Preparation of PPy/cellulose fibre as an effective potassium diclofenac adsorbent

Highly sensitive electrochemical biosensor for MUC1 detection based on DNA-functionalized CdTe quantum dots as signal enhancers

In this paper, an electrochemical biosensor based on a cadmium telluride/polypyrrole (CdTe/PPy) nanocomposite was developed for the detection of MUC1 with high selectivity and sensitivity. Results indicate that the CdTe/PPy nanocomposite is modified on the surface of the glassy carbon electrode (GCE), which affords a large surface area for immobilizing cap-DNA, ensuring its high selectivity and sensitivity. Next, CdTe-linked sig-DNA (MUC1 aptamer) was introduced, allowing the MUC1 aptamer to hybridize with cap-DNA. CdTe is a signal amplification element used to generate a differential pulse voltammetry (DPV) signal. Conceivably, target MUC1 detection was based on current signal change due to concentration change in the signal amplification element CdTe. In the presence of MUC1, the MUC1 aptamer specifically binds to MUC1, resulting in the release of CdTe-sig-DNA from the electrode surface and a decrease in peak current. Under optimized experimental conditions, the electrochemical biosensor is highly selective, sensitive, stable, and reproducible for MUC1 ranging from 0.1 nM to 100 nM with a detection limit of 0.05 nM (S/N = 3). Therefore, the electrochemical biosensor has potential applications in medical disease diagnosis.

Encapsulation of a 5FU-curcumin hybrid on bacterial nanocellulose for colorectal cancer treatment

The traditional treatment of colorectal cancer (CRC) involves a combination of chemotherapy and synthetic and natural drugs. In this study, a hybrid compound of 5-fluorouracil-curcumin encapsulated in bacterial nanocellulose (BNC) was evaluated for CRC treatment. Bacterial nanocellulose was produced using K. medellinensis and spray-dried. The encapsulation technique involved solvent evaporation. The interactions between cellulose and the hybrid were evaluated using adsorption isotherms and kinetics, and the system was morphologically and physiochemically characterized. The capsules were tested in vitro using Dukes' C and B CRC cells. The results indicated heterogeneous and incomplete adsorption of the hybrid onto the active sites of cellulose. Capsules with a BNC:hybrid mass ratio of 1:1 maintained the encapsulant properties while maximizing the drug load according to desorption in simulated stomach and colon fluids, where desorption in the colon was 1.79 times greater than that in the stomach. Finally, the cancer cell inhibition results indicated that the encapsulated hybrid performed better on Dukes' C-stage cells than on Duke's B-stage cells. In this study, a new system based on a hybrid cellulose compound was proposed for CRC treatment, specifically for metastatic CRC.

Pharmaceutical Pollutants: Ecotoxicological Impacts and the Use of Agro-Industrial Waste for Their Removal from Aquatic Environments

Medicines are pharmaceutical substances used to treat, prevent, or relieve symptoms of different diseases in animals and humans. However, their large-scale production and use worldwide cause their release to the environment. Pharmaceutical molecules are currently considered emerging pollutants that enter water bodies due to inadequate management, affecting water quality and generating adverse effects on aquatic organisms. Hence, different alternatives for pharmaceuticals removal from water have been sought; among them, the use of agro-industrial wastes has been proposed, mainly because of its high availability and low cost. This review highlights the adverse ecotoxicological effects related to the presence of different pharmaceuticals on aquatic environments and analyzes 94 investigations, from 2012 to 2024, on the removal of 17 antibiotics, highlighting sulfamethoxazole as the most reported, as well as 6 non-steroidal anti-inflammatory drugs (NSAIDs) such as diclofenac and ibuprofen, and 27 pharmaceutical drugs with different pharmacological activities. The removal of these drugs was evaluated using agro-industrial wastes such as wheat straw, mung bean husk, bagasse, bamboo, olive stones, rice straw, pinewood, rice husk, among others. On average, 60% of the agro-industrial wastes were transformed into biochar to be used as a biosorbents for pharmaceuticals removal. The diversity in experimental conditions among the removal studies makes it difficult to stablish which agro-industrial waste has the greatest removal capacity; therefore, in this review, the drug mass removal rate (DMRR) was calculated, a parameter used with comparative purposes. Almond shell-activated biochar showed the highest removal rate for antibiotics (1940 mg/g·h), while cork powder (CP) (10,420 mg/g·h) showed the highest for NSAIDs. Therefore, scientific evidence demonstrates that agro-industrial waste is a promising alternative for the removal of emerging pollutants such as pharmaceuticals substances.

