Mechanistic insights into simultaneous removal of copper, cadmium and arsenic from water by iron oxide-functionalized magnetic imogolite nanocomposites

Imogolite and magnetic imogolite-Fe oxide nanocomposites (Imo-Fe50 and Imo-Fe25, at 50 and 25 % Fe loading (w/w), respectively) were synthesized and tested for the removal of aqueous copper (Cu), cadmium (Cd), and arsenic (As) pollutants. The materials were characterized by transmission electron microscopy, and specific surface area and isoelectric point measurements. The Fe-containing samples were additionally characterized by Mössbauer spectroscopy and vibrating-sample magnetometry. Significant differences were found in the morphological, electrophoretic, and magnetic characteristics between imogolite and the nanocomposites. The in-situ Fe-oxide precipitation process modified the active surface sites of the imogolite. The Fe–oxide, mainly magnetite, favored the contaminants’ adsorption over the pristine imogolite. The adsorption kinetics of these pollutants were adequately described by the pseudo-second order and intraparticle diffusion models. The kinetic models showed that surface adsorption was more important than intraparticle diffusion in the removal of the pollutants by all the adsorbents. The Langmuir-Freundlich model described the experimental adsorption data, and both nanocomposites showed greater adsorption capacity than the imogolite. The adsorption of Cu and Cd was sensitive to cationic competition, showing a decrease of the adsorption capacity when the two cations coexisted, while their adsorption increased in the presence of arsenate

Efficient and selective removal of SeVI and AsV mixed contaminants from aqueous media by montmorillonite-nanoscale zero valent iron nanocomposite

Nanoscale zero-valent iron (NZVI) and NZVI supported onto montmorillonite (NZVI-Mt) were synthetized and used in this study to remove SeVI and AsV from water in mono- and binary-adsorbate systems. The adsorption kinetics and isotherm data for SeVI and AsV were adequately described by the pseudo-second-order (PSO) (r2>0.94) and Freundlich (r2>0.93) equations. Results from scanning electron microscopy showed that the dimension of the NZVI immobilized on the Mt was smaller than pure NZVI. Using 0.05 g of adsorbent and an initial 200 mg L−1 AsV and SeVI concentration, the maximum adsorption capacity (qmax) and partition coefficient (PC) for AsV on NZVI-Mt in monocomponent system were 54.75 mg g-1 and 0.065 mg g-1·μM-1, which dropped respectively to 49.91 mg g-1 and 0.055 mg g-1·μM-1 under competitive system. For SeVI adsorption on NZVI-Mt in monocomponent system, qmax and PC were 28.63 mg g-1 and 0.024 mg g-1·μM-1, respectively. Values of qmax and PC were higher for NZVI-Mt than NZVI and montmorillonite, indicating that the nanocomposite contained greater adsorption sites for removing both oxyanions, but with a marked preference for AsV. Future research should evaluate the effect of different operational variables on the removal efficiency of both oxyanions by NZVI-Mt

Use of isoelectric point and pH to evaluate the synthesis of a nanotubuar aluminosilicate

7 páginas, ilustraciones y tablas estadísticas.To follow the synthesis of imogolite, transmission electron microscopy is needed. In this paper, the isoelectric point (IEP) and the aging pH are proposed as alternative methods. Two synthetic procedures were used (S-I and S-II), both involving a co-precipitation followed by an aging treatment where the aluminosilicate evolves from proto-imogolite (detected after the co-precipitation step), to imogolite; its formation is reached after 120 h (S-I) or 168 h (S-II) of aging, depending on the co-precipitation method used. In S-I the isoelectric point increases from 7.1 to 10.5, while in S-II it increases from 6.6 to 9.2 during the aging treatment. Additionally, a linear relationship between the IEP and the pH at different aging steps was found. That relationship may be used to follow the process of synthesis by simply measuring the pH, becoming an alternative to more complex methods.FONDECYT Project 1070116, (AGL 2005-07017-C03-03)Peer reviewe

