Silica modified with poly(ethylene oxide) for phenol preconcentration from aqueous solution (original) (raw)
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Facile synthesis and application of poly(ionic liquid)-bonded silica hybrid materials
The Analyst, 2012
Chemicals 2,2-Azobisisobutyronitrile (AIBN) was purchased from Jun-sei Chemical Co. (Tokyo, Japan). 1-Vinylimidazole (>98%), allyl chloride (>98%), and 1-chlorohexane (>95%) were from Tokyo Chemical Industry Co. Ltd. (Tokyo, Japan). (3-Chloropropyl)trimethoxysilane (97%) was from Sigma-Aldrich (St. Louis, MO, USA). The silica particles (≤7 μm) were purchased from SUNJIN Chemical Co. Ltd. and a specific surface are (BET) of 300 m 2 g-1. The 15 μm C 18 particles were purchased from Merck Chemicals Ltd. and a specific surface are (BET) of 420 m 2 g-1. 1-Octanol, toluene, acetonitrile and other organic solvents were from Duksan Pure Chemicals Co., Ltd. (Ansan, Korea). Distilled water was filtered using a vacuum pump and a filter (HA-0.45, both from Millipore, USA) before use. All other solvents were of HPLC or analytical grade. All samples were filtered (MFS-25, 0.2 μm TF, Whatman, USA) before being injected into the HPLC system. Synthesis SilprCl: Silica was first immersed in hydrochloric acid for 24 h and then washed with deionized water and dried at 100 o C for 8h. The activated silica (5.0g) was suspended in 50.0 mL of dry toluene, after which an excess of 3-chloropropyltrimethoxysilane
Journal of Separation Science, 2011
The chromatographic behaviors of some basic solutes were evaluated on stationary phases based on poly(methyloctylsiloxane) immobilized onto silica (PMOS-SiO 2 ). The test solutes present both hydrophobic and hydrophilic properties. Evaluations of the pH effect used 80:20 v/v methanol/buffered mobile phase over the pH range of 5-11.5 with inorganic buffers such as borate, carbonate and phosphate and with organic buffers such as citrate, tricine and triethylamine. Evaluations in acidic mobile phases used 50:50 v/v and 30:70 v/v methanol/buffer (pH 2.5; 20 mmol/L) mobile phases. The buffer concentration effect used 65:35 v/v methanol/phosphate (pH 7; 20 and 100 mmol/L) mobile phases. The results are compared with those obtained with two chemically bonded stationary phases. The immobilized phases show greater contributions from an ion-exchange mechanism than do the commercial phases. The results indicate that the silanol activity of PMOS-SiO 2 stationary phases can be adequately evaluated by using appropriate basic probes and mobile phases having different pH, using different buffers.
Evaluation of a new solid-phase cartridge for the preconcentration of phenolic compounds in water
Journal of Separation Science, 2004
The aim of this study is to evaluate the efficiency of a new solid-phase extraction cartridge, Spe-ed Advanta, in the extraction and preconcentration of four phenolic compounds (phenol, 2-chlorophenol, 2-nitrophenol, and 2,4-dichlorophenol) from water. The solid phase is a polystyrene-divinylbenzene resin modified with carboxylic groups, these polar groups improve the contact between the matrix and the aqueous solutions in the extraction of polar analytes. We studied several elution solvents in order to find the most efficient one. Sample concentration, sample volume, and sample pH are also investigated as well as the best method for drying the cartridge. Recoveries achieved with the new phase are compared with those obtained with Isolute ENV+, a non-modified polystyrene-divinylbenzene stationary bed. The best experimental conditions were then used for determination of the phenols in spiked environmental waters.
Journal of Chromatography A, 1985
The breakthrough volumes (V,) of a number of porous polymeric sorbents (Amberlite XAD-2, XAD-4, XAD-7; Chromosorb 102, 105, 106) have been determined for a variety of organosulphur compounds (thiols, sulphides, disulphides, thiophenes) in aqueous samples. The determination was based on a headspace gas chromatographic technique developed earlier. Among the investigated sorbents, Chromosorb 106 and Amberlite XAD-2 were found to be best suited for preconcentration of organic sulphur compounds from water. An attempt was undertaken to correlate the experimental VB values with the aqueous solubility determined previously from the distribution constants in gas-liquid systems, in order to predict the capacity of sorbents for any organic solute using only the solubility of the analyte. The prediction is useful as a guide for estimating the appropriate ratio of sample to sorbent size in the preconcentration of organic solutes from water.
Journal of Chromatography A, 2000
The chromatographic properties of a new stationary phase, phenylaminopropyl silica (PhA-silica), containing phenylaminopropyl residues covalently bonded to the silica surface were studied. The presence of secondary amino groups, phenyl rings and alkyl linkers in the attached molecule makes it especially suitable for the separation of phenols by mixed mode retention mechanism including a combination of hydrogen-bonding, hydrophobic, electrostatic and p-p interactions with the stationary phase. The effects of mobile phase pH, ionic strength, nature and concentration of organic modifier on the retention of phenols on PhA-silica were investigated under conditions of reversed-phase HPLC. To elucidate the role of the amino group in the attached molecule in retention of phenols the selectivity of PhA-silica was compared with that obtained for phenylpropyl silica in the framework of a linear solvation energy relationship (LSER) model. The isocratic separation of phenol, and its nine methyl-, chloro-and nitro-substituted derivatives was achieved on a 15034.6 mm I.D. chromatographic column packed with 7 mm particles of PhA-silica.
