ALVES, Ana paula Melo. Vermiculitas tratadas quimicamente na obten??o de s?lidos microporosos como precursores para h?bridos inorg?nico-org?nicos com aplica??es adsortivas. 2009. 124 f. Tese (Doutorado em Quimica) - Centro de Ci?ncias Exatas e da Natureza, Universidade Federal da Para?ba, Jo?o Pessoa, PB, 2009. / Submitted by Sonia Leite (sonia@geologia.ufrn.br) on 2010-09-27T16:18:21Z No. of bitstreams: 2 2000Tese_AnaPaulaMAlves.pdf: 2643720 bytes, checksum: 1e6e5bae6c1a2fb7113b073819b6445a (MD5) license_rdf: 19710 bytes, checksum: aa65da15f424ff71c620a992a187295c (MD5) / Rejected by clediane guedes(clediane@bczm.ufrn.br), reason: ALVES dever? est? em mai?sculo on 2010-09-27T18:01:29Z (GMT) / Submitted by Sonia Leite (sonia@geologia.ufrn.br) on 2010-09-27T18:28:33Z No. of bitstreams: 2 2000Tese_AnaPaulaMAlves.pdf: 2643720 bytes, checksum: 1e6e5bae6c1a2fb7113b073819b6445a (MD5) license_rdf: 19710 bytes, checksum: aa65da15f424ff71c620a992a187295c (MD5) / Approved for entry into archive by clediane guedes(clediane@bczm.ufrn.br) on 2010-09-30T12:05:26Z (GMT) No. of bitstreams: 2 2000Tese_AnaPaulaMAlves.pdf: 2643720 bytes, checksum: 1e6e5bae6c1a2fb7113b073819b6445a (MD5) license_rdf: 19710 bytes, checksum: aa65da15f424ff71c620a992a187295c (MD5) / Made available in DSpace on 2010-09-30T12:05:26Z (GMT). No. of bitstreams: 2 2000Tese_AnaPaulaMAlves.pdf: 2643720 bytes, checksum: 1e6e5bae6c1a2fb7113b073819b6445a (MD5) license_rdf: 19710 bytes, checksum: aa65da15f424ff71c620a992a187295c (MD5) / A lixivia??o seletiva de argilominerais ? um m?todo importante na prepara??o de silicatos porosos constituindo-se em uma rota simples, efetiva e de baixo custo. Neste estudo a vermiculita foi submetida a tratamento ?cido com acido n?trico nas concentra??es 1, 2, 3 e 4 mol dm-3, originando os s?lidos precursores denominados VacX (x=1 a 4), respectivamente. As matrizes ativadas e a vermiculita reagiram covalentemente com os organosilanos aminopropil-, propiletilenodiamino-,propildietilenotriamino- e glicid?xipropiltrimetoxissilano (GPTS) atrav?s dos grupos metoxilas do silano e as hidroxilas da superf?cie das matrizes. O h?brido Vac3G, derivado da silaniza??o do Vac3 com GPTS, sofreu rea??es subseq?entes com as diaminas etil, propil, butildiamina e 2-aminopiridina, possibilitando a entrada de novos centros b?sicos. Os diversos s?lidos foram caracterizados por an?lise qu?mica, espectroscopia na regi?o do IV, DRX, RMN 29Si e 27Al, MEV, volume de poro e ?rea superficial. A lixivia??o da vermiculita s?dica originou s?lidos porosos reestruturados com elevadas ?reas superficiais cujos valores foram 133, 334, 673 e 575 m2 g-1 para os s?lidos Vac1, Vac2, Vac3 e Vac4,respectivamente. Independentemente do s?lido, observou-se que ? medida que a lixivia??o se torna mais acentuada, houve um aumento na reatividade das matrizes ativadas em rela??o ? vermiculita original, sendo a matriz Vac3 a mais reativa diante das rea??es aqui propostas. Todos os s?lidos modificados apresentaram altos teores de grupos org?nicos incorporados. A s?rie de vermiculitas modificadas com o grupo aminopropil foi utilizada para a adsor??o de c?tions divalentes de cobre e n?quel em solu??o aquosa, mostrando maior afinidade para os ?ons de Ni2+(aq) do que para Cu2+(aq) como ilustrado pelos valores Nf de 2,97 e 1,23 mmol g-1, respectivamente. Os s?lidos porosos argilosos derivados de tratamento ?cido da vermiculita s?o substratos potenciais para imobiliza??o de silanos apresentando importantes aplica??es como adosrventes para esp?cies poluentes como metais pesados. ABSTRACT: The selective leaching of clay minerals is an important method in the preparation of porous silicates presenting as a simple, effective and low cost route. In this study, vermiculite was submitted to acid treatment at concentrations 1, 2, 3, and 4 mol dm-3, resulting the precursor solids named as VacX (x=1 a 4), respectively. The lixiviated matrices and vermiculite reacted covalently with the organosilanes aminepropyl-, propyletilenediamine-, ropyldietilenetriamine- and glycidoxypropyltrimethoxisilane (GPTS). The hybrid Vac3G, derived from silanization reaction between Vac3 and GPTS, was submitted to subsequent reactions with ethyl, propyl, butyldiamines and 2- aminepiridine resulting in the entrance of new basic centres. The products were characterized by chemical analysis, infrared spectroscopy, X-ray diffraction, 29Si and 27Al NMR in solid state, SEM, and pore volume and surface area determination. The lixiviation of sodic vermiculite originated the restructured porous solids with high superficial area showing the values133, 334, 673 e 575 m2 g-1 for VacX where X = 1,2,3,4, respectively. These solids and sodic vermiculite reacted covalently with each organosilane through methoxyl groups of silane and the hydroxyl surface of matrices. Independently of solid, it was observed that the lixiviation favored the reactivity of activated matrices compared with sodic vermiculite, showing the Vac3 as more reactive comparing with others solids. All modified solids presented high nitrogen content showing the values of 6,31 %. The set of modified vermiculites containing aminepropyl group was applied as adsorbent for divalent cations as copper and nickel in aqueous solution. These solid showed highest affinity for Ni2+ than Cu2+ ions as illustrated by Nf values of 2,97 and 1,23 mmol g-1, respectively. Clay porous solids obtained of leaching treatment of vermiculite are potential substrates for grafting of silanes showing important applications as adsorbents for contaminant species as heavy metals

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-06-03T23:35:59Z No. of bitstreams: 1 IzabelCristinaMedeirosCosta_DISSERT.pdf: 7508849 bytes, checksum: baba9399e7458c8670380f1bc49a950c (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-06-07T00:21:16Z (GMT) No. of bitstreams: 1 IzabelCristinaMedeirosCosta_DISSERT.pdf: 7508849 bytes, checksum: baba9399e7458c8670380f1bc49a950c (MD5) / Made available in DSpace on 2016-06-07T00:21:16Z (GMT). No. of bitstreams: 1 IzabelCristinaMedeirosCosta_DISSERT.pdf: 7508849 bytes, checksum: baba9399e7458c8670380f1bc49a950c (MD5) Previous issue date: 2015-11-30 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) / Neste trabalho foi realizado um estudo dos par?metros de s?ntese da ze?lita MCM-22 (estrutura MWW) com o intuito de otimizar a obten??o deste material e aumentar sua acessibilidade, tanto pelo aumento de superf?cie externa, quanto pela gera??o de mesoporos. Foram realizadas s?nteses de rela??o Si/Al= 15 e Si/Al=50 sob condi??es est?ticas em diferentes temperaturas e com indu??o por sementes, as quais resultaram em MCM-22 pura e cristalina de rela??o Si/Al= 15 em 3 dias e Si/Al=50 em 11 dias. A redu??o do teor de hexametileneimina (HMI) foi estudada na s?ntese em agita??o. As condi??es de redu??o foram de 30 % de HMI na s?ntese padr?o de 7 dias e em s?ntese empregando sementes com tempos de 1, 2, 3 e 4 dias. Redu??o de 45 % de HMI com adi??o de ?gua-m?e e tempos de 2, 4, 5 e 7 dias. Quanto ao aumento de acessibilidade na MCM-22, buscou-se aumentar a velocidade de cristaliza??o e redu??o do tempo, com o objetivo de se obter cristais de menor tamanho. Alguns agentes foram empregados para acelerar a obten??o da MCM-22, foram estes as sementes, ?gua-m?e, incremento de temperatura e dissolu??o da s?lica. Com rela??o ainda ao aumento de acessibilidade na MCM-22, foram estudados tratamentos ?cidos para retirada de alum?nio e gera??o de mesoporos e a silaniza??o de proto-unidades zeol?ticas, que atua tamb?m na forma??o de mesoporos e na diminui??o dos cristais. O tratamento com ?cido ox?lico de concentra??o 0,5 mol/ L resultou na forma??o de mesoporos de 3 nm e a s?ntese empregando a silaniza??o de proto-unidades zeol?ticas de pr?