Anti-inflammatory drug diclofenac removal by a synthesized MgAl layered double hydroxide

Bifunctional adsorbents based on hyper-cross-linked polymers containing carbonyl and amine species for the efficient removal of diclofenac from water in a broad pH range

Development of new adsorbents for the efficient removal of organic pollutants from water is one of the most emerging environmental issues. Current studies in this field focus on improving the adsorption capacity of various materials and/or broadening the pH range in which the adsorbents can efficiently remove target pollutants. In this study, we designed bifunctional hyper-cross-linked polymers (HCPs) containing both carbonyl and amine species to investigate the effect of amine functional groups on the efficiency of adsorptive removal of non-steroidal anti-inflammatory drugs (NSAIDs) from water. We revealed that post-synthesis functionalization of carbonyl-rich HCPs with amine species does not have a significant impact on the adsorption capacity of these polymers under strongly acidic conditions (pH < 4; qe ∼ 544 mg/g), but significantly extends the pH range in which bifunctional polymers can adsorb diclofenac. For example, at native pH (pH ∼ 6), bifunctional HCP-based adsorbents exhibited an adsorption capacity approximately 8 times higher than that of pristine materials (qe = 191 vs. 24 mg/g, respectively). Furthermore, it was revealed that the adsorbents designed in this study can efficiently remove diclofenac from complex water matrices and exhibit high stability in several adsorption-desorption cycles. Moreover, we demonstrated that selecting a cross-linker with a longer chain results in a polymer with a lower surface area and smaller average pore size, while enabling higher efficiency in amine incorporation via post-synthesis functionalization. This latter feature was crucial for ensuring the high adsorption capacity of HCP-based adsorbents in the removal of NSAID at neutral pH.

Highly efficient and rapid removal of Congo red dye from textile wastewater using facile synthesized Mg/Ni/Al layered double hydroxide

Layered double hydroxides (LDH) are compounds with unique structures of hydroxide functional groups on their surfaces, and they have the proper arrangement of divalent and trivalent cations to adjust their unique catalytic actions. LDH was synthesized utilizing the co-precipitation technique and was thermally treated at 300 °C. The prepared compounds were chemically and structurally elucidated using FT-IR, XRD, SEM, BET, TG-DTA, and XPS characterization. We found that the thermal treatment of the prepared magnesium/nickel-LDH resulted in dehydration and dehydroxylation in its chemical structure. The crystallinity, the surface area, and the pore volume of the formed meso- and micropores were improved considerably after the thermal treatment. The efficiency of the uptake process was increased from 84 to 97% after the thermal treatment process, and the adsorption process tracked the Freundlich adsorption isotherm and pseudo-second-order kinetic model. The kinetics indicated the occurrence of three stages, and the diffusion of dye molecules into the pores was the rate-determining step. Different real water sample treatments showed the applicability of the thermally treated Mg/Ni/Al-LDH in the treatment process under optimized conditions. The presented mechanism of the uptake process using the prepared compounds comprises several interactions between the dye molecules and the thermally treated Mg/Ni/Al-LDH. The study presented the new application for Mg/Ni/Al-LDH in the as-prepared and thermally treated forms to uptake Congo-red (CR) dye from textile effluents.

Construction of biocatalysts based on P450BM3 for the degradation of non-steroidal anti-inflammatory drugs

Non-steroidal anti-inflammatory drugs (NSAIDs) are widespread pollutants in aquatic environments, posing significant risks to both ecosystems and human health due to their persistence and bioaccumulation. Effective and sustainable degradation methods are urgently required to address this environmental challenge. This study aims to design and optimize a cytochrome P450BM3-based biocatalyst for the rapid and efficient degradation of NSAIDs by direct chemical intervention and protein engineering. The novel biocatalyst achieved efficient biodegradation of four common NSAIDs. Notably, the F87I/T268D mutant achieved 99.22 % degradation of diclofenac (DCF) within 10 min, and degraded meloxicam (MEL) and phenylbutazone (PBZ) at rates of 98.86 % and 90.51 % within 5 min, respectively. Furthermore, the F87G mutant accomplished 99.08 % degradation of acetaminophen (APAP) within just 2 min. The catalytic properties of P450BM3 and its mutants were evaluated through kinetic studies, and potential degradation pathways of the four NSAIDs were proposed in conjunction with UPLC-MS. This study provides a novel biocatalytic approach for the rapid degradation of NSAIDs in aquatic systems, offering considerable environmental benefits for pollution mitigation.

Multi-biomarker response of cyanobacteria Synechocystis salina and Microcystis aeruginosa to diclofenac

The cyanobacterial response to pharmaceuticals is less frequently investigated compared to green algae. Pharmaceuticals can influence not only the growth rate of cyanobacteria culture, but can also cause changes at the cellular level. The effect of diclofenac (DCF) as one of the for cyanobacteria has been rarely tested, and DCF has never been applied with cellular biomarkers. The aim of this work was to test the response of two unicellular cyanobacteria (Synechocystis salina and Microcystis aeruginosa) toward DCF (100 mg L-1) under photoautotrophic growth conditions. Such endpoints were analyzed as cells number, DCF uptake, the change in concentrations of photosynthetic pigments, the production of toxins, and chlorophyll a in vivo fluorescence. It was noted that during a 96 h exposure, cell proliferation was not impacted. Nevertheless, a biochemical response was observed. The increased production of microcystin was noted for M. aeruginosa. Due to the negligible absorption of DCF into cells, it is possible that the biochemical changes are induced by an external signal. The application of non-standard biomarkers demonstrates the effect of DCF on microorganism metabolism without a corresponding effect on biomass. The high resistance of cyanobacteria to DCF and the stimulating effect of DCF on the secretion of toxins raise concerns for environment biodiversity.

