Template synthesis of mesoporous silicas containing phosphonic groups

Mesoporous silicas containing the functional group ≡Si(CH₂)₂P(O)(OC₂H₅)₂ in the surface layer have been obtained using the template method (template—P123). Their treatment by a concentrated hydrochloric acid results in the formation of functional groups of the composition ≡Si(CH₂)₂P(O)(OH)₂ that is in agreement with the IR spectroscopy data. It has been shown that the above treatment causes an increase of the sample specific surface area (up to 605 m²/g), sorption capacity, and pore diameter. As established by means of the CP/MAS NMR spectroscopy on ³¹P nuclei, the sample drying in vacuum at 110°C results in the formation of fragments ≡Si(CH₂)₂P(O)(OH)—OSi≡ with the content of 10–15 wt %. However, according to the TEM data, the sample mesoporous structure is retained.     

Synthesis and characterization of a surface imprinting silica gel polymer functionalized with phosphonic acid groups for selective adsorption of Fe(III) from aqueous solution

A Fe(III) ion‐imprinted silica gel polymer functionalized with phosphonic acid groups (IIP‐PA/SiO₂) was prepared with surface imprinting technique by using Fe(III) ion as template ion, grafted silica gel as support, and vinylphosphonic acid as functional monomer. The polymer was characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, Brunauer–Emmett–Teller, and thermogravimetric analysis. The synthesized imprinted silica gel polymer was used as a sorbent for Fe(III) adsorption. The adsorption properties, such as the effect of solution pH, adsorption kinetic, adsorption isotherm, adsorption selectivity as well as the regeneration of sorbent were studied. The results showd that the prepared sorbent (IIP‐PA/SiO₂) had a short adsorption equilibrium time (12 min) and high adsorption capacity (29.92 mg g^?1) for Fe(III) at the optimal pH of 2.0. The selectivity coefficients of the sorbent for Fe(III) in presence of Cr(III), M_n (II), and Zn(II) were 51.76, 27.86, and 207. 76, respectively. Moreover, the adsorption capacity of the prepared sorbent did not decrease significantly after six repeated use. Thus, the prepared ion‐imprinted silica gel polymer was a promising candidate sorbent for the selective adsorption of Fe(III) from aqueous solutions. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45165.     

Perchlorate removal in aqueous solutions using periodic mesoporous organosilicas (PMOs) functionalized with quaternary ammonium groups

Perchlorate anion (ClO₄⁻) in water has become an environmental issue of concern because it can impair proper functioning of the thyroid gland. For the removal of perchlorate anions from water, adsorption using anionexchange resins has been generally used as the most suitable method. In this work, we prepared periodic mesoporous organosilica materials (PMOs) functionalized with quaternary ammonium ligands, and used them for the removal of perchlorate anions from aqueous solutions. The physical and chemical properties of prepared samples were measured using nitrogen adsorption-desorption measurement, elemental analyses, X-ray diffractometer, and infrared spectrometer. We also investigated equilibrium isotherms for the measurement of adsorption capacities and kinetic performance of the prepared samples.     

Synthesis,characterization and catalytic activity of MCM-41-type mesoporous silicas functionalized with sulfonic acid

This paper reports the results obtained in the synthesis, characterization and catalytic activity of thiol-MCM-41 materials synthesized using an improved method of preparation.This novel method of synthesis includes the partial replacement of the surfactant used previously — hexadecyltrimethylammonium bromide, for a shorter chain surfactant such as dodecyltrimethylammonium bromide. It also includes the use of tetramethylammonium hydroxide (TMAOH) as co-structuring agent instead of NaOH. The materials obtained from this modified gels present a higher order in the channels arrangement confirmed by X-ray diffraction (XRD) and transmission electron microscopy (TEM) measurements.These materials incorporates an important amount of thiol groups which can be oxidized with H₂O₂ in order to obtain the corresponding sulfonic groups, with a very strong acidity. The catalysts so obtained have been tested in the esterification of glycerol with fatty acids — oleic and lauric. The results obtained indicate that the catalysts prepared with mixtures of surfactants are more selective to the monoglycerides than the ones synthesized only with hexadecyltrimethylammonium bromide, probably due to the higher order in the channels packing.     

