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.

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.

ß-Cyclodextrin Polymerized in Cross-Flowing Channels of Biomass Sawdust for Rapid and Highly Efficient Pharmaceutical Pollutants Removal from Water.

Water pollution arising from pharmaceuticals has raised great concerns about the potential risks for biosphere and human health. However, rapid and efficient removal of pharmaceutical contaminants from water remains challenging. Wood sawdust, a byproduct of the wood-processing industry, is an abundant, cost-effective, and sustainable material with a unique hierarchically porous microstructure. These features make wood sawdust quite interesting as a filtration material. Here, we report a novel cross-flow filtration composite based on ß-cyclodextrin-polymer-functionalized wood sawdust (ß-CD/WS) in which the pharmaceutical contaminant water flows through the sawn-off vessel channels and the micropores on the surface of the cell walls, generating the turbulence. Such water flow characteristics ensure full contact between pharmaceutical pollutants and ß-CD grafted on the cellulose backbone of wood sawdust, thereby enhancing the water treatment efficiency. Consequently, the ß-CD/WS filter device shows a high removal efficiency of over 97.5% within 90 s for various pharmaceutical contaminants including propranolol, amitriptyline, chlortetracycline, diclofenac, and levofloxacin, and a high saturation uptake capacity of 170, 156, 257, 159, and 185 mg g-1, respectively. The high-performance wood-sawdust-based cross-flow filtration opens new avenues for solving the global water pollution issues, especially those caused by pharmaceutical contaminants.

Transition element doped octahedral manganese molecular sieves (Me-OMS-2) as diclofenac adsorbents.

Diclofenac (DCF) control measures have become an area of increased interest for environmental researchers due to the high environmental concentration and risk of DCF. Adsorption seems to be promising for DCF removal from the aqueous phase because of its specific superiority in comparison with biodegradation, membrane separation, and advanced oxidation or reduction. In this study, OMS-2 and metal-doped OMS-2 ((Me-OMS-2, with Me = Co, Cu or Ce) were prepared and tested as adsorbents for the removal of DCF. It was evident that the maximum adsorption capacity and rate of Ce-OMS-2 were much higher than those of the other adsorbents, which could be attributed to its large specific surface area and stereoscopic aperture structure. The experimental data are fitted the pseudo-second-order model, the Elovich equation and the Langmuir model well; moreover, the process is an endothermic and spontaneous thermodynamic process, during which the entropy increased, based on the experimental results, indicating that chemisorption was dominant during the DCF adsorption process onto Ce-OMS-2. By the integral of the peak deconvoluted from the XPS spectrum, the ratio of Mn3+/Mn4+ increased from 0.393 to 0.407, revealing that Mn(IV) is rarely reduced into Mn(III) during the DCF adsorption process.

Removal of carbamazepine, diclofenac and trimethoprim by solar driven advanced oxidation processes in a compound triangular collector based reactor: A comparison between homogeneous and heterogeneous processes.

Contaminants of emerging concern (including pharmaceuticals) are not effectively removed by municipal wastewater treatment plants (WWTPs), so particular concern is related to agricultural wastewater reuse due to their possible uptake in crops irrigated with WWTPs effluents. Advanced oxidation processes (AOPs) and solar AOPs have been demonstrated to effectively remove pharmaceuticals from different aqueous matrices. In this study, an heterogeneous photocatalytic process using powdered nitrogen-doped TiO2 immobilized on polystyrene spheres (sunlight/N-TiO2) was compared to the benchmark homogenous AOP sunlight/H2O2 in a compound triangular collector reactor, to evaluate the degradation of three pharmaceuticals (carbamazepine (CBZ), diclofenac (DCF), trimethoprim (TMP)) in water. The degradation of the contaminants by sunlight and sunlight-AOPs well fit the pseudo-first order kinetic model (but for TMP under sunlight). High removal efficiency by solar photolysis was observed for DCF (up to 100%, half-life sunlight cumulative energy QS,1/2 = 2 kJ L-1, half-life time t1/2 = 32 min), while CBZ (32%, QS,1/2 = 28 kJ L-1, t1/2 = 385 min) and TMP (5% removal after 300 min) removal was poor. The degradation rate of CBZ, TMP and DCF was found to be slower during sunlight/H2O2 (QS,1/2 = 5 kJ L-1, t1/2 = 77 min; QS,1/2 = 20 kJ L-1, t1/2 = 128 min; QS,1/2 = 4 kJ L-1, t1/2 = 27 min, respectively) compared to sunlight/N-TiO2 (QS,1/2 = 4 kJ L-1, t1/2 = 55 min; QS,1/2 = 3 kJ L-1, t1/2 = 42 min; QS,1/2 = 2 kJ L-1, t1/2 = 25 min, respectively). These results are promising in terms of solar technology upscale because the faster degradation kinetics observed for sunlight/N-TiO2 process would result in smaller treatment volume, thus possibly perspective compensating the cost of the photocatalyst.

