Aqueous fluoride removal using ZnCr layered double hydroxides and their polymeric composites: Batch and column studies

Removal of phosphate from industrial wastewater using uncalcined MgAl-NO3layered double hydroxide: batch study and modeling

“…Several studies have investigated the removal of phosphate by calcined and uncalcined LDHs [19,[23][24][25]. However, until now, studies on the use of nitrate-containing LDHs as anion-exchanger for phosphate removal are scarce [26,27].…”

“…LDHs are layered materials with hydroxide sheets, where a net positive charge is developed on the layer due to partial substitution of trivalent by divalent cations [16]. Due to the high charge density of the sheets and the exchangeability of the interlayer anions as well, LDHs have been used in several studies as a sorbent to remove different harmful anions, such as arsenate [17], phosphate [18], fluoride [19], and chromium [20].…”

Behavior of Fluoride Removal by Aluminum Modified Zeolitic Tuff and Hematite in Column Systems and the Thermodynamic Parameters of the Process

“…Researchers are mostly focusing their study on various types of inexpensive and effective materials such as different clays, coconut shell carbon, chemically activated carbon, bone charcoal, natural zeolites, burnt clay, activated alumina (Ayoob et al 2008), red mud (Tor et al 2009) alum sludge (Sujana et al 1998), chitosan beads (Viswanathan and Meenakshi 2008), carbonaceous materials (Márquez-Mendoza et al 2012;Ikuo et al 2004), calcite (Yang et al 1999), montmorillonite (Tor 2006), Citrus limonum (lemon) leaf (Tomar et al 2014), Zr-Mn composite material (Tomar et al 2013), kanuma mud (Chen et al 2011), acid-treated bentonite (Ma et al 2011), polypyrrole/Fe 3 O 4 magnetic nanocomposite (Bhaumik et al 2011), bayerite/boehmite nanocomposites (Jia et al 2015), Fe-Mg-La triple-metal composite , hydrous ferric oxide (Nur et al 2014), hydroxyapatite (Jiménez-Reyes and Solache-Ríos 2013), ZnCr-layered double hydroxides and their polymeric composites (Koilraj and Kannan 2013), Ce(IV)-Zr(IV) mixed oxide nanoparticles (Ghosh et al 2015), spent bleaching earth (Mahramanlioglu et al 2002), and other low-cost adsorbents with various degrees of success (Ali 2006;Yadav et al 2006). So, there is a crucial need to explore locally available inexpensive defluoridation materials for safe and easy use at both household and small community levels.…”

Effect of formation pH, molar ratio and calcination temperature on the synthesis of an anionic clay based adsorbent targeting defluoridation

“…In this method, bivalent and trivalent metal ions form LDH upon precipitation in fixed or variable pH (de Sá et al, 2013;Koilraj and Kannan, 2013). The literature suggests that the molar ratio of bivalent and trivalent metals has a significant effect upon LDH characteristics (Kang et al, 2013).…”