energy consumption of mechanical dehumidifiers by synthesizing humidity control materials using alumino-silicate raw materials extracted from stone sludge and cathode ray tube (CRT) waste panel glass. The structure of the synthesized materials matches that of Mobil Composition of Matter No. 41 (MCM-41) mesoporous molecular sieves, which was subjected to amine functionalization using (3-Aminopropyl) triethoxysilane at various concentrations (2.5, 5, 7.5 vol.%). The resulting materials were characterized using X-ray fluorescence analysis, small angle X-ray diffractometry, Fourier transform infrared spectroscopy, transmission electron microscopy, the Brunauer–Emmett–Teller method, and 27Al solid-state nuclear magnetic resonance spectrometry. Al-MCM-41 molecular sieves with 5.0% grafted amine functional groups presented high specific surface area and high pore uniformity resulting in the highest equilibrium moisture content (39.4 kg/kg). The high thermal and humidity buffer capacity of the proposed material could greatly enhance the comfort of interior spaces without the energy consumption of mechanical dehumidifiers.

Synthesis, Characterizations, and Recent Applications of the Silica-based Mobil Composition of Mesoporous Material: A Review

Silica-based mesoporous materials are a class of porous materials with unique characteristics such as ordered pore structure, large surface area, and large pore volume. This review covers the different types of porous material (zeolite and mesoporous) and the physical properties of mesoporous materials that make them valuable in industry. Mesoporous materials can be divided into two groups: silica-based mesoporous materials and non-silica-based mesoporous materials. The most well-known family of silica-based mesoporous materials is the Mesoporous Molecular Sieves family, which attracts attention because of its beneficial properties. The family includes three members that are differentiated based on their pore arrangement. In this review, the major applications of the Mobil Mesoporous Molecular Sieves family, such as catalysts, adsorbents, and drug delivery agents, have been surveyed. Furthermore, the synthesis of the Mesoporous Molecular Sieves materials, the silica sources, the importance of templates, and the mechanisms of the synthesis are discussed herein. Members of this material family are characterized by many physicochemical properties that are closely related to their high silica content, crystalline structure, and pore arrangement. Commonly, the members of this family have large surface areas, high pore volumes, small pore sizes, and narrow and uniform particle size distributions. These properties enable numerous industrial applications and opportunities for scientific studies to further develop existing materials or manufacture new ones.

Modification of cobalt doped mesoporous sieve by grafting N,N-dihydroxypyromellitimide to enhance desulfurization catalyst stability

Elaborate design of high stability catalytic active site is of great concern for the development of advanced organic–inorganic composite catalysts. Herein, cobalt-doped mesoporous molecular sieve grafted with N,N-dihydroxypyromellitimide catalyst (Co-SBA-15-NDHPI) is developed for the catalytic oxidative desulfurization (ODS) in diesel fuels. The close integration of organic active components and porous supports strengthens the synergistic catalytic effect, resulting enhancement of selective oxidation of sulfides to sulfone derivatives. In detail, N,N-dihydroxypyromellitimide is bonded to a Co-based mesoporous molecular sieve by 3-glycidyloxypropyltrimethoxysilane as the coupling agent allowing exclusive retention of NHPI, which serve as the active sites that result in boosted catalytic ODS performance. Meanwhile, taking advantage of strong chemical anchoring strategies, the Co-SBA-15-NDHPI catalyst exhibits the highest stability compared to other NHPI-containing desulfurization catalysts. This work opens the way for the development of a more stable organic–inorganic hybrid desulfurization catalyst.

Enhancements on volatile organic compounds (VOCs) adsorption and desorption performance of ZSM-5 by fabricating hierarchical MCM-41.

ZSM-5 zeolite has been considered a promising adsorbent for capturing VOCs. However, its hydrophilicity and narrow micropore structure limit their practical application especially under humid atmospheres. In this study, the pure silica mesoporous molecular sieve MCM-41 was assembled on ZSM-5 zeolite with different SiO2/Al2O3 ratios (SARs) via a surfactant-mediated recrystallization method. Then, its adsorption-desorption behaviors were investigated using n-hexane, toluene, and ethyl acetate as VOC model molecules. The results showed that the hydrophobicity of ZSM-5/MCM-41 composites and their VOC diffusion behaviors were significantly improved. Furthermore, the SARs of the ZSM-5 precursors had a remarkable influence on the adsorption performance of ZSM-5/MCM-41 composites. ZSM-5/MCM-41(130) was the optimum option, and its dynamic adsorption capacity for ethyl acetate (111.30 mg·g-1) was higher than that of the corresponding ZSM-5 zeolites even under statured humidity. Meanwhile, the ratios of dynamic adsorption capacities at humid and dry atmospheres (qs,wet/qs,dry) of ZSM-5/MCM-41(130) for n-hexane, toluene, and ethyl acetate were 84.89%, 61.46%, and 73.81% respectively. The results will provide guidelines for the preparation of hydrophobic adsorbents.

