Removal of heavy metals from aqueous media by biosorption

In this literature review, the removal of heavy metals from aqueous media by an environmentally friendly method, known as biosorption has been discussed. Biosorption can be referred to as an alternative to the common unsustainable industrial methods currently used. Removal of heavy metals from aqueous media by biosorption can take place by the aid of different types of biomass including algae, fungi, bacteria and plants. The mechanism(s) of biosorption can vary accordingly, mechanisms include physical adsorption, ion exchange, complexation, precipitation and transport across the cells. The efficiency of removal of heavy metals by a specific biosorbent at specified conditions can be compared by the calculated biosorption capacity of the respected biosorbent. Several factors can influence the biosorption capacity of different biosorbents, that mainly includes water pH, temperature, contact time, biomass dosage and initial heavy metal concentration. This literature review focuses on the types of biosorbents, mechanisms of biosorption and factors affecting biosorption capacity. In addition, biosorption, as a method which has the potential of competing with common industrial methods has been critically analysed.