Integrated Synthesis of Zeolites Using Coal Fly Ash: Element Distribution in the Products, Washing Waters and Effluent

Abstract

Coal fly ash has been proposed as an alternative raw material for zeolite synthesis, however, the mobilization of toxic elements of this material into zeolite products, washing water and effluent is rarely addressed. In this study, Brazilian coal fly ash was used in the integrated synthesis (two steps) of zeolites Na-P1 and 4A and the distribution of approximately 40 major, minor and trace elements was investigated in all the input and output flows involved in the process. The mobilization of several elements was observed in the zeolite products, a number of which are highly toxic, such as As, Cd, Cr, Ni and Pb. With regard to the amount present in the ash, both zeolites were enriched in several elements, such as Ni in zeolite Na-P1 and As in zeolite 4A. The latter exhibited high purity, with most of the elements investigated having concentrations close to those measured in commercial zeolite 4A. Important information was gathered regarding zeolite synthesis using fly ash, which will ensure safer application of these materials and, if necessary, propose a contaminant-free synthesis route.

Comparative lead adsorptions in synthetic wastewater by synthesized zeolite A of recycled industrial wastes from sugar factory and power plant

“…Zeolite A synthesis from CFA also consisted of two steps which were the raw material pretreatment and zeolite A synthesis shown in Figure 1 b. The purpose of pretreatment step by an acid washing method was the purification of raw material and increasing of mainly mass of silicon (Si) element for zeolite A synthesis by removing of contaminated elements such as copper (Cu), sodium (Na), chlorine (Cl), arsenic (As) [ 42 ]. For zeolite A synthesis, the modified method from Wang et al., 2008 [ 43 ] by alkaline fusion method followed by hydrothermal method was applied in this study.…”

Development of ZSM-22/Polyethersulfone Membrane for Effective Salt Rejection

“…Zeolites are alumina silicates materials widely used in ion exchanging, hydrocracking, adsorption and catalysis [42,43]. Recently, they have gained much consideration in the derivation of composite membrane materials owing to their external surface properties such as silinol, their negatively charged framework, shape selectivity and pore size exclusion [44][45][46][47]. These features promote high interaction between the polymer and additive as well with the solute cations and anions.…”

Síntesis De Zeolita Linde F Mediante Tratamiento Alcalino Con Potasa Caústica a Partir De Roca De Origen Volcánico Proveniente De Sillar, Perú; Su Aplicación en La Adsorción De Cobre(ii)

“…al. [11], indican que esta relación debe ser mayor a 89%, además de que estos elementos se encuentran presentes en minerales como el cuarzo (SiO2) y mullita (3Al2O3.2SiO2) y los compuestos que contienen Ca, Fe son impurezas que pueden limitar su aplicación en la síntesis de zeolitas.…”