A novel and sustainable composite of L@PSAC for superior removal of pharmaceuticals from different water matrices: Production, characterization, and application.

This study endeavors to develop cost-effective environmentally friendly technology for removing harmful residual pharmaceuticals from water and wastewater by utilizing the effective adsorption of pistachio shell (PS) biochar and the degradation potency of laccase immobilized on the biochar (L@PSAC). The carbonatization and activation of the shells were optimized regarding temperature, time, and NH4NO3/PS ratio. This step yielded an optimum PS biochar (PSAC) with the highest porosity and surface area treated at 700 °C for 3 h using an NH4NO3/PS ratio of 3% wt. The immobilization of laccase onto PSAC (L@PSAC) was at its best level at pH 5, 60 U/g, and 30 °C. The optimum L@PSAC maintained a high level of enzyme activity over two months. Almost a complete removal (>99%) of diclofenac, carbamazepine, and ciprofloxacin in Milli-Q (MQ) water and wastewater was achieved. Adsorption was responsible for >80% of the removal and the rest was facilitated by laccase degradation. L@PSAC maintained effective removal of pharmaceuticals of ≥60% for up to six treatment cycles underscoring the promising application of this material for wastewater treatment. These results indicate that activated carbon derived from the pistachio shell could potentially be utilized as a carrier and adsorbent to efficiently remove pharmaceutical compounds. This enzymatic physical elimination approach has the potential to be used on a large-scale.

Visible-light activation of TiO2 by dye-sensitization for degradation of pharmaceutical compounds.

This work reports the improvement in the photon absorption and degradation of acetaminophen (ACF) and diclofenac (DFC) by photosensitizing TiO2 with two types of dyes Eosin Y (Ey) and Rhodamine B (RhB). Experimental tests were carried out in a solar simulator for three hours for different systems and both pollutants. The influences of the TiO2 concentration (100, 200 and 800 mg L-1) and the catalyst-dye ratio (2%, 5% and 10%) were investigated. The degradation of the compounds was higher in the presence of TiO2-Ey compared to the TiO2-RhB and TiO2 for both pharmaceutical compounds, which was attributed to the anionic nature of Ey. DFC total degradation was achieved using 100 mg L-1 of catalyst loading and 10% of catalyst-dye ratio and the highest ACF degradation (71%) was obtained at 800 mg L-1 of catalyst loading and 5% of catalyst-dye ratio. The photon absorption was studied for both dyes using the six-flux absorption scattering model (SFM) for estimating the LVRPA (local volumetric rate of photon absorption). This was done by modifying the apparent optical thickness equation. It was found that the presence of dye in the photocatalytic systems considerably increases the LVRPA. The rate coefficients for the degradation of pharmaceutical compounds in the presence of the organic dyes were also obtained.

Simultaneous extraction of acidic and basic drugs via on-chip electromembrane extraction using a single-compartment microfluidic device.

In this study, a new chip was designed for simultaneous extraction of acidic and basic drugs by a single chamber on-chip electromembrane extraction (CEME) followed by high performance liquid chromatography. Diclofenac (DIC) and nalmefene (NAL) were selected as acidic and basic model analytes, respectively. In this device, simultaneous extraction of the analytes was carried out using a single compartment. The chip was composed of three PMMA (polymethyl methacrylate) parts with sandwiched structures and carved spiral microfluidic channels in each part. The middle part was cut and an "M" pattern provided interfaces for contact between the sample solution flow and two porous polypropylene sheets on both sides. Two other parts had the same spiral channels dedicated to the corresponding acceptor phases of the acidic and basic analytes and were located at both sides. Each polypropylene sheet was impregnated with the appropriate organic solvent for the acidic and basic analytes. Two platinum electrodes connected to a power supply were mounted at the bottom of the acceptor channels. These electrodes provided the electrical fields across SLMs to extract the analytes from a single sample flow. When the extraction was completed, the acceptor solutions were collected, mixed, and then injected into the chromatographic system. The effective parameters on the extraction efficiency were investigated and optimized. Under the optimal conditions, the calibration curves were linear in the range of 9.0-500 µg L-1 for NAL and 11.0-500 µg L-1 for DIC with the coefficient of determination (R2) higher than 0.9913. The relative standard deviations (RSD%) based on five replicate measurements were less than 6.3%. LOD values were 4.0 and 3.0 µg L-1 for DIC and NAL, respectively. Finally, the method was successfully applied to determine DIC and NAL in the human urine samples and satisfactory results were obtained (recovery ≥90).

