Synthesis of Hydroxy Sodalite from Coal Fly Ash for Biodiesel Production from Waste-Derived Maggot Oil

Abstract

Zeolites are aluminosilicate crystalline materials known for their unique characteristics, and have been prominent for nearly half a century due to their wide and important industrial applications. The production of zeolites, however, remains a challenge due to the high cost of commercial reagents conventionally used as feedstocks. In the current study, hydroxy sodalite (HS) zeolite samples were synthesised from coal fly ash feedstock by a direct hydrothermal synthesis method. The effects of hydrothermal crystallisation synthesis time on phase crystallinity, crystal size, and morphology of the formed HS were investigated. The prepared samples were characterised using XRD, SEM, EDS and FT-IR techniques. The XRD results of the samples prepared with varying synthesis times confirmed the formation of HS from low to high phase purity and crystallinity from 11 to over 98%. The SEM results reflected gradual variation in crystal morphology, of which highly crystalline HS samples were associated with hexagonal-cubic and cubic-platelet crystals. The FTIR, depicting zeolite characteristics of T-O and T-O-T stretching vibrations in the molecular framework, further confirmed the formation of HS zeolites for samples obtained above the 24-h synthesis time. These zeolite samples were then evaluated for their catalytic activities in the conversion of maggot oil to biodiesel. The application of the various hydroxy sodalite samples for the transesterification of maggot oil yielded up to 84.10% biodiesel (FAME) with physicochemical properties that were in compliance with the biodiesel specification standards. This study investigated the novel use of a coal fly ash-derived, heterogeneous HS catalyst in biodiesel production from maggot oil, and indicates its potential to enhance biodiesel yield and quality upon process optimisation tests.

Hydrothermal Synthesis of Sodalite-Type N-A-S-H from Fly Ash to Remove Ammonium and Phosphorus from Water

“…The T-O asymmetric stretching vibrational region corresponding to the SOD is shifted to 991 cm −1 due to the incorporation of aluminum atoms into the tetrahedral framework. The internal bending vibration of the two samples T-O is between 450 and 500 cm −1 [ 31 ]. The continuous bands are detected by SOD at 660 and 720 cm −1 correspond to the bicyclic vibrations of tetrahedral Si-O and Si-O-Al, respectively.…”

Use of synthetic zeolite materials from fly ash to remove copper(II) ions from aqueous solutions

“…The bands at 1095 cm -1 can be attributed to the quartz phase presence (Malonda Shabani et al, 2019). Si-or Al-O bending vibrations were detected between 450-500 cm -1 (Malonda Shabani et al, 2019;Alehyen et al, 2017;Ojha et al, 2004). There are no significant differences between FTIR spectra for raw fly ash and fly ash after Cu(II) adsorption.…”

“…In the case of FTIR spectra measured for fly ash from Turów coal-powered power station (FA1), there are distinctive peaks at 1060 cm -1 , 750 cm -1 , 550 cm -1 and 450 cm -1 . The bands at 1095 cm -1 can be attributed to the quartz phase presence (Malonda Shabani et al, 2019). Si-or Al-O bending vibrations were detected between 450-500 cm -1 (Malonda Shabani et al, 2019;Alehyen et al, 2017;Ojha et al, 2004).…”

“…The characteristic FT-IR vibration bands and their interpretation for fly ash and zeolite were presented in Table 4 ( Malonda Shabani et al, 2019;Alehyen et al, 2017;Polowczyk et al, 2017;Hałas et al, 2017;Król et al, 2016;Naikoo, 2016;Chindaprasirt et al, 2009;Ojha et al, 2004;Barnett et al, 2002;Henmi, 1987). Detailed description of individual bands of fly ashes and zeolite materials before and after Cu(II) adsorption are discussed below.…”

Synthesis of Hydroxy-Sodalite from Rice Husk Silica and Food-Grade Aluminum Foil as A Catalyst for Biomass Pyrolysis

“…Hydroxy-sodalite (HS) is a type of synthetic zeolite with structural network characterized by varied ordered channel-like structures and different particle sizes. This unique network arrangement provides hydroxy-sodalite with characteristics suitable for diverse applications such as adsorbent for elimination of heavy metals from water [1][2][3], ion exchange agent [4], catalyst [5][6][7], and membrane [8,9]. Several preparation methods have been developed, such as in situ hydrothermal synthesis [2][3][4], vapor phase transport method [10], secondary growth method [11] or embedding microcrystals of zeolite into a matrix [12].…”