关键词: 膜, 纳滤, 反渗透, 硅垢

Abstract:

Silica scaling led to irreversible decline of the nanofiltration/reverse osmosis (NF/RO) membrane permeation flux and severely limited the water productivity of the membrane system, which was widely considered as a difficult challenge in water treatment process. Two types of silica scale on NF/RO membrane were introduced firstly, namely inorganic scale and combined inorganic-organic scale. Then, the effects of influent water quality, membrane surface chemical properties and topology on the formation of silica scale on membrane surface were emphatically reviewed, as well as the control strategies for the formation of silica scale on membrane surface, including influent pretreatment, scale inhibitor addition, membrane surface chemical modification and morphology regulation. Finally, the existing problems and future research directions of silica scaling control on membrane surface were summarized, mainly including the research on silica scaling behavior using model substrates with controllable surface properties, the in-depth exploration of the relationship between membrane surface chemical properties and silica scaling potential, the thorough research on the delay and inhibition mechanism of polymer scale inhibitors at the molecular level, the development of novel membrane materials to simultaneously inhibit silica scaling and organic fouling, and the establishment of a comprehensive database related to membrane surface properties and silica scaling under different influent water quality conditions, which were of important guiding significance for the development of efficient silica scale control strategies.

Key words: membranes, nanofiltration, reverse osmosis, silica scale