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C. Colella - One of the best experts on this subject based on the ideXlab platform.
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Surface interaction of humic acids with natural and synthetic Phillipsite
Journal of Porous Materials, 2015Co-Authors: A. Colella, B. De Gennaro, Stefano Salvestrini, C. ColellaAbstract:Starting from previous encouraging results, pointing out the ability of natural zeolites to remove large, hydrophilic, organic molecules from water, this paper deals with the surface interactions between humic acids, a frequent contaminant of natural waters, and the zeolite Phillipsite, with the aim to obtain valuable insights on the possible use of low-cost, natural Phillipsite-rich materials in decontamination technology. Accordingly, an enriched sample of Neapolitan yellow tuff, containing ca. 70 % Phillipsite, was compared with a synthetic Phillipsite in both kinetic and equilibrium sorption experiments of humic acids from model waters. Tests, carried out at 25 °C, were performed on Ca2+-pre-exchanged samples, which proved to be more effective in the sorption process. The results highlighted the marked affinity of Phillipsite for the humic acids, better than any other zeolite tested previously, pointing out, moreover, that natural Phillipsite behaves as a slightly diluted Phillipsite, with no adverse effects from the mineral impurities present in the sample. Moreover, natural Phillipsite performance, in both kinetic tests and in sorption capacity, was comparatively better than the synthetic counterpart, which was attributed to the presence of structural defects in the latter, due to the stressing conditions under which it had been obtained.
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Permanent and safe storage of Ba2+ in hardened Phillipsite-rich tuff/cement pastes
Applied Clay Science, 2005Co-Authors: F. Iucolano, D. Caputo, C. ColellaAbstract:Ba2+ removal from wastewater by cation exchange using Phillipsite-rich tuffs and the subsequent stabilization of the resulting sludge in a cement matrix is reported. Moderate amounts of Phillipsite-rich tuff were able to bring, in a short time, the Ba2+ concentration of an experimental wastewater below the legal limits allowed for discharge. Pastes of Portland cement/Ba- loaded tuff were cured for 28 days and characterized from a mechanical and chemical point of view. The compressive strength of the hardened compacts, containing 25–75% of zeolitic material, was much higher than the value of 0.44 MPa, suggested by international protocols for handling and landfilling the solidified wastes. Moreover, experimental leaching of the hardened pastes resulted in a Ba2+ concentration in the leachates much lower than the legal limits allowed for discharge of barium in bodies of water (20 mg/l)
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permanent and safe storage of ba2 in hardened Phillipsite rich tuff cement pastes
Applied Clay Science, 2005Co-Authors: F. Iucolano, D. Caputo, C. ColellaAbstract:Abstract Ba 2+ removal from wastewater by cation exchange using Phillipsite-rich tuffs and the subsequent stabilization of the resulting sludge in a cement matrix is reported. Moderate amounts of Phillipsite-rich tuff were able to bring, in a short time, the Ba 2+ concentration of an experimental wastewater below the legal limits allowed for discharge. Pastes of Portland cement/Ba-loaded tuff were cured for 28 days and characterized from a mechanical and chemical point of view. The compressive strength of the hardened compacts, containing 25–75% of zeolitic material, was much higher than the value of 0.44 MPa, suggested by international protocols for handling and landfilling the solidified wastes. Moreover, experimental leaching of the hardened pastes resulted in a Ba 2+ concentration in the leachates much lower than the legal limits allowed for discharge of barium in bodies of water (20 mg/l).
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01-O-05 - Ion-exchange features of intermediate-silica sedimentary Phillipsite
Studies in Surface Science and Catalysis, 2001Co-Authors: C. Colella, Domenico Caputo, B. De Gennaro, A. Colella, E. Torracca, M. De'gennaroAbstract:Publisher Summary This chapter discusses the ion-exchange features of intermediate-silica sedimentary Phillipsite. Equilibrium ion-exchange data for intermediate-silica sodium (Na)-exchanged Phillipsite at 25°C, in the presence of cation pairs Na/X, where X is barium (Ba), cobalt (Co), potassium (K), or calcium (Ca), are collected, and the relevant thermodynamic parameters are computed. Phillipsite is found very selective for Ba, K, and ammonium (NH 4 ), unselective for Co, whereas only about 50% Na could be readily replaced by Ca. This behavior is interpreted in terms of Phillipsite's structural features.
