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The mesoporous silica KIT-6 was synthesized and functionalized with 3-aminopropyltriethoxysilane (APTES) by grafting at 110 ◦C. The composites were prepared with three different concentrations of APTES: 20, 30 and 40 wt.%. The as-prepared samples were characterized by thermal gravimetric analysis in air and nitrogen atmosphere (TG/DTA), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction and nitrogen adsorption–desorption. In this study, CO2 adsorption–desorption was investigated using temperature programmed desorption mass spectrometry (TPD-MS) at different temperatures. The adsorption capacity of the prepared composites is 2.23 mmol CO2/g at 40 ◦C and decreases to 0.95 mmol/g at 70 ◦C. Regarding the efficiency of the amino groups, the best result was obtained for APTES-grafted KIT-6 at 40 ◦C, with 0.512 mmol CO2/mmol NH2 . The results showed good cyclical stability in adsorption capacities even after nine adsorption–desorption cycles. [ABSTRACT FROM AUTHOR]

The generation of nuclear energy produces a large amount of uranium containing wastewater, which must be treated. In this study, amino functionalized bentonite (Bent-NH2) was prepared by modifing Gaomiaozi bentonite with 3-Aminopropyltriethoxysilane. Various characterization results confirmed the successful grafting. The batch adsorption experiments indicated Bent-NH2 reached its maximum adsorption capacity rapidly (20 min), 49.168 mg/g. Notably, Bent-NH2 had better adsorption performance than unmodified bentonite in really groundwater with different pH. This work demonstrates that Bent-NH2 has excellent adsorption performance and can be used for low uranium wastewater treatment and geological disposal. [ABSTRACT FROM AUTHOR]

In this paper, two types of microspheres encapsulating magnetic carboxyl-modified Fe3O4 have been synthesized to compare their adsorption to Congo Red, one has been prepared by taking 3-aminopropyltriethoxysilane (APTES) as the functional monomer; the other has utilized chitosan and gelatin as the wall materials. The former is named as ASM and the latter is called as CGM. SEM, FTIR, XRD and TGA have been used to characterize the morphology and structure of microspheres. The adsorption experiments have shown that they both could absorb the dye rapidly and continuously and adsorption kinetics conform to pseudo-second-order model. The adsorption test data of ASMs have been fitted better with the Freundlich isotherms. The CGMs follow Langmuir isotherms. The maximum adsorption capacity of the dye onto the former at room temperature is 585 mg/g and the latter is 364 mg/g, indicating highly efficient adsorption capacity. The high reusability means that the products have promising potentials in advanced treatment of industrial wastewater. [ABSTRACT FROM AUTHOR]

Dye effluent damaged the water environment and human health with its massive discharge. In order to eliminate dye from the water environment, a variety of adsorbents were used to investigate dye removal. Graphene oxide (GO) attracted extensive attention due to its excellent surface property in the degradation of dye wastewater. Modified GO with multifunctional groups helped to improve adsorption performance. 3-Aminopropyltriethoxysilane modified GO (AS-GO) was fabricated for the removal of Orange G (OG) in this study. The results showed that AS-GO had an excellent adsorption ability of OG. During the reaction process, the maximum adsorptive capacity of OG was up to 576.6 mg/g at T = 313 K and pH = 3 with the initial OG concentration of 100 mg/L and the initial adsorbent dose of 2.5 g/L. The adsorption kinetic process of AS-GO conformed to the pseudo-second-order and Langmuir models. The spontaneous and endothermic adsorption of OG occurred in the adsorption process. The main adsorption mechanisms were electrostatic, π–π and hydrogen bonding interactions in the reaction process. After four cycles of AS-GO, it maintained high removal efficiency owing to its remarkable stability. The scheme of GO modified with AS could hinder the agglomeration of GO and provide more active sites, which would further enhance the adsorption properties and expand its application in water purification. [ABSTRACT FROM AUTHOR]