Polypyrrole as Adsorbent in Magnetic Solid Phase Extraction for Progesterone Determination from Human Plasma

A straightforward and effective chromatographic method has been created for the analysis of progesterone from human plasma using a composite based on polypyrrole/magnetic nanoparticles in the sample preparation procedure. The quantification of progesterone is necessary due to its importance in human development and fertility. The employed conditions used acetonitrile:ultrapure water (70:30, v/v) as the mobile phase at 1.0 mL min-1 and an octadecyl silane column (Phenomenex Gemini, 250 mm × 4.6 mm, 5 μm) at a wavelength of 235 nm. The composite and its precursors were synthesized and properly characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy/energy dispersive spectroscopy, thermogravimetric analysis, and point of zero charge. The main factors affecting the extraction recovery of progesterone from pool human plasma samples employing magnetic solid phase extraction have been studied, such as sample pH (without adjustment), sample volume (1000 μL), washing solvent (ultrapure water), eluent (acetonitrile), eluent volume (1000 μL), and amount of adsorbent (10 mg). The extraction recoveries ranged from 98% to 102%, and linearity ranged from 5 to 3000 ng mL-1. The correlation coefficient (r) was ≥0.99, and acceptable relative standard deviation (precision), relative error (accuracy), and p-values (robustness) were observed. Lastly, the plasma samples from pregnant women were successfully analyzed by the validated method.

Experimental and modeling of potassium diclofenac uptake on activated carbon

The presence of pharmaceuticals in wastewater resulting from human activities has driven researchers to explore effective treatment methods such as adsorption using activated carbon (AC). While AC shows promise as an adsorbent, further studies are essential to comprehend its entire interaction with pharmaceuticals. This article investigates the adsorption of potassium diclofenac (PD) onto AC using experimental and modeling approaches. Batch adsorption studies coupled with Fourier transform infrared spectroscopy (FTIR) were employed to clarify the adsorption mechanism of PD on AC. Various kinetic and isotherm adsorption models were applied to analyze the adsorbent-adsorbate interaction. The kinetics were best described by Avrami's fractional order (AFO) nonlinear model. Also, the intraparticle diffusion (IP) model reveals a three-stage adsorption process. The experimental equilibrium data fitted well with the three-parameter nonlinear Liu model, indicating a maximum adsorption capacity (Qmax) of 88.45 mg g-1 and suggesting monolayer or multilayer adsorption. Thermodynamic analysis showed favorable adsorption (ΔG° < 0), with an enthalpy change (ΔH° = -30.85 kJ mol-1) characteristic of physisorption involving hydrogen bonds and π-π interactions. The adsorption mechanism was attributed to forming a double layer (adsorbate-adsorbent and adsorbate-adsorbate).

In-depth study of adsorption mechanisms and interactions in the removal of pharmaceutical contaminants via activated carbon: a physicochemical analysis

This study presents a theoretical analysis of the adsorption process of pharmaceutical pollutants, specifically acetaminophen (ATP) and diclofenac (DFC), onto activated carbon (AC) derived from avocado biomass waste. The adsorption isotherms of ATP and DFC were analyzed using a multilayer model, which revealed the formation of two to four adsorption layers depending on the temperature of the aqueous solution. The saturation adsorption capacities for ATP and DFC were 52.71 and 116.53 mg/g, respectively. A steric analysis suggested that the adsorption mechanisms of ATP and DFC involved a multi-molecular process. The calculated adsorption energies (ΔE1 and ΔE2) varied between 12.86 and 22.58 kJ/mol, with the highest values observed for DFC removal. Therefore, the adsorption of these organic molecules was associated with physisorption interactions: van der Waals forces and hydrogen bonds. These findings enhance the understanding of the depollution processes of pharmaceutical compounds using carbon-based adsorbents and highlight the potential of utilizing waste biomass for environmental remediation.

