Abstract: The invention relates to the use of grafted celluloses, in fibrous form, particularly paper, non-woven web, flock, yarn, woven fabric, comprising quaternary ammonium functions, for eliminating humic substances and nitrates contained in natural water or industrial sewage.The grafted cellulose is for example obtained by radical grafting with the aid of a non-saturated monomer with quaternary ammonium function, particularly quaternized diethyl-amino-ethyl methacrylate.Its capacity is greater than or equal to 0.2 meq/g.

Abstract: The process consists firstly in adding, to the solution, an excess of a polyelectrolyte capable of forming an ionic association with the dissolved substance which it is desired to retain, and then in bringing the solution thus obtained into contact with a material possessing ionic groups which retain the polyelectrolyte by virtue of its ionic groups not associated with the said substance. The solution and the material can be brought into contact either by filtration or by tangential bathing. The polyelectrolyte can be retained either by ion exchange or by a charge repulsion effect.The material is advantageously a fibrous material of which the ionic groups are obtained by grafting.