Poly(vinyl alcohol)/α-chitin/nanocellulose composites developed from oil palm empty fruit bunch (OPEFB) for removal of cationic dyes / Mok Chun Fah

Mok , Chun Fah (2020) Poly(vinyl alcohol)/α-chitin/nanocellulose composites developed from oil palm empty fruit bunch (OPEFB) for removal of cationic dyes / Mok Chun Fah. PhD thesis, Universiti Malaya.

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Abstract

In search of an eco-friendly polymeric adsorbent for dye effluent treatment application, poly(vinyl alcohol) (PVA)/chitin/nanocellulose composites were synthesized. The composites were reinforced by oil palm empty fruit bunch fibers (OPEFB)-derived nanocrystalline cellulose (NCC). With addition of 1 wt.% NCC, a maximum improvement of 57.64% and 50.66% in tensile strength and Young’s Modulus were achieved, respectively. However, the PVA-based composites exhibited low resistance in aqueous medium. Hence, maleic acid (MA) was incorporated, in view of modifying PVA-based composites through cross-linking reactions. The effect of varying chitin content (10 wt.%-30 wt.%) and MA content (10%-50% based on total solid content of composite) towards the swelling, gel content and contact angle of the PVA/Chitin/NCC composites were evaluated. The effect of PVA-based composite composition, solution pH, adsorbent dosage and initial dyes concentration on removal of methylene blue (MB) as model cationic dye from aqueous solution were investigated by batch adsorption studies. The best adsorption performance was determined for PVA/Chitin-10/NCC/MA_30 sample after experimental parameters were optimized, with the calculated maximum adsorption capacity amounted to 467.5 mg/g. The adsorption kinetics were determined to be of pseudo-second order. From thermodynamic studies, it was found that the adsorption processes were spontaneous, exothermic and less-ordered reactions. Lastly, the PVA/Chitin-10/NCC/MA-30 adsorbent showed high adsorption reusability since the adsorption percentage was retained at 83.67 ± 1.08% even at the fifth adsorption_desorption cycle.

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