Two amino-functionalized diatomite (DE) composites modified by 3-aminopropyltriethoxysilane (APTS) or glycine (GLY) (i.e., APTS/DE and GLY/DE) were successfully synthesized via the wet chemical method for the time- and cost-efficient removal of indoor formaldehyde (HCHO). First, the optimal preparation conditions of the two composites were determined, and then their microstructures and morphologies were characterized and analyzed. Batch HCHO adsorption experiments with the two types of amino-modified DE composites were also conducted to compare their adsorption properties. Experimental results indicated that the pseudo-second-order kinetic and Langmuir isotherm models could well describe the adsorption process, and the maximum adsorption capacities of APTS/DE and GLY/DE prepared under optimal conditions at 20°C were 5.83 and 1.14 mg·g−1, respectively. The thermodynamic parameters of the composites indicated that the adsorption process was spontaneous and exothermic. The abundant amine groups grafted on the surface of DE were derived from the Schiff base reaction and were essential for the high-efficient adsorption performance toward HCHO. [ABSTRACT FROM AUTHOR]

The authors report a novel, effective and enhanced method of conjugating anticancer drug, paclitaxel and gallic acid with magnetosomes. Here, anticancer drugs were functionalised with magnetosomes membrane by direct and indirect (via crosslinkers: glutaraldehyde and 3‐aminopropyltriethoxysilane) adsorption methods. The prepared magnetosome–drug conjugates were characterised by Fourier transform infrared, zeta potential, field‐emission scanning electron microscope and thermogravimetric analysis/differential scanning calorimetry. The drug‐loading efficiency and capacity were found to be 87.874% for paclitaxel (MP) and 71.3% for gallic acid (MG), respectively as calculated by ultraviolet spectroscopy and high‐performance liquid chromatography. The drug release demonstrated by the diffusion method in phosphate buffer (PBS), showing a prolonged drug release for MP and MG, respectively. The cytotoxicity effect of the MP and MG displayed cytotoxicity of 69.71%, 55.194% against HeLa and MCF‐7 cell lines, respectively. The reactive oxygen species, acridine orange and ethidium bromide and 4, 6‐diamidino‐2‐phenylindole staining of the drug conjugates revealed the apoptotic effect of MP and MG. Further, the regulation of tumour suppressor protein, p53 was determined by western blotting which showed an upregulation of p53. Comparatively, the magnetosome–drug conjugates prepared by direct adsorption achieved the best effects on the drug‐loading efficiency and the increased percentage of cancer cell mortality and the upregulation of P53. The proposed research ascertains that magnetosomes could be used as effective nanocarriers in cancer therapy. [ABSTRACT FROM AUTHOR]

2,4-Dichlorophenoxyacetic acid (2,4-D) is the most commonly used herbicide in plant protection products. 2,4-D is poorly biodegradable and it is often found in aquatic environment. The development of an effective way to reduce the amount of this toxic contaminant from aqueous solution became an urgent issue. Therefore, in this study series of aminosilane-grafted mesoporous carbons were synthesized, characterized and then applied as adsorbents for 2,4-D. The impact of various factors such as the contact time (0–360 min) of herbicide with adsorbents, pH (2–11), temperature (25, 45, 60 °C) and initial concentration (6.25–150 mg/l) of the 2,4-D on the sorption capacity of materials was analyzed. The results proved that functionalization of mesoporous carbons with aminosilane increased the sorption capacity (qe = 142–191 mg/g) towards herbicide compared to pristine material (qe = 109 mg/g). The functional groups presented on the surface of materials enhanced the interaction between mesoporous carbons and herbicide. The most effective adsorbent for 2,4-D was the material that had the highest amount of basic groups on the surface (2.79 mmol/g) of all samples tested (0.06–0.52 mmol/g). For all studied materials the Langmuir model was the most suitable to describe the isotherms of 2,4-D adsorption (R2 = 0.999). While the kinetics of herbicide adsorption on the functionalized mesoporous carbons were best fitted to the pseudo-second-order model. The presented study proved that the aminosilane-grafted mesoporous carbons could be promising adsorbents for effective removal of 2,4-D from aqueous environment. [ABSTRACT FROM AUTHOR]

