Cellulose is the most abundant natural polymer on Earth and serves as a key renewable feedstock for a wide range of sustainable materials, including biocomposites, nanocelluloses, membranes, packaging materials, and pharmaceutical excipients [1]. Structurally, cellulose is a linear polysaccharide composed of β-D-glucose units linked through β-1,4-glycosidic bonds, forming highly ordered crystalline and amorphous regions that contribute to its remarkable mechanical strength, biodegradability, and chemical versatility [2]. Due to increasing environmental concerns and the growing demand for sustainable materials, cellulose has gained substantial attention as a viable alternative to petroleum-derived materials in several industrial applications.

Conventionally, cellulose is obtained primarily from wood pulp and cotton. However, the increasing depletion of forest resources, rising processing costs, and environmental impacts associated with conventional extraction routes have intensified research into alternative lignocellulosic feedstocks, particularly agricultural residues and non-food biomass [3]. Utilizing agricultural waste as a cellulose source not only reduces environmental burden associated with biomass disposal but also supports circular-economy principles through waste valorization and resource efficiency.

Among the various agricultural residues investigated, corn husk, an abundant by-product generated during maize processing, has emerged as a promising cellulose source because of its high cellulose content, low cost, biodegradability, and widespread availability [4]. Large quantities of corn husk are generated annually and are often discarded through open dumping or burning, contributing to environmental pollution and underutilization of potentially valuable biomass resources. The conversion of corn husk into value-added cellulose materials therefore presents an environmentally sustainable approach for managing agricultural waste while creating functional biomaterials for industrial applications.

Corn husk is primarily composed of cellulose, hemicellulose, lignin, waxes, and other minor extractives arranged within a complex lignocellulosic matrix [5]. The presence of lignin and hemicellulose strongly influences the purity and performance of the extracted cellulose, thereby necessitating effective pretreatment and purification processes [6]. Several studies have demonstrated that alkaline treatment combined with bleaching processes can effectively disrupt the lignocellulosic structure, remove non-cellulosic components, and enhance cellulose purity and crystallinity [7][8]. However, the efficiency of cellulose extraction is highly dependent on the extraction conditions employed, including alkali concentration, bleaching intensity, treatment duration, and reaction temperature.

Although cellulose extraction from corn husk has been reported in literature [2][9], inconsistencies still exist regarding the optimization of extraction procedures and the extent to which extraction methods influence the purity of the isolated cellulose. This research analyses the effect of extraction methods on the purity of extracted cellulose from Corn husk a waste agricultural biomass using FTIR testing which is variously used to find and identify material contaminants. In addition, limited emphasis has been placed on using spectroscopic analysis to systematically verify the effectiveness of extraction treatments in removing lignin and hemicellulose residues from corn husk cellulose. Since the physicochemical properties and potential applications of cellulose are strongly affected by its purity, there remains a need for reproducible extraction strategies capable of producing high-quality cellulose from agricultural waste under relatively mild and environmentally conscious processing conditions.

The waste plant materials (Corn husk) were sourced from Eziobodo and Ihiagwa Communities in Owerri-west LGA of Imo State, Nigeria. Sodium hydroxide (NaOH) pellets, Benzene, Toluene, Acetic acid, Nitric acid (HNO₃), Sodium Borate (Na₂B₄O₇∙10H₂O), Ethanol (CH₃COOH), Hydrogen peroxide (H₂O₂), distill water, and Hydrochloric acid. All reagents are of analytical grade and were purchased from Pac Besh scientific Ltd. Owerri in Imo State, Nigeria.

Corn husk is a lignocelluloses material consisting of cellulose, hemicelluloses and lignin. FTIR is one of the most widely used procedures for quality control in material testing which is what informed our choice. The FTIR spectrum of each of the samples showed two distinct zones—the lower zone (400 - 1800 cm⁻¹) and the higher zone (2000 - 3500 cm⁻¹). The broad peak at the wave number between 3294.97 cm⁻¹ to 3500 cm⁻¹ of the three samples (Figure 1Figures 1-3) corresponds to the

Figure 1.Raw corn husk powder (C).