Effective adsorption of diclofenac sodium from neutral aqueous solution by low-cost lignite activated cokes.

Activated cokes have attracted great interest inwater treatment to remove organic pollutants due to their low cost and specific textural properties. In this study, adsorptive removal of diclofenac sodium (DCF) from neutral aqueous solution by available lignite activated cokes (LACs) was reported for the first time. Diclofenac sodium could be quickly removed from aqueous solution by LAC-2, with the maximum Langmuir adsorption capacity qm of 224 mg/g at pH 6.5. Characterization results (including scanning electron microscopy, transmission electron microscopy, elemental analyses, Boehm titrations, N2 adsorption-desorption isotherms and Fourier transform infrared spectroscopy) and a series of adsorption kinetics, adsorption isotherms model studies revealed that high porosity with developed macro- and micropore structures on LAC-2, as well as high content of phenolic groups, could obviously enhance the DCF adsorption capacity and rate. Moreover, LAC-2 showed high affinity towards DCF at low concentrations, as well as good reusability after three adsorption-desorption cycles. pH effect studies revealed that hydrogen-bonding interaction plays an important role during adsorption, accompanied with certain contribution from electrostatic interaction and π-π interaction. This study indicates the promising potential of LAC-2 as an efficient, low-cost and recyclable material for DCF removal from water bodies.

The effect of peroxymonosulfate in WS2 nanosheets for the removal of diclofenac: Information exposure and degradation pathway.

The search for a suitable heterogeneous catalyst in peroxymonosulfate (PMS) activation holds tremendous promise for the degradation of organic pollutants. Two-dimensional (2D) transition metal dichalcogenides such as WS2 exhibit broad applications in heterogeneous catalysis, and we first extended its application in PMS activation in this work. It was found that WS2 could efficiently activate PMS resulting in the degradation of diclofenac (DCF). The results show that the PMS offers direct oxidation, and WS2 could initiate PMS to produce singlet oxygen (1O2) and superoxide radical (·O2-). This resulted in the improved removal of DCF in the WS2/PMS system. Furthermore, the degradation pathway of DCF was proposed according to the detected intermediates/products and density functional theory (DFT) calculation. Degradation intermediates and the evaluation of product toxicity indicated that the developed WS2/PMS system was a safe and detoxifying process while also offering efficient DCF removal. This study offers more insight into the development of suitable materials for the activation of PMS and gives clear direction for the degradation of DCF and its toxic intermediates.

Electrospun NiFe layered double hydroxide/Nylon 6 composite nanofibers as a sorbent for micro solid phase extraction by packed sorbent of non-steroidal anti-inflammatory drugs in human blood.

In the present work, NiFe layered double hydroxide (LDH)/Nylon 6 composite nanofibers were prepared by electrospinning method and used as a new sorbent for the extraction and measurement of non-steroidal anti-inflammatory drugs (naproxen, mefenamic acid, and diclofenac) in whole blood samples. The method is based on micro solid phase extraction (µSPE) by packed sorbent followed by HPLC-UV analysis. Effective parameters on the extraction efficiency were optimized using a central composite design (CCD). In order to characterize the sorbent, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), field emission scanning electron microscopy (FESEM), energy dispersive X-ray analysis (EDX) and elemental mapping were applied. The method was fully validated based on linearity, limits of detection (LOD) and quantification (LOQ), precision, and recovery. Under the optimal conditions, LOD values were found to be 25 ng mL-1 for naproxen and diclofenac and 15 ng mL-1 for mefenamic acid. A seven-point calibration curve was obtained in the range of 75-2000 ng mL-1 for naproxen and diclofenac and 50-2000 for mefenamic acid. The method showed good linearity with coefficients of determination, r2> 0.9962, for the three drugs. In the entire analytical range, the relative standard deviations (RSD%) were less than 8.1%. Finally, the efficiency of the method was investigated for the analysis of the target analytes in human blood samples, and the recoveries were obtained in the range of 90.7-109.8%.