Cellulose-based adsorbents for solid phase extraction and recovery of pharmaceutical residues from water

Cellulose has attracted interest from researchers both in academic and industrial sectors due to its unique structural and physicochemical properties. The ease of surface modification of cellulose by the integration of nanomaterials, magnetic components, metal organic frameworks and polymers has made them a promising adsorbent for solid phase extraction of emerging contaminants, including pharmaceutical residues. This review summarizes, compares, and contrasts different types of cellulose-based adsorbents along with their applications in adsorption, extraction and pre-concentration of pharmaceutical residues in water for subsequent analysis. In addition, a comparison in efficiency of cellulose-based adsorbents and other types of adsorbents that have been used for the extraction of pharmaceuticals in water is presented. From our observation, cellulose-based materials have principally been investigated for the adsorption of pharmaceuticals in water. However, this review aims to shift the focus of researchers to the application of these adsorbents in the effective pre-concentration of pharmaceutical pollutants from water at trace concentrations, for quantification. At the end of the review, the challenges and future perspectives regarding cellulose-based adsorbents are discussed, thus providing an in-depth overview of the current state of the art in cellulose hybrid adsorbents for extraction of pharmaceuticals from water. This is expected to inspire the development of solid phase exraction materials that are efficient, relatively cheap, and prepared in a sustainable way.

Lignin nanoparticle-decorated nanocellulose cryogels as adsorbents for pharmaceutical pollutants

Adsorption is a relatively simple wastewater treatment method that has the potential to mitigate the impacts of pharmaceutical pollution. This requires the development of reusable adsorbents that can simultaneously remove pharmaceuticals of varying chemical structure and properties. Here, the adsorption potential of nanostructured wood-based adsorbents towards different pharmaceuticals in a multi-component system was investigated. The adsorbents in the form of macroporous cryogels were prepared by anchoring lignin nanoparticles (LNPs) to the nanocellulose network via electrostatic attraction. The naturally anionic LNPs were anchored to cationic cellulose nanofibrils (cCNF) and the cationic LNPs (cLNPs) were combined with anionic TEMPO-oxidized CNF (TCNF), producing two sets of nanocellulose-based cryogels that also differed in their overall surface charge density. The cryogels, prepared by freeze-drying, showed layered cellulosic sheets randomly decorated with spherical lignin on the surface. They exhibited varying selectivity and efficiency in removing pharmaceuticals with differing aromaticity, polarity and ionic characters. Their adsorption potential was also affected by the type (unmodified or cationic), amount and morphology of the lignin nanomaterials, as well as the pH of the pharmaceutical solution. Overall, the findings revealed that LNPs or cLNPs can act as functionalizing and crosslinking agents to nanocellulose-based cryogels. Despite the decrease in the overall positive surface charge, the addition of LNPs to the cCNF-based cryogels showed enhanced adsorption, not only towards the anionic aromatic pharmaceutical diclofenac but also towards the aromatic cationic metoprolol (MPL) and tramadol (TRA) and neutral aromatic carbamazepine. The addition of cLNPs to TCNF-based cryogels improved the adsorption of MPL and TRA despite the decrease in the net negative surface charge. The improved adsorption was attributed to modes of removal other than electrostatic attraction, and they could be π-π aromatic ring or hydrophobic interactions brought by the addition of LNPs or cLNPs. However, significant improvement was only found if the ratio of LNPs or cLNPs to nanocellulose was 0.6:1 or higher and with spherical lignin nanomaterials. As crosslinking agents, the LNPs or cLNPs affected the rheological behavior of the gels, and increased the firmness and decreased the water holding capacity of the corresponding cryogels. The resistance of the cryogels towards disintegration with exposure to water also improved with crosslinking, which eventually enabled the cryogels, especially the TCNF-based one, to be regenerated and reused for five cycles of adsorption-desorption experiment for the model pharmaceutical MPL. Thus, this study opened new opportunities to utilize LNPs in providing nanocellulose-based adsorbents with additional functional groups, which were otherwise often achieved by rigorous chemical modifications, at the same time, crosslinking the nanocellulose network.

