Cassava stem cellulose (CSC)Nanocrystal for optimal methylene BlueBio sorption with response surface design

• Main Authors: C.M. Obele, M.I. Ejimofor, C.U. Atuanya, M.E Ibenta
• Format: Article
• Language: English
• Published: Elsevier 2021-01-01
• Series: Current Research in Green and Sustainable Chemistry
• Subjects: Cellulose; Cellulose nanocrystal; Bio-sorbent; Dye removal; Microporous
• Online Access: http://www.sciencedirect.com/science/article/pii/S266608652100014X

The removal of cationic methylene blue (MB) dye from aqueous solution was studied using cellulose nanocrystal (CNC) from cassava stem cellulose extracted via acid hydrolysis. The cellulose nanocrystal was converted to 2, 2, 6, 6- tetramethylpiperidine-1-oxyl(TEMPO) CNC. CNC yield from cassava stem was 72%. FTIR showed absorption patterns typical of cellulose and CNC. It also proved the removal of lignin and hemicellulose in CNC. SEM and TEM analysis revealed that CNC has spherical particles. X-ray analysis showed that extracted CNC was crystalline in nature with crystallinity index of 83.24%. The adsorption behaviour of the CNC bio-adsorbent in aqueous solution revealed the effects of some process variables such as pH, temperature, ionic strength, initial dye concentration and contact time on the adsorption capacity of the CNC. Best dye adsorption of 93.3% was recorded at pH 2, MB concentration of 200 ​mg and 25mins via one factor at a time. High adsorption capacity of 823 ​mg/g was obtained. The adsorption of methylene blue was best described by Freundlinch model which indicates that the adsorption is on multiple heterogeneous surfaces and multiple adsorption layers provided by modified macro porous CNC. Optimal dye removal of 76% was obtained at 0.4 ​mg of CNC, 14mins and pH of 2 via RSM. Therefore CNC from cassava stem can be used in particles removal from contaminated water.