The method relates to the modification of mineral adsorbent particularly halloysite in the form of clay or tube using dendritic polymer for treating wastewater containing ionic or nonionic water pollutants such as heavy metal ions, dyes, surfactants, high molecular weight coagulants and mineral oils. The method will increase surface activity of the adsorbent and can be applied to create positive or negative charges on the surface of the adsorbent. The modified mineral can be used as: adsorbent of pollutant such as dye, heavy metal ion, aromatic material from aqueous solutions, for removal of cations from aqueous solutions, for removal of anions from aqueous solutions, as filler in nano-composite, as nano-particle in polymeric membrane, adsorbent for soil, and special pharmaceutical application.