Abstract Stereoscopic porous carbons have shown good potential in humic acid (HA) removal. In this work, a novel stereoscopic porous activated carbon (SPAC) was designed and synthesized via the self-assembly of a hydrogel based on food waste during in-situ polymerization, vacuum drying, carbonization, and activation. Then, the SPAC was functionalized with 3-aminopropyltriethoxysilane (APTES) and the adsorption behavior of the modified SPAC (SPAC-NH 2) was studied systematically. The effects of pH, contact time, initial concentration of HA, and adsorbent dose were investigated, showing that optimal HA removal efficiency (> 98.0%) could be achieved at an initial HA concentration of 100 mg/L. The experimental adsorption isotherm data was fitted to the Langmuir model with a maximum adsorption capacity of 156.0 mg HA/g SPAC-NH 2. Analysis of the mechanism indicated that the removal of HA was mainly realized through the amidization reaction between the COOH groups of HA and the NH 2 groups of APTES. All of the above results showed that SPAC-NH 2 powder is an efficient, eco-friendly, and reusable adsorbent which is suitable for the removal of HA from wastewater. Graphical abstract Unlabelled Image [ABSTRACT FROM AUTHOR]

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The adsorption of cobalt (II) by 3-aminopropyltriethoxysilane (APTS) modified halloysite nanotubes (HNTs) was studied. The modified halloysite was characterized by Fourier transform infrared spectroscopy (FT-IR), X-Ray diffraction (XRD) and thermogravimetry (TG). In addition, a batch method was used to study the adsorption behavior and the mechanism of removal Co (II) by modified HNTs; the effective factors influencing the adsorption process including adsorbent concentration, contact time, initial pH, temperature and the initial concentration of Co (II) have been investigated. The results showed that the APTS was successfully grafted on the HNTs surface. The modified HNTs exhibited rapid adsorption speed, which reached the adsorption equilibrium within 30 min. The adsorption capacity of the adsorbent increased significantly with the increase of pH. The adsorption data of Co (II) on the modified HNTs are well consistent with the Langmuir model and the pseudo-second-order kinetic model. [ABSTRACT FROM AUTHOR]

The modification of bentonite (Bt) was performed using the 3-aminopropyltriethoxysiIane (γ-APS) and sodium silicate (Na2Si03) as main and auxiliary modifier, respectively. The composite modified bentonite (M-Bt) was characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and thermo gravimetric analysis (TGA). The results showed that the γ-APS was successfully intercalated in the interlayer space of Bt and suggested a parallel-bilayer arrangement. The Na2SiO3 not only reduced the electropositive of the end surface of Bt, but also improved the suspension property of bentonite. The preparation conditions were optimized by the adsorption test of Cd2+ in water. The optimum ratio of Bt to γ-APS dosage was l:l(g/mL); the dosage of Na2SiO3 was 10% of Bt quality; the ratio of liquid-solid was 40:l(mL/g); the pH was at 10; and the reaction lasted 3 hours at room temperature. The saturated adsorption amount of the M-Bt to Cd2+ reached to 35.7mg/g, which was significantly improved compared with those without modification (1.38mg/g). [ABSTRACT FROM AUTHOR]

In this study, the property of 3-aminopropyltriethoxysilane modified graphite nanosheets (GNS) decorated with Fe3O4nanoparticles (Fe3O4-GNS-NH2hybrids) for adsorption of Hg(II) in aqueous solution were evaluated by batch methods. The adsorption mechanism was also studied by X-ray photoelectron spectroscopy. The effect of factors, such as pH, contact time, initial concentration of Hg(II) and the GNS content (wt.%) for Fe3O4in Fe3O4-GNS-NH2hybrid materials on Hg(II) removal were investigated. The equilibrium data were analyzed using the Langmuir and Freundlich isotherm models. The pseudo-first-order adsorption and the pseudo-second-order adsorption models were used to fit kinetics experimental data. The results showed that the main adsorption mechanism for Hg(II) was the formation of N-metal ions chemical complex, the solution pH value had a major impact on Hg(II) adsorption with optimal removal observed around pH 4.0–6.0, the Langmuir isotherm model was found to be suitable for the Hg(II) adsorption and the adsorption kinetic followed the pseudo-second-order equation for Fe3O4-GNS-NH2hybrid materials. [ABSTRACT FROM PUBLISHER]