A nanohybrid composed of polyoxotungstate and graphene oxide for dispersive micro solid-phase extraction of non-steroidal anti-inflammatory drugs prior to their quantitation by HPLC.

A nanohybrid was prepared from polyoxotungstate anion and graphene oxide (POT/GO) and characterized in terms of porosity by applying Fourier transform infrared and transmission electron microscopy. The nanohybrid was applied as a sorbent for the dispersive micro solid-phase extraction of the non-steroidal anti-inflammatory drugs (NSAIDs) ibuprofen, diclofenac, and naproxen. Different types of sorbents were compared, and the POT/GO nanohybrid was found to have the best adsorption affinity. The NSAIDs were quantified via HPLC with UV detection. Under the optimum conditions, the limits of detection (at an S/N ratio of 3) range between 0.02-0.03 ng.mL-1, and the linear response ranges extend from 0.08-200 ng.mL-1, respectively. The relative standard deviations (RSDs) for five replicates at three concentration levels (0.1, 5 and 100 ng.mL-1) of NSAIDs ranged from 4.1 to 6.1%. The applicability of the method was confirmed by analyzing spiked real water samples, and satisfactory results were obtained, with recoveries between 95.6 and 99.6%. Graphical abstract Schematic representation of the polyoxotungstate/graphene oxide nanohybrid preparation.

A magnetic adsorbent grafted with pendant naphthyl polymer brush for enrichment of the nonsteroidal anti-inflammatory drugs indomethacin and diclofenac.

Poly(2-naphthyl acrylate) was first grafted onto silica-coated magnetic nanoparticles by surface-initiated atom transfer radical polymerization to prepare a reversed-phase magnetic adsorbent. The resulting polymer brush displays enhanced extraction efficiency by offering active sites on the surfaces of adsorbent. It was applied to the preconcentration of the non-steroidal antiinflammatory drugs (NSAIDs) indomethacin (InDo) and diclofenac (DIC). These drugs interact with the sorbent through hydrophobic and π-interactions, and via electrostatic attraction. By coupling the magnetic solid-phase extraction with HPLC, a method for analysis of InDo and DIC in the environmental water samples was established. The limits of detection range from 0.62 to 0.64 ng·mL-1, and the relative standard deviations for intra-and inter-day analyses of spiked water samples are <11.9%, and relative recoveries are between 62.1 and 96.7%. Graphical abstract A reversed-phase magnetic adsorbent was prepared by grafting poly(2-naphthyl acrylate) brush on the surface of silica coated magnetic nanoparticles. Due to the two conjugated aromatic rings of the monomer, the polymer brush can effectively extract non-steroidal anti-inflammatory drugs through strong π- and hydrophobic interactions.

Single-drop microextraction combined in-line with capillary electrophoresis for the determination of nonsteroidal anti-inflammatory drugs in urine samples.

This study describes a method to determine nonsteroidal anti-inflammatory drugs (NSAIDs) in urine samples based on the use of single-drop microextraction (SDME) in a three-phase design as a preconcentration technique coupled in-line to capillary electrophoresis. Different parameters affecting the extraction efficiency of the SDME process were evaluated (e.g. type of extractant, volume of the microdroplet, and extraction time). The developed method was successfully applied to the analysis of human urine samples with LODs ranging between 1.0 and 2.5 µg/mL for all of the NSAIDs under study. This method shows RSD values ranging from 8.5 to 15.3% in interday analysis. The enrichment factors were calculated, resulting 27-fold for ketoprofen, 14-fold for diclofenac, 12-fold for ibuprofen, and 44-fold naproxen. Samples were analyzed applying the SDME-CE method and the obtained results presented satisfactory recovery values (82-115%). The overall method can be considered a promising approach for the analysis of NSAIDs in urine samples after minimal sample pretreatment.

