State Key Laboratory of Separation Membranes and Membrane Processes, School of Environmental Science and Engineering, Tiangong University, Tianjin 300387, China; School of Chemical Engineering and Technology, National Engineering Research Center of Distillation Technology, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin University, Tianjin 300072, China; Tianjin Haiyuanhui Technology Co., Ltd., Tianjin 300457, China.
State Key Laboratory of Separation Membranes and Membrane Processes, School of Environmental Science and Engineering, Tiangong University, Tianjin 300387, China.
Chemosphere. 2022 Dec;308(Pt 1):136300. doi: 10.1016/j.chemosphere.2022.136300. Epub 2022 Sep 2.
A novel gravity sedimentation - forward osmosis (G-FO) hybrid reactor was built up for separating and concentrating the biomass from the algal-rich water (microalgal dewatering). The extracellular organic matter (EOM) from Chlorella vulgaris (C. vulgaris) was divided into dissolved EOM (dEOM) and bound EOM (bEOM). Water flux, flux recovery rate and moisture content (MC) were investigated. Through sedimentation rate, zeta potential and hydrophilicity/hydrophobicity to analyze the experimental results. Scanning electronic microscopy (SEM) was used to observe the different morphologies of accumulated algae cells and EOM on the surface of the membrane. The results showed that cell + bEOM solution had the fastest sedimentation rate and fewest negative charge, so the pollutants accumulated more easily on the membrane surface, resulting in the highest flux decline. Its algal cake layer was the densest from the view of SEM. Cell + bEOM + dEOM solution had the lowest flux decline and the cake layer was the loosest. Cell + bEOM solution had the most severe irreversible fouling and the lowest flux recovery rate (FRR). The membrane fouling of cell solution was lower than that of cell + bEOM + dEOM solution, and the FRR of cell solution was almost 100%. According to the nonionic macro-porous resin fraction results of EOM, cell + bEOM + dEOM solution contained more hydrophilic components, resulting in the lowest MC. On the contrary, cell + bEOM solution showed the highest MC, which contained more hydrophobic components. Effects of bEOM and dEOM on microalgae dewatering performance of a novel gravity sedimentation - forward osmosis (G-FO) hybrid system were investigated, which provided a theoretical basis for large-scale application of FO technology for microalgae dewatering.
建立了一种新型重力沉降-正向渗透（G-FO）混合反应器，用于从富藻水中分离和浓缩生物质（微藻脱水）。从普通小球藻（C. vulgaris）中分离出胞外有机物（EOM），分为溶解胞外有机物（dEOM）和结合胞外有机物（bEOM）。考察了水通量、通量恢复率和水分含量（MC）。通过沉降速率、zeta 电位和亲水性/疏水性来分析实验结果。扫描电子显微镜（SEM）用于观察膜表面上不同形态的积累藻类细胞和 EOM。结果表明，细胞+bEOM 溶液具有最快的沉降速率和最少的负电荷，因此污染物更容易在膜表面积累，导致通量下降最高。从 SEM 图上看，其藻饼层最致密。细胞+bEOM+dEOM 溶液通量下降最小，饼层最疏松。细胞+bEOM 溶液不可逆污染最严重，通量恢复率（FRR）最低。细胞溶液的膜污染低于细胞+bEOM+dEOM 溶液，且细胞溶液的 FRR 几乎为 100%。根据 EOM 的非离子大孔树脂级分结果，细胞+bEOM+dEOM 溶液含有更多的亲水性成分，因此 MC 最低。相反，细胞+bEOM 溶液表现出最高的 MC，其中含有更多的疏水性成分。考察了 bEOM 和 dEOM 对新型重力沉降-正向渗透（G-FO）混合系统微藻脱水性能的影响，为 FO 技术在微藻脱水方面的大规模应用提供了理论依据。