Magnetic COFs for the adsorptive removal of diclofenac and sulfamethazine from aqueous solution: Adsorption kinetics, isotherms study and DFT calculation.

Covalent organic frameworks (COFs) are emerging and promising adsorbents for the adsorptive removal of many types of pollutants. However, most COFs fabricated by various methods are in the form of microcrystalline powders, making them difficult in separation. In this study, magnetic COFs were prepared by a simple impregnation method. The as-prepared samples with Ms = 5.2 emu g-1 showed a good magnetic separation capability. Additionally, the adsorption performance of magnetic COFs towards antibiotics (e.g., diclofenac and sulfamethazine) was also studied. Various adsorption kinetic models (e.g., the pseudo first-order, the pseudo second-order, and mixed-order models) and adsorption isotherm models (e.g., the Freundlich, the Langmuir, and the Sips models) were used to study their adsorption kinetics and isotherms. Furthermore, density functional theory (DFT) was utilized to predict the interaction between adsorbents and adsorbates and to explain the partial adsorption mechanisms.

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.

Construction of carbon-doped supramolecule-based g-C3N4/TiO2 composites for removal of diclofenac and carbamazepine: A comparative study of operating parameters, mechanisms, degradation pathways.

An eco-friendly 2D heterojunction photocatalyst composites (BCCNT) consisting of carbon-doped supramolecule-based g-C3N4 (BCCN) layers and TiO2 nanoparticles has been fabricated via an in-situ method. Based on the SEM and XPS results affirmed that the coaction of doped carbon and supramolecule precursors lead to the different morphology of pure g-C3N4, C-doped g-C3N4 have improved the photodegradation diclofenac (DCF) and carbamazepine (CBZ). And the degradation efficiencies of DCF and CBZ could reach 98.92% and 99.77%, which were separately corresponded to 30 min (min) and 6 h (h) of LED lamp illumination. Additionally, the effects of catalysis dosage, solution pH, natural organic matter (NOM), inorganic anions (Cl-, SO42-, NO3-) and different water matrices were deeply investigated. The scavenger experiments demonstrated that •O2-, h+ were main active species under visible irradiation. Furthermore, the photodegradation pathways of DCF and CBZ were detected by high-resolution mass spectrometry (HRMS) instruments and three-dimensional excitation-emission matrix fluorescence spectra (3D EEMs). Eventually, the possible photocatalytic mechanisms of BCCNT were proposed.

Cyclodextrin-functionalized cellulose filter paper for selective capture of diclofenac.

An environmentally friendly and low-cost material based on cellulose filter paper modified with ß-cyclodextrin (ß-CD) was designed to uptake and elute drugs for water purification. To carry out the work, a ß-CD derivative was first obtained through reaction of ß-CD with N-(hydroxymethyl) acrylamide (NMA), and then ß-CD-NMA was grafted on cellulose by means of the Fenton's reaction. The CD-grafted cellulose paper was characterized by ATR-FTIR analysis, SEM images, and mechanical properties. CD-functionalized (F1) and non-functionalized (NF) papers were tested in aqueous media containing an antibiotic (ciprofloxacin) or a non-steroidal anti-inflammatory drug (diclofenac) covering a wide range of salinity levels. Ciprofloxacin was similarly adsorbed by both papers through ionic interactions, while diclofenac was selectively and remarkably captured by the CD-functionalized filter (up to 25 mg g-1 from saline medium under biorelevant conditions; ca. 60 mg g-1 Langmuir isotherm model). Effects of diclofenac concentration, volume of medium, and incubation time on the amount adsorbed were investigated in detail. Elution tests involved the combination of several organic solvents and alkaline solutions and revealed that acetonitrile:NaOH 10 mM aq. solution (50:50, v/v) allows for an effective recovery of the previously trapped diclofenac. Application of ultrasounds shortened the process to 10 min. Reusability of F1 papers was also evaluated. Overall, the CD-grafted cellulose paper appears as a suitable material for bioremediation and analytical purposes.

