Chitosan (CS) with good hydrophilicity and charged property was used to modify graphene oxide (GO), the obtained GO‐CS was used as a novel modifier to fabricate thin film composite forward osmosis (FO) membranes. The results revealed that the amino groups on CS reacted with carboxyl groups on GO, and the lamellar structure of the GO nanosheets was peeled off by CS, resulting in the reducing of their thicknesses. The GO‐CS improved the hydrophilicity of polyethersulfone (PES) substrate, and their contact angles decreased to 64° with the addition of GO‐CS in the substrate. GO‐CS also increased the porosity of the substrate and surface roughness of FO membrane, thereby optimizing the water flux and reverse salt flux of FO membrane. The average water flux of the FO membrane reached the optimal flux of 21.34 L/(m² h) when GO‐CS addition was 0.5 wt%, and further addition of GO‐CS to the substrate would decrease the water flux of FO membrane, and the reverse salt flux also decreased to the lowest value of 2.26 g/(m² h). However, the salt rejection of the membrane increased from 91.4% to 95.1% when GO‐CS addition increased from 0.5 to 1.0 wt% under FO mode using 1 mol/L sodium chloride (NaCl) solution as draw solution (DS). In addition, high osmotic pressure favored water permeation, and at the same concentration of DS, magnesium chloride (MgCl₂) exhibited better properties than NaCl. These results all suggested that GO‐CS was a good modifier to fabricate FO membrane, and MgCl₂ was a good DS candidate.

中文翻译：

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壳聚糖改性的氧化石墨烯作为改进正渗透膜结构和性能的改性剂

使用具有良好亲水性和带电性的壳聚糖（CS）改性氧化石墨烯（GO），将获得的GO-CS用作新型改性剂来制备薄膜复合正向渗透（FO）膜。结果表明，CS上的氨基与GO上的羧基反应，GO纳米片的层状结构被CS剥离，导致其厚度减小。GO‐CS改善了聚醚砜（PES）基材的亲水性，并且在基材中添加GO‐CS使其接触角降至64°。GO‐CS还增加了基材的孔隙率和FO膜的表面粗糙度，从而优化了FO膜的水通量和反盐通量。FO膜的平均水通量达到最佳通量21.34 L /（m ²h）当GO‐CS添加量为0.5 wt％时，再向基材中添加GO‐CS将会降低FO膜的水通量，反盐通量也降至2.26 g /（m ² h ）。但是，当使用1 mol / L氯化钠（NaCl）溶液作为吸液（DS）时，FO模式下GO-CS的添加从0.5 wt％增加到1.0 wt％时，膜的脱盐率从91.4％增加到95.1％。此外，高渗透压有利于水的渗透，在相同的DS浓度下，氯化镁（MgCl ₂）的性能优于NaCl。这些结果都表明，GO-CS是制造FO膜的良好改性剂，而MgCl ₂是DS的良好候选物。