Synthesis, characterization, and Ni(II) ion sorption properties of poly(styrene-co-divinylbenzene) functionalized with aminophosphonic acid groups

In this study, novel chelating resins containing aminophosphonic acid groups grafted on poly(styrene-co-divinylbenzene) (1 % or 15 % DVB) were obtained by “one-pot” reactions. The phosphorus contents were determined in order to calculate the degree of functionalization with pendant aminophosphonic acid groups. The fraction of repetitive units functionalized with aminophosphonic acid groups was determined by accepting the statistical structure of the repetitive unit of initial and final copolymer. These materials were characterized by FT-IR spectroscopy, EDX, and TGA. Adsorption properties of aminophosphonic acids grafted on poly(styrene-co-divinylbenzene) were examined for the removal of Ni(II) ions from aqueous solutions using the batch equilibrium procedure. By applying the kinetic models to the experimental data it was found that the adsorption of Ni(II) on the studied chelating resins is described by the pseudo-second-order kinetic model. For all the studied systems, Langmuir isotherm model provided an excellent fit of the equilibrium adsorption data.     

含磺酸基介孔分子筛SBA-15-SO3H催化合成油酸乙酯

采用水热法直接合成含磺酸基的介孔分子筛SBA-15-SO₃H。以油酸和乙醇为原料催化合成油酸乙酯，进行了不同催化剂的对比实验以及催化剂组成、反应温度、酸醇物质的量比和催化剂用量等反应条件的考察。得到最佳反应条件：温度130 ℃，n(酸)∶n(醇)=1∶2.5，反应时间4 h，催化剂质量分数为10%。     

含磺酸基的介孔分子筛SO3H-SBA-15催化合成油酸丁酯

采用水热法直接合成了含磺酸基的介孔分子筛SO3H-SBA-15.以油酸与正丁醇为原料催化合成油酸丁酯,进行了不同催化剂的对比实验以及反应条件包括催化剂用量、反应温度、反应时间、酸醇摩尔比的考察.得到最佳反应条件为：催化剂质量分数为10%,反应温度120 ℃,反应时间3 h,酸醇摩尔比1∶2.     

苄基磺酸官能化介孔分子筛催化合成邻苯二甲酸二乙二醇双甲基丙烯酸酯

以苄基磺酸官能化的介孔分子筛（MCM-41-B-S）为催化剂,以邻苯二甲酸酐（PA）、一缩二乙二醇（DEG）、甲基丙烯酸（MA）为原料,经两步酯化法合成了邻苯二甲酸一缩二乙二醇双甲基丙烯酸酯（PA-DEG-DMA）。结果表明,合成PA-DEG-DMA的反应温度在85～90℃,催化剂用量为DEG质量的4.5%,MA与邻苯二甲酸一缩二乙二醇酯（DEGP）的物质的量比为1.1∶1,带水剂甲苯用量为反应总质量的40%,阻聚剂4-甲氧基酚的用量为DEG质量的1.0%和回流时间为6h的优化条件下,获得了最佳反应结果,产品总收率可达83.4%,纯度大于98%。且产品外观质量好,反应后处理方便。并用X-射线衍射（XRD）、红外光谱（IR）、差示扫描量热（DSC）和Hammett指示剂对催化剂的结构和酸强度进行了表征和测定。     

New materials from dimethacrylates bearing phosphonic acid and thioether groups

A new series of crosslinkable dimethacrylates containing thioether and phosphonic acid were synthesized. The structures of the different synthesized crosslinkable agents based on oleic acid, cinnamic acid, acrylated glycerol 1,3‐dimethacrylate and a chalcone derivative were established by electrospray ionization, DSC, NMR and Fourier transform infrared spectroscopy. In order to prove the accessability of the double bonds on network formation, the radical curing of these compounds with N,N‐dimethylacrylamide as comonomer was examined. © 2015 Society of Chemical Industry     

Low molecular weight polyacrylic acid with pendant aminomethylene phosphonic acid groups

Low molecular weight poly(acrylic acid‐co‐vinyl aminomethylene phosphonic acid)s were prepared by consecutively applying the Hofmann degradation and the Mannich reaction to polyacrylamide and poly(acrylamide‐co‐acrylic acid)s. ¹H‐NMR, ³¹P‐NMR, and microanalysis were used for structural analyses. These polymers were tested as anti‐scalent and they showed better anti‐scalent effect than commercial poly(acrylic acid)s. The scale inhibition properties of copolymers increased with increasing amount of aminomethylene phosphonic acid groups. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 870–874, 2000     

Soybean hull functionalized by phosphoric acid for sorption of copper from aqueous solution