Rapid in situ microwave synthesis of Fe3O4@MIL-100(Fe) for aqueous diclofenac sodium removal through integrated adsorption and photodegradation.

Metal-Organic Frameworks (MOFs) are efficient adsorbent and catalyst, however, the prepare of MOFs can be extremely time consuming. The rapid in situ microwave synthesis process offers the possibility of MOFs to a large-scale application. In this study, Fe3O4@MIL-100(Fe) was rapidly prepared via microwave in 30 min using Fe3O4 as metal precursor and applied as the adsorbent and photocatalyst to remove diclofenac sodium (DCF) from water. Fe3O4@MIL-100(Fe) exhibited an excellent adsorption effect to DCF with the maximum adsorption capacities of 400 mg/L. The presence of H2O2 could promote the removal of DCF during photocatalytic process. Approximately 99.4% of the DCF was removed in Fe3O4@MIL-100(Fe)/vis/H2O2 system via adsorption removal and consequent photocatalytic degradation. The high efficiency was attributed to the large BET surface area (1244.62 m2/g) and abundant iron metal sites (Fe(III) and Fe(II)) of Fe3O4@MIL-100(Fe). The adsorptive, photocatalytic property of Fe3O4@MIL-100(Fe) and the Fenton-like reaction were the main mechanisms for DCF removal. TOC analyzer was served to assess the mineralization of solutions treated by Fe3O4@MIL-100(Fe)/vis/H2O2 in 12 h. High elimination of TOC (87.8%) was observed during the DCF mineralization process. In addition, the major products were illuminated using HPLC-Q-TOF-MS and DCF degradation pathways were also proposed.

Adsorption of diclofenac sodium on bilayer amino-functionalized cellulose nanocrystals/chitosan composite.

Residual diclofenac sodium (DS) in the environment is harmful to human health. A promising method for DS removal is the use of adsorbents functionalized with amino groups that can form an ionic bond with the carboxyl group of DS at a suitable pH. In this work, a novel composite adsorbent composed of cellulose nanocrystals (CNC) and chitosan (CS) has been synthesized and functionalized by ethylenediamine (ED) in both layers. Characterization methods, including scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, Fourier-transform infrared spectrometry, and X-ray photoelectron spectroscopy, were used to confirm the morphology and synthetic mechanism of the double- amino-functionalized adsorbent. Based on the optimization of adsorption conditions and modeling of the adsorption mechanism, the DS adsorption process on CNC-ED@CS-ED involves chemical adsorption, and the maximum adsorption capacity obtained from the Langmuir model is 444.44 mg/g. CNC-ED@CS-ED exhibits good adsorption capacity and high sustainability; thus, it is a promising composite material for the removal of DS from wastewater.

Removal of diclofenac by three-dimensional electro-Fenton-persulfate (3D electro-Fenton-PS).

Diclofenac (DIC) is a new type of contaminant that has been widely detected in the water environment, posing threats to the ecological environment and human health. However, the conventional wastewater treatment process has a very limited ability to reduce DIC. In this research, persulfate is added to electro-Fenton with the three-dimensional particle electrode (TDE) process whose particle electrodes were formed from manganese slag with loaded active substance (Cu: Fe = 1:1) to construct a three-dimensional electro-Fenton-persulfate (3D electro-Fenton-PS) process to investigate the removal rate of DIC under the optimum working conditions. The effects of different persulfate addition, activator addition and different activators on the removal rate of DIC were researched, respectively. The removal rate of DIC reached 96.3% when the persulfate and the Fe0 addition were 1.50 mM and 3.00 mM, respectively. The results showed that and OH existed simultaneously in the reaction system, and the removal of DIC was the result of the two free radicals. Moreover, degradation pathways and mechanism of DIC were also discussed. The study may provide a new theoretical basis and technical support for the treatment of DIC in municipal wastewater.

