Removal of 2‐naphthoxyacetic acid from aqueous solution using quaternized chitosan beads

Abstract

The present study investigates the use of quaternized chitosan hydrogels for the adsorption of an aromatic organic carboxylate, 2‐naphthoxyacetic acid (2‐NAA), to demonstrate the applicability of this type of adsorbent towards the removal of naphthenic acids (NAs) from oil sands process‐affected water (OSPW). The effects of varying three processing parameters on the physical and adsorption characteristics of the resulting adsorbents were investigated, namely the density, degree of cross‐linking, and degree of quaternization of the hydrogel beads. Their effects on the swelling behaviour and Langmuir adsorption capacity of 2‐NAA were reported. The Langmuir adsorption isotherm provided adequate fit for the equilibrium adsorption data (R2 ≥ 0.99), while the pseudo second order rate equation described the kinetic adsorption data quite well (R2 ≥ 0.95). The effects of adsorbate concentration, adsorbent dosage, agitation rate, ionic strength, pH, and temperature on the adsorption process were also studied. At the initial concentration of approximately 200 mg/L, up to 91 % of 2‐NAA was adsorbed. The best quaternized chitosan hydrogel adsorbents reported in this study possessed a maximum adsorption capacity of 315 mg/g.

Experimental methods in chemical engineering: Ultraviolet visible spectroscopy—UV‐Vis

“…Chemical engineering applications include waste‐water treatment, dye degradation, characterizing colloidal nanoparticles—silver, gold, and copper—metallic coordination of molybdenum and cobalt, bimetallic mesoporous materials with cobalt and chromium, and composites of graphene oxide and silver nanoparticles …”

Biomedical Applications of Quaternized Chitosan

“…The mode of adsorption signified Langmuir isotherm following pseudo first-order kinetics. The developed QCh hydrogel beads were moderately swellable and demonstrated effective adsorption of 2-naphthoxyacetic acid (91%) at the initial concentration of 200 mg/mL [ 128 ].…”

Quantification of nickel, cobalt, and manganese concentration using ultraviolet-visible spectroscopy

“…As discussed earlier, even though the studied elements do not chemically interact with each other, their presence with another element can inuence the corresponding absorbance depending upon their absorbance at l max of the other element. Therefore, if a cobalt peak is observed from the absorbance spectrum of nickel and vice versa, it is suggested to use eqn (10) and ( 14) instead of the equation for pure elements to calculate the concentration of nickel and cobalt, respectively, for more accurate results. The presence of manganese has no or insig-nicant effect on the absorbance spectrum of nickel and cobalt due to its extremely low absorbance regardless of its concentration.…”

“…UV-Vis spectroscopy has a wide range of applications and is used in almost every eld including wastewater treatment, 9,10 characterizing colloidal nanoparticles 11,12 and polymer impregnation, 13 and measuring the size distribution of emulsions, 13 and the release rates of antibiotics. 13 It is also a powerful tool to calculate reaction rates and can monitor multiple wavelengths concurrently when coupled with mass spectroscopy.…”