Restricted double access mesoporous polypyrrole as adsorbent in pipette-tip solid phase extraction for simultaneous determination of progesterone, pyriproxyfen, and deltamethrin in chicken eggs

In this study, two sample preparation techniques were evaluated in the simultaneous determination of three compounds with different physicochemical properties, progesterone, pyriproxyfen, and deltamethrin that may be present in the chicken egg. In this procedure, firstly the restricted double access mesoporous polypyrrole was synthesized, which was evaluated as adsorbent in pipette-tip solid phase extraction and dispersive solid phase extraction. After optimizing the extraction parameters, it was found that pipette-tip solid phase extraction was more efficient and, therefore, it was used in the validation and application of the method. The analytical method showed good recoveries, acceptable linearity (r > 0.99), limits of quantification, precision and accuracy, robustness and stability within the limits of the literature. Finally, the developed method was successfully applied in simultaneous determination of analytes in different chicken egg samples. Therefore, this work provided a promising strategy for the extraction of different organic compounds from egg products.

Adsorption behavior of copper ions using crown ether-modified konjac glucomannan

A novel supramolecular polysaccharide composite [KGM + DB18C6] was prepared from konjac glucomannan (KGM) and dibenzo-18-crown-6 (DB18C6) using ceric ammonium nitrate as initiator. The products were characterized by FTIR, TG, DSC, UV-Vis, XRD, solid-state ¹³C NMR, and SEM. Due to the introduction of crown ether, [KGM + DB18C6] showed good adsorption performance for Cu²⁺ in aqueous, and the maximum adsorption capacity was 194 mg/g under the optimal adsorption condition. The adsorption kinetics of [KGM + DB18C6] on Cu²⁺ could be described by the pseudo-second-order kinetic model. The adsorption isotherms of [KGM + DB18C6] on Cu²⁺ followed the dual-site Langmuir-Freundlich model. In addition, high recoveries of Cu²⁺ (from 82.65 to 88.47%), and low relative standard deviation (below 5.00%) were obtained by applying the product in real samples, indicating that [KGM + DB18C6] was a good absorbent for removing Cu²⁺ in wastewater.

Synthesis of mesoporous magnetic polypyrrole and its application in studies of removal of acidic, neutral, and basic pharmaceuticals from aqueous medium

As an alternative to traditional adsorbents, mesoporous magnetic polypyrrole (MMPPy) was first used as an adsorbent for the removal of acid, neutral, and basic pharmaceutical compounds considered aqueous pollutants. Ibuprofen (IBU, acid), caffeine (CAF, neutral), and bupropion (BUP, basic) were chosen as adsorbates and applied in adsorption studies. They proved to be pH dependent of the aqueous solution and the best results were found at pH 4 for IBU and CAF and pH 7 for BUP and 60 mg was the optimal amount of adsorbent to be used in the studies. Adsorption was extremely fast and the equilibrium was reached up to 180 s. The adsorption data of all analytes could be well interpreted by the pseudo second-order kinetic model and the dual-site Langmuir-Freundlich isotherm model. The adsorption capacities obtained by the dual-site Langmuir-Freundlich model were 53.67 mg g^-1, 16.74 mg g^-1, and 24.72 mg g^-1 for IBU, CAF, and BUP, respectively. Thermodynamic parameters revealed that IBU adsorption becomes spontaneous as temperature increases and CAF and BUP adsorption occurs through a non-spontaneous process. In addition, this study shows endothermic nature of the adsorption process. Analytes were desorbed using an aqueous solution at pH 10 for IBU, pH 7 for CAF, and pH 4 for BUP and then the material was regenerated successfully. The results suggest that MMPPy can be efficiently used in the removal of different organic analytes found in contaminated water.

Magnetic molecularly imprinted conducting polymer for determination of praziquantel enantiomers in milk

A new selective adsorbent based on magnetic molecularly imprinted conducting polymer was firstly synthetized and applied to the magnetic solid phase extraction (MSPE) for the determination of PZQ enantiomers in milk samples.

Synthesis and characterization of polyaniline, polypyrrole and zero-valent iron-based materials for the adsorptive and oxidative removal of bisphenol-A from aqueous solution