Figure 2.Corn husk cellulose (C1).

Figure 3.Corn husk cellulose (C2).

–OH stretching vibration, a characteristic absorption band of lignocelluloses materials [11]-[13]. The variation in the intensity of this broad peak signifies the OH content level, which reflects the degree of removal of non-cellulosic components such as lignin and hemicellulose during the extraction and bleaching process [14]. The peak at 2922, 2897 and 2892.41 cm⁻¹ in C, C1 and C2 respectively is associated with C–H assymetrical stretching vibrations, consistent with values reported for cellulose extracted from various lignocellulosic sources [11][15][16]. Peaks within 2000 - 2500 can be attributed to Carbon dioxide (CO₂) not fully removed from the background air during the analysis [17][18]. We observed the absence of peaks 1722, 1513, and 1241 cm⁻¹ found in the raw corn husk fig 1 representing C=O acetyl group in hemicellulose, and C–O–C of aryl-alkyl-ether in lignin respectively [19][20] from the extracted cellulose C1 and C2. This is an indication that both extraction methods used removed hemicellulose and lignin from the raw corn husk powder. The bands at 1647 and 1640.03 cm⁻¹ of C1 and C2 respectively is the O–H bending of absorbed water, mainly associated with cellulose [13][21]. The vibration at 1431 and 1423.84 cm⁻¹ is CH₂ scissoring bending in cellulose [11], while the band at 1373 and 1364.21 cm⁻¹ is attributed to C–H bending in cellulose [11][22]. The peak at 1317 and 1315 cm⁻¹ is caused by CH₂ rocking vibration [23]. The band at 1163 and 1159 cm⁻¹ represents the C–O–C stretching, corresponding to the β-(1,4)-glycosidic linkages between the glucose units in cellulose [11]. The broad peak at 1017 - 1133 cm⁻¹ represents the C–O–H bending vibration, further supporting the cellulosic nature of the extracted material [16].

The band observed at 894.56 cm⁻¹ is linked to cellulose crystallinity, representing the β-glycosidic linkage characteristic of the Iβ cellulose structure [14]. It has been reported the intensities of 1420 - 1430 cm⁻¹ is associated with the crystallinity level of cellulose (Iβ cellulose structure), while the intensities of 893 - 897 cm⁻¹ are associated with the β-(1,4)-glycosidic structure and Iα cellulose [23]-[25]. Our results show that the intensities of the various peaks are higher in C1 than in C2. This difference is attributed to effect of the different extraction methods used. Peak intensities have also been linked to material content with higher intensities indicating higher content [26]. It is also likely that the high NaOH concentration used in the extraction of C2 affected the cellulose content. High concentration of NaOH has been reported to affect cellulose adversely [27][28].

Successful Cellulose extraction from corn husk using two different methods has been reported. The report of our analysis result was based solely on FTIR purity assessment carried out on the extracted cellulose from the different methods. Both extraction methods were green and removed hemicelluloses and lignin which are the major constituents of lignocelluloses materials. The intensities of the cellulose functional groups were however not the same. C1 cellulose had more cellulose content than C2 cellulose based on the FTIR intensities of their constituent groups. The use of high concentration of NaOH is a major factor affecting the cellulose content of extracted from corn husk and other plant biomass. Whereas our first extraction method yielded cellulose with higher contents it requires more reagents and time hence will be costlier than the second method. We therefore recommend the use of our second extraction method with reduced sodium hydroxide concentration. FTIR analysis provided solid confirmatory evidence of cellulose identity, however use of other characterization procedures is recommended for further studies.

The authors gratefully acknowledge the TETFund/DR & D-CE/ NRF 2020 Laboratory at Federal University of Technology, Owerri were the research was performed.

This research is part of TETFund Institution Based Research (FUT/OVC/TETF/GEN.8/VOL.4) 2025 funded by TETFund.