-cristaliza??o de tr?s dias resultou na redu??o de 70 % no tamanho dos cristais e em poros mais abertos, com alguns destes com di?metros na faixa de mesoporos (2,6 nm). / In this paper a synthesis parameters study was conducted in order to optimize the obteinment of MCM-22 (MWW structure) and increase its accessibility, getting higher external surface and generating mesopores. Syntheses with Si / Al = 15 and Si / Al = 50 ratios were performed under static conditions at different temperatures and with seeds induction, which resulted in MCM-22 pure and crystalline (Si / Al ratio = 15) after 3 days and Si / Al = 50 after 11 days. The reduction of hexamethyleneimine content (HMI) was studied in the stirring synthesis and a HMI reduction of 47% was possible through the mother liquor reuse, in addition, a specific area of 481 m? / g has been obtained in the fourth synthesis day. Regarding the increase of accessibility of the MCM-22 zeolite skeins of MCM-22 plates with about 2 ?m were obtained, through the use of dissolved silica, addition of seeds, increased temperature and synthesis time of 2 days. A significant value of specific area was found for this material, around 500 m? / g. Also with respect to the increase of MCM-22 accessibility, treatment with oxalic acid concentration of 0.5 mol / L and silanization of proto-zeolitic units resulted in the mesopores formation . Furthermore, silanization still favored reduction of 70 % in crystal size and a specific area of 566 m? / g.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-05-30T22:35:15Z No. of bitstreams: 1 AnelieseLunguinhoFigueiredo_TESE.pdf: 2224810 bytes, checksum: a3cbfc32831dba5f9b8a0085f1244167 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-06-01T19:31:41Z (GMT) No. of bitstreams: 1 AnelieseLunguinhoFigueiredo_TESE.pdf: 2224810 bytes, checksum: a3cbfc32831dba5f9b8a0085f1244167 (MD5) / Made available in DSpace on 2016-06-01T19:31:41Z (GMT). No. of bitstreams: 1 AnelieseLunguinhoFigueiredo_TESE.pdf: 2224810 bytes, checksum: a3cbfc32831dba5f9b8a0085f1244167 (MD5) Previous issue date: 2015-07-24 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / As ze?litas s?o amplamente utilizadas pela ind?stria em processos de cat?lise, adsor??o, separa??o e troca i?nica. No entanto, a presen?a apenas de microporos limita a difus?o de mol?culas volumosas em seus canais, favorecendo a ocorr?ncia de rea??es indesej?veis devido ao longo tempo de resid?ncia dos reagentes e produtos ao serem transportados ao longo dos microporos das ze?litas. Com o intuito de superar este problema, foram estudados neste trabalho m?todos de s?ntese para a obten??o da ze?lita ZSM-5 nanocristalina com porosidade hier?rquica sintetizada na aus?ncia de direcionador org?nico de estrutura. Primeiramente foi realizada a s?ntese da ze?lita ZSM-5 atrav?s do m?todo assistido por sementes em um sistema ausente de direcionador org?nico, onde as amostras foram sintetizadas utilizando tr?s tipos diferentes de sementes: duas destas baseadas em solu??es aquosas claras contendo os precursores de ZSM-5 (n?o silanizada e silanizada) e a terceira semente baseada em uma ze?lita ZSM-5 comercial na forma de p?, a fim de direcionar na forma??o da estrutura MFI. O segundo m?todo empregado foi o processo de silaniza??o, utilizando como agente silanizante o fenilaminopropiltrimetoxisilano (PHAPTMS), com a finalidade de diminuir ou impedir o crescimento dos cristais ze?liticos da ZSM-5, favorecendo a obten??o de cristais com menores dimens?es. A s?ntese da ZSM-5 tamb?m foi realizada na aus?ncia de direcionador org?nico a 180?C por 27 horas ap?s a adi??o do PHAPTMS. Todas as amostras sintetizadas foram caracterizadas por diversas t?cnicas, dentre elas a Difra??o de Raios-X (DRX), Espectroscopia na regi?o do Infravermelho com Transformada de Fourier (FTIR), adsor??o-dessor??o de Arg?nio (Ar), Microscopia Eletr?nica (SEM e TEM) e dessor??o a temperatura programada TPD-NH3. Notou-se que o uso de sementes proporciona uma maior ?rea espec?fica BET e provoca um aumento na ?rea externa, devido ? diminui??o do tamanho dos cristais. Da mesma forma para amostra funcionalizada com o agente silanizante (HZSM-5 (PHAPTMS)), que apresentou a mais, um duplo sistema de poros, o primeiro associado ? microporosidade da ze?lita ZSM-5 (0,5 - 2 nm) e o outro relacionado ? mesoporos intercristalinos (2 - 6 nm), confirmando a obten??o da ze?lita HZSM-5 hier?rquica. Todas as amostras sintetizadas apresentaram aglomerados globulares formados por pequenas nanounidades (30 - 90 nm), com morfologia e tamanho dos cristais diferentes da ze?lita HZSM-5 utilizada como refer?ncia. Os testes catal?ticos utilizando o craqueamento do polietileno de baixa densidade (PEBD) e o processo de pir?lise do poli(etileno tereftalato) - PET provaram que a melhoria nas propriedades texturais das ze?litas sintetizadas ? vantajoso em tais processos, apresentando um desempenho superior quando comparado ? amostra de refer?ncia, fornecendo produtos que podem ser utilizados como mat?rias-primas na ind?stria petroqu?mica. / Zeolites are widely used by the industry in catalysis processes, adsorption, separation and ion exchange. However, the presence of only micropores limits the diffusion of bulky molecules in their channels, favoring the occurrence of adverse reactions due to long residence time of the reactants and products are transported through the micropores of the zeolite. In order to overcome this problem has been studied in this work synthesis methods for obtaining hierarchical nanocrystalline ZSM-5 zeolite synthesized in the absence of organic template. First it carried out a synthesis of zeolite ZSM-5 by the seed-assisted method from an organic-templatefree system, where the samples were synthesized utilizing three different types of seeds: two of these based on aqueous clear solutions containing the ZSM-5 precursors (non-silanized and silanized) and the third seed based on a commercial ZSM-5 zeolite in powder form, in order to direct the formation of the MFI structure. The second method used was the silanization process, using as silanizante agent phenylaminopropyltrimethoxysilane (PHAPTMS), in order to lessen or prevent the growth of zeolitic crystals of ZSM-5, obtaining favoring smaller crystals. The synthesis of ZSM-5 was also performed in the absence of organic template 180?C for 27 hours after addition of PHAPTMS. All synthesized samples were characterized by several techniques, among them X Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Argon adsorption-desorption, Electronic Microscopy (SEM and TEM), and Temperature Programmed Desorption of Ammonia (NH3-TPD). It was noted that the use of seeds gives a higher BET surface area and causes an increase in the external surface area outside due to the decreasing size of the crystals. Similarly for sample functionalized with silanizante agent (MFI (PHAPTMS)), which is the lowest a dual system of pores, the first associated with the microporosity of the zeolite ZSM-5 (0.5 - 2 nm) and the other related to intercrystalline mesopores (2 - 6 nm), confirming the obtaining of HZSM-5 zeolite hierarchical. All samples were synthesized globular agglomerates formed by small nanounits (30 - 90 nm) with different size and morphology of crystals of zeolite HZSM-5 used as reference. The catalytic tests using the cracking of low density polyethylene (LDPE) and pyrolysis of poly(ethylene terephthalate) - PET proved that the improvement in the textural properties of the synthesized zeolite is advantageous in such processes, with a better performance when compared to the reference sample, generating products which can be useful feedstocks in the petrochemical industry.