Chemically Modified Biosorbents and Their Role in the Removal of Emerging Pharmaceutical Waste in the Water System

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.

Cleaner Approach for Atrazine Removal Using Recycling Biowaste/Waste in Permeable Barriers

“…The selection of a suitable desorption eluent, with a high affinity for the sorbate and able to remove it from the surface of the sorbent, without substantially changing its morphology and efficiency, while being competitive and environmentally friendly, is seen as challenge in the field of biosorption [31].…”

“…After the selection of the best desorbing eluent, it is essential to evaluate the number of cycles of adsorption/regeneration that selected materials can cope with, as they may reduce the overall operational costs. These processes can be performed either in batch or continuous procedures; however, when the pollutant retention is conducted in PRB columns, it is better to perform the regeneration step in continuous mode [31]. When the PRB column becomes saturated, the adsorption process is stopped and switched to the desorption/regeneration step.…”

“…The reuse of residues allows their life cycle to increase and energy requirements to decrease, resources and emissions [72]. Moreover, it allows the waste disposal problem and the costs for producing new adsorbents for water treatment to be reduced [31]. Through waste valorization, a circular and sustainable economy is promoted, a prevailing priority in the EU in order to achieve a continuous decrease in the negative environmental effects of services and products throughout their life cycle [73].…”

“…There are several reported wastebased materials with proven sorption capacity; however, very few studies report their proneness to regeneration [41]. Some of the reported materials are not easily regenerated, as their morphology and adsorption capacity are affected after desorption processes [31]. The selection of an effective, but also eco-friendly and competitive, desorption process that enables adsorbent reusability is a crucial step of the overall project.…”

The combined chemical and mechanical modifications of cigarette: a novel methodology to reduce harmful effects

“…The performance of the biosorption process is depending on the chemical, structural, morphological, and surface properties of the used biosorbent (Adewuyi 2020). Thus, having an idea about the surface of biosorbent used can facilitate the prediction of the main reactions that may occur during the removal of Amaranth dye by biosorption and bisorption coupling AO.…”