Understanding the factors affecting adsorption of pharmaceuticals on different adsorbents - A critical literature update.

Remediation of emerging pharmaceutically active compounds (PhACs) as micropollutants in wastewater is of foremost importance as they can cause extremely detrimental effects on life upon bioaccumulation and generation of drug-resistance microorganisms. Presently used physicochemical treatments, such as electrochemical oxidation, nanofiltration and reverse osmosis, are not feasible owing to high operating costs, incomplete removal of contaminants along with toxic by-products formation. Adsorption with the utilization of facile and efficient nanoparticulate adsorbents having distinctive properties of high surface area, excellent adsorption capacity, ability to undergo surface engineering and good regeneration displays great potential in this aspect along with the incorporation of nanotechnology for effective treatment. The application of such nanosorbents provides optimal performance under a wide range of physicochemical conditions, decreased secondary pollution with reduced mechanical stress along with excellent organic compound sequestration capacity, which in turn improves the quality of potable water in a sustainable way compared to current treatments. The present review intends to consolidate the range of factors that affect the process of adsorption of different PhACs on to various nanosorbents and also highlights the adsorption mechanism aiding in the retrieval.

Performance study on adsorptive removal of acetaminophen from wastewater using silica microspheres: Kinetic and isotherm studies.

Owing to the global industrialization, a new generation of pharmaceutical pollutants with high toxicity and persistency have been detected. In the present study, silica microspheres, a promising adsorbent has been employed to investigate the extent of removal of prevalent therapeutic acetaminophen, an emerging micropollutant, from wastewater in isolated batch experiments. The BET surface area of the adsorbent was 105.46 m2/g with a pore size of 15 nm. Characterization of adsorbent by scanning electron microscopy analysis revealed the microparticulate nature with a 15 ± 5 µm particle size. Optimization of reaction parameters for enhanced assimilative removal of pollutants was performed and the highest adsorption of 96.7% of acetaminophen with an adsorption capacity of 89.0 mg/g was observed upon contact time of only 30 min. Mild process conditions of pH 5.0, 20 ppm of acetaminophen, temperature of 303 K, and 100 ppm sorbent concentration further aided in the removal process. Obtained data were best corresponded with the Freundlich isotherm (n = 2.685), indicating highly favorable adsorption. Acetaminophen adsorption kinetics obeyed the pseudo second order and feasible energetic changes were yielded through the thermodynamic analysis. Silica microspheres recovery carried out through a single-step desorption process had a 99.14% retrieval ability.