Rapid analysis of diclofenac and some of its transformation products in the three-spined stickleback, Gasterosteus aculeatus, by liquid chromatography-tandem mass spectrometry.

Pharmaceuticals are emerging organic contaminants ubiquitously present in the environment due to incessant input into the aquatic compartment mainly resulting from incomplete removal in wastewater treatment plants. One of the major preoccupations concerning pharmaceuticals released into surface waters is their potential for bioaccumulation in biota, possibly leading to deleterious effects on ecosystems especially as they could affect a broad variety of organisms living in or depending on the aquatic environment. Thus, the development of accurate and sensitive methods is necessary to detect these compounds in aquatic ecosystems. Considering this need, this study deals with the analytical development of a methodology to quantify traces of diclofenac together with some of its biotic and abiotic transformation products in whole-body tissue of three-spined stickleback. A simple and reliable extraction method based on a modified QuEChERS extraction is implemented on 200 mg of fish. The detection and quantification of the ten target compounds are performed using liquid chromatography-tandem mass spectrometry. The whole process was successfully validated regarding linearity, recovery, repeatability, and reproducibility. The method limits of detection and quantification do not exceed 1 ng/g. To reproduce environmental conditions, we measured the concentration of DCF and its transformation products in three-spined sticklebacks after a 6-month exposure in mesocosms at several levels of DCF ranging from 0.05 to 4.1 µg/L. The phase I metabolite 4'-hydroxydiclofenac was detected in fish samples exposed at the highest DCF concentration. Graphical abstract Analysis of diclofenac and some of its transformation products in the three-spined stickleback, Gasterosteus aculeatus, by QuEChERS extraction followed by LC-MS/MS.

Bioinspired production of magnetic laccase-biotitania particles for the removal of endocrine disrupting chemicals.

Microbial laccases are powerful enzymes capable of degrading lignin and other recalcitrant compounds including endocrine disrupting chemicals (EDCs). Efficient EDC removal on an industrial scale requires robust, stable, easy to handle and cost-effective immobilized biocatalysts. In this direction, magnetic biocatalysts are attractive due to their easy separation through an external magnetic field. Recently, a bioinspired immobilization technique that mimics the natural biomineralization reactions in diatoms has emerged as a fast and versatile tool for generating robust, cheap, and highly stable (nano) biocatalysts. In this work, bioinspired formation of a biotitania matrix is triggered on the surface of magnetic particles in the presence of laccase in order to produce laccase-biotitania (lac-bioTiO2 ) biocatalysts suitable for environmental applications using a novel, fast and versatile enzyme entrapment technique. Highly active lac-bioTiO2 particles have been produced and the effect of different parameters (enzyme loading, titania precursor concentration, pH, duration of the biotitania formation, and laccase adsorption steps) on the apparent activity yield of these biocatalysts were evaluated, the concentration of the titania precursor being the most influential. The lac-bioTiO2 particles were able to catalyze the removal of bisphenol A, 17α-ethinylestradiol and diclofenac in a mixture of six model EDCs and retained 90% of activity after five reaction cycles and 60% after 10 cycles.

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

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.

Parallel artificial liquid membrane extraction of acidic drugs from human plasma.