One pot synthesis of a polypyrrole, polyaniline and Fe0 nano-composite (Fe0-PPY/PANI) was achieved by polymerizing aniline and pyrrole with FeCl3 followed by the reduction of Fe3+ to Fe0 with NaBH4. PPY/PANI was synthesized the same way as Fe0-PPY/PANI, except that all the FeCl3 was removed by rinsing. The presence of Fe0 was demonstrated using several analytical techniques; this was shown in comparison to materials that are without Fe0. A series of materials were screened as both adsorbents and catalyst for the activation of H2O2 towards bisphenol A (BPA) removal in batch experiments. Polymers performed better than composites containing Fe0 at adsorption, whereas Fe0 based materials were better catalysts for the activation of H2O2. BPA samples were then spiked with other contaminants including sewage water to test the performance of the various adsorbents and Fenton catalysts. PPY/PANI was found to be a better adsorbent than the rest, whereas Fe0-PPY/PANI was the best Fenton catalyst. The adsorption kinetics of BPA onto PPY/PANI was studied; it was found that the process was governed by the pseudo-second-order kinetic model. The adsorption isotherms revealed that the amount of BPA taken up by PPY/PANI increased with increasing temperature and was governed by the Langmuir adsorption isotherm. The mechanism in which Fe0-PPY/PANI and H2O2 degraded BPA was studied, it was found that surface-bound hydroxyl radicals were responsible for the degradation of BPA. It was also shown that the degradation process included the formation of smaller compounds leading to the reduction of the total organic content by 57%.

Functional polyaniline/multiwalled carbon nanotube composite as an efficient adsorbent material for removing pharmaceuticals from aqueous media

The composite polyaniline/multiwalled carbon nanotube (PAni/MWCNT, 1:0.1 w/w) was developed with the intention of binding the adsorbent properties of two materials and using it to adsorb pharmaceuticals from aqueous media. PAni/MWCNT was characterized by scanning electron microscopy, thermogravimetry, infrared spectroscopy, pH at the point of zero charge, and the effect on the surface wettability of the material. As proof of concept, adsorption studies were carried out using meloxicam (MLX) as the pharmaceutical and it was evaluated as a function of pH, temperature, ionic strength, contact time and variation in concentration. Kinetics and isothermal models were applied to evaluate the mechanism of the adsorption process. The best MLX adsorption result was at pH 2 with 6 min of contact with PAni/MWCNT. The kinetics models that fitted the experimental data were pseudo-second order and Elovich and the kinetics model was the dual-site Langmuir-Freundlich. Both models suggest that the adsorption occurs by the chemical nature of the surface and in the pores of the energetically heterogeneous composite. The PAni/MWCNT presented an adsorption capacity of 221.2 mg g^-1, a very good value when compared with the literature and can be used to remove pharmaceuticals from aqueous environments.

Toward Improved Understanding of the Interactions between Poorly Soluble Drugs and Cellulose Nanofibers

Cellulose nanofibers (CNFs) have interesting physicochemical and colloidal properties that have been recently exploited in novel drug-delivery systems for tailored release of poorly soluble drugs. The morphology and release kinetics of such drug-delivery systems heavily relied on the drug-CNF interactions; however, in-depth understanding of the interactions was lacking. Herein, the interactions between a poorly soluble model drug molecule, furosemide, and cationic cellulose nanofibers with two different degrees of substitution are studied by sorption experiments, Fourier transform infrared spectroscopy, and molecular dynamics (MD) simulation. Both MD simulations and experimental results confirmed the spontaneous sorption of drug onto CNF. Simulations further showed that adsorption occurred by the flat aryl ring of furosemide. The spontaneous sorption was commensurate with large entropy gains as a result of release of surface-bound water. Association between furosemide molecules furthermore enabled surface precipitation as indicated by both simulations and experiments. Finally, sorption was also found not to be driven by charge neutralization, between positive CNF surface charges and the furosemide negative charge, so that surface area is the single most important parameter determining the amount of sorbed drug. An optimized CNF-furosemide drug-delivery vehicle thus needs to have a maximized specific surface area irrespective of the surface charge with which it is achieved. The findings also provide important insights into the design principles of CNF-based filters suitable for removal of poorly soluble drugs from wastewater.

Efficient removal of anti-inflammatory phenylbutazone from an aqueous solution employing a composite material based on poly(aniline-co-pyrrole)/multi-walled carbon nanotubes

Poly(Ani-co-Py)/MWCNT was synthesized by chemical oxidation in a triple-phase interface system and presented a high capacity for the removal of PBZ from wastewater.

Preparation of cationic polymeric nanoparticles as an effective adsorbent for removing diclofenac sodium from water

New cationic polymeric nanoparticles were synthesised with high adsorption capacities for diclofenac sodium and showed fast adsorption and desorption.