Advanced Water Treatment: Adsorption discusses the application of adsorption in water purification. The book reviews research findings on the preparation of five different nano/microcellulose-based adsorbents, their characterization, the study of adsorption kinetics and isotherms, the determination of adsorption mechanisms, and an evaluation of adsorbents’ regeneration properties. The book describes modification microfibrillated cellulose (MFC), the use of succinic anhydride modified mercerized nanocellulose, and aminosilane and hydroxyapatite modified nanostructured MFC for the removal of heavy metals from aqueous solutions. Final sections describe the use of aminosilane, epoxy and hydroxyapatite modified MFC as a promising alternative for H2S removal from aqueous solutions, along with new findings on the adsorption properties of carbonated hydroxyapatite modified MFC as multifunctional adsorbent for the removal of both cations and anions ions from water.