The new sample preparation concept "Parallel artificial liquid membrane extraction (PALME)" was evaluated for extraction of the acidic drugs ketoprofen, fenoprofen, diclofenac, flurbiprofen, ibuprofen, and gemfibrozil from human plasma samples. Plasma samples (250 µL) were loaded into individual wells in a 96-well donor plate and diluted with HCl to protonate the acidic drugs. The acidic drugs were extracted as protonated species from the individual plasma samples, through corresponding artificial liquid membranes each comprising 2 µL of dihexyl ether, and into corresponding acceptor solutions each comprising 50 µL of 25 mM ammonia solution (pH 10). The liquid membranes and the acceptor solutions were located in a 96-well filter plate, which was sandwiched with the 96-well donor plate during extraction. Parallel extraction of several samples was performed for 15 to 60 min, followed by high-performance liquid chromatography-ultraviolet detection of the individual acceptor solutions. Important PALME parameters including the chemical composition of the liquid membrane, extraction time, and sample pH were optimized, and the extraction performance was evaluated. Except for flurbiprofen, exhaustive extraction was accomplished from plasma. Linearity was obtained for all six drugs in the range 0.025-10 µg/mL, with r (2) values ranging between 0.998 and 1.000. Precision data were in the range 3-22% RSD, and accuracy data were within 72-130% with spiked plasma samples. Based on the current experiences, PALME showed substantial potential for future high-throughput bioanalysis of non-polar acidic drugs.

Comparative evaluation of adsorption kinetics of diclofenac and isoproturon by activated carbon.

Adsorption mechanism of diclofenac and isoproturon onto activated carbon has been proposed using Langmuir and Freundlich isotherms. Adsorption capacity and optimum adsorption isotherms were predicted by nonlinear regression method. Different kinetic equations, pseudo-first-order, pseudo-second-order, intraparticle diffusion model and Bangham kinetic model, were applied to study the adsorption kinetics of emerging contaminants on activated carbon in two aqueous matrices.

Comparative removal of commercial diclofenac sodium by electro-oxidation on platinum anode and combined electro-oxidation and electrocoagulation on stainless steel anode.

Aqueous solution of diclofenac sodium (DCFNa) from commercial analgesic pill was electro-oxidized on platinum and stainless steel (SS) anodes. On platinum anode, 66% degradation of the parent drug was achieved at pH 4.5 with a corresponding COD reduction of 49% for a specific charge of 4200 Coulombs/L. Degradation and COD reduction were less at higher pHs of 8.5 and 10.9. A number of intermediates were detected with some of them persisting at the end of the treatment. On SS anode, 84% drug removal and 80% COD decline were achieved for a specific charge of 4200 Coulombs/L at pH 10.9, owing to combined electro-oxidation and electrocoagulation. Contrary to platinum anode, here the drug removal and COD reduction were lesser at lower pHs of 8.5 and 4.5. Electrocoagulation was found to proceed with the organics directly forming complex with iron in the matrix of the SS anode with the iron oxidizing to Fe(III) at pH 10.9 and Fe(II) at pHs 8.5 and 4.5. Intermediates detected in residual liquid were much less in number and abundance.

Serial coupling of RP and zwitterionic hydrophilic interaction LC-MS: suspects screening of diclofenac transformation products by oxidation with a boron-doped diamond electrode.

The presence of pollutants and their transformation products (TPs) in the water system is a big concern because of possible adverse effects on the aquatic environment. Their identification is still a challenge that requires the combination of different chromatographic techniques. In the current research, serial coupling of RPLC and zwitterionic hydrophilic interaction LC with TOF-MS was investigated as a single separation technique for the screening of suspected TPs from electrochemical oxidation of diclofenac using a boron-doped diamond electrode. Diclofenac oxidation was performed in three water matrices in order to study its transformation in different chemical contexts. 47 TPs resulting from similar oxidation methods were selected from the literature. As in most cases standards were not available, an identification procedure based on accurate mass data and chromatographic behavior was proposed. According to this procedure, 11 suspected TPs, previously analyzed by LC, GC, or ion chromatography, were detected in a single injection. The method was proved to be reliable and versatile and it could be efficiently employed as a comprehensive analytical tool for the simultaneous analysis of compounds in a wide polarity range.

Effect of feeding strategies on pharmaceutical removal by subsurface flow constructed wetlands.

