Micro- and Nano-Hollow Spheres in Heavy Metal Removals from Water

Metal micro-/nano-hollow spheres have enormously been applied in numerous fields during last decade. This review will only focus on the synthetic strategies to synthesize hollow spherical structures in the enhancement of their absorption activity, especially the metal and carbon hollow spherical materials. We present comprehensive overview of synthetic strategies for hollow spherical structures which have been approached specifically in absorptivity quality towards heavy metals and arsenic. These synthetic methods are mainly categorized as hard templates, soft templates, sacrificial templates, and without templates. The review further includes application approaches towards heavy metal removals from ground water.