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Selective water adsorption from aqueous ethanol-containing vapours by Phillipsite-rich volcanic tuffs
Microporous Materials, 1994Co-Authors: C. Colella, M. Pansini, Francesco Alfani, Maria Cantarella, Alberto GallifuocoAbstract:Abstract The use of Neapolitan yellow tuff (NYT), a Phillipsite/chabazite-containing volcaniclastic rock, rich in Phillipsite, is proposed for an inexpensive dehydration process of ethanol vapours. NYT selective water adsorption kinetics was investigated both in a continuous microbalance apparatus and in laboratory-scale fixed-bed columns. The influence of operational parameters such as tuff grain dimensions, column temperature and pressure, volumetric flow-rate and partial pressure of adsorbates was studied. A preliminary study on the fluid dynamics of the column is also described. Finally, evidence is reported that a partial, but economical bed regeneration can be attained at the column working temperature by simply flushing the system with dry nitrogen.
M. M. Gonzalez Martin - One of the best experts on this subject based on the ideXlab platform.
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Cation-exchange selectivity in Na+ - and in H+ - Phillipsite
Applied Clay Science, 1994Co-Authors: J. E. Garcia Hernandez, J.s. Notario Del Pino, M. M. Gonzalez MartinAbstract:Abstract The selectivity of Phillipsite in exchange reactions involving a series of cations (Li+, K+, NH4+, Cu2+, Zn2+, Cd2+, Ba2+ and Pb2+) is investigated. Phillipsite was initially treated to give the Na+- and H+-exchanged forms. The selectivity sequences found were Ba2+ ⪢ Pb2+ ⪢ Cd2+ > NH4+ > Cu2+ ≈ Zn2+ ≈ K+ > Na+ ⪢ Li+ for Na+-exchanged Phillipsite and Ba2+ ≈ Pb2+ > Cd2+ ≈ NH4+ > K+ ≈ Cu2+ ≈ Zn2+ > H3O+ ⪢ Li+ for acid-treated Phillipsite. A single linear relationship was found between the ionic radius multiplied by the valency of the cation and the logarithm of the selectivity coefficient. The results show that Phillipsite is a suitable sequester for heavy metal ions in dilute solutions.
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NH+4Na+-exchange and NH+4-release studies in natural Phillipsite
Applied Clay Science, 1994Co-Authors: J. E. Garcia Hernandez, J.s. Notario Del Pino, R. Diaz Diaz, M. M. Gonzalez MartinAbstract:Abstract The exchange properties of Tenerife Phillipsite in the NH4Na system have been studied. Exchange isotherms at 20, 37 and 50°C show that Phillipsite prefers NH4+ over Na+ at any given temperature. The selectivity coefficient (Ks) decreases with temperature. Thermodynamic data for the reaction (equilibrium constant, standard enthalpy and standard entropy) are also provided. The kinetics of NH4+ release from Phillipsite previously saturated with (NH4)2SO4 includes two stages. The exchange and the release properties of Tenerife Phillipsite with regard to the NH4+ ion are favourable for its use in wastewater treatment and for preparing slow-release fertilizers.
Carmine Colella - One of the best experts on this subject based on the ideXlab platform.
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Ion exchange behaviour of two synthetic Phillipsite-like phases
Studies in Surface Science and Catalysis, 2002Co-Authors: Carmine Colella, B. De Gennaro, Barbara Liguori, E. TorraccaAbstract:Two Phillipsite-like phases have been synthesized at 80°C treating a rhyolitic pumice in a mixed Na + -K + alkaline environment, having different Na + /K + molar ratios. The synthesized samples, displaying distinct X-ray diffraction patterns, have been characterized as regards their ion exchange properties. Ion exchange isotherms for the cation pairs Na/NH 4 , Na/Ba, Na/K and Na/Ca have been obtained and the relevant thermodynamic equilibrium constants calculated with the help of a computer program. Both Phillipsite-like phases revealed an excellent to good selectivity for Ba, NH 4 and K and a substantial unselectivity for Ca, in substantial accordance with previous results obtained with a sedimentary Phillipsite. Nevertheless, the different shapes of some isotherms and therefore the different occupancy of peculiar ion exchange sites indicate that the two synthetic Phillipsites are structurally distinct, even if this supposition should be confirmed by a structural analysis.