One kind of potentially biodegradable cationic sorbent, which bears hydroxyl groups of phosphoric acid as its functional groups, with high sorption capacity of copper was prepared by thermochemically esterifying phosphoric acid (PA) onto soybean hull. Sorption of Cu(II) from aqueous solution onto modified soybean hull (MSH) was investigated in a batch system. The sorption experiments were performed under various conditions such as different initial pH, copper concentration, MSH dosage, and contact time. The maximum copper sorption was obtained when initial solution pH≥3.5. The isothermal data of copper sorption fitted the Langmuir model and the sorption process could be described by the pseudo-first-order kinetic model. The maximum sorption capacity (Q _m ) of MSH for Cu(II) was 31.55 mg/g. For 100 mg/l of Cu(II) solution, a sorption ratio above 91% could be achieved by 5.0 g/l of MSH. The equilibrium of Cu(II) sorption was reached within 50 min. The foreign cation and chelator in Cu(II) solution caused decline of Cu(II) sorption.     

Characterization of thiourea-formaldehyde chelating resin by sorption of chromium(III) in water

With a simple model for a surfactant consisting of a hydrophilic head group and hydrophobic tail groups connected by harmonic springs, the structural change of the association structures of the surfactant in an aqueous solution was studied by using the dissipative particle dynamics (DPD) simulation. The effect of the interaction parameter of DPD particles on the structural change of the association structures was also studied. Simulations show that the proper relative values of these interaction parameters could yield desirable changes for the association structure depending on the concentration of the surfactant. That is, a spherical structure forms at ϕ=0.15, structural change from a spherical to cylindrical one occurs at ϕ=0.26, and a hexagonal structure appears at ϕ=0.30, where ϕ is the volume fraction of surfactant SDS (sodium dodecyl sulfate), and they are in good agreement with observation.     

Synthesis of formaldehyde-dibenzo-18-crown-6 condensation resins containing phosphonic acid groups and their alkali-metal cation sorption

Ion-exchange resins are prepared by introducing phosphonic acid monoethyl ester or phosphonic acid groups into formaldehyde condensation poly(dibenzo-18-crown-6) resin. The phosphonic acid ion-exchange groups provide accessibility for metal cations, while the ion-selective cyclic polyether binding site influences the selectivity. The selectivities and efficiencies for competitive alkali-metal cation sorption from aqueous solutions by these crown ether-containing phosphonic acid resins are strongly influenced by the pH of the aqueous solution, the identity of the phosphonic acid groups, and the molar ratio of ion-exchange groups to crown ether units. © 1995 John Wiley & Sons, Inc.     

Porous properties of mesoporous silicas from two silica sources (acid-leached kaolinite and Si-alkoxide)

Two different mesoporous silicas (MesoPS) were synthesized by hydrothermal treatment in NaOH solution of two silica sources. One of these starting silicas was derived from selectively acid leached metakaolinite, and the other was from tetraethylorthosilicate (TEOS). The syntheses used a surfactant, cethyltrimethylammonium bromide (CTABr) and were carried out at different CTABr/Si, NaOH/Si and H₂O/Si ratios. In the MesoPS from kaolinite, the specific surface areas (S _BET) of the products were >1500 m²/g when prepared with 0.2 ≤ CTABr/Si ≤ 0.4, 0.3 ≤ NaOH/Si ≤ 0.6 and H₂O/Si = 150. These S _BET values are higher than those obtained from TEOS (ca. 1300 m²/g). The XRD patterns of these products contain a hexagonal (10-) peak with a lattice parameter a ₀ = 4.2–5.2 nm in the MesoPS derived from kaolinite and a ₀ = 4.0–4.6 nm in the products from TEOS. The regularity of the hexagonal structure is higher in the MesoPS derived from TEOS than from kaolinite. The pore size distributions of the products show a sharp peak at 2.8 nm in the MesoPS from kaolinite and at 2.4–2.5 nm in those from TEOS. The meso-structure is found to be formed during the stirring step of the synthesis and becomes more regular after hydrothermal treatment. The differences in the porous properties of the two MesoPSs from kaolinite and TEOS are attributed to differences in the dissolution rates and silica concentrations in the synthesis solutions. The ²⁹Si MAS NMR spectra show a higher number of Q ³ (Si(OSi)₃OH) units in the MesoPS from kaolinite and this is suggested to be related to the difference in their porous properties.     

