Mechanism of Acid Activation of Magnesic Palygorskite

Abstract

Abstract--This paper compares the texture of palygorskite after acid leaching with that of the product after extraction silica is removed. These effects were evaluated on the basis of nitrogen adsorptiondesorption and mercury penetration porosimetry. Acid leaching at reflux temperature with 2 N HC1 resulted in an increase in surface area from 138 to 399 mVg, due to a partial (~ 50%) dissolution of the octahedral sheet and the creation of microporosity. This microporosity disappeared if the silica generated by the leaching was removed. The surface area also decreased from 399 to 214 mVg, and the pore volume decreased from 0.538 to 0.507 cm3/g. The microporosity must therefore have been due to texture development in the generated silica.

Caracterização Mineralógica, Morfológica E De Superfície Da Atapulgita De Guadalupe-Pi

“…A atapulgita ou paligorsquita é um argilomineral hidratado de magnésio e alumínio com morfologia microfibrosa, cargas superficiais baixas e alta área superficial (Neaman & Singer, 2004 (Corma, et al, 1987;Gonzalez, et al, 1989a;Gonzalez, et al, 1989b). Esta fórmula mostra que o argilomineral contém três formas de água na sua estrutura: (a) coordenada a cátions da folha octaédrica, (b) zeólitica presente nos canais no qual interage tanto com a molécula de H 2 O coordenada quanto a folha tetraédrica e (c) água hidroxila ligada à estrutura do argilomineral no centro da folha octaedrica de acordo Gionis, et al (2006).…”

“…A análise de capacidade de troca catiônica da atapulgita indicou que esta apresenta um excelente valor de troca com 40 meq/100g e este resultado se encontram dentro do valor de CTC esperado quando comparando com os dados da literatura (Chen & Wang, 2007;Chen, et al, 2011;Gonzalez, et al, 1989a…”

Benzene Uptake onto Modified Tea Waste: Perspective Applicability of Empirical Sorption Kinetic Models

“…Chemical and thermal reforms are the most common and frequent techniques applied on sorbents. Chemical treatment in sorbent modification is to enhance particle disaggregation, surface cleaning, removal of mineral impurities, partial dissolution of external layers and free silica generation (Gonzalez et al, 1989;Bhattacharyya and Gupta, 2009). Thermal reform of sorbent, that is, carbonization (biomass) or calcination (clay) improves it porosity hence the sorption capacity.…”

Effects of acid treatment on the clay palygorskite: XRD, surface area, morphological and chemical composition

“…Each talc-like ribbon alternates with channels along the fiber axis 2 . The palygorskite has the theoretical formula: Si 8 Mg 5 O 20 (OH) 2 (OH 2 ) 4 .4H 2 O, which was first proposed by Bradley [3][4][5] . However, the chemical composition of these mineral clays varies within certain limits according to their origin.…”