RESUMO
The accumulation of organic micropollutants (OMP) in aquatic systems is a major societal problem that can be addressed by approaches including nanofiltration, flocculation, reverse osmosis and adsorptive methods using insoluble materials (e.g. activated carbon, MOFs, nanocomposites). More recently, polymeric versions of supramolecular hosts (e.g. cyclodextrins, calixarenes, pillararenes) have been investigated as OMP sequestrants. Herein, we report our study of the use of water insoluble dimethylcatechol walled acyclic cucurbit[n]uril (CB[n]) hosts as solid state sequestrants for a panel of five OMPs. A series of hosts (H1 - H4) were synthesized by reaction of glycoluril oligomer (monomer - tetramer) with 3,6-dimethylcatechol and fully characterized by spectroscopic means and x-ray crystallography. The solid hosts sequester OMPs from water with removal efficiencies exceeding 90% in some cases. The removal efficiencies of the new hosts parallel the known molecular recognition properties of analogous water soluble acyclic CB[n]. OMP uptake by solid host occurs rapidly (≈120 seconds). Head-to-head comparison with CB[6] in batch-mode separation and DARCO activated carbon in flow-through separation mode show that tetramer derived host (H4) performs very well under identical conditions. The work establishes insoluble acyclic CB[n]-type receptors as a promising new platform for OMP sequestration.
Assuntos
Transtorno Bipolar/etiologia , Terapia por Estimulação Elétrica/efeitos adversos , Epilepsia/terapia , Nervo Vago/fisiologia , Adulto , Terapia por Estimulação Elétrica/instrumentação , Terapia por Estimulação Elétrica/métodos , Falha de Equipamento , Feminino , Humanos , Próteses e Implantes/efeitos adversosRESUMO
The experiences of black staff in the workplace are well known: inequality of treatment; lack of opportunities for advancement; exodus when they fail to gain promotion; and little representation on trust decision-making boards.
