Removal of chromium(VI) using nano-hydrotalcite/SiO2 composite

Application of chitosan-citric acid nanoparticles for removal of chromium (VI)

“…As can be seen from Table 4, variations in removal efficiency and uptake capacity and desorption efficiency on different kinds adsorbents are associated with adsorbent properties, such as physical and chemical structure of the adsorbents, metal-bonding functional groups, initial pH of the solution and initial Cr (VI) concentration, Cr (VI) species (i.e., CrO 4 2− , Cr 2 O 7 2− , HCrO 4 − , H 2 CrO 7 , HCr 2 O 7 − , Cr 3 O 10 2− , Cr 4 O 13 2− ) and adsorbent dose. Several nano-adsorbent such as polyacrylonitrile (PAN) nanofibers functionalized with amine groups (PAN-NH2) [29], manganese oxide nanofibers (MONFs) [30], guar gum-nano zinc oxide (GG/nZnO) [31], polypyrrole-titanium(IV) phosphate (PPy-TiP) nanocomposite [32], polyaniline/zeolite (PANI/zeolite) nanocomposite [33], nano-hydrotalcite supported on supported on silica (nano-HT/SiO 2 ) [34], and maghemite/polydopamine core/shell nanoparticles (MNP@PDA) [35] have been investigated for their Cr (VI) adsorption capacity. As can be seen from Table 4, hydrotalcite [34], magnetotactic bacteria [36] and wheat bran (WB) [37] and polyacrylonitrile nanofibers functionalized with amine groups (PAN-NH 2 ) [29] were used for Cr (VI) removal from aqueous solution and the results showed that the removal efficiency Table 3 Thermodynamic parameters of Cr (VI) adsorption onto CS-CA nanoparticles.…”

Evaluation of Nickel–Aluminium Complex Hydroxide for Adsorption of Chromium(VI) Ion

“…Therefore, NA11 is useful for rapid removal of chromium(VI) ion from aqueous solution. 1,3,5,10,25) To investigate the reaction pathway and the rate-controlling mechanism of the adsorption process, adsorption kinetic data were further analyzed in terms of pseudo-first-order (Eq. 3) and pseudo-second-order (Eq.…”

“…This study of the physical and chemical characteristics of NA11 revealed that it is a potential adsorbent that may be improved further. 10)…”

“…Previous studies have reported the removal of chromium(VI) ion from aqueous solution using Ca-Al hydrotalcite (prepared through co-precipitation method using calcium and aluminium ions), nano-hydrotalcite/SiO 2 composite, hydrotalcite/carbon composite, Mg-Al hydrotalcite (prepared through co-precipitation method using magnesium and aluminum ions) supported kaolin clay, carboxymethylcellulose-layered double hydroxide (CMC-LDH) beads, solgel hydrotalcite-like compounds, bamboo biochar, straw bio char, pig manure biochar, and biochar with magnesium and aluminum-layered double hydroxide intercalated with ethylenediaminetetraacetic acid etc. 1,3,5,[10][11][12][13][14] In addition, our previous work focused on enhancing the removal of toxic anionic compounds (heavy metals, inorganic nitrogen, phosphate ion, etc.) from water.…”

Hydrotalcites with heterogeneous anion distributions: a first approach to producing new materials to be used as vehicles for the successive delivery of compounds

“…Hydrotalcites, also known as layered double hydroxides or double metal hydroxides, are anionic clays with a two-dimensional layered structure, alternating positively charged mixed-metal hydroxide sheets and negatively charged interlayer anions along with water molecules (Gastuche et al , 1967; del Arco et al , 2008; Wang & O'Hare, 2012). They are used in many applications in various fields, such as in catalysis, ion exchange and adsorption (Pérez et al , 2015; Abderrazek et al , 2017; Benedictto et al , 2018; de Castro et al , 2018). More recently, these materials have been employed successfully as vehicles for the controlled delivery of medicines, in which the distribution of the intercalated drug species between the hydrotalcite layers determines its effectiveness (Rives et al , 2014).…”