Preparation and Characterization of Carbon Microspheres From Waste Cotton Textiles By Hydrothermal Carbonization

Abstract

Carbon microspheres were prepared from waste cotton fibers by hydrothermal carbonization (HTC) with the addition of copper sulphate in this work. The important influence factors, temperature, concentration of copper sulphate, resident time were explored here. The smooth and regular carbon microspheres could be formed at 330°C with 0.15 wt% copper sulphate after 6 h from waste cotton fibers. The crystal structures of cotton fibers were destructed in a short resident time with 0.15 wt% copper sulphate from SEM images and XRD patterns of solid products. This strategy provides a new, mild and efficient method to prepare carbon microspheres from waste cotton fibers by HTC. FTIR spectra verified that the abundant functional groups existed on the surface of synthesized carbon microspheres. From XPS and element analysis results, the copper sulphate participated in the forming process of carbon microspheres indeed. The presence of copper sulphate in the carbon microspheres provided a possibility for the application in antibacterial field. Besides, the catalytic mechanism of copper sulphate on the hydrolysis and carbonization of waste cotton fibers were also discussed. In conclusion, the copper sulphate is an efficient agent for preparing carbon microspheres by HTC from waste cotton fibers.

Process Analysis of Main Organic Compounds Dissolved in Aqueous Phase by Hydrothermal Processing of Açaí (Euterpe oleraceae, Mart.) Seeds: Influence of Process Temperature, Biomass-to-Water Ratio, and Production Scales

“…degraded at 200 • C, 240 min, and the biomass-to-water ratio of 1:10 was 16.17% (wt. ), giving a degradation percentage of 54.28%, very close to the results reported by Zhang et al [22] who stated that approximately 50% (wt.) cotton fibers decompose at 210 • C over 8.0 h with a 1:41 biomass-to-water ratio.…”

“…by a severity factor between 4.5 and 5.0 (as reported by Borrero-López et al [21]), and that approximately 50% (wt.) cotton fibers decompose at 210 • C over 8.0 h with a 1:41 biomass-to-water ratio (as reported by Zhang et al [22]), one may perform a centesimal mass balance to compute the approximate theoretical mass degradation of Açaí seeds at 200 • C, 2 • C/min, 240 min, and a biomass-to-water ratio of 1:10, using the following equation, computed in Table 2. The Y Hydro-char/Cellulose is computed by multiplying the percentage of cellulose in the centesimal composition of Açaí seeds by the fraction of non-degraded cellulose (Y Hydro-char/Cellulose = 40.29% × (100 − 61.25)/100 = 15.6124%), as summarized in Table 2.…”

“…cotton fibers decompose at 210 • C over 8.0 h with a 1:41 biomass-to-water ratio. [7,12], decomposition cellulose and lignin [16], decomposition of lipids and proteins [20], decomposition of hemicellulose [21], decomposition of cotton fibers [22]. By analyzing the thermal decomposition behavior of cellulose and lignin reported by Falco et al [16], one observes that the decomposition of cellulose is almost constant between 200 • C and 240 • C (38.75→37.00), showing that degradation/de-polymerization of cellulose is less intense [19], while lignin loses only 7.5% of its initial mass (85%→77.5%), thus making it possible to explain the small differences for the solid phase yields between 200 • C and 250 • C.…”

Preparation of Double‐Layer Hollow Porous Carbon Microspheres by a Hydrothermal Method

“…The wider absorption peak between 3750-3100 cm À 1 (Figure 8) was caused by the stretching vibration of OÀ H in the hydroxyl or carboxyl group. [18,19] The sharp absorption peak at 2921 cm À 1 and 1706 cm À 1 were the characteristic peak of a CÀ H bond stretching vibration [20] and the stretching vibration of C=O, [21] respectively. The existence of these functional groups indicated that the surface of the DPCMs was rich in active groups such as À OH and À COOH, which thus laid a foundation for their functional modification.…”

Recent advancement of biomass-derived porous carbon based materials for energy and environmental remediation applications

“…Even though the HTC method can be well accomplished without using any catalyst, such as the case of kiwifruit-derived porous carbon aerogels by Wang et al, wherein results from high-resolution transmission electron microscope (HRTEM), Xray diffraction (XRD) and Raman spectroscopy analyses reveal the amorphous structure, intra-layer condensation form and graphitic nature, respectively, of the carbonaceous nanospheres, 151 there are some reports that examined the inuence of catalysts on the morphological aspect of the hydrochars as well as on the reaction rates. 152 Common catalysts include acidic catalysts like HCl, H 2 SO 4 , H 2 O 2 and H 3 PO 4 that can accelerate the hydrolysis and dehydration reaction rates. [153][154][155] Similarly, citric and ascorbic acid-assisted HTC obtained hydrochar from Malaysian oil palm residues exhibited excellent yield and high thermal stability.…”