Zeolitization of Diatomite Residues by a Simple Method

Abstract

The possibility of transforming a diatomite-rich waste from the brewing industry into synthetic zeolites has been investigated. After precalcination at 550 °C to eliminate the retained organic matter, the clean diatomite (Dt; with a Si/Al molar ratio of 17.4), was hydrothermally treated for 24 h with continuous stirring in a 3M NaOH solution at 80 °C. The results of mineralogical characterization by X-ray diffraction with Rietveld refinement have shown a crystallization of 55% of zeolite P, which was neoformed from the amorphous phase, opal-CT and quartz of the starting sample. The spectra obtained by Fourier Transform Infrared Spectrometry have corroborated such zeolitization. N2 adsorption–desorption isotherms have shown that the zeolitized material (Dt-Z) is mesoporous, with almost 60% more specific surface area than Dt (62.6 m2/g vs. 39.4 m2/g), greater microporosity and 40% smaller average pore size than Dt (71 Å vs. 118 Å). This study is a first approximation to know the potential of diatomite wastes as zeolite precursors, for which additional research including an aluminum source will be required.

Insight into the synergetic, steric and energetic properties of zeolitization and cellulose fiber functionalization of diatomite during the adsorption of Cd(ii): advanced equilibrium studies

“…24,30 The zeolitization transformation of siliceous diatomite frustules completely into synthetic zeolite phases or hybridized forms of zeolite/diatomite has been reported as a promising modication technique that strongly enhances the textural properties (surface area and porosity) as well as the physicochemical properties (adsorption, surface reactivity, and ion exchange capacity). [31][32][33] Moreover, the polymeric hybridization of such structures with the chains of the biopolymers (chitosan, cellulose, and b-cyclodextrin) commonly produces advanced structures that are characterized by signicantly enhanced adsorption capacity, biodegradability, and enrichment in the active sites. [34][35][36][37] Cellulose, cellulose-based materials, and cellulosefunctionalized materials were studied recently as promising eco-friendly materials in different medical and environmental applications.…”

Controllable Preparation of Zeolite-P/Calcined Diatomite with MgCl2

“…Hence, M-D samples can used as lter aids. Notably, the BET value of M-D-0.3 (237.47 m 2 /g) was larger than that of M-D-0 (119.02 m 2 /g), which was higher than the maximum S BET obtained by Du(Du et al, 2020) and Manuel(Manuel et al, 2022).…”

Synergetic and advanced isotherm investigation for the enhancement influence of zeolitization and β-cyclodextrin hybridization on the retention efficiency of U(vi) ions by diatomite

“…20,26 The phase conversion of such natural reactive forms of silica into different species of zeolite, either completely or partially in the form of zeolite/diatomite composite, was suggested in several studies as an effective approach to enhance the technical properties, including surface reactivity, surface area, porous structure, ion exchange capacities, and retention affinities. [27][28][29] Furthermore, the organic surcial modication or polymeric hybridizing processes, particularly using safe and eco-friendly biopolymers (cellulose, chitosan, and b-cyclodextrin), signicantly induce surface reactivity and the abundance of the numerous effective uptake sites on the surface of the silicate structures. This resulted in a promising hybridized adsorbent with enhanced uptake efficiency in addition to its environmental and biodegradable value.…”