Cellulose nanofibril-based aerogel derived from sago pith waste and its application on methylene blue removal

Abstract

<p class="first" id="d8129714e93">Sago pith cellulose nanofibril (SPCNF) aerogel derived from sago pith waste (SPW) was successfully produced through three consecutive steps, namely dewaxing and delignification, ultra-sonication and homogenization and freeze drying. The aerogel was characterized using field emission scanning electron microscopy (FE-SEM), Fourier-transform infra-red spectroscopy (FTIR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). Results of the analyses collectively showed that lignin &amp; hemicellulose were absent in the SPCNF aerogel product which has a high crystallinity index of 88%. The diameters of individual nanofibril constituents of the SPCNF were between 15 and 30 nm and aspect ratios &gt;1000 were observed. The SPCNF aerogel, with a density measured at 2.1 mg/cm3, was efficient in methylene blue (MB) removal with a maximum MB adsorption of 222.2 mg/g at 20 °C. The adsorption of MB onto the SPCNF aerogel was rapid and found to follow a pseudo-second-order kinetic model with the adsorption isotherm being in congruence with the Langmuir model. The SPCNF aerogel exhibited outstanding MB removal efficacies with 5 mg and 20 mg of SPCNF capable of removing over 90% and almost 99% MB, respectively. The optimized pH value and temperature for MB adsorption were determined as pH 7 and 20 °C. </p>