Chemically Modified Biosorbents and Their Role in the Removal of Emerging PharmaceuticalWaste in the Water System
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Date
2020-05-29
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MDPI
Abstract
Presence of pharmaceutically active compounds (PACs) as emerging contaminants in
water is a major concern. Recent reports have confirmed the presence of PACs in natural and
wastewater systems, which have caused several problems indicating the urgent need for their removal.
The current review evaluates the role of chemically modified biosorbents in the removal of PACs in
water. Reported biosorbents include plant and animal solid waste, microorganisms and bio-composite.
Bio-composites exhibited better prospects when compared with other biosorbents. Types of chemical
treatment reported include acid, alkaline, solvent extraction, metal salt impregnation and surface
grafting, with alkaline treatment exhibiting better results when compared with other treatments.
The biosorption processes mostly obeyed the pseudo-second-order model and the Langmuir isotherm
model in a process described mainly by ionic interaction. Desorption and regeneration capacity
are very important in selecting an appropriate biosorbent for the biosorption process. Depending
on the type of biosorbent, the cost of water treatment per million liters of water was estimated as
US $10–US $200, which presents biosorption as a cheap process compared to other known water
treatment processes. However, there is a need to conduct large-scale studies on the biosorption
process for removing PACs in water.