This study presents findings on an assessment of the effect of continuous and batch feeding strategies on the removal of selected pharmaceuticals from synthetic wastewater. Six mesocosm-scale constructed wetlands, including three horizontal subsurface flow constructed wetlands and three sand filters, were set up at the campus of Nanyang Technological University, Singapore. The findings showed that ibuprofen and diclofenac removal in the wetlands was significantly ( < 0.05) enhanced in the batch versus continuous mode. In contrast, naproxen and carbamazepine showed no significant differences ( > 0.05) in elimination under either feeding strategy. Our results also clearly showed that the presence of plants exerts a stimulatory effect on pharmaceutical removal for ibuprofen, diclofenac, and naproxen in batch and continuous mode. Estimation of the quantitative role of this stimulatory effect on pharmaceutical elimination of batch operation as compared with the effect of the presence of the higher plant alone showed that batch operation may account for 40 to 87% of the contribution conferred by the aquatic plant. The findings of this study imply that where maximal removal of pharmaceutical compounds is desired, periodic draining and filling might be the preferred operational strategy for full-scale, subsurface flow constructed wetlands.

Removal of trace organic chemical contaminants by a membrane bioreactor.

Emerging wastewater treatment processes such as membrane bioreactors (MBRs) have attracted a significant amount of interest internationally due to their ability to produce high quality effluent suitable for water recycling. It is therefore important that their efficiency in removing hazardous trace organic contaminants be assessed. Accordingly, this study investigated the removal of trace organic chemical contaminants through a full-scale, package MBR in New South Wales, Australia. This study was unique in the context of MBR research because it characterised the removal of 48 trace organic chemical contaminants, which included steroidal hormones, xenoestrogens, pesticides, caffeine, pharmaceuticals and personal care products (PPCPs). Results showed that the removal of most trace organic chemical contaminants through the MBR was high (above 90%). However, amitriptyline, carbamazepine, diazepam, diclofenac, fluoxetine, gemfibrozil, omeprazole, sulphamethoxazole and trimethoprim were only partially removed through the MBR with the removal efficiencies of 24-68%. These are potential indicators for assessing MBR performance as these chemicals are usually sensitive to changes in the treatment systems. The trace organic chemical contaminants detected in the MBR permeate were 1 to 6 orders of magnitude lower than guideline values reported in the Australian Guidelines for Water Recycling. The outcomes of this study enhanced our understanding of the levels and removal of trace organic contaminants by MBRs.

Removal of diclofenac potassium from wastewater using clay-micelle complex.

The presence of an ionized carboxyl group in the widely used non-steroidal anti-inflammatory (NSAID) drug diclofenac potassium results in a high mobility of diclofenac and in its low sorption under conditions of slow sand filtration or subsoil passage. No diclofenac degradation was detected in pure water or sludge during one month. Tertiary treatments of wastewater indicated that the effective removal of diclofenac was by reverse osmosis, but the removal by activated carbon was less satisfactory. This study presents an efficient method for the removal of diclofenac from water by micelle-clay composites that are positively charged, have a large surface area and include large hydrophobic domains. Adsorption of diclofenac in dispersion by charcoal and a composite micelle (otadecyltrimethylammonium [ODTMA] and clay [montmorillonite]) was investigated. Analysis by the Langmuir isotherm revealed that charcoal had a somewhat larger number of adsorption sites than the composite, but the latter had a significantly larger binding affinity for diclofenac. Filtration experiments on a solution containing 300 ppm diclofenac demonstrated poor removal by activated carbon, in contrast to very efficient removal by micelle-clay filters. In the latter case the weight of removed diclofenac exceeded half that of ODTMA in the filter. Filtration of diclofenac solutions at concentrations of 8 and 80 ppb yielded almost complete removal at flow rates of 30 and 60 mL min(-1). One kilogram of ODTMA in the micelle-clay filter has been estimated to remove more than 99% of diclofenac from a solution of 100 ppb during passage of more than 100 m3.

Synthesis of glutaraldehyde-modified silica/chitosan composites for the removal of water-soluble diclofenac sodium.

