Radiation grafting: A voyage from bio-waste corn husk to an efficient thermostable adsorbent

• Published in: Carbohydrate polymers 2018-03, Vol.183, p.151-164
• Main Authors: Paul Guin, Jhimli, Bhardwaj, Y.K., Varshney, Lalit
• Format: Article
• Language: English
• Subjects: Acrylic acid; Corn husk; Grafting; Methylene blue dye; Radiation
• ISSN: 0144-8617; 1879-1344
• DOI: 10.1016/j.carbpol.2017.11.101

[Display omitted] •Chemistry of radiation grafting of PAA onto bio-waste corn-husk (CH) is presented.•Chemical, XRD, morphological & thermal properties of CH are modified after grafting.•The thermally stable PAA grafted CH adsorbs 1682mg/g of MB dye at 320K and pH 9.•The endothermic adsorption follows Langmuir isotherm & pseudosecond order kinetics.•The adsorbent shows best recyclability (90% desorption of MB) in 1M HCl in ethanol. The initiator free environmentally benign gamma radiation is employed to graft poly-acrylic acid (PAA) onto the widely produced bio-waste corn husk to develop promising, cheap, efficient and reusable adsorbent (AAc-g-husk) having specific adsorption capacity of 1682.7mgg−1 of methylene blue (MB) at pH 9.0 and 320K. The most suitable grafting yield is found by optimizing absorbed dose, dose rate and concentrations of monomer, Mohr’s salt and inorganic acid. The inter-planar hydrogen bonding among (002) planes of cellulose in the husk decreases after diversifying grafting of PAA on ad-axial, ribs and micro-fibrils surfaces of the corn husks. The chemically and structurally modified AAc-g-husk shows superior thermal stability. The mechanism of MB dye adsorption by AAc-g-husk has been discussed through six two-parameters adsorption isotherm and ten three-parameters adsorption isotherm models at three different temperatures (300, 310 and 320K), seven kinetic models at room temperature, FT-IR and desorption studies in different solvent compositions.