Aluminosilicates-Based Nanosorbents for Heavy Metal Removal: A Review

Contamination of water bodies with heavy metals poses a significant threat to human health and the environment, requiring the development of effective treatment techniques. In this context, aluminosilicates emerge as promising sorbents due to their cost-effectiveness and natural abundance. This review provides a clear, in-depth, and comprehensive description of the structure, properties, and characteristics of aluminosilicates, supporting their application as adsorbents and highlighting their diversity and adaptability to different matrices and analytes. Furthermore, the functionalization of these materials is thoroughly addressed, detailing the techniques currently used, exposing the advantages and disadvantages of each approach, and establishing comparisons and evaluations of the performances of various functionalized aluminosilicates in the extraction of heavy metals in aqueous matrices. This work aims not only to comprehensively review numerous studies from recent years but also to identify trends in the study of such materials and inspire future research and applications in the field of contaminant removal using aluminosilicates

Aluminosilicates-Based Nanosorbents for Heavy Metal Removal: A Review

Contamination of water bodies with heavy metals poses a significant threat to human health and the environment, requiring the development of effective treatment techniques. In this context, aluminosilicates emerge as promising sorbents due to their cost-effectiveness and natural abundance. This review provides a clear, in-depth, and comprehensive description of the structure, properties, and characteristics of aluminosilicates, supporting their application as adsorbents and highlighting their diversity and adaptability to different matrices and analytes. Furthermore, the functionalization of these materials is thoroughly addressed, detailing the techniques currently used, exposing the advantages and disadvantages of each approach, and establishing comparisons and evaluations of the performances of various functionalized aluminosilicates in the extraction of heavy metals in aqueous matrices. This work aims not only to comprehensively review numerous studies from recent years but also to identify trends in the study of such materials and inspire future research and applications in the field of contaminant removal using aluminosilicates

Enhanced removal of mercury and lead by a novel and efficient surface-functionalized imogolite with nanoscale zero-valent iron material

A novel hybrid nanomaterial, nanoscale zero-valent iron (nZVI)-grafted imogolite nanotubes (Imo), was synthesized via a fast and straightforward chemical procedure. The as-obtained nanomaterial (Imo-nZVI) was characterized using transmission electron microscopy (TEM), electrophoretic mobility (EM), and vibrating sample magnetometry (VSM). The prepared Imo-nZVI was superparamagnetic at room temperature and could be easily separated by an external magnetic field. Sorption batch experiments were performed for single- and multicomponent systems and demonstrated that Hg2+ and Pb2+ could be quantitatively adsorbed at pH 3.0. For multicomponent systems, maximum adsorption capacities of 61.6 mg·g−1 and 76.9 mg·g−1 were obtained for Hg2+ and Pb2+ respectively. It was observed that the functional groups in Imo-nZVI interact preferentially with analytes according to the Misono softness parameter. The higher performance of Imo-nZVI compared with Imo and nZVI is related to the increased number of adsorption sites in the functionalized nanomaterial. The sorption equilibrium data obeyed the Langmuir model, while kinetic studies demonstrated that the sorption processes of Hg2+ and Pb2+ followed the pseudo-second-order model. This study suggests that the Imo-nZVI composite can be used as a promising sorbent to provide a simple and fast separation method to remove Hg and Pb ions from contaminated water.Fil: Martinis, Estefanía Mabel. Universidad Nacional de Cuyo. Facultad de Ingeniería; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: Denardin, Juliano Casagrande. Universidad de Santiago de Chile; ChileFil: Calderón, Raul. Universidad Bernardo O’Higgins; ChileFil: Flores, Cristóbal. Universidad de Santiago de Chile; ChileFil: Manquián Cerda, Karen. Universidad de Santiago de Chile; ChileFil: Maldonado, Tamara. Universidad de Santiago de Chile; ChileFil: Arancibia Miranda, Nicolás. Universidad de Santiago de Chile; Chil

Impact on Some Soil Physical and Chemical Properties Caused by Metal and Metallic Oxide Engineered Nanoparticles: A Review

In recent years, the release of metal and metallic oxide engineered nanoparticles (ENPs) into the environment has generated an increase in their accumulation in agricultural soils, which is a serious risk to the ecosystem and soil health. Here, we show the impact of ENPs on the physical and chemical properties of soils. A literature search was performed in the Scopus database using the keywords ENPs, plus soil physical properties or soil chemical properties, and elements availability. In general, we found that the presence of metal and metallic oxide ENPs in soils can increase hydraulic conductivity and soil porosity and reduce the distance between soil particles, as well as causing a variation in pH, cation exchange capacity (CEC), electrical conductivity (EC), redox potential (Eh), and soil organic matter (SOM) content. Furthermore, ENPs or the metal cations released from them in soils can interact with nutrients like phosphorus (P) forming complexes or precipitates, decreasing their bioavailability in the soil solution. The results depend on the soil properties and the doses, exposure duration, concentrations, and type of ENPs. Therefore, we suggest that particular attention should be paid to every kind of metal and metallic oxide ENPs deposited into the soil