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ion exchange selectivity of Phillipsite for cs a structural investigation using the rietveld method
Microporous and Mesoporous Materials, 1999Co-Authors: Alessandro F. Gualtieri, Domenico Caputo, Carmine ColellaAbstract:Abstract Different ion exchange selectivities for Cs of two Phillipsites, one sedimentary and one synthetic, having similar framework compositions, were interpreted by means of Rietveld structural analysis. Both Phillipsites were pre-exchanged to achieve Na forms throughout exhaustive elution using an NaCl solution and then enriched in Cs by contact with mixed Cs + and Na + solutions. X-ray diffraction data of the original and Cs-exchanged samples were refined using the Rietveld method. Four extra-framework sites labelled I, II, II′, and II″ were refined. Cation distribution in the four sites showed that, although sites I and II are readily occupied by Cs, some Na is prone to be retained in site II′, which displays therefore a reduced selectivity for Cs. The new site II″ is occupied by Cs. The synthetic sample retains much more Na than the sedimentary sample, and this is the reason for the higher selectivity of the sedimentary Phillipsite for Cs compared with the synthetic one. The results of this work also suggest that Phillipsite may be utilized as a selective cation exchanger for the removal of Cs + radionuclide in nuclear waste.
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Ion exchange selectivity of Phillipsite for Cs and Sr as a function of framework composition
Microporous and Mesoporous Materials, 1999Co-Authors: M. Adabbo, Domenico Caputo, B. De Gennaro, Michele Pansini, Carmine ColellaAbstract:Abstract Cs and Sr exchange reactions for Na on sedimentary, hydrothermal and synthetic Phillipsites are studied by determining their exchange isotherms at 25°C and 0.1 total normality, and computing the related thermodynamic quantities K a and Δ G °. Sedimentary and synthetic Phillipsite, characterized by a higher Si/Al ratio, display good selectivity for Cs and moderate selectivity for Sr. The more aluminous hydrothermal Phillipsite displays a lower selectivity for Cs and a higher selectivity for Sr than sedimentary and synthetic Phillipsite do. These results, perfectly explainable in terms of field strength of the anionic zeolite framework and of ion charge density, demonstrate that the joint removal of Cs and Sr from water by Phillipsite would be possible, provided cheap widespread aluminous Phillipsite-rich materials were available.
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Ion exchange selectivity of Phillipsite for Cs+: a structural investigation using the Rietveld method
Microporous and Mesoporous Materials, 1999Co-Authors: Alessandro F. Gualtieri, Domenico Caputo, Carmine ColellaAbstract:Abstract Different ion exchange selectivities for Cs of two Phillipsites, one sedimentary and one synthetic, having similar framework compositions, were interpreted by means of Rietveld structural analysis. Both Phillipsites were pre-exchanged to achieve Na forms throughout exhaustive elution using an NaCl solution and then enriched in Cs by contact with mixed Cs + and Na + solutions. X-ray diffraction data of the original and Cs-exchanged samples were refined using the Rietveld method. Four extra-framework sites labelled I, II, II′, and II″ were refined. Cation distribution in the four sites showed that, although sites I and II are readily occupied by Cs, some Na is prone to be retained in site II′, which displays therefore a reduced selectivity for Cs. The new site II″ is occupied by Cs. The synthetic sample retains much more Na than the sedimentary sample, and this is the reason for the higher selectivity of the sedimentary Phillipsite for Cs compared with the synthetic one. The results of this work also suggest that Phillipsite may be utilized as a selective cation exchanger for the removal of Cs + radionuclide in nuclear waste.
