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

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.

NaOH/Urea Swelling Treatment and Hydrothermal Degradation of Waste Cotton Fiber

In this study,waste cotton fabric was used as cellulose raw material and pretreated in aqueous NaOH/urea solution system to investigate the effect of NaOH/urea pretreatment solution on the hydrolysis of cotton fiber.The cotton fiber was pretreated with different conditions of aqueous NaOH/urea solution,and the pretreated cotton fiber was hydrolyzed under the same conditions as the original cotton fiber.The results of characterization analysis showed that water retention value of pretreated cotton fiber was higher than that of unpretreated sample.Moreover,the cotton fiber presented both a convoluted structure and a coarser surface,XRD results suggested that the crystallinity degree of cellulose decreased dramatically,more cellulose II appeared,and the hydrogen bond is broken.Among the different pretreatment conditions,the pretreatment effect was the best when the reaction temperature was 0°C,the solid-liquid ratio was 2:50,and the NaOH/urea ratio was 7:12.The hydrolysis experiments of pretreated and unpretreated cotton fibers showed that when the hydrothermal temperature was 230°C,the heat preservation was 2 h,and the hydrochloric acid concentration was 5 wt.%,the glucose yield reached 29.99%.H+could catalyze the hydrolysis of cotton fiber more effectively due to damage to crystal structure and hydrogen bonds.

Waste cotton fabric derived porous carbon containing Fe_(3)O_(4)/NiS nanoparticles for electrocatalytic oxygen evolution

Developing low-cost,active and durable electrocatalysts for oxygen evolution reaction(OER)is an urgent task for the applications such as water splitting and rechargeable metal-air battery.Herein,this work reports the fabrication of a metal and hetero atom co-doped fibrous carbon structure derived from cotton textile wastes and its use as an efficient OER catalyst.The free-standing fibrous carbon structure,fabricated with a simple two-step carbonization process,has a high specific surface area of 1796 m^2/g and a uniform distribution of Fe_(3)O_(4)/NiS nanoparticles(Fe_(3)O_(4)/NiS@CC).The composite exhibits excellent OER performance with an onset potential of 1.44 V and a low overpotential of 310 mV at the current density of 10 mA/cm^2in a 1.0 M KOH solution,which even surpass commercial Ru O_(2)catalyst.Additionally,this ternary catalyst shows remarkable long-term stability without current density loss after continuous operation for 26 h.It can be believed that the outstanding OER performance is attributed to the synergistic effect between the iron oxides and nickel sulphides,as well as the micro-meso porous carbon structure.This study demonstrates a new strategy to use conventional textile materials to prepare highly efficient electrocatalysts;it also provides a simple approach to turn textile waste into valuable products.

Application of microalgal-ZnO-NPs for reusing polyester/cotton blended fabric wastes after modification by cellulases enzymes

Polyester/cotton(PET/C)blended fabric wastes are produced daily in huge amounts,which constitutes an economic loss and an environmental threat if it is not reused appropriately.Modern textile waste recycling technologies put much effort into developing fabric materials with unique properties,such as bioactivity or new optical goods based on modern technologies,especially nano-biotechnology.In this study,zinc oxide nanoparticles(ZnO-NPs)were biosynthesized using the aqueous extract of Dunaliella sp.and immobilized on PET/C waste fabrics after enzymatically activated with cellulases.The produced Dunaliella-ZnO-NPs(10–20 nm with a spherical shape)were characterized by High-resolution transmission electron microscopy(HRTEM),Fourier-transform infrared spectroscopy(FTIR),X-Ray diffraction analysis(XRD),and Scanning electron microscopy-energy dispersive X-ray analyzer(SEM-EDAX),and some functional groups,such as CH,CO,NH,and CN(due to the presence of carboxyl,proteins and hydroxyl groups),were detected,revealing the biosynthesis of ZnO-NPs.The analysis showed that the resulting ZnO-NPS had potent antimicrobial effects,Ultraviolet(UV)protection capabilities,and no cytotoxic effects on the normal human fibroblast cell line(BJ1).On the other hand,enzymatic treatments of PET/C fabric waste with cellulases enhanced the immobilization of biosynthetic nanoparticles on their surface.Modified PET/C fabrics loaded with Dunaliella-ZnO-NPs showed antibacterial and UV protection capabilities making them an eco-friendly and cost-effective candidate for numerous applications.These applications can include the manufacture of active packaging devices,wastewater treatment units,and many other environmental applications.

Opportunities for New Biorefinery Products from Ethiopian Ginning Industry By-products:Current Status and Prospects

The global demand for textile products is rapidly increasing due to population growth,rising living standards,economic development,and fast fashion trends.Ethiopian growth and transformation plan(GTP)gives high priorities for the textile and apparel sectors to transform its agriculturally led economy to an industrial-based economy.To achieve this,the number of tex-tile and apparel industries is rapidly expanding.However,the rapid growth in textile industry is generating mountains and mountains of by-products.In this review,possible applications of cotton stalk and cotton ginning waste in a variety of technologies and products are discussed in Ethiopian context.The finding of this study shows that Ethiopian current cotton cultivating area is about 80000 hm^(2),even though the country has a potential of about 3000810 hm^(2) land for cotton cultivation.From the current cultivated area,more than 240000 t of cotton stalk and 9240 t of cotton ginning trash have been generated as a by-product.But only a very little portion of the cotton stalk is being used as a raw fuel for household purposes and a small portion of cotton ginning trash is used for animal feed.Therefore,these underutilized lignocellulosic biomasses can be used as raw materials for producing different high-value biomaterials and thus country can perceive an economic and environmental benefit.A closer look at the structure and composition of the by-products shows that the whole part of cotton stalk and ginning waste can be used as a source of cellulose which can be exploited for conversion into a number of high-value biomaterials.Thus,conversion of the waste into valuable products can make cotton stalk and ginning by-products an attractive raw material for the production of high value bio-products.