One-pot synthesis of bimodal (macro-meso, micro-mesoporous) silica by polyHIPE: parameter studies
Journal of Porous Materials, 2019
Porous silica with hierarchical organization of pore structure is desired for a variety of applications such as, chromatography, sensing, control release, scaffold for biomedical applications and catalysis. Highly porous polymers obtained from high internal phase emulsion (HIPE) templating route have attracted increasing attention of researchers due to their hierarchical porous and interconnected structure with high porosity and low density. The novel method adopted in our approach combines redox initiated polymerization using HIPE polymerization and an in-situ sol-gel processing technique followed by calcination to obtain highly porous materials. The obtained materials have reminiscent of polyHIPE morphology containing pores and interconnected pore throats in micrometer size range with mesopores on the wall of macropores. The effect of concentration of TEOS, volume of dispersed phase, crosslinker concentration, shear rate and surfactant concentration as well as variation in calcination temperatures on the properties of silica materials were examined.
Journal of Separation Science, 2013
In this work, a silica surface chemically modified with [3-(2,2-dipyridylamine)propyl] groups, named [3-(2,2-dipyridylamine)propyl]silica (Si-Pr-DPA) was prepared, characterized, and evaluated for its heavy metal adsorption characteristics from aqueous solution. To our knowledge, we are the first authors who have reported the present modification. The material was characterized using infrared spectroscopy, SEM, and NMR 29 Si and 13 C solid state. Batch and column experiments were conducted to investigate for heavy metal removal from dilute aqueous solution by sorption onto Si-Pr-DPA. From a number of studies the affinity of various metal ions for the Si-Pr-DPA sorbent was determined to follow the order Fe(III) > Cr(III) >> Cu(II) > Cd(II) > Pb(II) > Ni(II). Two standard reference materials were used for checking the accuracy and precision of the method. The proposed method was successfully applied to the analysis of environmental samples. This ligand material has great advantage for adsorption of transition-metal ions from aqueous medium due to its high degree of organofunctionalization associated with the large adsorption capacity, reutilization possibility, and rapidity in reaching the equilibrium.
Phenol removal from aqueous solution using amino modified silica nanoparticles
Korean Journal of Chemical Engineering, 2019
Phenols constitute a widespread class of water pollutants that are generated from many industries and are known to cause a significant threat to the aquatic environment. Phenols are, therefore, considered as dangerous pollutants by global international quality organizations. This has led to a growing demand for an efficient technology for phenol removal from wastewater. Different sizes of amino-modified silica nanoparticles (SiNPs) were synthesized with 10-40 nm in diameter (AMS-10 to 40), and their properties were characterized in terms of size and surface modification using transmission electron microscope (TEM), dynamic light scattering (DLS), zeta potential, elemental analyses (C, H, N), thermal gravimetric analysis (TGA) and Fourier transform infra-red (FTIR). The adsorption process was carried out utilizing batch mode experiment; the influence of various factors including pH of the medium, the contact time, the initial concentration of the adsorbate and the dose of the adsorbent on the phenol adsorption efficiency of SiNPs of various sizes were investigated. Phenol removal efficiency was found to be size-dependent, such that the phenol adsorption capacity of the SiNPs was in the following order: AMS-10>AMS-20>AMS-30>AMS-40 nm. The adsorption capacity and binding coefficient were calculated to be 35.2 mg/g and 0.192 mg/L, respectively, for AMS-10. The amino-modified SiNPs were found to be promising adsorbents for the phenol ions removal from the aqueous medium.
CORROSION 2007, 2007
Colloidal silica is one of the most unwanted deposits in the water treatment industry. Its control is a complicated issue and the decision on which control method to apply is frequently based on a number of factors. Our goal is the discovery, design and application of organic additives (preferably "green" and environmentally friendly) that have some effect on silicate polymerization. This paper reports the inhibition efficiency of a variety of polymeric additives and some combinations in retarding silicate polymerization is supersaturated aqueous solutions. There are three classes of polymeric additives studies: (1) neutral, (2) cationic of varying positive charge density, and (3) combinations of anionic and cationic polyelectrolytes. As a neutral polymer PEOX (poly(2-ethyl-2-oxazoline)) was tested. Cationic additives included PEI (polyethyleneimine), PALAM (polyallylamine) and PAMALAM (poly(acrylamide-co-diallyl-dimethylammonium chloride)). Blends of cationic/anionic polymers were PEI+CMI (CMI = carboxymethylinulin), PEI+PAA (PAA = polyacrylate)). All aforementioned additives and/or blends exhibited inhibition features from "good" to "excellent". Inhibition efficiency was found to depend on a multitude of factors, such as cationic charge density, inhibitor dosage, time, etc.