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A reusable adsorbent was developed based on semi-interpenetrated hydrogel made of poly(vinyl alcohol) (PVA) and poly(2-acrylamido-2-methylpropane sulfonic acid) (PAMPS) for the adsorptive removal of cationic methylene blue (MB) dye. The developed PVA/PAMPS adsorbent hydrogel was characterized using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analyzer (TGA) and scanning electron microscope (SEM) analysis tools. Consequence of the variation of AMPS concentration on water uptake profile and polymer add-on (%) was explored. In addition, batch adsorption studies were performed to evaluate the aptitude of the developed adsorbent for MB dye removal under several adsorption conditions. The results showed an increase in the add-on (%) value up to 70% with increasing AMPS content up to 5%. Moreover, the MB dye removal was occurred quickly at the initial stage and recorded 60% after only 5 min from the initial contact time, while it recorded a maximum value of 86% at 25 ºC. The experimental adsorption data were well-fitted to the Langmuir isotherm model and followed the pseudo-second-order kinetic model. Moreover, the adsorption of MB dye by the adsorbent hydrogel was an endothermic process. Besides, the PVA/PAMPS adsorbent exhibited better reusability with a maximum removal (%) exceeded 70% after five consecutive cycles. The results obtained from this study infer that the PVA/PAMPS adsorbent hydrogel could be effectually used as an appropriate and reusable adsorbent for removing cationic MB dye molecules from wastewater bodies. [ABSTRACT FROM AUTHOR]

In this study, amylose, known as the food-grade biopolymers has been proved as a feasible solution for the controlled delivery of quercetin. The effect of reaction variables including reaction temperature, time, pH and quercetin addition amount on the content and conversion rate of quercetin was analyzed. Meanwhile, fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) provided evidence of quercetin complexation with amylose. Then, the molecular, cluster, and fractal structures of the complexes were investigated using 13C cross-polarization/magic angle spinning nuclear magnetic resonance (13C CP/MAS NMR) and small-angle X-ray scattering (SAXS). Furthermore, laser scanning confocal microscopy (CLSM) identified the precise encapsulation structure from direct observation and scanning electron microscope (SEM) was conducted to show that complexes displayed a larger size granule with smooth and angular appearance. From the antioxidant study, amylose/quercetin complexes presented effective scavenging capacity toward DPPH•. Besides, complexes showed high retention of quercetin in simulated stomach conditions but gradual release in simulated small intestine conditions. It was therefore confirmed that the amylose/quercetin complexes could be served as suitable carriers for the controlled release of quercetin in the digestive tract. The present research expanded the application range of starch, meanwhile proved an alternative application prospect for the ameliorative bioactive quercetin products. [ABSTRACT FROM AUTHOR]