Aluminosilicate Clay Minerals Research Articles

Impurity Ions Mn<sup>2+</sup> and Fe<sup>3+</sup> as Paired Spin Labels for the Study of Structural Transformations in Phyllosilicates by the ESR Method

Impurity paramagnetic ions Mn2+ and high spin Fe3+ (S = 5/2) are shown to be very informative “paired spin labels” to investigate structural transformations in natural aluminosilicate clay minerals by ESR spectroscopy. Second derivative ESR (SD ESR) enables to detect minor narrow lines of the ions against the background of intense broad lines of other paramagnetic impurities. Complex SD ESR spectra of the ions are explained by the Jahn-Teller effect and hyperfine interactions with OH-groups. SD ESR spectra before and after heating (620°C and 900°C) proved transformations of octahedral crystal cells accompanied by the loss of the OH-groups, displacement of the ions to equivalent positions.

Study of the metal ion adsorption capacity of palygorskite by computer simulation

Palygorskite is a magnesium-rich aluminosilicate clay mineral with a unique chain-layered structure. This structure gives palygorskite a large specific surface area and interesting physical properties. Many researchers have investigated the applications of palygorskite in various fields, including heavy metal adsorption, petroleum and chemical industries, building materials, medicine and agriculture. In this study, molecular dynamics simulations were used to explore the heavy metal adsorption ability of palygorskite. The results showed that polyacrylic acid (PAA) had a heavy metal adsorption ability. In terms of the ability of the substrate to adsorb Pb2+, Ni2+ and Cr3+, palygorskite (attapulgite, ATP) was more effective than SiO2 or clay. Based on this study, the same phenomenon reported in the literature was confirmed, and it was demonstrated that molecular dynamics could properly simulate the filtration of heavy metal ions in water using novel materials. Moreover, H+ was found to play an essential role in assisting PAA/ATP in capturing heavy metal ions. Using this method, we were able to observe the details of heavy-ion adsorption.

AKILLI MALZEMELER VE İLERİ BİYOMEDİKAL UYGULAMALARI: HNT VE HNT-POLİMER KOMPOZİTLERİ

The aluminosilicate clay minerals (Al2Si2O5(OH)4·nH2O) known to exist in nature are called halloysite nanotubes (HNTs). HNTs, which are found in layered, spherical, flat and other forms, can be obtained naturally as well as synthetically. HNTs with an outer diameter of 50 nm and a length ranging from 500 to 1000 nm have a hollow and nanotube-shaped structure. It has natural deposits in Brazil, Turkey, New Zealand, China, the United States, Korea, Japan, and France, and it is a low-cost material that can be obtained through ore purification. Thanks to their high surface area, large pore volume, rheological properties, high interactions, and high binding capacities with biopolymers, HNTs are used in a wide range of areas. For example, HNTs have become a frequently used material in environmental applications such as wastewater treatment and removal of organic contaminants and dyes. It is also used in the production of nanoelectronics and nanocomposites, catalytic studies, flame retardants in make-up materials, forensic sciences and biomedical fields. The specific properties of HNT used in the biomedical field lead to numerous applications. In this review, it is aimed to present the advantages of HNTs for use in drug delivery systems, immune therapy, anti-infection applications, cancer therapy, bioimaging, biosensing applications, tissue engineering applications, implants and hygiene-cosmetics materials.

Aluminosilicate Clay Minerals: Kaolin, Bentonite, and Halloysite as Fuel Additives for Thermal Conversion of Biomass and Waste

The current focus on renewable energy sources and the circular economy favors the thermal conversion of low-quality fuels, such as biomass and waste. However, the main limitation of their usability in the power sector is the risk of slagging, fouling, ash deposition, and high-temperature corrosion. These problems may be avoided or significantly mitigated by the application of aluminosilicate clay minerals as fuel additives. In this paper, the three most commonly occurring aluminosilicates are reviewed: kaolin, halloysite, and bentonite. Their application has been proven to minimize combustion-related problems by bonding alkalis in high-melting compounds, thus increasing ash melting temperatures, reducing ash deposition tendencies, and decreasing the particulate matter emission. Due to excellent sorption properties, aluminosilicates are also expected to fix heavy metals in ash and therefore decrease their emissions into the atmosphere. The application of aluminosilicates as fuel additives may be a key factor that increases the attractiveness of biomass and other low-quality fuels for the power sector.

