This chapter presents engineered nanomaterials synthesized or studied by the author, including cadmium-based adsorbents, carbon materials, synthetic nano-zeolites, and advanced photocatalysts, such as Ag2SO4/BiFeO3, Cd3OSO4, ferrous oxides and its components, vanadium-based (Cu3V2O8, Zn3(VO4)2), and organic photocatalysts (nanophthalhydrazide, NPHD). Experimental data illustrate how heterojunction formation, surface modification, and compositional tuning significantly enhance visible-light photocatalysis and adsorption capacity. This chapter provides an overview of novel non-natural photocatalysts and adsorbents, their mechanisms, and their application potential in sustainable environmental remediation, illustrating the author’s contributions to advanced adsorbent and photocatalyst design.