Muhammad Asad Saleem,Liujun Pei,Muhammad Faizan Saleem,Sumaira Shahid,Jiping Wang
Because of the prevailing issue of water scarcity , the application of non-aqueous media Decamethylcyclopentasiloxane (D5) was employed in the chemical fiber dyeing and washing process. Confocal laser scanning microscope (CLSM) and X-ray photoelectron spectroscopy (XPS) analysis have been carried out to analyze the penetration of D5 into the interior of nylon fiber and its distribution in fiber cross-section. The solubility of pure disperse dye in D5 has been measured to check the feasibility of dispersing agent exclusion from dyeing formulation. For developing the solvent dyeing and washing process for nylon, nylon fabric was dyed with pure disperse dyes in D5 solvent and washed with D5 without any process auxiliaries. Findings from CLSM and XPS spectrum showed that D5 can diffuse into the nylon fabric surface with and without the addition of accelerant. And accelerant doesn’t affect D5’s ability to penetrate and uniform distribution within the fiber structure. As compared to aqueous dyeing, the 30 and 43 percent increase in K/S was achieved for azo and anthraquinone dyes by using D5 as dyeing media. Furthermore, more than 99 percent solvent can be recycled or recovered. The level dyeing with commercial dyes under conventional dyeing conditions in D5 solvent dyeing media prove the commercial feasibility of this dyeing technology .
Siloxanes are detrimental trace impurities that can severely impair the performance and operational efficiency of biogas combustion systems, making their effective removal essential. Given the relatively high concentration of cyclic siloxanes and their susceptibility to acid-catalyzed ring-opening polymerization, a combined adsorption–polymerization approach on a solid acid adsorbent may offer higher removal efficiency compared to conventional adsorption methods. In this work, we employed activated carbon as a support and fabricated sulfuric acid-supported activated carbon (CSA) via a simple impregnation method. This study represents the first systematic investigation of the synergistic adsorption and acid-catalyzed polymerization of decamethylcyclopentasiloxane (D5) using this material. The activated carbon function as an adsorbent, providing mass transfer channels for D5, whereas the supported sulfuric acid serves as a catalyst to promote its ring-opening polymerization. Dynamic adsorption tests showed that CSA exhibited a high D5 removal capacity, with a theoretical maximum capacity ( Q m, th ) of 3219.7 mg g −1 at 0 °C. A series of characterizations, kinetic interpretation, mass balance analysis and density functional theory (DFT) calculations were also conducted to elucidate the potential adsorption/polymerization mechanisms responsible for D5 removal. The results confirmed that the formation of highe-molecular-weight polysiloxane structures on the CSA surface imparted a high degree of hydrophobicity to the spent CSA material. These findings highlight the potential of CSA as a cost-effective and practical solution for siloxane removal.
Traditional poly(lactic acid) (PLA) dyeing with synthetic disperse dyes in water medium presents a significant environmental risk since it consumes a large amount of chemicals and generates dyeing wastewater. In order to comply with the demands of clean production and sustainable development, a dispersant-free solvent dyeing system was developed by employing decamethylcyclopentasiloxane (D5) as dyeing medium and microbial prodigiosins prepared through surfactant-assisted fermentation as natural disperse dye. The influence of D5 medium on PLA fiber and prodigiosins was investigated. It was discovered that D5 could swell PLA fibers by penetrating the inside of the fibers while having no adverse effects on prodigiosins. The dyeing parameters were subsequently optimized in terms of K/S value and strength loss. The results indicated that PLA fabrics dyed in a modified solvent dyeing system containing 250% (owf) water exhibited the highest K/S value and minimum strength loss when they were dyed at dyeing temperature 105 °C, aqueous pH7.0 and dyeing time 30 min. The colorfastness of solvent dyed fabrics were equivalent to that of aqueously dyed fabrics in terms of rubbing and washing. The solvent dyeing process developed in this study effectively reduces the consumption of dispersant agents, being conducive to facilitate the further development of sustainable PLA industry.
危险品化学品经营许可证（带存储）