Near-Infrared-II Activatable Symbiotic 2D Carbon-Clay Nanohybrids for Dual Imaging-Guided Combinational Cancer Therapy.

Two-dimensional (2D) nanomaterials hold great potential for cancer theranostic applications, yet their clinical translation faces great challenges of high toxicity and limited therapeutic/diagnostic modality. Here, we have created a kind of symbiotic 2D carbon-2D clay nanohybrids, which are composed of a novel 2D carbon nanomaterial (carbon nanochips, or CNC), prepared by carbonizing a conjugated polymer polydiiodobutadiyne, and a 2D layered aluminosilicate clay mineral montmorillonite (MMT). Intriguingly, with the formation of the nanohybrids, MMT can help the dispersion of CNC, while CNC can significantly reduce the hemolysis and toxicity of MMT. The symbiotic combination of CNC and MMT also leads to a synergistic anti-cancer theranostic effect. CNC has a strong absorption and high photothermal conversion efficiency in the second near-infrared region (NIR-II, 1000-1700 nm), while MMT contains Fe3+ that can facilitate the generation of reactive oxygen species from highly expressed H2O2 in tumor microenvironment. The nanohybrids not only enable a synergy of photothermal therapy and chemodynamic therapy to suppress the extremely rapid growth of RM1 tumors in mice but also allow for dual photoacoustic and magnetic imaging to guide the drug delivery and NIR-II irradiation execution, hence establishing a highly efficient and biosafe "all-in-one" theranostic platform for precision nanomedicine.

Catalytic hydrothermal liquefaction of sewage sludge: Effect of metal support heterogeneous catalysts on products distribution

Industrial wastes and natural mixed oxide materials were evaluated as inexpensive heterogeneous catalysts supports for catalytic hydrothermal liquefaction (HTL) of biomass. In this study, Palygorskite (ATP) clay, a hydrated magnesium aluminosilicate clay mineral supported metal catalysts (Co, Mo and Co–Mo/ATP) and Al2O3 supported (Co, Mo, Co–Mo/Al2O3) catalysts were examined for the sewage sludge (SS) hydrothermal liquefaction (HTL). The highest biocrude yield of 34.2 wt% was obtained with Co–Mo/ATP bimetal catalyst. Biocrude characterization revealed that significantly different families of molecules were formed in the presence and absence of catalysts, implying that the main role of the catalyst is to promote rates of thermal reactions, leading to biocrude production. The improved catalytic HTL performance with Co–Mo metal catalyst as attributed to the synergistic effects of both metal sites present on catalyst surfaces. The main components of bio-oil were phenols, N-containing compounds and hydrocarbons, and the increased selectivity to hydrocarbons with Co–Mo/ATP was observed. Maximum yield of aromatic hydrocarbon (20% observed in case of HTL with metal supported ATP catalyst. presence of Co–Mo metal catalysts promoted the deoxygenating by reduction of oxygen in the form of carbon dioxide or water. The distribution of biocrude samples indicates that most compounds in biocrude were light-weighted and had low boiling points. There were more light-weight compounds in biocrude by adding catalyst.

Full-Scale Investigation of Dry Sorbent Injection for NOx Emission Control and Mercury Retention

An innovative dry SNCR method realized by a sorbent injection applied to a stoker furnace is presented. The process is based on urea powder admixed with halloysite, an aluminosilicate clay mineral. Field tests were performed at an industrial stoker hot water boiler of 30 MWth capacity. A unique nozzle design for injecting powdery sorbents into the combustion zone was implemented. The base NOx emission without SNCR was determined to be 365 mg/Nm3. During the reference test, the emission was reduced to avg. 175 mg/Nm3, which produces a NOx reduction of 52%. NH3 slip in the flue gas was stable and did not exceed 2 ppm. Combining urea and halloysite powders leads to a number of positive effects; not only is NOx emission reduced to values typical for wet SNCR, but also a significant, over ten-fold increase in the concentration of adsorbed mercury in fly ash was observed. When confronted with wet SNCR, dry SNCR has no adverse effect on boiler efficiency because it does not increase the stack heat loss. The presented method can be used in any small- or medium-scale furnace, including waste-to-energy units or medical and hazardous waste incineration units.

