title: Single and multi-component adsorption of salicylic acid, clofibric acid, carbamazepine and caffeine from water onto transition metal modified and partially calcined inorganic-organic pillared clay fixed beds.
abstract: Fixed-beds of transition metal (Co(2+), Ni(2+) or Cu(2+)) inorganic-organic pillared clays (IOCs) were prepared to study single- and multi-component non-equilibrium adsorption of a set of pharmaceutical and personal care products (PPCPs: salicylic acid, clofibric acid, carbamazepine and caffeine) from water. Adsorption capacities for single components revealed that the copper(II) IOCs have better affinity toward salicylic and clofibric acid. However, multi-component adsorption tests showed a considerable decrease in adsorption capacity for the acids and an unusual selectivity toward carbamazepine depending on the transition metal. This was attributed to a combination of competition between PPCPs for adsorption sites, adsorbate-adsorbate interactions, and plausible pore blocking caused by carbamazepine. The cobalt(II) IOC bed that was partially calcined to fractionate the surfactant moiety showcased the best selectivity toward caffeine, even during multi-component adsorption. This was due to a combination of a mildly hydrophobic surface and interaction between the PPCP and cobalt(II). In general, the tests suggest that these IOCs may be a potential solution for the removal of PPCPs if employed in a layered-bed configuration, to take care of families of adsorbates in a sequence that would produce sharpened concentration wavefronts.
authors.affiliation: Department of Chemical Engineering, University of Puerto Rico-Mayagüez Campus, Mayagüez, PR 00681-9000 United States.
authors.forename: Wilman A
authors.initials: WA
authors.lastname: Cabrera-Lafaurie
authors.affiliation: Department of Chemistry, University of Puerto Rico-Mayagüez Campus, Mayagüez, PR 00681-9000 United States.
authors.forename: Félix R
authors.initials: FR
authors.lastname: Román
authors.affiliation: Department of Chemical Engineering, University of Puerto Rico-Mayagüez Campus, Mayagüez, PR 00681-9000 United States. Electronic address: arturoj.hernandez@upr.edu.
authors.forename: Arturo J
authors.initials: AJ
authors.lastname: Hernández-Maldonado
mesh_terms: D000327:Adsorption; D001546:Bentonite / Q000737:chemistry*; D002110:Caffeine / Q000737:chemistry; D002220:Carbamazepine / Q000737:chemistry; D002995:Clofibric Acid / Q000737:chemistry; D003035:Cobalt / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D009532:Nickel / Q000737:chemistry*; D004364:Pharmaceutical Preparations / Q000737:chemistry*; D020156:Salicylic Acid / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods
chemical_list: D004364:Pharmaceutical Preparations; D014874:Water Pollutants, Chemical; D001546:Bentonite; D002220:Carbamazepine; D003035:Cobalt; D002110:Caffeine; D002995:Clofibric Acid; D003300:Copper; D009532:Nickel; D020156:Salicylic Acid
keywords: Clays; Competitive adsorption; Emerging contaminants; Fixed beds; PPCP; Transition metals