Removal of some potentially toxic metal ions and dyes from aqueous solutions by nanobiosorbent: A review

Adsorption techniques are widely used to remove certain groups of inorganic and organic pollutants from waters, especially those that are not easily biodegradable. Dyes and heavy metals represent one of the problematic classes. Currently, a combination of biosorption treatment and adsorption on nanomaterials is becoming more common for removal of pollutants from wastewater. This paper reviews the current nano-biosorbents applied to treat contaminants wastewater and their characteristics. Nanosized materials provide high surface area and specific affinity for heavy metals and dye adsorption from aqueous systems and biosorbents as inexpensive and biocompatible substances pose high efficiency to remove pollutants due to functional groups present in their structure viz. acetamido, alcoholic, carbonyl, phenolic, amido, amino, sulphydryl groups etc. This review examines some new nano-biosorbents, which are capable of uptake of hazardous pollutants, discusses the effects of various parameters such as pH, temperature, concentrations of pollutant, other ions, and biomass dose in solution, pretreatment method, etc. on adsorption, reports some elution and regeneration methods for adsorbent and summarizes the equilibrium and kinetic models used in batch and continuous biosorption systems which are important to determine the adsorption capacity of nano-biosorbents and to design of treatment processes.