The aggregation and charging of natural clay allophane: Critical coagulation ionic strength in the presence of multivalent counter-ions

Allophane is an amorphous aluminosilicate clay mineral which is typically found in young volcanic ash soils. The aggregation-dispersion and charging behaviors of allophane may affect the usability and protection of the volcanic ash soils and surrounding environment. To understand the aggregation-dispersion and charging of natural allophane, dynamic and electrophoretic light scattering experiments were carried out at pH 5 as a function of potassium salt concentration and counter-ion (Cl - , SO 4 2- , Fe(CN) 6 3- , and Fe(CN) 6 4- ) valence. The temporal increase of particle hydrodynamic diameters and electrophoretic mobilities (EPM) were measured, and the stability ratio, critical coagulation concentration (CCC), critical coagulation ionic strength (CCIS), zeta potential, and surface charge density were further obtained. The experimental results of stability ratio and EPM of allophane particles were affected by the counter-ion valence, and the CCCs strongly depended on the counter-ion valence. The behavior was well described by the well-known empirical Schulze-Hardy rule. The allophane particles showed a low surface charge density in the presence of multivalent counter-ions. Thus, Derjaguin-Landau and Verwey-Overbeek (DLVO) theory with the Debye-Huckel (DH) approximation was applied to consider the CCIS. The experimental relationship between CCIS and surface charge density was well explained by DLVO theory by taking account of particle size. We conclude that, in the presence of multivalent counter-ions, the DLVO theory with DH approximation has a good applicability to the aggregation-dispersion of natural clay allophane particles. • Counter-ion valence affects the aggregation and charging of allophane particles. • Tetravalent counter-ion induces charge reversal and re-stabilization of allophane. • Critical coagulation ionic strength vs. surface chare follows DLVO theory. • DLVO theory has a good applicability to the aggregation and dispersion of allophane.

Surface Charge Measurements with Scanning Ion Conductance Microscopy Provide Insights into Nitrous Acid Speciation at the Kaolin Mineral-Air Interface.

Unique surface properties of aluminosilicate clay minerals arise from anisotropic distribution of surface charge across their layered structures. Yet, a molecular-level understanding of clay mineral surfaces has been hampered by the lack of analytical techniques capable of measuring surface charges at the nanoscale. This is important for understanding the reactivity, colloidal stability, and ion-exchange capacity properties of clay minerals, which constitute a major fraction of global soils. In this work, scanning ion conductance microscopy (SICM) is used for the first time to visualize the surface charge and topography of dickite, a well-ordered member of the kaolin subgroup of clay minerals. Dickite displayed a pH-independent negative charge on basal surfaces whereas the positive charge on edges increased from pH 6 to 3. Surface charges responded to malonate addition, which promoted dissolution/precipitation reactions. Results from SICM were used to interpret heterogeneous reactivity studies showing that gas-phase nitrous acid (HONO) is released from the protonation of nitrite at Al-OH2+ groups on dickite edges at pH well above the aqueous pKa of HONO. This study provides nanoscale insights into mineral surface processes that affect environmental processes on the local and global scale.

Multi-element signatures in solid and solution phases in a tropical mixing zone: A case study in the Cai River estuary, Vietnam

This study provides baseline concentrations of major, trace, and rare earth elements (REEs) in the solid and solution phases of the tropical Cai River estuary under influence of multiple stresses.The application of the selected multivariate analysis tools (principal component analysis and redundancy analysis) to the enrichment factor and partitioning coefficients (KSPM/Water and KSPM/Sed) calculated from the bulk element contents highlighted the strongest relationships (considered as multi-element signatures) according to the efficiency of the transfer across the estuarine gradients (considered as a selective geochemical filter). Thus, most of the major and trace elements, and REEs studied mainly settle within the mixing zone due to the association with terrigenous aluminosilicate clay minerals, whereas Co, Ni, Cu, As, and Mo are transferred seaward because of their association with the most labile fraction of the fluvial particulate load (such as clays, organic colloids, and carbonates).The major and trace elements, and REEs investigated in this study are mainly introduced in the Cai River and its estuary via basement rock weathering under enhanced monsoonal precipitation, whereas Bi showed the most severe enrichment in the non-weathering distribution pattern. The fractionation of the fluvial element load within the estuarine geochemical filter is mainly controlled by the differential settling of fluvial mineral element-bearing phases along with estuarine colloid dynamics – a topic that must warrants further investigation.

