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Composting is a process of converting potentially harmful organic matter into harmless organic fertilizer through microbial fermentation. This process enables the rational use of resources and represents an embraced technology marked with sustainable development features. Hindering ammonia emissions during composting is vital, as ammonia is a valuable resource and harmful if emitted excessively. Polytetrafluoroethylene (PTFE) membranes are often used as functional covering membranes to prevent ammonia produced by composting from releasing due to its hydrophobicity. However, they are susceptible to oily aerosols in oily composting, which affects microbial decomposition in aerobic composting. Thus, the development of amphiphobic PTFE membrane is necessary and meaningful. For the amphiphobic PTFE membrane, an important issue is the amphiphobic stability of the membrane, especially in the special alkaline environment of composting. Herein, we suggest the use of the polymer to wrap around nanoparticles and PTFE membrane fibers to prepare stable amphiphobic membranes as functional covering membranes for oil-containing composting. Poly(methyl-3,3,3-trifluoropropylsiloxane) (PTFPMS) and 1H, 1H, 2H, 2H-perfluorodecyltrichlorosilane (PFTS) entangled with each other and then wrapped the nanoparticles and membrane fibers to form stable amphiphobic membranes with high roughness and low surface energy. The prepared membrane had high liquid repellency to water (～152.8°), diiodomethane (～127.5°), and n-hexadecane (～127.0°). This membrane also possessed a high anti-oil fouling. Moreover, the membrane amphiphobicity exhibited a high stability. This is attributed to the stable fixation of nanoparticles on PTFE membrane fibers with PFTS/PTFPMS. Therefore, the amphiphobicity of the membrane was not affected by ammonia. As for the ammonia filtration efficiency, the amphiphobic membrane had a filtration efficiency of 77.4 % within 10 min, an increase of 6.8 % compared to the PTFE membrane, demonstrating the potential of the membrane we developed toward hindering ammonia emission. This work provides a new way of developing high-performance membrane for the oily composting process. [Display omitted] • An amphiphobic PTFE membrane was developed for oily composting. • The membrane repelled both water and oil highly because of low surface energy and high roughness. • The polymer wrapped the nanoparticles and membrane fibers to form a stable amphiphobic PTFE membrane. • The developed membrane exhibited a good ability for hindering ammonia emission. [ABSTRACT FROM AUTHOR]

Macroporous substrates have great potential in the development of high performance thin film composite forward osmosis (TFC FO) membranes. This paper reports on the preparation of TFC FO membrane via support-free interfacial polymerization (SFIP) technology on a macroporous substrate. SFIP technology can effectively break the bottleneck of conventional interfacial polymerization (IP) technology, which makes it difficult to form a complete polyamide (PA) film on the macroporous substrate. Briefly, the complete PA film is formed at the free water-organic phase interface and then attached to the macroporous substrate by vacuum filtration. The monomer concentration and filtration pressure were adjusted to form the optimal SFIP-PA film. Meanwhile, we chose a macroporous polyvinylidene fluoride (PVDF) microfiltration substrate and screened the pore size to reduce the structural parameters and then the internal concentration polarization, which caused the improvement of water flux. The performance of SFIP-PVDF membranes was investigated and discussed. Under the AL-FS mode with DI water and 1.0 M NaCl solution as the feed solution and draw solution, respectively, the SFIP-PVDF membrane, which used a macroporous PVDF substrate with a pore size of 0.45 μm exhibited a water flux (20 L/m2·h) and a reverse salt flux (2.5 g/m2·h). Besides, the membrane showed good stability in the 72 h test. The specific salt flux (J s /J w) of SFIP-PVDF membranes was much lower than that of IP-PVDF membranes prepared via IP technology, which were incomplete and defective, suggesting that SFIP technology was superior to IP technology. This work effectively exploits the potential of macroporous substrates for the development of high performance TFC FO membranes and provides an insight into the high performance FO membrane design. [Display omitted] • Support-free interfacial polymerization (SFIP) technology was proposed to prepare FO membranes on macroporous substrates. • Macroporous substrates with a pore size of 0.45 μm had high porosity and low tortuosity. • Low ICP, high water flux, and low reverse salt flux were exhibited. • SFIP technology was superior to IP technology on macroporous substrates. [ABSTRACT FROM AUTHOR]