Removal of diclofenac sodium from aqueous solution using different ionic liquids functionalized tragacanth gum hydrogel prepared by radiation technique

Diclofenac sodium (DCF) was reported as an important emerging environmental pollutant and its removal from wastewater is very urgent. In this study, different alkyl substituted ionic liquids (1-alkyl -3-vinyl- imidazolium bromide [CnVIm]Br, n = 4, 6, 8, 10, 12) functionalized tragacanth gum (TG-CnBr) are prepared by radiation induced grafting and crosslinking polymerization. The adsorption behaviors of ionic liquids functionalized tragacanth gum for diclofenac sodium from aqueous solutions are examined. The adsorption capacity of TG-CnBr for diclofenac sodium increases with the increasing of alkyl chain length of the imidazolium cation and the hydrophobicity of the hydrogels. The maximum adsorption capacity by TG-C12Br for diclofenac sodium at 30, 40 and 50 °C were 327.87, 310.56 and 283.29 mg/g, respectively. The adsorption of TG-C12Br towards diclofenac sodium was little decreased with NaCl increasing. The removal efficiency was still remained 94.55 % within 5 adsorption-desorption cycles by 1 M HCl. Also, the adsorption mechanism including electrostatic attraction, hydrophobic interaction, hydrogen bonding, and π - π interaction was proposed.

Engineering the Morphostructural Properties and Drug Loading Degree of Organic-Inorganic Fluorouracil-MgAl LDH Nanohybrids by Rational Control of Hydrothermal Treatment

Layered double hydroxides (LDHs) or hydrotalcite-like compounds have attracted great attention for the delivery of anticancer drugs due to their 2D structure, exhibiting a high surface-to-volume ratio and a high chemical versatility. The drug is protected between the layers from which it is slowly released, thus increasing the therapeutic effect and minimizing the side effects associated to nonspecific targeting. This work aimed to design LDHs with Mg and Al (molar ratio of 2/1) in brucite-like layers, which retained fluorouracil (5-FU; 5-FU/Al = 1, molar ratio) in the interlayer gallery as the layers grow during the co-precipitation step of the synthesis. To rationally control the physicochemical properties, particularly the size of the crystallites, the aging step following the co-precipitation was performed under carefully controlled conditions by changing the time and temperature (i.e., 25 °C for 16 h, 100 °C for 16 h, and 120 °C for 24 h). The results revealed the achievement of the control of the size of the crystals, which are gathered in three different agglomeration systems, from tight to loose, as well as the loading degree of the drug in the final organic-inorganic hybrid nanomaterials. The role played by the factors and parameters affecting the drug-controlled release was highlighted by assessing the release behavior of 5-FU by changing the pH, solid mass/volume ratio, and ionic strength. The results showed a pH-dependent behavior but not necessarily in a direct proportionality. After a certain limit, the mass of the solid diminishes the rate of release, whereas the ionic strength is essential for the payload discharge.

Ecofriendly and sustainable Sargassum spp.-based system for the removal of highly used drugs during the COVID-19 pandemic

Analgesic consumption increased significantly during the COVID-19 pandemic. A high concentration of this kind of drug is discarded in the urine, reaching the effluents of rivers, lakes, and seas. These medicines have brought serious problems for the flora and, especially, the ecosystems’ fauna. This paper presents the results of removing diclofenac, ibuprofen, and paracetamol in an aqueous solution, using Sargassum spp. from the Caribbean coast. The study consisted of mixing each drug in an aqueous solution with functionalized Sargassum spp in a container under constant agitation. Therefore, this work represents an alternative to solve two of the biggest problems in recent years; first, the reduction of the overpopulation of sargassum through its use for the remediation of the environment. Second is the removal of drug waste used excessively during the COVID-19 pandemic. Liquid samples of the solution were taken at intervals of 10 min and analyzed by fluorescence to determine the concentration of the drug.

The sorption capacity for diclofenac, ibuprofen, and paracetamol was 2.46, 2.08, and 1.41 μg/g, corresponding to 98 %, 84 %, and 54 % of removal, respectively. The removal of the three drugs was notably favored by increasing the temperature to 30 and 40 °C, reaching efficiencies close to 100 %. Moreover, the system maintains its effectiveness at various pH values. In addition, the Sargassum used can be reused for up to three cycles without reducing its removal capacity. The wide diversity of organic compounds favors the biosorption of drugs, removing them through various kinetic mechanisms. On the other hand, the Sargassum used in the drugs removal was analyzed by X-ray diffraction, FTIR spectroscopy, TGA analysis, and scanning electron microscopy before and after removal. The results showed an evident modification in the structure and morphology of the algae and demonstrated the presence of the biosorbed drugs. Therefore, this system is sustainable, simple, economical, environmentally friendly, highly efficient, and scalable at a domestic and industrial level that can be used for aquatic remediation environments.