Weibin Cai,Jiangyu Xie,Jingyu Luo,Xiaohan Chen,Mingqian Wang,Yujun Wang,Jiding Li
In this study, zeolite molecular sieve SAPO-34/polydimethylsiloxane (PDMS) mixed matrix membranes (MMMs) were prepared to recover propane. n-Octyltrichlorosilane (OTCS) was introduced to improve compatibility between SAPO-34 and PDMS, and enhance the separation performance of the MMMs. Physicochemical properties of the MMMs were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and water contact angle (WCA). Results showed that, after modification, alkyl chains were successfully grafted onto SAPO-34 without changing its crystal structure, particles in the MMMs were evenly distributed in the base film, and the hydrophobicity of the MMMs was enhanced. Moreover, the effects of SAPO-34 filling content, operating pressure, and feed gas concentration on the separation performance was explored. This indicated that the modification with OTCS effectively enhanced the separation performance of SAPO-34/PDMS MMMs. When the filling content of modified SAPO-34 was 15%, the maximal separation factor of 22.1 was achieved, and the corresponding propane permeation rate was 101 GPU.Keywords:MMMs;SAPO-34;PDMS;OTCS;propane recovery
Siyuan Jiang,Ziquan Liu,Ruibao Jia,Baozhen Liu,Guilin He,Zhenqi Du,Yonglei Wang
Effective removal of typical compounds like perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) is crucial for drinking water safety. Foam fractionation shows promise for PFAS removal, but its efficacy is limited by the low PFAS concentrations in natural waters, which hinder interfacial adsorption and foam stability. This study synthesized a novel green surfactant, octanoyl chloride-modified chitosan (OTCS), and developed an enhanced foam fractionation system coupled with micro-nano bubbles technology (OTCS-MNBs) for the efficient removal of PFOA and PFOS. Compared to the OTCS-conventional air bubbles foam fractionation system OTCS (OTCS-CABs), the OTCS-MNBs system achieved removal efficiencies of 98.73% and 99.21% for PFOA and PFOS, respectively, representing improvements of 1.47-fold for PFOA and 1.29-fold for PFOS. The system demonstrated pH adaptability (pH 3–9) and excellent foam stability, with moderate ionic strength enhancing reaction kinetics through salting-out effects. Analysis revealed that micro-nanobubbles exhibited higher specific surface area, longer residence time, and superior resistance to coalescence compared to conventional bubbles, thereby providing more adsorption sites and sufficient contact time for PFAS. In practical water experiments conducted with four typical Chinese lakes and reservoir sources, the system achieved removal efficiencies exceeding 80% for PFOA/PFOS, demonstrating its potential for practical application in complex water conditions. This highly efficient and environmentally friendly foam fractionation process effectively mitigates the environmental and health risks associated with PFAS and provides valuable technical guidance for water treatment plants addressing emerging contaminant challenges.
危险品化学品经营许可证（带存储）