Nowadays, with the rapid population growth as well as technological advancement, the use of heavy metals has been remarkably accelerated. Among all the heavy metals, chromium is widely-used in textile, metal finishing, tanning, nutrition, electroplating, wood preservative, etc. The uncontrolled release of trivalent chromium (Cr (III)) and hexavalent chromium (Cr (VI)) into water sources and soils have caused significant environmental problems, as Cr (VI) is highly carcinogenic with negative impacts on human health. In this study, a low-cost and high-efficiency cationic nanostructured cellulose bio-adsorbent was prepared by oxidizing cellulose microscale fibers (extracted from sugar cane) with sodium periodate followed by modification with Girard’s reagent T. The resulting cationic dialdehyde celluloses (c-DAC) having different degrees of substitution were tested for the Cr (VI) adsorption, where effects of the chromium concentration, contact time and pH value were investigated. The cationization modification also generated a great deal of internal surface through partial defibrillation within the microfibers. The maximum adsorption capacity of the c-DAC against Cr (VI) was found to be 80.5 mg g<sup>-1</sup> at an initial concentration of 300 mg L<sup>-1</sup>. The chosen isotherm model for the analysis of equilibrium adsorption was the Langmuir Model, while the kinetic study showed that the adsorption mechanism could also be fitted by the pseudo-second-order model. c-DAC samples exhibited reasonable and stable adsorption capacity under a wide pH range, as the cationic charge on c-DAC’s surface remains positive. The results suggest that the adsorption mechanism is dominated by the electrostatic interactions between the positively charged cellulose surface and the negatively charged chromate ions.

Removal of chromium (VI) from aqueous solutions by cationic nanostructured cellulose

2019 Fall National Meeting

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