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Leila Chabane, Omar Bouras
Laboratoire Eau Environnement et Développement Durable L2E2D, Faculté de Technologie-Université Blida 1, Route de Soumâa, BP 270, 09000 Blida, Algeria
https://doi.org/10.5004/ic202409
ABSTRACT
The development of new economical and recyclable adsorbents for the removal of pollutants from contaminated water is receiving increasing attention. The production of nanocellulose from waste is of great interest. In this study, cellulose nanocrystals (CNCs) were synthesized from industrial cotton waste and subsequently immobilized in sodium alginate (NaAlg) gels, resulting in the formation of porous hydrogel beads (CNCs-PHB). The obtained resulting CNCs-PHB porous hybrid adsorbents were then characterized by FTIR spectrocopy and XRD analysis. The functional group analysis of FTIR spectra confirmed that the CNCs-PHB adsorbent is characterized by appropriate functional groups which are favorable for sorption of methyl red (MR) dye. The XRD diffraction pattern shows that the CNCs have the crystalline configuration of cellulose with a crystallinity index of 73%. The obtained CNCs-PHB adsorbents were used in the removal of MR in aqueous solutions. Batch adsorption studies were conducted by examining the effects of adsorbent dose (0.1–0.5 g), contact time (5–480 min), pH (2–10) and initial concentration of MR (10–50 mg/L). The results of the kinetic study show that the pseudo-equilibrium state is reached after 250 minutes. It has been shown that the adsorption capacity decreases with increasing amount of adsorbent. Strong MR elimination of 83% was achieved in very acidic environments (pH = 2) with CNC-PHB adsorbents at initial concentrations of 10 mg/L. These results clearly show that the adsorption process is better correlated with pseudo second order (PSO) kinetics. The mathematical modelling by isothermal models of Freundlich, Langmuir, Sips, Dubinin-Radushkevich and Temkin showed that only the Langmuir and Sips models are best adapted to experimental data since the values of the correlation coefficient R2 are at 0.98. The maximum adsorption capacity obtained is of the order of 32 mg g–1.
Keywords: Cotton waste; Cellulose nanocrystals; Porous hydrogel beads; Adsorption; Acid hydrolysis; Methyl red
Leila Chabane, Omar Bouras
Laboratoire Eau Environnement et Développement Durable L2E2D, Faculté de Technologie-Université Blida 1, Route de Soumâa, BP 270, 09000 Blida, Algeria
https://doi.org/10.5004/ic202409
ABSTRACT
The development of new economical and recyclable adsorbents for the removal of pollutants from contaminated water is receiving increasing attention. The production of nanocellulose from waste is of great interest. In this study, cellulose nanocrystals (CNCs) were synthesized from industrial cotton waste and subsequently immobilized in sodium alginate (NaAlg) gels, resulting in the formation of porous hydrogel beads (CNCs-PHB). The obtained resulting CNCs-PHB porous hybrid adsorbents were then characterized by FTIR spectrocopy and XRD analysis. The functional group analysis of FTIR spectra confirmed that the CNCs-PHB adsorbent is characterized by appropriate functional groups which are favorable for sorption of methyl red (MR) dye. The XRD diffraction pattern shows that the CNCs have the crystalline configuration of cellulose with a crystallinity index of 73%. The obtained CNCs-PHB adsorbents were used in the removal of MR in aqueous solutions. Batch adsorption studies were conducted by examining the effects of adsorbent dose (0.1–0.5 g), contact time (5–480 min), pH (2–10) and initial concentration of MR (10–50 mg/L). The results of the kinetic study show that the pseudo-equilibrium state is reached after 250 minutes. It has been shown that the adsorption capacity decreases with increasing amount of adsorbent. Strong MR elimination of 83% was achieved in very acidic environments (pH = 2) with CNC-PHB adsorbents at initial concentrations of 10 mg/L. These results clearly show that the adsorption process is better correlated with pseudo second order (PSO) kinetics. The mathematical modelling by isothermal models of Freundlich, Langmuir, Sips, Dubinin-Radushkevich and Temkin showed that only the Langmuir and Sips models are best adapted to experimental data since the values of the correlation coefficient R2 are at 0.98. The maximum adsorption capacity obtained is of the order of 32 mg g–1.
Keywords: Cotton waste; Cellulose nanocrystals; Porous hydrogel beads; Adsorption; Acid hydrolysis; Methyl red