Composite materials are effective adsorbents for the removal of various types of contaminants, such as pharmaceutical products. However, they require improvement to achieve a good adsorption capacity. This study presents the development of a promising adsorbent: silica/chitosan modified with different proportions of glutaraldehyde, which involves the D-glucosamine units from chitosan. The developed materials were evaluated for their ability to remove diclofenac sodium. The adsorption data showed that the diclofenac adsorption efficiency increased with increasing degree of glutaraldehyde crosslinking. The equilibrium and kinetic data were well fit by the Liu and Elovich models, respectively, and the maximum adsorption capacity was 237.8 mg/g. Therefore, it can be assumed that the process is predominantly chemical and exothermic, with a high affinity between the adsorbents and diclofenac sodium. The adsorption mechanisms were investigated to better understand the interactions, and the predominance of covalent bonds with the self-polymerized glutaraldehyde was verified.

Biosupported bimetallic Pd-Au nanocatalysts for dechlorination of environmental contaminants.

Biologically produced monometallic palladium nanoparticles (bio-Pd) have been shown to catalyze the dehalogenation of environmental contaminants, but fail to efficiently catalyze the degradation of other important recalcitrant halogenated compounds. This study represents the first report of biologically produced bimetallic Pd/Au nanoparticle catalysts. The obtained catalysts were tested for the dechlorination of diclofenac and trichlorethylene. When aqueous bivalent Pd(II) and trivalent Au(III) ions were both added to concentrations of 50 mg L(-1) and reduced simultaneously by Shewanella oneidensis in the presence of H(2), the resulting cell-associated bimetallic nanoparticles (bio-Pd/Au) were able to dehalogenate 78% of the initially added diclofenac after 24 h; in comparison, no dehalogenation was observed using monometallic bio-Pd or bio-Au. Other catalyst-synthesis strategies did not show improved dehalogenation of TCE and diclofenac compared with bio-Pd. Synchrotron-based X-ray diffraction, (scanning) transmission electron microscopy and energy dispersive X-ray spectroscopy indicated that the simultaneous reduction of Pd and Au supported on cells of S. oneidensis resulted in the formation of a unique bimetallic crystalline structure. This study demonstrates that the catalytic activity and functionality of possibly environmentally more benign biosupported Pd-catalysts can be improved by coprecipitation with Au.

ssDNA aptamer-based column for simultaneous removal of nanogram per liter level of illicit and analgesic pharmaceuticals in drinking water.

Aptamers are a new class of single-stranded DNA/RNA molecules selected from synthetic nucleic acid libraries for molecular recognition. Our group reports a novel aptamer column for the removal of trace (ng/L) pharmaceuticals in drinking water. In this study, cocaine and diclofenac were chosen as model molecules to test the aptamer column which presented high removal capacity, selectivity, and stability. The removal of pharmaceuticals was as high as 88-95%. The data of adsorption were fitted with Langmuir isotherm and a pseudo-second-order kinetic model. A thermodynamic experiment proved the adsorption processes were exothermic in spontaneity. The kinetics of aptamer was composed of three steps: activation, binding, and hybridization. The first step was the rate-controlling step. The adsorption system was divided into three parts: kinetic, mixed, and thermodynamic zones from 0% to 100% binding fraction of aptamer. Furthermore, the aptamer column was reusable and achieved strong removal efficiency from 4 to 30 °C at normal cation ion concentration (5-100 mg/L) for multipollutants without cross effects and secondary pollution. This work indicates that aptamer, as a new sorbent, can be used in the removal of persistent organic pollutants, biological toxins, and pathogenic bacteria from surface, drinking, and ground water.

Behavior of pharmaceuticals in waste water treatment plant in Japan.

The fate of pharmaceuticals in a wastewater treatment plant (WWTP) in Kumamoto, Japan with activated sludge treatment is reported. Selected pharmaceuticals were detected in influent. Results from the present study confirmed that Acetaminophen, Amoxicillin, Ampicillin and Famotidine were removed at a high rate (>90% efficiency). In contrast, removal efficiency of Ketoprofen, Losartan, Oseltamivir, Carbamazepine, and Diclofenac was relatively low (<50%). The selected pharmaceuticals were also detected in raw sludge. In digestive process, Indomethacin, Atenolol, Famotidine, Trimethoprim and Cyclofosamide were removed at a high (>70% efficiency). On the other hand, removal of Carbamazepine, Ketoprofen and Diclofenac was not efficient (<50%).