Miscanthus
is a rich source of lignocellulosic biomass with low mineral content
suitable for applications that range from biofuel production to value-added
biomass-derived products including a sustainable biosorbent. Herein,
Miscanthus and its modified forms were used for the fractionation
of water (W) and ethanol (E) mixtures that were analyzed by an in situ analytical method, referred to as quantitative NMR
(qNMR) spectroscopy. Miscanthus was pretreated by hydrolysis and subsequent
grinding to yield materials with variable biopolymer content (cellulose
and lignins) and particle size. The Miscanthus materials were evaluated
as sorbents in binary water–ethanol (W-E) mixtures. The maximum
biomass adsorption capacity (Q
m; g g–1) with water (Q
m,W) and
ethanol (Q
m,E) fractions were determined
by the best-fit Sips model parameters listed in parentheses: raw Miscanthus
biomass (Q
m,W = 8.93 and Q
m,E = 4.15) and pretreated Miscanthus biomass (Q
m,W = 4.73 and Q
m,E = 3.22, g g–1). The fractionation properties of
Miscanthus and its biopolymer constituents show molecular selectivity
[R
selectivity = Q
m,W/Q
m,E] between W and E. The R
selectivity values are given in parentheses,
as follows: untreated Miscanthus (3:1), pretreated Miscanthus (1.5:1),
and lignins (1:5.4). The pretreated Miscanthus was prepared by acid
and base hydrolysis for the removal of hemicellulose and lignins,
respectively, leading to cellulose enrichment. The raw and pretreated
Miscanthus have preferential water uptake properties that relate to
the relative biopolymer composition. To test the reusability and regeneration
of Miscanthus, the biosorbent was tested over four adsorption–desorption
cycles. This work contributes to a greater understanding of chemical
treatment effects on biomass adsorption properties and evaluation
of the adsorptive contributions of biopolymer components for the fractionation
of water–ethanol mixtures.