Degradation of Sodium Acetate by Catalytic Ozonation Coupled with a Mn-Functionalized Fly Ash: Reaction Parameters and Mechanism.

Supported ozone catalysts usually take alumina, activated carbon, mesoporous molecular sieve, graphene, etc. as the carrier for loading metal oxide via the impregnation method, sol-gel method and precipitation method. In this work, a Mn-modified fly ash catalyst was synthesized to reduce the consumption and high unit price of traditional catalyst carriers like alumina. As a solid waste discharged from coal-fired power plants fueled by coal, fly ash also has porous spherical fine particles with constant surface area and activity, abd is expected to be applied as the main component in the synthesis of ozone catalyst. After the pretreatment process and modification with MnOx, the obtained Mn-modified fly ash exhibited stronger specific surface area and porosity combined with considerable ozone catalytic performance. We used sodium acetate as the contaminant probe, which is difficult to directly decompose with ozone as the end product of ozone oxidation, to evaluate the performance of this Mn-modified fly. It was found that ozone molecules can be transformed to generate ·OH, ·O2- and 1O2 for the further oxidation of sodium acetate. The oxygen vacancy produced via Mn modification plays a crucial role in the adsorption and excitation of ozone. This work demonstrates that fly ash, as an industrial waste, can be synthesized as a potential industrial catalyst with stable physical and chemical properties, a simple preparation method and low costs.

Recycling of cathode ray tubes and stone sludge for the synthesis of Al-MCM-41 grafted amine functional group and environmental humidity control material applications

There is a growing need for economical methods by which to reuse industrial waste. This paper reports on the recycling of industrial waste in the preparation of amine functionalized mesoporous molecular sieves (Al-MCM-41), for use as a building material applicable to the energy-free regulation of indoor humidity. The preparation of amine functionalized Al-MCM-41 for experiments involved combining stone sludge, cathode ray tube panel waste glass, an alkali agent (sodium hydroxide), and cetyltrimethylammonium bromide with aminopropyltriethoxysilane in various proportions. The water vapor adsorption of amine functionalized Al-MCM-41 (42.85 g/m2) far exceeded of amine functionalized Al-MCM-41 without surface grafting (28.64 g/m2). Al-MCM-41 with 2.5 vol% amine functional groups achieved the highest 24-h water vapor adsorption performance in compliance with JIS A 1470 standards. This research provides an economical approach to the recovery and recycling of industrial waste that is rich in silicon and aluminum.

Immobilization of Horseradish Peroxidase for Phenol Degradation.

The use of enzymes to degrade environmental pollutants has received wide attention as an emerging green approach. Horseradish peroxidase (HRP) can efficiently catalyze the degradation of phenol in the environment; however, free HRP exhibits poor stability and temperature sensitivity and is easily deactivated, which limit its practical applications. In this study, to improve their thermal stability, HRP enzymes were immobilized on mesoporous molecular sieves (Al-MCM-41). Specifically, Al-MCM-41(W) and Al-MCM-41(H) were prepared by modifying the mesoporous molecular sieve Al-MCM-41 with glutaraldehyde and epichlorohydrin, respectively, and used as carriers to immobilize HRP on their surface, by covalent linkage, to form the immobilized enzymes HRP@Al-MCM-41(W) and HRP@Al-MCM-41(H). Notably, the maximum reaction rate of HRP@Al-MCM-41(H) was increased from 2.886 × 105 (free enzyme) to 5.896 × 105 U/min-1, and its half-life at 50 °C was increased from 745.17 to 1968.02 min; the thermal stability of the immobilized enzyme was also significantly improved. In addition, we elucidated the mechanism of phenol degradation by HRP, which provides a basis for the application of this enzyme to phenol degradation.

Characterization of new modified mesostructured silica nanocomposites fabricated for effective removal of aromatic acids

