Alkaline hydrothermal conversion of fly ash precipitates into zeolites 3: The removal of mercury and lead ions from wastewater

Abstract

Filtrates were collected using a codisposal reaction wherein fly ash was reacted with acid mine drainage. These codisposal filtrates were then analyzed by X-ray Fluorescence spectrometry for quantitative determination of the SiO 2 and Al 2 O 3 content. Alkaline hydrothermal zeolite synthesis was then applied to the filtrates to convert the fly ash material into zeolites. The zeolites formed under the experimental conditions were faujasite, sodalite, and zeolite A. The use of the fly ash-derived zeolites and a commercial zeolite was explored in wastewater decontamination experiments as it was applied to acid mine drainage in different dosages. The concentrations of Ni, Zn, Cd, As, and Pb metal ions in the treated wastewater were investigated. The results of the treatment of the acid mine drainage with the prepared fly ash zeolites showed that the concentrations of Ni, Zn, Cd, and Hg were decreased as the zeolite dosages of the fly ash zeolite (FAZ1) increased.

Surface and bulk characterization of an ultrafine South African coal fly ash with reference to polymer applications

“…The beneficiation of South African FA after it has been put through a process of air classification, electrostatic recovery and/or density separation has been described before [1], and specific size fractions of FA, with specific physical and chemical properties, may be used in suitable applications. The country's research and development involving FA includes its application in building and construction as cement extender and into lightweight aggregates [4], environmental rehabilitation in the form of counteracting acid mine drainage, wastewater treatment, and toxic element immobilization by zeolites [5][6][7], mine backfilling, the recovery of alumina [8,9], production of geopolymers [10,11] and hydrotalcites [12], soil amelioration [13], refractories and bricks, road stabilization, CO 2 capture [14], and as a processing aid and functional filler in polymers [15].…”

In situ ultrasonic monitoring of zeolite A crystallization from coal fly ash

“…Over recent years, unconventional starting materials such as coal fly ash [2][3][4][5][6][7][8], metakaolin [9], cupola slag and aluminum sludge [10], municipal solid waste ash [11], chrysotile and rice husk [12] have also been used to synthesize zeolites. The synthesis of zeolite from coal fly ash was pioneered by Holler and Wirsching [13], and since then numerous researchers have followed in synthesizing different types of zeolites [5].…”

Reducing the Hardness of Mine Water Using Transformed Fly Ash

“…They have been successfully used to remove heavy metals from mine water (Cama et al 2005;Fungaro and Izidoro 2006;Moreno et al 2001;Somerset et al 2005Somerset et al , 2008 and have also been used as a reactive permeable barrier for ground water remediation (Czurda and Hans 2002). In the present work, we investigated the treatment of the Jharia mine water with FAZ (that we prepared) for its efficiency in removing hardness from mine water.…”