Abstract
This study was aimed at gaining further insight on the role of hydration in adsorption processes of biopolymer/adsorbate systems using complementary methods (electromagnetic interference (EMI) shielding, calorimetry, and solvent/vapour adsorption isotherms). Cellulose and starch-based materials were used as the adsorbents, whereas water (liquid and vapour), ethanol and p-nitrophenol (PNP) in aqueous solution were the adsorbate systems. The biopolymer/water systems had higher uptake capacity overall, where starch materials showed higher uptake capacity than cellulose among the various solvents. The secondary and tertiary structure of the biopolymers was a key factor affecting their uptake capacity, as evidenced by the enhanced adsorption properties of starch over cellulose, along with higher uptake of amylose (AM) versus amylopectin (AP) in starch biopolymers. EMI results also confirmed that AM starch had higher adsorption toward water than ethanol. The textural properties and surface chemistry of the biopolymers were probed using dye adsorption (PNP at pH 8.5) in aqueous solution that showed parallel trends with water vapour adsorption isotherms. Isothermal Titration Calorimetry (ITC) revealed that the heat of adsorption in AP differed from that of AM since the biopolymer tertiary structure governs the accessibility of biopolymer adsorption sites. The role of branching in AP and amorphous domains in AM/AP composites are inferred to play a key role in hydration-driven allosterism known for such biopolymer/water vapour adsorption processes.
Highlights
IntroductionThe low toxicity, low cost, and synthetic versatility of starch lend to its use as a platform for the design of modified biopolymer sorbents [1] [2]
Starch is one of the most abundant and renewable polymers in Nature
The water vapour sorption process in cellulose and starch bear similarities that relate to the structural similarity of these biopolymers and the key role of –OH adsorption sites
Summary
The low toxicity, low cost, and synthetic versatility of starch lend to its use as a platform for the design of modified biopolymer sorbents [1] [2]. Biopolymers such as starch have gained interest in the field of nanotechnology due to their potential as carriers for advanced drug delivery systems, biomedical devices, tissue engineering scaffolds, wastewater treatment technologies and feedstocks for bio-refineries [3] [4]. Starch is a key energy source for plants and animals, where it is found in different natural forms such as granules (small compact form) that contain linear (amylose) and branch (amylopectin) biopolymers [5]. The structural analysis of granules reveals a repeating structure with amorphous and crystalline domains [8] [9], containing amylopectin and amylose, respectively [10] [11]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