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Evaluation of Phillipsite as cation exchanger in lead removal from water
Microporous Materials, 1996Co-Authors: Michele Pansini, Domenico Caputo, Carmine Colella, M. De'gennaro, Alessio LangellaAbstract:Abstract The ability of Phillipsite to remove lead from water was evaluated by determining lead exchange isotherms with sodium- or potassium-exchanged Phillipsite and by studying the kinetics of sodium exchange for lead and, lastly, by testing lead uptake in a column, in which fixed beds of sodium-enriched Phillipsite tuff grains were percolated by lead-containing solutions. The collected data evidenced a remarkable selectivity of sodium Phillipsite for lead in equilibrium experiments, fast kinetics, and massive lead removal from water in column runs, even in the presence of substantial amounts of sodium as interfering cation. The favourable lead elution during regeneration of exhausted Phillipsite together with the above mentioned results in the exchange experiments allow to forecast a profitable utilization of Phillipsite in lead removal from waste water.
Kunihiro Fukui - One of the best experts on this subject based on the ideXlab platform.
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synthesis of zeolite from coal fly ash by microwave hydrothermal treatment with pulverization process
Advanced Powder Technology, 2017Co-Authors: Tomonori Fukasawa, Achmad Dwitama Karisma, Daiki Shibata, Anni Huang, Kunihiro FukuiAbstract:Abstract Coal fly ash was hydrothermally treated with a NaOH aqueous solution at 373 K using microwave heating with zirconia beads. We investigated the effect of the pulverization of coal fly ash on the generation rate and crystalline phase of synthesized zeolite. As a result, it was found that the pulverization process increased the generation rate of Phillipsite in the early stage of the hydrothermal treatment because it enhances the dissolution of aluminate and silicate ions from coal fly ash and the generation rate of the aluminosilicate-gel precursor. On the other hand, prepulverization before the hydrothermal treatment and long-term pulverization during the hydrothermal treatment promote the formation of hydroxysodalite rather than Phillipsite. In addition, we examined the effect of the addition of an aluminum source on the yield of synthesized Phillipsite. This examination revealed that the excess addition of aluminate ions promotes the generation of hydroxysodalite and that timely and proper addition improves the yield of synthesized Phillipsite. From these results, it was concluded that pulverization in the early stage of the hydrothermal treatment is effective for the generation of Phillipsite from coal fly ash. Moreover, the timely and proper addition of an aluminum source improves the yield of synthesized Phillipsite.
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Utilization of NaCl for Phillipsite synthesis from fly ash by hydrothermal treatment with microwave heating
Advanced Powder Technology, 2009Co-Authors: Kunihiro Fukui, Manabu Katoh, Tetsuya Yamamoto, Hideto YoshidaAbstract:Abstract The coal fly ash was treated hydrothermally with the mixture of NaOH aqueous solution and NaCl aqueous solution at 373 K, using the microwave heating and the conventional heating in order to clarify influences of the NaCl concentration in the hydrothermal solution on the growth rate and the crystalline phase of synthesized zeolites. As a result, it was found that Phillipsite crystallinity of product powder increases with the additive NaCl concentration in the hydrothermal solution when the concentration of NaOH is so low as not to generate the zeolite from fly ash. On the other hand, in case that NaOH concentration is relatively high, the addition of NaCl to the hydrothermal solution using the conventional heating hardly affects Phillipsite crystallinity of product powder; however, the generation of hydroxysodalite is enhanced by the microwave heating. Moreover, it was revealed that the necessary treatment time to complete the crystallization of Phillipsite increases with increasing concentration of NaCl in the hydrothermal solution. This is because the substitution of NaCl for NaOH reduces the dissolution rate of aluminate and silicate ions from fly ash and the generation rate of the precursor aluminosilicate gel. However, this delay of the completion of the crystallization can be shortened by the microwave heating method. These experimental results concluded that the utilization of NaCl for the hydrothermal solution is effective in Phillipsite synthesis from fly ash only when the NaOH concentration is relatively low in the hydrothermal solution and especially, when the microwave heating is used.
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improvement in the purity and yield of Phillipsite synthesized from incineration ash with multi stages synthesis method
Journal of The Society of Powder Technology Japan, 2005Co-Authors: Kunihiro Fukui, Mayumi Takiguchi, Tatsunori Noriyasu, Hideto YoshidaAbstract:This paper proposes a new multi-stage synthesis method of Phillipsite at a high purity and an improved yield from coal fly ash and rice husk ash. Fly ashes are treated hydrothermally with NaOH solution to form aluminate ion and silicate ion and they are separated from insoluble residues of fly ash for the preparation of Phillipsite. The products of Phillipsite obtained from coal fly ash and rice husk ash are over 90% in purity and the adsorption performance is comparable to the artificial zeolite available on the market. Total yield of Phillipsite is also improved to 35.0% from 25.0% which was attained in our previous work (Fukui, et al., J. Society of Powder Technology, Japan, 40, 497-504, 2003). It is also found that the aluminate ion concentration is higher at a higher NaOH concentration and that the generated amount of Phillipsite increases with the aluminate ion concentration.
