Recycling Waste Cotton Cloths for the Isolation of Cellulose Nanocrystals: A Sustainable Approach

Abstract

There is an interest in the sustainable utilization of waste cotton cloths because of their enormous volume of generation and high cellulose content. Waste cotton cloths generated are disposed of in a landfill, which causes environmental pollution and leads to the waste of useful resources. In the present study, cellulose nanocrystals (CNCs) were isolated from waste cotton cloths collected from a landfill. The waste cotton cloths collected from the landfill were sterilized and cleaned using supercritical CO2 (scCO2) technology. The cellulose was extracted from scCO2-treated waste cotton cloths using alkaline pulping and bleaching processes. Subsequently, the CNCs were isolated using the H2SO4 hydrolysis of cellulose. The isolated CNCs were analyzed to determine the morphological, chemical, thermal, and physical properties with various analytical methods, including attenuated total reflection-Fourier transform-infrared spectroscopy (ATR-FTIR), field-emission scanning electron microscopy (FE-SEM), energy-filtered transmission electron microscopy (EF-TEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The results showed that the isolated CNCs had a needle-like structure with a length and diameter of 10-30 and 2-6 nm, respectively, and an aspect ratio of 5–15, respectively. Additionally, the isolated CNCs had a high crystallinity index with a good thermal stability. The findings of the present study revealed the potential of recycling waste cotton cloths to produce a value-added product.

Biosorption of Cr(VI) Using Cellulose Nanocrystals Isolated from the Waterless Pulping of Waste Cotton Cloths with Supercritical CO2: Isothermal, Kinetics, and Thermodynamics Studies

“…There is a growing attentiveness to the sustainable utilization of WCCs to reduce carbon footprints and environmental pollutions [ 1 ]. The rise of fast-fashion demand in textile industries has increased cotton cloth production, which has enhanced the generation of WCCs.…”

“…A large number of WCCs are generated every year. The most preferred disposal method of WCCs is open dumping in landfill sites, along with other domestic and municipal wastes [ 1 , 2 , 3 ]. This inappropriate disposal practice leads to the demolition of valuable cellulosic materials and poses severe environmental pollutions.…”

“…Cellulose nanocrystals (CNCs) are the crystalline region of cellulose, isolated from cellulose pulp fiber using acid hydrolysis by removing the amorphous region of cellulose while leaving the only crystalline region of cellulose [ 1 , 6 ]. CNCs exhibit as elongated and cylindrical rod of crystalline cellulose with a width of 2–70 nm, length of 100–600 nm, and crystallinity index of 75–88% [ 6 , 7 , 8 ].…”

“…The isolation of CNCs from WCCs requires various processing steps, including delignification of lignocellulosic biomass for the extraction of cellulose and conversion of cellulose to CNCs [ 1 , 6 , 9 ]. The existing process for the extraction of cellulose from the WCCs is the combination of alkaline pulping and bleaching processes.…”

“…The existing process for the extraction of cellulose from the WCCs is the combination of alkaline pulping and bleaching processes. However, the extraction of cellulose using conventional pulping and bleaching requires toxic chemicals and consumes a massive amount of freshwater, resulting in the generation of toxic effluent [ 1 , 6 ]. Therefore, environmentalists and scientists are keen to define alternative technologies for minimizing the toxic effluent generation from the cellulose extraction of various lignocellulosic biomass.…”