High Surface Area Support/Catalyst Derived from Natural Pumice. Study of Pretreatment Variables

Abstract

The aim of this study was to obtain a catalyst or support material from a natural pumice that could then be used in the hydroisomerization of n-pentane. Acid treatment of the raw material with HCl was found to extract a larger amount of cations than NH 4 Ac (Ac ) acetate), yielding a product with a better developed texture and structure. The total number of protons present in the solution affects potassium extraction, while sodium is affected by both factors of concentration and volume of dissolution independently. The specific area of the material (meters squared per gram) obtained depends on the treatment conditions, and it value can be calculated by means of the treatment condition variables or by the total number of moles of the cations extracted. The treatments could be carried out by working at and above ambient temperatures and with and without fresh acid replacements. The optimum treatment for obtaining a catalytic support was 10 mL/g of pumice of 3 M HCl for 10 h with three replacements of fresh acid working at 70 °C.

Convenient conversion of hazardous nitrobenzene derivatives to aniline analogues by Ag nanoparticles, stabilized on a naturally magnetic pumice/chitosan substrate

“…Results conrmed the occupation of some of the internal pores aer composition with CTS and Ag nanoparticles. 59,60 Also, X-ray photoelectron spectroscopy (XPS) was employed to characterize the valence state of the Ag element ( Fig. 4d and e).…”

Pumice as a Remarkable Substrate for the Origin of Life

“…These grow alongside smectite clays when siliceous pumice reacts with alkaline waters (e.g., Tomita et al, 1993), forming infillings called amygdales. Interestingly, such zeolite minerals can greatly boost the catalytic activity of pumice during industrial processes today (Brito et al, 2004). Hence, zeolites (or ''silicalite zeolites'' with periodic Ti atoms in place of Si; e.g., Yamashita et al, 2007) are used for the synthesis of organic polymers (e.g., de Vos and Jacobs, 2001) as well as for the cracking of hydrocarbons and the commercial liberation of hydrogen gas (van Bekkam et al, 2001).…”

A Hydrothermal-Sedimentary Context for the Origin of Life

“…It can, however, naturally absorb organic carbon and phosphate (Brasier et al, 2013). Titanium oxide and zeolite coatings within the vesicles are known catalysts in industrial processes (Brandes et al, 1998; Brito et al, 2004 ). Thus, where flushed perhaps by hydrothermal fluids in shallow-water settings, organic molecules could penetrate into the porous rock.…”