The CO2 adsorption capacity of different functionalized mesoporous silicas of the SBA-15 type was investigated and the influence of textural properties and the effect of the silicon source on the CO2 uptake studied. Several adsorbents based on SBA-15 were synthesized using sodium silicate as silicon source, replacing the commonly used tetraethyl orthosilicate (TEOS). Thus, we synthesized three couples of supports, two at room temperature (RT, RT-F), two hydrothermal (HT, HT-F) and two hydrothermal with addition of swelling agent (1,3,5-triisopropylbenzene) (TiPB, TiPB-F). Within each couple, one of the materials was synthesized with ammonium fluoride (NH4F). The supports were functionalized via grafting 3-aminopropyltriethoxysilane (APTES) and via impregnation with polyethylenimine ethylenediamine branched (PEI). The adsorption behavior of the pure materials was described well by the Langmuir model, whereas for the amine-silicas, a Dualsite Langmuir model was applied, which allowed us to qualify and quantify two different adsorption sites. Among the materials synthesized, only the SBA-15 synthesized at room temperatures (RT) improved its properties as an adsorbent with the addition of fluoride when the silicas were functionalized with APTES. The most promising result was the TiPB-F/50PEI silica which at 75 °C and 1 bar CO2 captured 2.21 mmol/g. [ABSTRACT FROM AUTHOR]

Surface modification of clay minerals has become increasingly important for improving the practical applications of clays such as fillers and adsorbents. An investigation was carried out on the surface modification of sepiolite with aminopropylsilyl groups in 3-aminopropyltriethoxysilane (3-APT). The zeta potential of the modified sepiolite suspensions was measured as a function of initial electrolyte concentration and equilibrium pH using a Zeta Meter 3.0 for modified sepiolite. The utility of the 3-APT-modified sepiolite was investigated as an adsorbent for removal of various heavy metal ions such as Fe, Mn, Co, Zn, Cu, Cd and Ni from aqueous solutions. The effects of various factors on the adsorption, such as pH, ionic strength and temperature of the solution were studied. The results showed that the amount adsorbed increases with solution pH in the pH range of 1.5 and 7.0; indicated that the modified sepiolite adsorbed Fe and Mn ions more than other metal ions such as Co, Zn, Cu, Cd and Ni. It was found that the temperature had an important effect on metal ion adsorption by the modified sepiolite. The adsorption isotherm has been determined and data have been analyzed according to the Langmuir and Freundlich models. [Copyright &y& Elsevier]

Abstract: Functionalization of montmorillonite clay has been done using 3-aminopropyltriethoxysilane in the presence of various solvent media. Qualitative evidence of the presence of aminosilane attached to the clay platelets have been identified using Fourier transform infrared spectroscopy (FTIR) and 29Si and 13C solid-state nuclear magnetic resonance (NMR) spectroscopy. Grafting yield has been calculated using thermogravimetric analysis and total grafting yield increases with the solvent surface energy. X-ray diffraction studies of the silane functionalized montmorillonite clay exhibits two peaks, which may be attributed to intercalation and surface interaction with the broken edge platelets. Functionalized clay has been characterized by surface area measurements to understand the influence of solvents on the surface area of the functionalized clay. [Copyright &y& Elsevier]

Resumo O presente estudo teve como objetivo avaliar a termodinâmica e o equilíbrio de adsorção, em solução aquosa, do íon Cu2+ em uma montmorilonita organofuncionalizada por 3-aminopropiltrietoxissilano. Esse adsorvente foi preparado pela intercalação inicial de brometo de cetiltrimetilamônio e depois a funcionalização com o 3-aminopropiltrietoxissilano. A organofuncionalização ocorreu na superfície externa da matriz inorgânica. A capacidade máxima de adsorção de Cu2+ pela amostra organofuncionalizada, prevista pela densidade de imobilização (1,46.10-3 mol.g-1) foi de cerca de 92 mg de Cu2+ por grama de argila. A variação da entalpia na adsorção (ΔH) obtida por via calorimétrica foi de -1,4±0,3 kJ.mol-1, valor muito pequeno para ser determinado por aplicação de método da segunda lei. Tomando por base o modelo de Langmuir, com modificações, obtiveram-se valores de constantes de afinidade de 47±10, 41±9 e 48±6 dm3.mol-1, para as temperaturas de 25, 35 e 45 °C, respectivamente, o que evidenciou grandezas iguais dentro das incertezas experimentais.