Removal of Cadmium Ion from Water/Wastewater by Nano-metal Oxides: A Review

Environmental water samples contain wide range of contaminants including heavy metal ions that are required only in trace amount. Excessive level of metal ions in water may be detrimental to health and environment. Heavy metal poisoning has been a serious concern all over the globe. Heavy metals are well known to be non-biodegradable and tend to bio-accumulate at various concentrations. A number of methods have been proposed to remove heavy metal ions from water and among them adsorption is one of the best methods. Cadmium has been identified as one of the toxic heavy metals that enters the water through disposal of waste from industries. The increasing technological use of cadmium has raised the concern for its removal from water/wastewater. This review article provides an overview of use of nano-metal oxides as adsorbents for removal of cadmium from water/wastewater. This study involves the identification of environmentally friendly, low-cost and efficient nano-metal oxide sorbents for water/wastewater purification. A detailed comparison of reported nano-metal oxide sorbents has been done in order to rank them and to predict the knowledge gaps in this area.