Developing Polycation-Clay Sorbents for Efficient Filtration of Diclofenac: Effect of Dissolved Organic Matter and Comparison to Activated Carbon

Abstract

The presence of nanoconcentrations of persistent pharmaceuticals in treated wastewater effluent and in surface water has been frequently reported. A novel organic-inorganic hybrid sorbent based on adsorbing quarternized poly vinylpyridinium-co-styrene (QPVPcS) to montmorillonite (MMT) was designed for the removal of the anionic micropollutants. QPVPcS-clay composites were characterized by X-ray diffraction, FTIR, thermal gravimetric analysis, Zeta potential and element analysis. Based on these measurements polymer-clay micro- and nanostructures, as a function of polymer loading, were suggested. The affinity of the anionic pharmaceutical, diclofenac (DCF), to the composite was high and did not decrease dramatically with an increase of ionic strength, indicating that the interactions are not only electrostatic. The presence of humic acid (HA) did not hinder DCF removal by the composite; whereas, its filtration by granulated activated carbon (GAC) was compromised in the presence of HA. The kinetics and adsorption at equilibrium of DCF to the composite and to GAC were measured and modeled by the time dependent Langmuir equation. The adsorption of DCF to the composite was significantly faster than to GAC. Accordingly, the filtration of micro- and nanoconcentrations of DCF by composite columns, in the presence of HA, was more efficient than by GAC columns.

Polymer supports for the removal and degradation of hazardous organic pollutants: an overview

“…The adsorption of diazinon was more significant for protonated pyridine groups due to a more specific interaction with the pesticide through hydrogen bonds . Similarly, the same adsorbent was studied for the removal of the herbicides simazine, atrazine and terbuthylazine, while its quaternized analogue adsorbent was studied for the removal of diclofenac …”

“…62 Similarly, the same adsorbent was studied for the removal of the herbicides simazine, atrazine and terbuthylazine, 63 while its quaternized analogue adsorbent was studied for the removal of diclofenac. 64 Further, Bhattacharyya and Ray removed Congo red and methyl violet from water using nanoclay-filled composite hydrogels of poly(acrylic acid) and poly(ethylene glycol). The maximum adsorption capacities of these dyes were 225 mg L -1 for Congo red and 92.14 mg L -1 for methyl violet, showing that this type of hydrogel can also be used for the removal of other cationic dyes or metal ions from water.…”

Ag3PO4 Deposited on CuBi2O4 to Construct Z-Scheme Photocatalyst with Excellent Visible-Light Catalytic Performance Toward the Degradation of Diclofenac Sodium

“…Since the removal rate of DS after the treatment of conventional wastewater treatment plants (WWTPs) is no more than 20%, most of the remaining DS would be discharged along with effluents into estuaries, rivers, surface water, ground water, and even drinking water [3,4,5]. The DS frequently detected in aquatic environments (estuaries, rivers, surface water, ground water, and even drinking water) has aroused great concern in that it endangers human health and poses great risks to the environment [6,7]. Over the last several years, various technologies encompassing adsorption [7,8], photocatalysis [9], Fenton reagents [10], ozonation [11], etc.…”

Designing a regenerable stimuli-responsive grafted polymer-clay sorbent for filtration of water pollutants

“…We have demonstrated that composites based on protonated poly(4-vinylpyridine) (PVP) electrostatically adsorbed, by cation exchange, to montmorillonite clay (MMT) perform better than other polymer clay composites [12] due to the range of interactions that PVP can form with micropollutants. In addition, the pyridine group of the polymer can be further functionalized to improve composite performance [13,14]. Indeed, adsorbed functionalized PVP–MMT composites were efficient sorbents for filtration of a variety of pollutants including dissolved organic matter [14], pyrene [15], phenolic derivatives [16], pharmaceuticals [13] and pesticides [12,17].…”