Santa Barbara Amorphous-15 (SBA-15) is a mesoporous molecular sieve with a large surface area and is extensively applied in purification, separation, and catalytic procedures. In this study, an SBA-15 was prepared from a sodium silicate precursor, and pentaethylene hexamine was anchored to its surface. A composite named N-SBA-15 was characterized using several experimental techniques. FTIR and XPS measurements confirmed that amino groups were conjugated on the surface of SBA-15. XRD and TEM confirmed that N-SBA-15 comprised highly ordered, hexagonal mesopore structures, which were not destroyed by the addition of amino groups. After functionalization, the surface area, pore volume, and pore size of the composite were 188 m2/g, 0.303 cm3/g, and 5.0 nm, respectively. N-SBA-15 was applied in the adsorption of aromatic acids, namely tannic acid (TA), acid red 1 (AR-1), and acid blue 40 (AB-40). The influence of various adsorption conditions such as dye concentration, adsorbent dosage, solution pH, and solution temperature was investigated. For AB-40 dye, the N-SBA-15 composite exhibited 40 times higher adsorption capacity than pure SBA-15. The highest adsorption capacities of N-SBA-15 for TA, AB-40, and AR-1 were 869, 818, and 308 mg/g, respectively. Thermodynamic studies were conducted to evaluate the exothermic property of the adsorption process and spontaneous behavior. The adsorptive data fitted well with pseudo-second-order and Langmuir isotherm models. Results confirmed that amino-modified SBA-15 material is a promising adsorbent for the elimination of aromatic acids form aqueous solution.

Long-Term and Stable Dental Therapies via an In Situ Spontaneous Medicine Delivery System.

Chronic oral diseases are boring, long-term, and discomfort intense diseases, which endanger the physical and mental health of patients constantly. Traditional therapeutic methods based on medicines (including swallowing drugs, applying ointment, or injection in situ) bring much inconvenience and discomfort. A new method possessing accurate, long-term, stable, convenient, and comfortable features is in great need. In this study, we demonstrated a development of one spontaneous administration for the prevention and therapy on a series of oral diseases. By uniting dental resin and medicine-loaded mesoporous molecular sieve, nanoporous medical composite resin (NMCR) was synthesized by a simple physical mixing and light curing method. Physicochemical investigations of XRD, SEM, TEM, UV-vis, N2 adsorption, and biochemical experiments of antibacterial and pharmacodynamic evaluation on periodontitis treatment of SD rats were carried on to characterize an NMCR spontaneous medicine delivery system. Compared to existing pharmacotherapy and in situ treatments, NMCR can keep a quite long time of stable in situ medicine release during the whole therapeutic period. Taking the periodontitis treatment as an instance, the probing pocket depth value in a half-treatment time of 0.69 from NMCR@MINO was much lower than that of 1.34 from the present commercial Periocline ointment, showing an over two times effect.

In Situ Growth of Lead-Free Cs2CuBr4 Perovskite Quantum Dots in KIT-6 Mesoporous Molecular Sieve for CO2 Adsorption, Activation, and Reduction.

Metal halide perovskites (MHPs) are emerging as promising candidates for photocatalytic CO2 conversion. However, their practical application is still restricted by the poor intrinsic stability and weak adsorption/activation toward CO2 molecules. The rational design of MHPs-based heterostructures with high stability and abundant active sites is a potential solution to this obstacle. Herein, we report the in situ growth of lead-free Cs2CuBr4 perovskite quantum dots (PQDs) in KIT-6 mesoporous molecular sieve, obtaining remarkable photocatalytic CO2 reduction activity and durable stability. The optimized Cs2CuBr4@KIT-6 heterostructure exhibits the photocatalytic CO and CH4 evolution rates of 51.6 and 17.2 μmol g-1 h-1, respectively, far exceeding those of pristine Cs2CuBr4. On the basis of in situ diffuse reflectance infrared Fourier transform spectra and theoretical investigations, the detailed CO2 photoreduction pathway is systematically revealed. This work provides a new route for the rational construction of perovskite-based heterostructures with strong CO2 adsorption/activation and good stability for photocatalytic CO2 reduction.

Adsorption of uranium by amination mesoporous molecular sieve HMS, using response surface methodology

ABSTRACT In this study, amino modified mesoporous silica (HMS-TEEPA-TEA) was used for the first time to remove uranium (VI) from aqueous solution. The synthesized HMS-TEEPA-TEA was characterized by SEM, EDS, FTIR, BET and XPS techniques. The present work attempted to optimize and compare the adsorption process parameters like pH, adsorbate concentration, and adsorbent dose using Box-Behnken designs of response surface methodology. The adsorption amount and removal rate reached 337.26 mg/g and 99.57%, respectively. Model P> F < 0.0001 in this experiment (generally P > F < 0.05 is considered significant), indicating that the model is extremely significant and can be considered as highly referable for its predicted response values. The fit of the data to the Langmuir isotherm and the proposed secondary kinetics indicates that the adsorption process is monolayer and chemical in nature. The effect of copper on HMS-TEEPA-TEA adsorption is more complex than other background ions. The removal of uranium (VI) by HMS-TEEPA-TEA remained above 80% for four consecutive experiments with repeated adsorbent use. The results indicate that HMS-TEEPA-TEA is an effective adsorbent for the removal of uranium (VI) from aqueous solutions with the advantages of low cost, high availability and easy production.