Exploration of a New Source of Sustainable Aluminosilicate Clay Minerals from Morocco: Mineralogical and Physico-Chemical Characterizations for Clear Upcoming Applications

A new source of clay mineral was explored and an extraction and purification protocol was developed to isolate it from raw clay samples acquired in the Oued Ziz region of southeastern Morocco. Clay minerals are always identified in the raw clay or soil by a purification step, as the presence of carbonates, iron oxides or organic matter interferes with the identification process. Purification is also necessary to study the properties of clay minerals. The process involved the collection of raw clay from the source, as well as mineralogical, and physicochemical characterizations. Characterization of the prepared materials was done using X-ray diffraction spectrometry (XRD) which makes it possible to determine the structure and nature of clay. The basic chemical analysis of the materials was carried out by X-ray fluorescence (XRF) and inductively coupled plasma—Atomic emission spectroscopy (ICP-AES). Moreover, Energy dispersive X-ray analysis (EDX) and Fourier transform-infrared spectroscopy (FT-IR Spectroscopy) were used to investigate the chemical composition or nature of minerals. The morphology of the clay samples is unveiled by scanning electron microscopy (SEM), thus thermal analysis (TGA-DTA) records the sample mass loss caused by thermal transformations such as dehydration or calcination for clay minerals. 57Fe Mossbauer spectrometry was also used to investigate the presence of iron in clay samples.

Manganese oxide anchored on carbon modified halloysite nanotubes: An electrochemical platform for the determination of chloramphenicol

Halloysite, a naturally occurring aluminosilicate clay mineral similar to kaolinite, displays high surface area, high stability, and tunable surface chemistry. In this study, preparation, and the electrochemical behavior of manganese oxide (Mn2O3) supported on carbon modified halloysite nanotube (CCH) composite for the selective recognition of CAP was successfully described. The carbon modified halloysite nanotubes were achieved via a glucose dehydration process using sulphuric acid and the Mn2O3 particles were prepared using a wet chemical process. Over and above, the wet impregnation method was engaged to anchor Mn2O3 particles on the CCH matrix. The structural and morphological details of the as-prepared Mn2O3@CCH composite were studied in detail. The CCH attached to the clump of Mn2O3 particles (9.69 m2 g–1) revealed an increase in surface area than pristine Mn2O3 particles (0.41 m2 g–1) using Brunauer–Emmett–Teller analysis. The electron transfer ability and their electrochemical performance on Mn2O3@CCH composite were scrutinized using electrochemical impedance spectroscopy, cyclic voltammetry, and differential pulse voltammetry studies. Under optimized conditions, DPV analysis shown a wide linear range of 0.005–91.94 μM with a detection limit of 0.03 μM. As proof of concept, the real-time viability was verified in water samples with satisfactory recovery results. In terms of sustainability, HNT and HNT modified composites are highly beneficial and it has remarkable potential as a low-cost catalyst.

Reduction of Hg(II) by Fe(II)-Bearing Smectite Clay Minerals

Aluminosilicate clay minerals are often a major component of soils and sediments and many of these clays contain structural Fe (e.g., smectites and illites). Structural Fe(III) in smectite clays is redox active and can be reduced to Fe(II) by biotic and abiotic processes. Fe(II)-bearing minerals such as magnetite and green rust can reduce Hg(II) to Hg(0); however, the ability of other environmentally relevant Fe(II) phases, such as structural Fe(II) in smectite clays, to reduce Hg(II) is largely undetermined. We conducted experiments examining the potential for reduction of Hg(II) by smectite clay minerals containing 0–25 wt% Fe. Fe(III) in the clays (SYn-1 synthetic mica-montmorillonite, SWy-2 montmorillonite, NAu-1 and NAu-2 nontronite, and a nontronite from Cheney, Washington (CWN)) was reduced to Fe(II) using the citrate-bicarbonate-dithionite method. Experiments were initiated by adding 500 µM Hg(II) to reduced clay suspensions (4 g clay L−1) buffered at pH 7.2 in 20 mM 3-morpholinopropane-1-sulfonic acid (MOPS). The potential for Hg(II) reduction in the presence of chloride (0–10 mM) and at pH 5–9 was examined in the presence of reduced NAu-1. Analysis of the samples by Hg LIII-edge X-ray absorption fine structure (XAFS) spectroscopy indicated little to no reduction of Hg(II) by SYn-1 (0% Fe), while reduction of Hg(II) to Hg(0) was observed in the presence of reduced SWy-2, NAu-1, NAu-2, and CWN (2.8–24.8% Fe). Hg(II) was reduced to Hg(0) by NAu-1 at all pH and chloride concentrations examined. These results suggest that Fe(II)-bearing smectite clays may contribute to Hg(II) reduction in suboxic/anoxic soils and sediments.