Tailoring the textural properties of an activated carbon for enhancing its adsorption capacity towards diclofenac from aqueous solution.

A series of activated carbons (ACs) were prepared by modifying a commercial AC by physical activation using CO2 during different activation times. The ACs were designated as F, F12, F24, and F40 corresponding to the activation times of 0, 12, 24, and 40 h, respectively. The surface area, total pore volume, micropore volume, and mean micropore width were determined for all the ACs. The textural properties of the modified ACs increased substantially with the activation time, and the capacity of the ACs for adsorbing diclofenac (DCF) was almost linearly dependent upon the surface area of the ACS. The maximum adsorption capacities of F, F12, F24, and F40 carbons towards diclofenac (DCF) from aqueous solution were 271, 522, 821, and 1033 mg/g, respectively. Hence, the adsorption capacities of ACs were considerably enhanced with the activation time, and F12, F24, and F40 carbons presented the highest adsorption capacities towards DCF reported in the technical literature. The F40 adsorption capacity was at least twice those of other carbon materials. The adsorption capacities decreased by raising the pH from 7 to 11 due to electrostatic repulsion between the ACs surface and anionic DCF in solution. The removal of DCF from a wastewater treatment plant (WWTP) effluent was effectively carried out by adsorption on F40. Hence, the capacity of ACs for adsorbing DCF can be optimized by tailoring the porous structure of ACs.

Efficient adsorption of diclofenac sodium from aqueous solutions using magnetic amine-functionalized chitosan.

In this study, we prepared a magnetic composite based on amine-functionalized chitosan (aminochitosan; AmCS) and Fe3O4 to remove diclofenac sodium (DS) from water. The fabricated AmCS@Fe3O4 composite was characterized using Fourier-transform infrared spectroscopy, transmission electron microscopy, scanning electron microscopy, vibrating sample magnetometry, X-ray diffraction, and thermogravimetric analysis. Furthermore, we investigated the influence of pH, initial DS concentration, and adsorbent dosage on the adsorption of DS. Through thermodynamic analysis, we found that the data corresponded with the Langmuir adsorption isotherm model. The maximum adsorption capacity reached 469.48 mg g-1, and the adsorption process followed the pseudo-second-order kinetic model. Finally, the AmCS@Fe3O4 composite retained good adsorption characteristics after four consecutive cycles, with removal efficiency exceeding 70%. Therefore, the developed adsorbent could be used for efficient adsorptive removal of trace drugs and personal care products from water bodies.

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).

Magnesium-aluminum-layered double hydroxide-graphene oxide composite mixed-matrix membrane for the thin-film microextraction of diclofenac in biological fluids.

Herein, the applicability of Mg-Al-layered double hydroxide-graphene oxide (LDH/GO) mixed-matrix membrane (MMM) for microextraction purposes is reported for the first time. The LDH/GO MMM was used as sorbent for the thin film microextraction (TFME) of diclofenac in human body fluids. The prepared LDH/GO composite has been incorporated into a mechanically stable polyvinylidene difluoride (PVDF) membrane. The contribution of GO in LDH/GO composites significantly improved the extraction efficiency of the TFME sorbent. After elution with methanol, diclofenac was quantified by high performance liquid chromatography-ultraviolet detection (HPLC-UV). Plackett-Burman design was used for screening the experimental factors of interest and specify the significant variables affecting the extraction efficiency. The effective factors were optimized using Box-Behnken design (BBD). Under the optimum conditions, limits of detections (LODs) were 0.14, 0.23 and 0.57 µg L-1 in water, urine and plasma samples, respectively. Limits of quantifications (LOQs) were 0.46, 0.76 and 1.8 µg L-1 in water, urine and plasma samples, respectively. Relative standard deviations (RSDs) at a spiked concentration of 10 µg L-1 were 6.7, 6.9 and 7.1% (as intra-day RSD) in water, urine and plasma samples, respectively. The linear dynamic ranges (LDRs) were in the range of 0.5-200 µg L-1. The applicability of the method was investigated by the extraction and determination of diclofenac in different biological fluids including urine and plasma samples.