Nanoscale zero valent supported by Zeolite and Montmorillonite: Template effect of the removal of lead ion from an aqueous solution

Artículo de publicación ISIIn this work, we have studied the Pb2+ sorption capacity of Zeolite (Z) and Montmorillonite (Mt) functionalized with nanoscale zero-valent iron (nZVI), at 50% w/w, obtained by means of an impregnating process with a solvent excess. The composites were characterized by several techniques including X-ray diffraction; scanning electron microscopy (SEM); BET area; isoelectric point (IEP); and, finally a magnetic response. Comparatively significant differences in terms of electrophoretic and magnetic characteristics were found between the pristine materials and the composites. Both structures show a high efficiency and velocity in the removal of Pb2+ up to 99.0% (200.0 ppm) after 40 min of reaction time. The removal kinetics of Pb2+ is adequately described by the pseudo second-order kinetic model, and the maximum adsorbed amounts (q(e)) of this analyte are in close accordance with the experimental results. The intra-particle diffusion model shows that this is not the only rate-limiting step, this being the Langmuir model which was well adjusted to our experimental data. Therefore, maximum sorption capacities were found to be 115.1 +/- 11.0, 105.5 +/- 9.0, 68.3 +/- 1.3, 54.2 +/- 1.3, and 50.3 +/- 4.2 mg g(-1), for Mt-nZVI, Z-nZVI, Zeolite, Mt, and nZVI, respectively. The higher sorption capacities can be attributed to the synergetic behavior between the clay and iron nanoparticles, as a consequence of the clay coating process with nZVI. These results suggest that both composites could be used as an efficient adsorbent for the removal of lead from contaminated water sources.FONDECYT 11100439 11130157 1120356 Conicyt 79090022 ICM by Fondo de Innovacion para la Competitividad-Minecon P10-061-F Basal Funding for Scientific and Technological Centers FB080

Preparation and characterization of a single-walled aluminosilicate nanotube-iron oxide composite: Its applications to removal of aqueous arsenate

A chemical method to synthesize a magnetite coating on aluminosilicate nanotubes (imogolite) that can be used as a magnetic adsorptive composite is reported via a new procedure based on impregnation with excess of solvent. This produced a nanocomposite of imogolite and magnetite, retaining at least two of the individual properties of its initial chemical species, which are determinant for some technological applications: large surface area and high saturation magnetization. Comparatively significant differences in terms of electrophoretic and magnetic characteristics were found between the direct solid mixture of the starting materials and the resultant imogolite-magnetite mixture. The adsorption kinetics of arsenate is described adequately by the pseudo-second model and the maximum adsorbed amounts (qe) of this anion were closed to those obtained experimentally. A high rate of arsenate adsorption on Fe-imogolite was initially observed, suggesting that the formation of new surface sites qualitatively and quantitatively improve the removal of arsenate. The combined use of different characterization techniques (XRD, TEM, Mössbauer spectroscopy, EM, VSM and SQUID) and the kinetic sorption study suggest that Fe-imogolite has a large potential for the treatment of arsenate polluted water or other nanotechnological applications, due to its high chemical reactivity. © 2013 Elsevier Ltd.This work was supported by FONDECYT under Project 1070116; by Proyecto de Inserción en la Academia 79090022; Center for the Development of Nanoscience and Nanotechnology (CEDENNA); by the Spanish Ministry of Science and Innovation (AGL 2005-07017-C03-03); and by the Brazilian agencies CNPq (grants 302479/2010-4 and Prosul 490096/2010-7) and FAPEMIG (PPM 00419-10). We are especially grateful to Mr. F. Pinto, Mr. M. Juanco and Dr. Martín Treps for their technical assistance. N. Arancibia-Miranda acknowledges a scholarship from CONICYT (Chile) and CAPES (Brazil) for granting the Visiting Professor PVNS fellowship to JDF at UFVJM