Semi-permeable membrane and manufacturing method thereof, concentration difference power generation method using semipermeable membrane

摘要

Provided is a semi-permeable membrane having high permeability which is suitable for concentration-difference power generation with high mechanical strength. The semi-permeable membrane has at least two layers: a dense layer (A) having substantial solute removal capability and a finely porous layer (B). The main component of the dense layer (A) is a polymer having the repeating unit structure shown in (Formula 1). (In this formula, Ar1, Ar2, Ar3 and Ar4 each have an aromatic ring structure; R1, R2, R3 and R4 are each a hydrogen atom or have structure P, structure P having any structure selected from among an alkyl group, alkylcarboxylic acid or a salt thereof, alkyl sulfonic acid or a salt thereof, and alkyl phosphate or a salt thereof; X is any structure selected from among a carboxylic acid group or salt thereof, a sulfonic acid group or salt thereof, and a phosphate group or salt thereof; and m and n are the constituent ratios (%) of the repeating unit structures; m = 0, n = 0, and m + n = 100 being satisfied, and at least one of R3 and R4 being structure P when m = 0.)