Dense Integration of Stable Aromatic Radicals within the Two-Dimensional Interlayer Space of Clay Minerals via Clay-Catalyzed Deamination of Arylammoniums

Here, we have successfully demonstrated the dense integration of aryl radical cations within two-dimensional interlayer nanospace of abundant magnesium aluminosilicate clay minerals via spontaneous...

Elimination of total coliforms and Escherichia coli from water by means of filtration with natural clays and silica sand in developing countries.

This research presents the results of a pilot system used for water treatment to be supplied to single-family or small housing nucleus at rural sector. The pilot system is constituted by an up-flow aerated filter with ceramic carrier, followed by a second down-flow filter of silica sand. The pilot plant was installed in a rural sector of the province of Loja, Ecuador, with the main purpose of monitoring the reduction in bacteria in the water for human consumption. Two natural clays from the area were tested. They were transformed into sphere-type ceramics, and then, they were placed in the pilot filters. These both natural clays are inorganic materials with high content of aluminosilicate clay minerals with favourable characteristics to achieve greater efficiency for the reduction in bacteria. The acclimatization time of 60days allowed to achieve optimum treatment efficiency performance until 90days of operation. The physicochemical parameters, namely temperature, pH, dissolved oxygen and total dissolved solids, were monitored throughout the experiments. Regarding microbiological parameters, up to 99% of total coliforms removal was reached for the clay called CF-CC and 79% for the other, called CF-CV. In addition, 100% of total coliforms and Escherichia Coli removal was reached for both clay systems. Social and economic viability of the proposed treatment is also analysed in the manuscript.

Soil ecological effect of attapulgite and its application prospect in ecological planting of Chinese materia medica

The long-term and extensive use of chemical fertilizers and pesticides in the cultivation of Chinese materia medica has resulted in serious soil ecological and environmental problems such as secondary salinization, soil consolidation, soil acidification, continuous cropping obstacles, micro-ecological imbalance, and serious soil pests and diseases in the production areas of Chinese materia medica. Therefore, promoting the ecological planting of Chinese materia medica is the only way for the production of Chinese materia medica. Attapulgite(ATP) is a kind of water-rich magnesium-rich aluminosilicate clay mineral with layered and chain structure. It has abundant reserves in China, possesses nano-material properties, strong adsorption and ion exchange properties, and has huge high value utilization space. ATP and its functional products have the potential of water and fertilizer conservation, regulating soil structure and micro-ecology, and are widely used in ecological planting of Chinese materia medica. This paper reviews the resource distribution, structural characteristics, the research and application progress in soil ecological effects of ATP, and prospects the application prospects of it in the ecological planting of Chinese materia medica.

The Effect of Halloysite Addition on the Material Properties of Chitosan-Halloysite Hydrogel Composites.

Chitosan-based hydrogels are being widely used in biomedical applications due to their eco-friendly, biodegradable, and biocompatible properties, and their ability to mimic the extracellular matrix of many tissues. However, the application of chitosan hydrogels has been limited due to their inherent mechanical weakness. Halloysite nanotubes (HNTs) are naturally occurring aluminosilicate clay minerals and are widely used as a bulk filler to improve the performance characteristics of many polymeric materials. HNTs have also been shown to be a viable nanocontainer able to provide the sustained release of antibiotics, chemicals, and growth factors. This study’s objective was to develop a stable drug delivery chitosan/HNT nanocomposite hydrogel that is biocompatible, biodegradable, and provides sustained drug release. In this study, chitosan/HNTs hydrogels containing undoped or gentamicin-doped HNTs were combined in different wt./wt. ratios and cross-linked with tripolyphosphate. The effects of chitosan and HNTs concentration and combination ratios on the hydrogel surface morphology, degradability, and mechanical properties, as well as its drug release capability, were analyzed. The results clearly showed that the addition of HNTs improved chitosan mechanical properties, but only within a narrow range. The nanocomposite hydrogels provided a sustained pattern of drug release and inhibited bacterial growth, and the live/dead assay showed excellent cytocompatibility.

