A method for the treatment of a substrate; the substrate comprises hollow fibre membranes, each having a side wall, comprising a base material, and an inner lumen, which is delimited by the side wall; the side wall has an outer surface provided with pores with a diameter from approximately 0.1 um to approximately 15 um and an inner surface provided with pores with a diameter from approximately 5 nm to approximately 200 nm; the base material is selected from the group consisting of polysulfone, polyethersulfone, derivatives thereof and a combination thereof; wherein the diameter of the pores is determined by scanning electron microscopy by measuring the dimension of a pore in one direction, taken at random; wherein the method comprises: a combination step, during which the substrate is combined with graphene oxide so as to obtain an intermediate compound; wherein during the combination step, the substrate and the graphene oxide are combined with each another inside a first liquid; a removal step, which is at least partially subsequent to the combination step and during which at least part of the first liquid is removed from the intermediate compound; a fixing step, during which the intermediate compound is thermally treated so that the graphene oxide is at least partially fixed to the substrate, thus obtaining a treated material comprising treated hollow fibre membranes; the fixing step being at least partially subsequent to the removal step; wherein during the fixing step, the intermediate compound undergoes a treatment selected from a group consisting of: treatment by means of microwaves, treatment by means of heating and a combination thereof; the microwave treatment entails treating the intermediate compound with microwaves having a power of approximately at least 50 W for approximately at least 20 minutes; the treatment by means of heating entails treating the intermediate compound in an oven having a temperature of approximately at least 80°C for approximately at least 90 minutes. the side wall has an outer surface provided with pores with a diameter from approximately 0.1 um to approximately 15 um and an inner surface provided with pores with a diameter from approximately 5 nm to approximately 200 nm; the base material is selected from the group consisting of polysulfone, polyethersulfone, derivatives thereof and a combination thereof; wherein the diameter of the pores is determined by scanning electron microscopy by measuring the dimension of a pore in one direction, taken at random; wherein the method comprises: a combination step, during which the substrate is combined with graphene oxide so as to obtain an intermediate compound; wherein during the combination step, the substrate and the graphene oxide are combined with each another inside a first liquid; a removal step, which is at least partially subsequent to the combination step and during which at least part of the first liquid is removed from the intermediate compound; a fixing step, during which the intermediate compound is thermally treated so that the graphene oxide is at least partially fixed to the substrate, thus obtaining a treated material comprising treated hollow fibre membranes; the fixing step being at least partially subsequent to the removal step; wherein during the fixing step, the intermediate compound undergoes a treatment selected from a group consisting of: treatment by means of microwaves, treatment by means of heating and a combination thereof; the microwave treatment entails treating the intermediate compound with microwaves having a power of approximately at least 50 W for approximately at least 20 minutes; the treatment by means of heating entails treating the intermediate compound in an oven having a temperature of approximately at least 80°C for approximately at least 90 minutes. a combination step, during which the substrate is combined with graphene oxide so as to obtain an intermediate compound; wherein during the combination step, the substrate and the graphene oxide are combined with each another inside a first liquid; a removal step, which is at least partially subsequent to the combination step and during which at least part of the first liquid is removed from the intermediate compound; a fixing step, during which the intermediate compound is thermally treated so that the graphene oxide is at least partially fixed to the substrate, thus obtaining a treated material comprising treated hollow fibre membranes; the fixing step being at least partially subsequent to the removal step; wherein during the fixing step, the intermediate compound undergoes a treatment selected from a group consisting of: treatment by means of microwaves, treatment by means of heating and a combination thereof; the microwave treatment entails treating the intermediate compound with microwaves having a power of approximately at least 50 W for approximately at least 20 minutes; the treatment by means of heating entails treating the intermediate compound in an oven having a temperature of approximately at least 80°C for approximately at least 90 minutes.