title: Fast dye removal from water by starch-based nanocomposites.
abstract: Robust and efficient methylene blue (MB) adsorbent was prepared based on starch/cellulose nanowhiskers hydrogel composite. Maximum MB adsorption capacity of ∼2050mgperg of dried hydrogel was obtained with the composite at 5wt.% of cellulose nanowhiskers and at pH 5. Adsorption capacity varied from 1450mg/g to 2050mg/g with increasing the initial MB concentration from 1500mg/L to 2500mg/L, respectively. For all the concentrations studied ca. 90% of MB was removed by the adsorbent. Optimal conditions were obtained at pH⩾5 due to the generation of negatively charged groups (COO(-)) in the adsorbent, which can strongly interact with the positive charges from MB. The main advantage of this system over other reported adsorbents, besides the fact of being synthesized from biodegradable polymers (starch and cellulose), is its fast adsorption kinetics that follows the pseudo-second order model, which is based on chimisorption phenomenon. Saturation condition was reached as fast as 1h of experiments owing to the formation of an adsorbed MB monolayer as suggested by the Langmuir isotherm model. Desorption experiments showed 60wt.% of MB loaded can be removed from the adsorbent by immersing it in a pH 1 solution, showing its feasibility to be reused. Therefore, starch/cellulose nanowhiskers hydrogel composite presents outstanding capacity to be employed in the remediation of MB contaminated wastewaters.
authors.affiliation: Coordenação de Química, Universidade Estadual Vale do Acaraú (UVA), Campus da Betânia, 62040-370 Sobral, CE, Brazil.
authors.forename: Raelle F
authors.initials: RF
authors.lastname: Gomes
authors.affiliation: Coordenação de Química, Universidade Estadual Vale do Acaraú (UVA), Campus da Betânia, 62040-370 Sobral, CE, Brazil.
authors.forename: Antonio C Neto
authors.initials: AC
authors.lastname: de Azevedo
authors.affiliation: Universidade Tecnológica Federal do Paraná (UTFPR), 85660-000 Dois Vizinhos, PR, Brazil.
authors.forename: Antonio G B
authors.initials: AG
authors.lastname: Pereira
authors.affiliation: Departamento de Química, Universidade Estadual de Maringá (UEM), 87020-900 Maringá, PR, Brazil.
authors.forename: Edvani C
authors.initials: EC
authors.lastname: Muniz
authors.affiliation: Centro de Ciências Químicas, Farmacêuticas e de Alimentos, Universidade Federal de Pelotas (UFPel), 96010-900 Pelotas, RS, Brazil. Electronic address: andre.fajardo@pq.cnpq.br.
authors.forename: André R
authors.initials: AR
authors.lastname: Fajardo
authors.affiliation: Coordenação de Química, Universidade Estadual Vale do Acaraú (UVA), Campus da Betânia, 62040-370 Sobral, CE, Brazil; Departamento de Química, Universidade Estadual de Maringá (UEM), 87020-900 Maringá, PR, Brazil.
authors.forename: Francisco H A
authors.initials: FH
authors.lastname: Rodrigues
keywords: Adsorption; Cellulose nanowhiskers; Dye removal; Hydrogel; Hydrogel nanocomposite; Starch