Selective Removal of Chromates by Macroporous Exchanger Amberlyst A-21

Abstract

Sorption studies of chromate on weakly basic macroporous anion exchanger Amberlyst A-21 were performed as a function of pH (2 - 9), temperature (20 - 40 degrees C) and concentration (0.4 - 80 mmol.l(-1)). Chromate sorption was observed to decrease with the increase in initial pH of the solution, with a sorption maxima at pH 2 and increased with the increase in temperature. The changes in pH and in the ratio of choride ions released to chromate ions sorbed suggested that the anion exchange process was accomanied by hydrolysis and Donnan invasion. The FTIR spectra and isoeteric heat of sorption besides showing the hydrolysis / Donnan invasion of resin under different experimental conditions of concentration, pH and temperature also showed the dimerization of the chromate species inside the resin phase.

Sorptive Potential of Beach Sand to Remove Ni(II) Ions: An Equilibrium Isotherm Study

“…(5). The values of KF and 1/n indicate the relative sorption capacity (mol g -1 ) and intensity, respectively.…”

“…Various substances, such as ion-exchange resins [5], zeolites [6,7], clay minerals [8,9], river sand [10 -13], and sea beach sand [14,15], have been investigated as adsorbents. Apart from natural materials, different industrial waste materials have been used as adsorbents for the removal of heavy metal ions from water and wastewater, e. g., pottery material, which is a waste of the ceramic industry [16].…”

Co-Ion Effect on Cr3+ Sorption by Amberlyst-15(H+)

“…It has two stable oxidation states, Cr 3+ and Cr 6+ . The Cr 3+ is an essential element playing an important role in the metabolism of glucose, lipid, and protein whereas Cr 6+ is reported to be toxic to the biological systems (Mustafa et al 2002;Wen et al 2002;Gazola et al 2006). It has been reported that the presence of strong oxidants in soil and water can change Cr 3+ to harmful Cr 6+ (Tadesse et al 2006).…”

Kinetic and Equilibrium Studies of Chromium(III) Removal by Macroporous Ion Exchanger Amberlyst‐15 (H+)

“…Cr(III) is considered as an essential element playing an important role in the metabolism of glucose, lipid and protein, whereas Cr(VI) is reported to be toxic to the biological systems. [2][3][4] The presence of strong oxidants in soil and water can change Cr(III) to harmful Cr(VI). 5 A lot of literature is available on Cr(VI) removal but very limited on chromium(III) removal from aqueous solutions.…”