Nanocellulose-Based Adsorption for the Removal of Heavy Metal from Wastewater—A Review

Water contamination is worsening with increasing industrialization. The effluents released from various kinds of industries adversely affect water bodies through heavy metal contamination. Heavy metals present in industrial waste, such as arsenic, lead, mercury, copper, titanium, chromium, zinc, nickel, cadmium, and vanadium, have harmful effects on all living organisms. To minimize the risk caused by heavy metals, eliminating these heavy metals via effective methods is necessary. Nanocellulose, one of the many environmentally friendly functional nanomaterials, is becoming more popular for its utilization in conserving the environment through technology because of its many distinctive qualities and functions. Typically, nanocellulose is created by bacteria or by the breakdown of naturally existing polymers. One advantage of this natural polymer is that it is widely distributed and abundant on Earth since it is present in most plants and organic wastes. In comparison to the unmodified form of nanocellulose, the functionalized NCs improve the matrix compatibility and quickly form robust network structures, which are crucial for the creation of channels for improved impurity adsorption and increased water flow. The regeneration characteristics of nanocellulose as an adsorbent also implies immense performance after several adsorption–desorption cycles, which bodes well for its stability in scaling-up applications. This article provides an in-depth examination of the use of modified nanocellulose and its forms in heavy metal removal from wastewater. The current study also offers numerous viewpoints concerning the dependability of isotherms related to adsorption and models that are kinetic, as well as speculative ideas on adsorption thermodynamics.