Adsorption of phenol and aniline onto original and with quaternary ammonium salts (QASs)-modified montmorillonite was described by sorption isotherms of type III and II, respectively. For the montmorillonite (MMT) modification - hydrophobisation, cetyltrimethyl- ammonium (CTMA) and tetramethylammonium (TMA ) cations were used. In comparison with phenol, aniline was adsorbed largely on original MMT but less on modified one. XRD pa tterns indicated that both aromatic compounds were intercalated in the MMT interlayer be ing perpendicularly oriented to silicate sheets. Alkyl chains of CTMA and TMA probably act as organic "pillars" stabilising the MMT tabular structure against exfoliation due to the intercalation with phenol and aniline of high concentrations., Hana Kostelníková, Petr Praus and Martina Turicová., and Obsahuje bibliografické odkazy
Phenolic compounds are common pollutants found particularly in the effluents from petroleum and petrochemical, coal conversion, and phenol producing industries. Due to their toxicity and carcinogenity, water and wastewater containing phenolic compounds must be treated before being used and discharged for receiving water bodies. There is a growing interest in using low-cost and commercially available materials for the adsorption of organic compounds. Clay minerals have great potential to remove phenols in water due to efficient sorbents which can be used as alternative adsorbents to replace the costly activated carbon. They are widely applied in many fields of adsorption technology including the removal of amines, metals, ketones, phosphates, chlorophyll, non-ionic contaminants, and organic pigments/dyes. Montmorillonitic smectites, {(Na,Ca)0.33(Al,Mg)2(Si4O10)-(OH)2.nH2O} are one of the natural clay minerals that have specific surface chemical properties. In this study, a factorial experimental design technique was used to investigate the adsorption of phenol from water solution on montmorillonite. Factorial design of experiments is employed to study the effect of three factors: pH (2.0 and 8.0), montmorillonite dosage (0.1 and 1.0 g/L) and initial low and high concentration (10 and 100 mg/L). The efficiency of phenol adsorption was determined after 60 min of treatment. Main effects and interaction effects of three factors were analyzed by using statistical techniques. A regression model was found to fit the experimental data very well. Through using the Student’s t-test, analysis of variance, F-test and lack of fit to define most important process variables affecting the percentage phenol adsorption., Feza Geyikçi and Semra Çoruh., and Obsahuje bibliografii
This research work involved the use of factorial design technique to investigate the adsorption of silver ions from water onto montmorillonite. There is a growing interest in using low-cost and commercially available materials for the adsorption of heavy metals. Clay particles are strongly anisotropic and exhibit faces and edges, which are very different in surface area and in chemical behavior. It has been reported that the abundance of clay minerals and their low cost has posed them a strong candidate as adsorbent for removal of heavy metal from wastewater. In this study, a factorial experimental design technique was used to investigate the adsorption of silver ions from water onto montmorillonite. The experimental factors and their respective levels that were selected include a pH of 3 - 8, an adsorbent dosage of 0.5-2.0 g/L and an initial silver ions concentration of 20-200 mg/L. The results were analyzed statistically using the Student’s t-test, analysis of variance, F-test and lack of fit to define most important process variables affecting the percentage silver ions adsorption., Feza Geyikçi and Hanife Büyükgüngör., and Obsahuje bibliografii
Hg(II) ions dissolved in aqueous solutions were adsorbed by montmorillonite (MMT). The Hg(II) ion-exchange was strongly limited by the competition with H+ ions: the maximal amounts of adsorbed Hg(II) and H+ ions were 0.21 mmol g-1 and 1.10 mmol g-1, respectively. MMTs saturated with Hg(II) (Hg-MMTs) were examined by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and thermal analysis. Hg(II) ions, such as Hg2+ and [Hg(OH)+], along with H+ ones were mostly adsorbed on permanent sites (75 % of cation exchange capacity (CEC)) and also on pH dependent surface sites (25 % of CEC). While heating, Hg-MMTs was loosing their mass up to 700 °C as a result of the MMT dehydration and dehydroxylation accompanied by release of adsorbed Hg(II)., Petr Praus, Marcela Motáková and Michal Ritz., and Obsahuje bibliografii
Adsorption procedure of two cationic surfactants hexadecyltrimethylammonium bromide (HDTMABr) and benzyldimethylhexadecylammonium chloride (BDHDACl) onto two samples of montmorillonite was studied. Infrared spectroscopy and X-ray diffraction proved intercalation of both quaternary cations into the interlayer space of montmorillonite. An aspect of time showed not to be important for the cations adsorption., Zuzana Navrátilová, Petr Wojtowicz, Lenka Vaculíková and Věra Šugárková., and Obsahuje bibliografické odkazy