For the problems that a large quantity of organic solvents and pore-foaming agents which are difficult to recycle are used in the traditional membrane preparing process, environmental
contamination is caused, the pore size distribution of membranes is wide, and the membranes lack of responsiveness, the invention provides a narrow pore size distributed hydrophilic filtering membrane sensitive to temperature and pH on the basis of the idea of
bionics by taking a
metal chloride saline solution as the
solvent. A preparation method of the membrane comprises the steps that
fibroin is grafted with
polyacrylonitrile and poly(N-isopropylacrylamide) in a homogeneous mode, and a membrane
casting solution is obtained; the membrane
casting solution is put into a water coagulating bath,
metal ions and
chloride ions are gradually scattered in water, an the
fibroin grafted with poly(N-isopropylacrylamide) and
polyacrylonitrile is subjected to phase transformation to form the membrane. The
metal ions and the
chloride ions play the role of hole forming, the
fibroin, poly(N-isopropylacrylamide) and
polyacrylonitrile are subjected to microphase separation, and water channels subjected to
ion hole forming are formed in the interface. By means of the fibroin and poly(N-isopropylacrylamide), the pH value sensitivity and
temperature sensitivity of the membrane are achieved. By means of the hole forming effect of the metal ions and the chloride ions, the
hole size of the membrane is smaller, and the
hole size distribution is narrow.