Waste coffee-grounds (WCG), a poorly explored source of biocompounds, were combined with chitosan (Cs) and poly(vinyl alcohol) (PVA) in order to obtain composites. Overall, WCG showed a good interaction with the polymeric matrix and good dispersibility up to 10 wt-%. At 5 wt-% WCG, the composite exhibited a noticeable enhancement (from 10 to 44%) of the adsorption of pharmaceuticals (metamizol (MET), acetylsalicylic acid (ASA), acetaminophen (ACE), and caffeine (CAF)) as compared to the pristine sample. The highest removal efficiency was registered at pH 6 and the removal followed the order ASA > CAF > ACE > MET. For all pharmaceuticals, the adsorption kinetics was found to follow the pseudo-second order model, while the adsorption mechanism was explained by the Freundlich isotherm. Reuse experiments indicated that the WCG-containing composite has an attractive cost-effectiveness since it presented a remarkable reusability in at least five consecutive adsorption/desorption cycles.
Keywords: Acetaminophen (PubChem CID: 1983); Acetic acid (PubChem CID: 176); Acetyl salicylic acid (PubChem CID: 2244); Adsorption; Caffeine (PubChem CID: 2519); Chitosan; Chitosan (PubChem CID: 71853); Chitosan composites; Coffee grounds; Emerging contaminants; Glutaraldehyde (PubChem CID: 3485); Hydrochloric acid (PubChem CID: 313); Metamizol (PubChem CID: 3111); Pharmaceutical contaminants; Poly(vinyl alcohol) (PubChem CID: 3083375); Sodium hydroxide (PubChem CID: 14798).
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