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selective synthesis of Phillipsite from fly ash and rice husk ash prepared by hydrothermal treatment
Journal of The Society of Powder Technology Japan, 2004Co-Authors: Kunihiro Fukui, Mayumi Takiguchi, Tatsunori Noriyasu, Masashi Ugumori, Hideto YoshidaAbstract:Zeolites were synthesized trom the mixture of the fly ash with a relatively low silica content and the rice husk ash by a hydrothermal treatment method. The fraction of Phillipsite in the formed zeolite was increased with the fraction of rice husk ash whereas the fraction of by-product hydroxysodalite was decreased. Phillipsite can be selectively synthesized from the mixture, using new or recycled NaOH aqueous solutions. It is found that the product powder prepared from the mixture of the fly ash and the rice husk ash has almost the same ammonium ion adsorption capacity as the product from the mixture of the fly ash and pure silica powder. Phillipsite can be synthesized from the mixture of the fly ash and the rice husk ash for shorter treatment time than that from the mixture of the fly ash and pure silica powder, being independent of NaOH concentration.
Elio Passaglia - One of the best experts on this subject based on the ideXlab platform.
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Natural zeolite (chabazite/Phillipsite) dietary supplementation influences faecal microbiota and oxidant status of working dogs
Italian Journal of Animal Science, 2016Co-Authors: Paola Superchi, Elio Passaglia, R. Saleri, Maria Cristina Ossiprandi, Enzo Riccardi, V. Cavalli, Valentino Beretti, Alberto SabbioniAbstract:AbstractWe evaluated whether chabazite/Phillipsite dietary supplementation might affect the faecal microbiota, oxidant and antioxidant status of working dogs at rest undergone to a trial test. Forty English Setter dogs were involved in two replicate trials. At each replicate, dogs were divided into two homogeneous groups (10 dogs/group). During a period of 28 days, diet was supplemented (Z group) or not supplemented (C group) with chabazite/Phillipsite at the dose of 5 g/head/day. On day 29, dogs were subjected to a trial test. Faecal characteristics were assessed at 0 and 29 days (within two hours from the end of the trial test). Faecal consistency was not affected by dietary supplementation (p > .05). On day 29, Lactobacillus spp. and Enterococcus spp. counts were higher and Enterobacteriaceae were lower in Z than in C group (p
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NH4 exchange in chabazite, heulandite–clinoptilolite, and Phillipsite
Rendiconti Lincei, 2013Co-Authors: Elio Passaglia, Angela LauroraAbstract:In order to evaluate the NH4 exchange capacity of the chabazite, heulandite–clinoptilolite, and Phillipsite zeolite species, crystals of “amygdaloidal” occurrence with different chemical compositions were treated in batch (static method) and in column (dynamic method) with 1 N NH4Cl solution in varying experimental conditions (temperature, grain size). The degree of exchange was expressed as the percentage of each exchanged cation (Ca, Na, and K) with respect to the theoretical value calculated from the original chemical composition. The total percentage of the exchanged cations was also reported. The 70 °C static treatments evidenced that the exchange was especially high in chabazite. At the same temperature the exchange increased in heulandite–clinoptilolite at decreasing grain size. With respect to the 70 °C treatments, the room temperature static treatments showed a lowered exchange in Phillipsite and heulandite–clinoptilolite, and subordinately in chabazite. In the dynamic treatments, the exchange was significantly higher in chabazite than in Phillipsite and heulandite–clinoptilolite, and increased at decreasing grain size. On the whole, chabazite revealed the highest degree of exchange. The exchange capacity was slightly influenced by the Si/(Si + Al) ratio, and strongly influenced by the type of exchangeable cation present in the examined zeolite species, since the degree of Na and K exchange is generally higher than that of Ca. The ratio between divalent and monovalent cation exchange resulted to be roughly correlated to the total degree of exchange, thus suggesting that kinetic factors are involved in the monovalent vs. divalent cation exchange processes, also according to their ionic potential values.
