Hydrous non-crystalline phosphates: structure, function and a new white pigment

Abstract

Sólidos inorgânicos não-cristalinos hidratados são em grande parte negligenciados devido a pouca compreensão de suas complexas propriedades físico-químicas e estruturais. Apesar disso, eles apresentam uma química muito rica e vasta, de interesse tanto do ponto de vista científico como tecnológico. Este trabalho resenha as características gerais dos sólidos não-cristalinos hidratados, com ênfase especial nos (poli)fosfatos de alumínio. Variações nos precursores e concentração, temperatura, envelhecimento e pH da reação de formação podem propiciar a formação de uma miríade de funções e compostos diferenciados. Produtos adequados a diferentes aplicações, todos eles fosfatos de alumínio amorfos, exemplificam o enorme potencial dos sólidos não-cristalinos.Hydrated non-crystalline inorganic solids are often neglected due to the limited comprehension of their complex physico-chemical and structural properties. However, these non-crystalline materials exhibit a rich and varied chemistry, interesting for scientific and technological reasons. This work reviews general aspects of formation of hydrated non-crystalline solids, with special emphasis on aluminum (poly)phosphate materials. Precursors and concentration variations, temperature, ageing and reaction pH are trivial synthetic variables, but they promote the formation of a myriad of compounds adequate for many functions. Amorphous aluminum phosphates are widely employed in different industrial applications, providing good examples of the potential of hydrous amorphous solids.

Electrostatic Charging of Hydrophilic Particles Due to Water Adsorption

“…Amorphous aluminum phosphate is a developmental product supplied by Bunge. − Chemical composition is (Al(OH) 0.7 Na 0.7 (PO 4 )·1.7H 2 O), particle size in aqueous dispersion is 293 nm, and zeta potential is −25.2 mV both measured at pH 7.8 by acoustic and electroacoustic techniques, respectively, using a Dispersion Technology Spectrometer DT 1200 instrument.…”

Contrasting structure-property relationships in amorphous, hierarchical and microporous aluminophosphate catalysts for Claisen-Schmidt condensation reactions

“…In contrast Am AlPO and Am FeAlPO(5) materials exhibited a broad PSD curve which indicates the presence of an array of irregular mesopores in these materials. These mesopores are attributed to the inter particle volumes between AlPO4 particles after the condensation of hydroxyl groups [12,36].…”

Acid–Base Site Detection and Mapping on Solid Surfaces by Kelvin Force Microscopy (KFM)

“…28 Amorphous aluminum phosphate is a developmental product supplied by Bunge. 34 The chemical composition is Al(OH) 0.7 Na 0.7 (PO 4 )•1.7H 2 O; the average particle size in aqueous dispersion is 293 nm, and the zeta potential is −25.2 mV, both measured at pH 7.8, via acoustic and electroacoustic techniques, respectively, using a Dispersion Technology Spectrometer instrument (Model DT 1200).…”