Characterisation of a rare earth element- and zirconium-bearing ion-adsorption clay deposit in Madagascar

The Ambohimirahavavy igneous complex (Ampasibitika intrusion) in Madagascar hosts a world-class rare-earth element (REE) bearing ion-adsorption clay (IAC) resource. In this study, we present an in-depth chemical and mineralogical characterisation of selected samples from two regolith profiles at Ambohimirahavavy with a focus on REE geochemistry, mineralogy and associations with clay mineralogy. μ-Synchrotron X-ray fluorescence mapping was combined with traditional characterisation techniques in order to ascertain REE distribution within varying clay mineralogy. The ion-adsorption clays consist of aluminosilicate clay minerals (e.g. kaolinite, illite, smectite) formed through in-situ lateritic weathering of REE-rich host rocks. The new data reveal a high level of inhomogeneity in the samples at micro- to macroscopic levels. The ores are characterised by negative cerium anomalies, which are similar to those reported from the South China IAC ores, but contrast with positive anomalies reported in many regolith profiles developing on acid rocks, including in Madagascar. Ce-LIII edge XANES spectroscopy shows that despite the negative Ce anomaly in the pedolith, Ce exists in trivalent form (mostly associated with clay minerals) and as Ce(IV); the latter is at least partially associated with textures reminiscent of the rhizosphere and with Mn- (and Fe-) oxides, highlighting the importance of micro-environments for Ce oxidation. The μSXRF images also reveal that a significant portion of REEs is associated with Zr; SEM imaging does not show the presence of Zr or REE (nano)-minerals, and the association is likely to reflect the decomposition of REE-Zr-rich host minerals and differential sorption of Zr and REEs on clay minerals.The Ambohimirahavavy ores are LREE-enriched, but contain HREE concentrations that are similar to those of the South China ores, making them an economically viable REE source. REE concentrations in the two studied profiles were particularly high in the saprolith relative to the pedolith, further contrasting with the South China ores, and indicating different mechanisms of ore formation.

Clay nanotubes as a novel multifunctional excipient for the development of directly compressible diclofenac potassium tablets in a SeDeM driven QbD environment

Halloysite is a unique biocompatible aluminosilicate clay mineral with powder particles predominantly comprising of concentrically rolled nanotubular aggregates. Some recent studies have also contributed to its prospective case in oral drug delivery and dosage forms albeit with limited commercial viability. In this study, we have investigated the use of halloysite nanotubes (HNTs) as a directly compressible multifunctional tableting excipient using SeDeM diagram expert tool. SeDeM experimentations revealed that ~68% HNTs in the formulations were enough to be used as a directly compressible filler, binder, and disintegrant in diclofenac potassium formulations. In the next phase, a total of 8 formulations blends (IRF1–8) of diclofenac potassium (50 mg) with HNTs and Starch 1500® were prepared in different ratio using simple lattice mixture design and all were found satisfactory for direct compression. Compressed tablets (167 mg) had narrow weight variation (SD = ± 1.78 mg), good hardness (~9–9.5 kg), acceptable friability (<0.7%) and fast disintegration time (<1.5 min). Moreover, the cumulative dissolution at 1 h in phosphate buffer pH 6.8 was found compliant with the compendial criteria (> 92% against 75%). The dissolution profile was best fitted with Peppas-Sahlin model with Fickian diffusion as the only mechanism. f2 similarity test revealed that almost all the tablets were pharmaceutical equivalent to the marketed formulation of the drug. A shelf-life of ~34 months was found upon long-term stability testing of the optimized formulation. This study demonstrates that this novel and economically viable clay material has a strong potential for commercial use in tableting of drug by direct compression.

Magnetic Aluminosilicate Nanoclay: a Natural and Efficient Nanocatalyst for the Green Synthesis of 4H-Pyran Derivatives

In this study, the magnetic nanoparticles have been loaded on the halloysite nanotubes (HNTs) as an aluminosilicate clay mineral. Fe3O4/HNTs nanocomposite was fully characterized by Fourier transform infrared (FT-IR) spectroscopy, energy dispersive X-ray (EDX) analysis, thermogravimetric analysis (TGA), field-emission scanning electron microscopy (FE-SEM) image, transmission electron microscope (TEM) image, inductively coupled plasma (ICP) analysis, X-ray diffraction (XRD) pattern and vibrating sample magnetometer (VSM) curve. The performance of the Fe3O4/HNTs as a heterogeneous catalyst was investigated in the synthesis of 4H-pyran derivatives. The high efficiently, mild reaction condition, green solvents and using the eco-friendly and recoverable catalyst are the most advantages of the present work. Moreover, the simple separation and reuse of the Fe3O4/HNTs nanocatalyst were confirmed stability and efficiency of the catalyst after 7 runs.