Catalytic applications of sulfonic acid functionalized mesoporous organosilicas with different fraction of organic groups in the pore wall

Organosulfonic acid functionalized mesoporous organosilicas with different fraction of organic groups in the pore wall was synthesized in the presence of P123 (EO₂₀PO₇₀EO₂₀) by controlling the molar ratio of tetramethoxysilane (TMOS) to 1,2-bis(trimethoxysilyl)ethane (BTME) in the initial mixture during the co-condensation process of silane precursors in acidic medium. Structural characterizations (X-ray diffraction, nitrogen sorption analysis, and transmission electron microscopy) show that all materials have ordered hexagonal mesoporous structure with large pore diameter (7–9 nm). The existence of ethane and sulfonic acid groups in the material was verified by ²⁹Si MAS and ¹³C CP MAS NMR and X-ray photoelectron spectroscopy (XPS). The mesoporous solid acids can adsorb both water and hexane (the adsorption capacity for water and hexane is 240 and 600 mg/g, respectively) due to the existence of surface hydroxyl groups, propyl sulfonic acid group, and the ethane moiety. These mesoporous solid acids are efficient catalysts for the dehydration of 1-butanol and the hydration of propylene oxide (PO).     

The dyeing of cellulose with reactive dyes containing phosphonic acid groups

The fixation of some Procion T phosphonated reactive dyes on cotton in the presence of dicyandiamide in different conditions of dyeing is reported, in order to clarify the role of the carbodiimide in the fixation process.Paper chromatographic studies on Procion Red T-2B show that the reaction mechanism between the phosphonic dye and cellulose in the presence of dicyandiamide is an initial condensation of the phosphonic dye with dicyandiamide to produce a phosphonic acid anhydride, followed by subsequent reaction with cellulose to give a dye covalently bonded to the cellulose. The phosphonic acid anhydride, isolated by means of column chromatography, shows the characteristic adsorption bands of the P—O—P linkage.     

Synthesis and application of amine functionalized silica mesoporous magnetite nanoparticles for removal of chromium(VI) from aqueous solutions

In this research, novel nanoparticles of Kit-6 mesoporous silica magnetite were synthesized with 9.6 nm pore diameter and 241.68 m² g^?1 surface area. The synthesized mesoporous magnetite nanoparticles (MMNPs) were functionalized with amine groups. Scanning electron microscopy, powder X-ray diffraction, Fourier transform infrared spectroscopy and nitrogen adsorption–desorption method confirmed the morphology and structure of the synthesized nanoparticles. The amine functionalized MMNPs were used for sorption of toxic chromate ions from aqueous samples. The effect of various experimental parameters (four factors at three levels) on the sorption efficiency of Cr(VI) was studied and optimized via Taguchi L₉ (3⁴) orthogonal array experimental design. At optimum conditions, the sorption of the Cr(VI) was best described by a pseudo second-order kinetic model with R² = 0.9999 and q_eq = 129.8 mg g^?1, suggesting chemisorption mechanism. Adsorption data were fitted well to the Langmuir isotherm and the synthesized sorbent showed complete ion removal with 185.2 mg g^?1sorption capacity.     

Kinetics of sorption of water vapors by fibres fabricated from cellulose copper-ammonia solutions

The water vapor diffusion coefficients were measured in copper-ammonia fibres fabricated in different conditions. It was shown that the diffusion coefficients vary extremely as a function of the conditions of fabrication of both copper-containing and finished hydrated cellulose fibres.All-Russian Scientific-Research Institute of Polymer Fibres, Mytishchi. Translated from Khimicheskie Volokna, No. 6, pp. 45–46, November–December, 1992.     

Separation of rhodium(III) and iridium(IV) chlorido complexes using polymer microspheres functionalized with quaternary diammonium groups

Merrifield resin functionalized with different quaternary diammonium groups derived from ethylenediamine (EDA), tetramethylenediamine (TMDA), hexamethylenediamine (HMDA), 1,8-diaminooctane (OMDA), 1,10-diaminodecane (DMDA) and 1,12-diaminododecane (DDMDA) were investigated for the separation of [RhCl₅(H₂O)]^2? and [IrCl₆]^2?. Selective loading of [IrCl₆]^2? in 6 M HCl medium onto the column was achieved in the presence of [RhCl₅(H₂O)]^2? by the synthesized sorbents. The iridium loading capacities were 3.80, 6.49, 13.07, 19.29, 27.09 and 4.36 mg/g for EDA, TMDA, HMDA, OMDA, DMDA and DDMDA-functionalized microspheres, respectively. The materials showed great potential for application in separating rhodium and iridium from aqueous HCl solutions.