Catecholamine coated maghemite nanoparticles for the environmental remediation: Hexavalent chromium ions removal

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.…”

“…After adjustment of pH at 5, a 5 g/l of the adsorbent was added. The effect of different temperature (25,35 and 45 • C) was studied on the removal of Cr (VI) by optimized CS-CA nanoparticles in different flasks containing 25 ml Cr (VI) solution (50 mg/l) at a dose 2 g/l and pH 4. All flasks were agitated on a shaker at 150 rpm at room temperature and contact time of 120 min, until equilibrium was reached.…”

“…The effect of temperature (25,35 and 45 • C) on the adsorption process was also evaluated in order to understand the thermodynamic parameters such as the Gibbs free energy ( G • ), enthalpy ( H • ) and entropy ( S • ), using the following equation:…”

Mussel‐inspired magnetic adsorbent: Adsorption/reduction treatment for the toxic Cr(VI) from simulated wastewater

“…The adsorption capacity of Fe 3 O 4 , PCBA, and Fe 3 O 4 @PCBA is compared (Supporting Information Figure S1), and it is found that the adsorption capacity of the 34,36 From the FTIR spectra of PCBA and Fe 3 O 4 @PCBA, the strong peaks at 1564 and 2945 cm 21 were attributed to the vibrations of benzene ring group and CAH bond in PCBA polymer. 9 The peak at 1274 cm 21 was ascribed to the vibration of CAO bond of catechol in PCBA and Fe 3 O 4 @PCBA.…”

Removal of chromium from industrial effluents using nanotechnology: a review

“…Besides being used as nanocomposites as discussed above, magnetite (Fe 3 O 4 ) nanoparticles can also be used individually for removal of Cr(VI) from wastewater [117]. Maghemite (c-Fe 2 O 3 ) coated with polydopamine (a catecholamine) showed a Cr(VI) removal efficiency of 97% at pH of 3 [118]. ZnO nanoparticles were used as photocatalysts for the reduction of Cr(VI) to Cr(III) in the presence of solar radiation [119,120].…”