Comparison of different removal techniques for selected pharmaceuticals

Abstract

a b s t r a c tRecently, there is an emergence of endocrine-disrupting compounds, pharmaceuticals, and personal care products (EDC/PPCPs) as important pollutants to remove from drinking water and reclaimed wastewater. In this work, the efficiency of removing pharmaceuticals (PCs) from model aqueous solutions and raw wastewater with ultrafiltration (UF), nanofiltration (NF), activated carbon adsorption (AC), biological methods (SBR) and oxidation with ClO 2 was investigated. Some treatments have also been used as combined processes: UF + NF, UF + AC, SBR + ClO 2 . Ibuprofen, Acetaminophen, Diclofenac, Sulfamethoxazole, Clonazepam, and Diazepam were selected as model compounds. In order to evaluate their removal, PC solutions were also considered at several operating conditions (pH, conductivity, concentration, and temperature), and optimal conditions were obtained. Experiments were performed at usual PC concentrations in wastewaters: 1000 ng/L for Ibuprofen and Acetaminophen, 300 ng/L for Diclofenac, Sulfamethoxazole, Clonazepam, and Diazepam. Separation was evaluated by liquid chromatography-mass spectroscopy. Results indicated that the removal efficiency depends on their Log K OW , which is intrinsically related to their hydrophobicity and then, to their adsorption onto the surface (UF, NF, and AC). Also, NF, AC, and combined processes (UF + NF, UF + AC) were the most suitable separation techniques to obtain high removal efficiencies for most of the PCs used, except for Acetaminophen (which showed great removal efficacy using SBR). UF presented low removal yields for all PCs tested. ClO 2 treatment was more effective at high concentration (50 mg ClO 2 /L). Furthermore, results also showed that there are significant differences on the performance of the processes applied and which treatment is the most effective for each PC analyzed.

Removal of pharmaceutically active compounds by using low-pressure membrane processes

“…where V is the volume of permeate stream (L), Am is the effective membrane area by selected reaction monitoring (SRM) and were previously described [10,19,20]. [19,21].…”

Incorporation of Graphene-Related Carbon Nanosheets in Membrane Fabrication for Water Treatment: A Review

“…Removal efficiency of solutes is also related to their octanol water partition coefficient (log K OW ), which is related to their hydrophobicity, and interaction with hydrophobic membranes. High log K OW (compounds such as diazepam, ibuprofen and diclofenac) and low solubility can lead to an increase in rejection, and this in turn can in part be attributed to hydrophobic adsorption to the membrane surface [94,95]. Ibuprofen, for example, in its neutral form, has a relatively high hydrophobicity, and reasonably high levels of adsorption to hydrophobic membrane surfaces will typically be observed.…”

“…For example, Clonazepam is protonated at highly acidic conditions and it becomes non-protonated (neutral) when the pH is increased up to 6. However, under alkaline conditions, the compound changes to its enolic form, which has an enhanced water affinity due to the charge on the molecule; this in turn leads to reduction in retention [94]. …”

Psychiatric Pharmaceuticals as Emerging Contaminants in Wastewater

“…Among the different advanced treatments, adsorption on activated carbon has been recognized as a highly efficient technique for the removal of emerging contaminants, such as pharmaceuticals (Snyder et al 2007b;Vona et al 2015;Rakić et al 2015). Adsorption on activated carbon is a well-known technique for the removal of organic compounds in drinking water treatment (Delgado et al 2012).…”

“…Due to its hydrophobic surface, activated carbon tends to adsorb nonpolar organic compounds, although ion-exchange interactions may allow the removal of polar contaminants. The functional groups of the surface, mainly composed by oxygen and hydrogen, contribute to the acid-base properties of the surface, which has an effect on particular interactions with adsorbed solutes (Vona et al 2015). The removal capacity of pharmaceuticals tends to decrease in wastewater with a high contamination level, since the natural organic matter present in water competes for the adsorption sites in activated carbon (Snyder et al 2003).…”