Cellulose nanowhiskers improve the methylene blue adsorption capacity of chitosan-g-poly(acrylic acid) hydrogel. (1st February 2018)

• Record Type: Journal Article
• Authors: Melo, Bruno C.; Paulino, Francisco A.A.; Cardoso, Varneir A.; Pereira, Antonio G.B.; Fajardo, André R.; Rodrigues, Francisco H.A.
• Is Part Of: Carbohydrate polymers. Volume 181(2018)
• Page Start: 358
• Page End: 367
• Publication Date: 2018-02-01
• Subjects: Chitosan (PubChem CID: 71853) -- Acrylic acid (PubChem CID: 6581) -- N, N, Ń, Ń-Tetramethylenediamine (PubChem CID: 8037) -- N, Ń-Methylenebisacrylamide (PubChem CID: 8041) -- Methylene blue (PubChem CID: 6099) -- Sodium persulfate (PubChem CID: 62655) -- Hydrochloric acid (PubChem CID: 313) -- Acetic acid (PubChem CID: 176) -- Sodium hydroxide (PubChem CID: 14798); Chitosan -- Cellulose nanowhiskers -- Hydrogel composite -- Methylene blue -- Adsorption -- Wastewater treatment; Polysaccharides -- Periodicals; Polysaccharides -- Periodicals; Polysaccharides -- Périodiques; Electronic journals; 547.78
• DOI: 10.1016/j.carbpol.2017.10.079
• Languages: English
• ISSNs: 0144-8617

Abstract

Graphical abstract: Highlights: Cellulose nanowhiskers were used to enhance the adsorption capacity of chitosan hydrogel. The resulting composite showed improved adsorption capacity towards methylene blue (MB). The highest MB adsorption (1968 mg/g) was observed for the composite at 5 w/w-% nanowhiskers. Desorption experiments showed that 75% of loaded-MB could be recovered at pH 1 solution. The post-utilized composite can be recycled and reused (5 times) with 2% of efficiency loss. Abstract: Cellulose nanowhiskers (CNWs, 90% crystalline) were used to enhance the adsorption capacity of chitosan- g -poly(acrylic acid) hydrogel. The composites up to 20 w/w-% CNWs showed improved adsorption capacity towards methylene blue (MB) as compared to the pristine hydrogel. At 5 w/w-% CNWs the composite presented the highest adsorption capacity (1968 mg/g). The maximum removal of MB (>98% of initial concentration 2000 mg/L) was achieved quickly (60 min) at room temperature, pH 6, and at low ionic strength (0.1 M). Adsorption mechanism was explained with the Langmuir type I model suggesting the formation of a MB monolayer on the adsorbent surface. The interaction between the adsorbent and MB molecules was explained by chemisorption, as suggested by the pseudo-second-order kinetic model. Desorption experiments showed that 75% of loaded-MB could be recovered from the adsorbent by its immersion in a pH 1 solution. Additional experiments showed the post-utilized composite could be regenerated and reused for at least 5 consecutive adsorption/desorption cycles with minimum efficiency loss (∼2%).