Efficient removal of both cationic and anionic dyes from aqueous solutions using a novel amphoteric straw-based adsorbent

► A novel amphoteric straw-based adsorbent is prepared. ► This adsorbent is proven effective in eliminating both cationic and anionic dyes. ► The fundamental adsorption behavior of the adsorbent is investigated. ► The adsorption mechanism is monolayer chemical adsorption with ion-exchange process.