Vermiculite modified with alkylammonium salts: characterization and sorption of ibuprofen and paracetamol

Diclofenac Removal by Alkylammonium Clay Minerals Prepared over Microwave Heating

Diclofenac is an emerging contaminant widely detected in water and has had adverse effects on the biota. In this study, the adsorbents were prepared by reacting tetradecyl-(C14), hexadecyl-(C16), and octadecyltrimethylammonium (C18) bromides with sodium vermiculite (Na-Ver) and used for the removal of the first time for diclofenac sodium from aqueous solution. Synthesis was carried out in a microwave-assisted reactor operating at 50 °C for 5 min, using proportions of organic salts in 100 and 200% of the phyllosilicate cation exchange capacity. The stability of loaded alkylammonium solids was evaluated under drug adsorption conditions. Adsorption was mainly influenced by the amount of surfactant incorporated into the clay mineral according to the thermogravimetric and CHN elemental analysis data. Samples prepared with 200% CEC presented lower stability at pH 6.0 and 8.0. Drug adsorption was more effective for C14-Ver-200%, C16-Ver-200%, and C18-Ver-200% samples, with a maximum retention of 97.8, 110.1, and 108.0 mg g-1, respectively. The adsorptive capacities of C14-Ver-200%, C16-Ver-200%, C18-Ver-200%, C14-Ver-100%, C16-Ver-100%, and C18-Ver-100% were reduced to 29.0, 36.8, 41.0, 61.0, 50.4, and 58.0%, respectively, compared with their initial value after three adsorption cycles. X-ray diffraction (XRD) patterns revealed that diclofenac was adsorbed into the interlayer region of organovermiculites. Fourier transform infrared spectroscopy (FTIR), Zeta potential results, and the pH study of adsorption indicated that van der Waals interactions are dominant in the adsorption mechanism.

Natural-derived porous nanocarriers for the delivery of essential oils

Essential oils (EOs) are natural, volatile substances derived from aromatic plants. They exhibit multiple pharmacological effects, including antibacterial, anticancer, anti-inflammatory, and antioxidant properties, with broad application prospects in health care, food, and agriculture. However, the instability of volatile components, which are susceptible to deterioration under light, heat, and oxygen exposure, as well as limited water solubility, have significantly impeded the development and application of EOs. Porous nanoclays are natural clay minerals with a layered structure. They possess unique structural characteristics such as large pore size, regular distribution, and tunable particle size, which are extensively utilized in drug delivery, adsorption separation, reaction catalysis, and other fields. Natural-derived porous nanoclays have garnered considerable attention for the encapsulation and delivery of EOs. This review comprehensively summarizes the structure, types, and properties of natural-derived porous nanoclays, focusing on the structural characteristics of porous nanoclays such as montmorillonite, palygorskite, halloysite, kaolinite, vermiculite, and natural zeolite. It also examines research advances in their delivery of EOs and explores engineering strategies to enhance the delivery of EOs by natural-derived porous nanoclays. Finally, various applications of natural-derived porous nanoclays for EOs in antibacterial, food preservation, repellent, and insecticide aspects are presented, providing a reference for the development and application of EOs.

Evaluation of organo-vermiculites as sorbent phases for solid-phase extraction of ibuprofen from water

The study of ibuprofen (IBU) preconcentration was carried out making use of a homemade column for solid-phase extraction (SPE), using vermiculite (VT) or organo-vermiculites (OVTs) as sorbent phases. Aqueous samples (50.0 mL) percolated the column and IBU was sorbed onto the VT or OVT and then desorbed using acetonitrile. Employing this SPE system and OVT, calibration curves were generated for IBU, by spectrophotometric quantification using the α-naphthylamine method. R2 values higher than 0.9950 and LOD between 12 and 18 μg L-1 were observed, for real enrichment factors of 21 and 31, by using OVTs. The analytical protocol was applied to three water samples, which were spiked with IBU solutions to evaluate the precision and accuracy of the method. Recoveries between 77 and 110% at three different IBU concentrations and RSD lower than 18% were observed, even by using the spectrophotometric method. The protocol developed in this study demonstrated that the OVT was appropriate to work as a preconcentration phase for IBU determination in water samples.

Reviving the Potential of Vermiculite-Based Adsorbents: Exceptional Ibuprofen Removal on Novel Amide-Containing Gemini Surfactants

In this study, we introduce a novel series of gemini surfactants with amide groups (HDAB, HDAHD, and HDAPX) and use these surfactants to decorate sodium vermiculite (Na-Vt) for the adsorption of Ibuprofen (IBP) from wastewater. Exceptional IBP uptake on organo-vermiculites (organo-Vts) is obtained, with maximum adsorption capacities reaching 249.87, 342.21, and 460.15 mg/g for HDAB-Vt, HDAHD-Vt, and HDAPX-Vt (C0 = 500 mg/L, modifier dosage = 0.2 CEC), respectively. The adsorption of IBP is well fitted by pseudo-second-order, intraparticle diffusion, and Freundlich isotherm models, verifying chemical adsorption processes with multilayer arrangement of IBP in organo-Vts. Thermodynamically, the removal of IBP on HDAHD-Vt is exothermic, while the endothermic nature aptly describes the adsorption process of HDAB-Vt and HDAPX-Vt. Moreover, organo-Vts can be stably regenerated in three cycles. Outstanding adsorption performance of organo-Vts is attributed to synergistic effects of the partition process and functional interaction, which are influenced by the steric hindrance and chain configuration of the modifier. A combined evaluation of adsorption tests and fitting calculations is employed to reveal the adsorption mechanism: (i) the incorporation of amides into the alkyl chain significantly enhances the utilization of the interlayer space in organo-Vts. (ii) Smaller steric hindrance and higher rigidity of the modifier spacer contribute to improved adsorption performance. The findings in this study rekindle interest in Vt-based adsorbents, which demonstrate comparable potential to other emerging adsorbents that are yet to be fully explored.

Organobeidellites for Removal of Anti-Inflammatory Drugs from Aqueous Solutions

Diclofenac (DC) and ibuprofen (IBU) are widely prescribed non-steroidal anti-inflammatory drugs, the consumption of which has rapidly increased in recent years. The biodegradability of pharmaceuticals is negligible and their removal efficiency by wastewater treatment is very low. Therefore, the beidelitte (BEI) as unique nanomaterial was modified by the following different surfactants: cetylpyridinium (CP), benzalkonium (BA) and tetradecyltrimethylammonium (TD) bromides. Organobeidellites were tested as potential nanosorbents for analgesics. The organobeidellites were characterized using X-ray powder diffraction (XRD), Infrared spectroscopy (IR), Thermogravimetry and differential thermal analysis (TG/DTA) and scanning microscopy (SEM). The equilibrium concentrations of analgesics in solution were determined using UV-VIS spectroscopy. The intercalation of surfactants into BEI structure was confirmed both using XRD analysis due to an increase in basal spacing from 1.53 to 2.01 nm for BEI_BA and IR by decreasing in the intensities of bands related to the adsorbed water. SEM proved successful in the uploading of surfactants by a rougher and eroded organobeidellite surface. TG/DTA evaluated the decrease in dehydration/dehydroxylation temperatures due to higher hydrophobicity. The Sorption experiments demonstrated a sufficient sorption ability for IBU (55–86%) and an excellent ability for DC (over 90%). The maximum adsorption capacity was found for BEI_BA-DC (49.02 mg·g⁻¹). The adsorption according to surfactant type follows the order BEI_BA > BEI_TD > BEI_CP.