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nh4 exchange in chabazite heulandite clinoptilolite and Phillipsite
Rend. Fis. Acc. Lincei, 2013Co-Authors: Elio Passaglia, Angela LauroraAbstract:In order to evaluate the NH4 exchange capacity of the chabazite, heulandite–clinoptilolite, and Phillipsite zeolite species, crystals of “amygdaloidal” occurrence with different chemical compositions were treated in batch (static method) and in column (dynamic method) with 1 N NH4Cl solution in varying experimental conditions (temperature, grain size). The degree of exchange was expressed as the percentage of each exchanged cation (Ca, Na, and K) with respect to the theoretical value calculated from the original chemical composition. The total percentage of the exchanged cations was also reported. The 70 °C static treatments evidenced that the exchange was especially high in chabazite. At the same temperature the exchange increased in heulandite–clinoptilolite at decreasing grain size. With respect to the 70 °C treatments, the room temperature static treatments showed a lowered exchange in Phillipsite and heulandite–clinoptilolite, and subordinately in chabazite. In the dynamic treatments, the exchange was significantly higher in chabazite than in Phillipsite and heulandite–clinoptilolite, and increased at decreasing grain size. On the whole, chabazite revealed the highest degree of exchange. The exchange capacity was slightly influenced by the Si/(Si + Al) ratio, and strongly influenced by the type of exchangeable cation present in the examined zeolite species, since the degree of Na and K exchange is generally higher than that of Ca. The ratio between divalent and monovalent cation exchange resulted to be roughly correlated to the total degree of exchange, thus suggesting that kinetic factors are involved in the monovalent vs. divalent cation exchange processes, also according to their ionic potential values.
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Ion exchange selectivity of Phillipsite
Studies in Surface Science and Catalysis, 2002Co-Authors: Alessandro F. Gualtieri, Elio Passaglia, Ermanno GalliAbstract:Phillipsite is one of the main components of the sedimentary zeolite-rich rocks called zeolitites used in a variety of applications (i.e., in the field of pollution abatement and agriculture) The interest for the understanding of the cation exchange properties for a proper and efficient use in industrial applications prompted in 1995 a long term project on the systematics of cation exchanged Phillipsites, their crystal chemistry and properties. Natural Phillipsite samples with different Si/(Si+Al) ratio were selected for the research project and exchanged with a number of either monovalent and divalent cations. In this paper we describe a general picture of the changes which occur in the structure of Phillipsite in response to the cation exchange either in terms of framework relaxation/contraction and cation migration, ion exchange selectivity and properties, and their prediction.
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Rietveld structure refinement of Sr-exchanged Phillipsites
Microporous and Mesoporous Materials, 1999Co-Authors: Alessandro F. Gualtieri, Elio Passaglia, Ermanno Galli, Alberto VianiAbstract:Abstract The structures of three Sr-exchanged Phillipsites with different Si/(Si+Al) ratio were refined by the Rietveld method on data collected with a conventional Bragg–Brentano geometry. The distribution of Sr in the extra-framework sites depends on its amount in the sample and hence on the value of Si/(Si+Al). The typical P 2 1 / m cell with Sr distributed over sites I and II is displayed in the two samples with Si/(Si+Al)=0.72 and 0.76 respectively. The sample with Si/(Si+Al)=0.63 instead undergoes a cell modification with Sr distributed in an ordered fashion in sites I, I′, II, and II′ of four adjacent cavities along the a axis. This ordered site distribution has the effect of changing the typical unit cell with a ≈9.8 A, b ≈14.0 A, c ≈8.6 A, and β ≈124° to a pseudo B-centered monoclinic cell with a ≈16.5 A, b ≈14.0 A, c ≈8.6 A, and β ≈99.4°. Nevertheless, the B-centering is broken by the ordered extra-framework site distribution. This study may help in the understanding of the interaction mechanism of Sr-cation exchange in Phillipsite for the potential use as a countermeasure amendment in radiostrontium-contaminated soils, and as sieve for 90 Sr in natural waters of nuclear facilities.