An Experimental Study on the Hot Alkali Extraction of Xylan-Based Hemicelluloses from Wheat Straw and Corn Stalks and Optimization Methods

Abstract

In this paper, we describe an experimental study on the hot alkali extraction of hemicelluloses from wheat straw and corn stalks, two of the most common lignocellulosic biomass constituents in Romania. The chemical compositions of the raw materials were determined analytically, and the relevant chemical components were cellulose, hemicelluloses, lignin, and ash. Using the response surface methodology, the optimum values of the hot alkaline extraction parameters, i.e., time, temperature, and NaOH concentration, were identified and experimentally validated. The physicochemical characterization of the isolated hemicelluloses was performed using HPLC, FTIR, TG, DTG, and 1H-NMR spectroscopy. The main hemicellulose components identified experimentally were xylan, arabinan, and glucan. The study emphasizes that both corn stalks and wheat straw are suitable as raw materials for hemicellulose extraction, highlighting the advantages of alkaline pretreatments and showing that optimization methods can further improve the process efficiency.

Optimization of Alkaline Extraction of Xylan-Based Hemicelluloses from Wheat Straws: Effects of Microwave, Ultrasound, and Freeze–Thaw Cycles

“…The extraction yields were measured after a standalone FT cycle and for FT cycles followed by HA. The HA procedure is described in our previous work [ 40 ]. For the screening trials, a 5% sodium hydroxide (NaOH) solution was used as an extractive agent at a temperature of 90 °C and 40 min at a solid-to-liquid ratio of 1:30.…”

“…Several benefits (efficient hemicellulose separation, effective removal of acetyl groups, mild reaction conditions, less sugar degradation, furan derivatives formation, and relatively low operation costs) [ 40 , 41 ] suggest that alkaline pretreatments are very effective for improving extraction yields in the case of biofuels’ production processes [ 11 , 42 , 43 , 44 , 45 ]. However, to make the process economically viable, the selectivity must be increased, the pretreatment time reduced, and the chemicals recycled [ 41 , 45 ].…”

Evaluation of Chemical Composition of Miscanthus × giganteus Raised in Different Climate Regions in Russia

“…The cellulose content was measured by the Kürschner method by extracting a weighed portion of Miscanthus with mixed alcohol/nitric acid in a ratio of 4:1 [ 5 , 42 ]. The acid-insoluble lignin content was determined using 72% sulfuric acid as per the TAPPI standard [ 43 ].…”

“…It is essential to advance alternative energy sources in order to replace fossil fuel resources, mitigate greenhouse gas emissions and abate the anthropogenic burden on the environment [ 2 , 3 ]. Lignocellulosic biomass is of great interest as an alternative energy resource because of the significant benefits it offers: great diversity, availability, carbon neutrality and low cost as compared to fossil fuels [ 2 , 4 , 5 ]. As of today, lignocellulosic biomass is estimated at almost 25% of the global energy supply [ 6 ].…”

Statistical Analysis and Optimization of the Brilliant Red HE-3B Dye Biosorption onto a Biosorbent Based on Residual Biomass

“…Computer-assisted data analysis packages are increasingly being used for statistical data processing [ 18 , 19 , 24 , 25 ]. The advantage of this software is that it allows for much more efficient work processing, which leads to significant time savings and helps in obtaining more in-depth information on data, which might otherwise be lost.…”