Barley Straw Fiber Extraction in the Context of a Circular Economy

Abstract

The potential for sustainable lignocellulosic agro-waste is immense, owing to the fact that it represents the most abundant organic compound on Earth. It is a valuable and desirable source for material production across numerous industries due to its abundance, renewability, and biodegradability. This paper explores the world of barley fibers, which are extracted from the straw of two different cultivars (old Rex or new Barun) and have tremendous potential for use, primarily for technical textiles. The quantity of the extracted fibers depends both on the type of barley used and on climate conditions that influence the plants’ growth, resulting in fiber yields ranging from 14.82% to 19.59%. The chemical composition of isolated fibers revealed an optimal content of cellulose and lignin in barley fibers isolated from the Rex variety. Those results were confirmed with FTIR analysis, which revealed a lower intensity of peaks associated with hemicellulose and lignin and, therefore, indicated their better removal after the chemical maceration process. In terms of fiber density, the quality of the fibers was comparable to that of cotton fibers, but they differed significantly in moisture regain (10.37–11.01%), which was higher. Furthermore, sufficient fiber tenacity (20.31–23.08 cN/tex) was obtained in a case of old-variety Rex, indicating the possibility of spinning those fibers into yarns, followed by their extended usage for apparel. Additionally, our paper reveals the possibility of fulfilling the requirements of the zero waste principle due to the fact that a high percentage of solid waste left after the fiber extraction (26.3–32.3%) was afterwards successfully used for the production of biofuels, enabling the closing of the loop in a circular economy.

Conversion of Waste Agricultural Biomass from Straw into Useful Bioproducts—Wheat Fibers and Biofuels

“…The bath was maintained at a ratio of 1:20, and the treatment duration spanned 90 min. Further intricacies of the experiment are elaborated upon in a prior publication [57]. A comprehensive explanation of the experimental process is presented in Figure 2.…”

“…Table 5 outlines the mechanical properties (tensile properties) of representative cellulose fibers in each category, encompassing fibers from seed, stem, leaf, and fruit. This study [57] [68]…”

“…The isolated fibers of wheat varieties Srpanjka and Kraljica were analyzed by the ATR-FTIR (Figures 9 and 10) where the impact of maceration with chemicals was assessed by characteristic cellulose, hemicellulose, and lignin peaks [45,57,65,[101][102][103].…”