Due to rapid population growth, technological advancement and industrial revolution, the rate of generated waste effluents has become a grave concern. Cesium which possesses high fission yield is generally transferred to liquid wastes especially those emanated from the nuclear power plants, reprocessing of spent fuels, nuclear weapon testing and radionuclides production facilities for medical applications etc. Radiocesium ( 137 Cs) is one of the hazardous radionuclides creates adverse effects on human health and environment.Due to its physical (T 1/2 =30.17 y) and chemical characteristics (alkalinity, solubility etc.), it can be easily assimilated by the living organisms. As a result, the removal of cesium from wastewater is imperative from the health point of view. Several techniques are implemented but in recent time, adsorption has been gaining increasing attention to the scientific community owing to a number of reasons. Hence, this paper presents an overview on sorption of cesium from wastewaters. Consequently, several critical parameters such as sorption capacity, percentage efficiency and the influence of several factors on cesium uptake by various adsorbents have been reviewed in details. 6
Adsorption/ ion exchange of cesium ions onto synthesized and natural adsorbentsThis is a method by which a sorbate is removed or accumulated on the immobile solid from its liquid or gaseous surroundings, and usually referred to as liquid-solid interaction.Normally, this process occurs at the phase of the sorbent and so, it is a surface-based phenomenon [40] . Adsorption can take different dimensions, if the process is initiated as a result of weak intermolecular forces (Van der Waals interactions) then it is specifically called physisorption and this force being weak in nature results into reversible adsorption, but if occurs due to the formation of chemical bonds between the molecules of adsorbate and the adsorbent it is known as chemosorption. Ion exchange on the other hand is a reversible chemical process in which an ion from solution exchanges with similarly charged ion attached to the adsorbent, the solid particle [40] . Due to their common features, adsorption and ion exchange are grouped together as sorption processes for effective sequester of toxins from waste/drinking waters [41,42] . Adsorption is recognized as an effective and economic method for the removal of radionuclides compared to the other approaches owing to a number of reasons such as; the ease of design and operation, adsorbate-specificity, better treatment with no/little secondary waste generation, possibility of using at low concentration, high efficient performance, ease of regeneration and reuse, suitability for both batch and column studies, and the availability of the adsorbents [43] . Normally, a good adsorbent must have a large surface area, good macroporous structure and be stable under chemical, radiation and thermal reaction conditions. However, the behaviour and efficiency of adsorbents can also be influenced by the condition of the so...