Prevalence of antibiotic resistance genes and bacterial pathogens along the soil-mangrove root continuum

An amine-functionalized olefin-linked covalent organic framework used for the solid-phase microextraction of legacy and emerging per- and polyfluoroalkyl substances in fish

Due to the environmental persistence and various health problems associated with per- and polyfluoroalkyl substances (PFASs), they have come under increased public scrutiny. However, the efficient extraction of PFASs from complex media remains challenging. Herein, an olefin-linked covalent organic framework (COF-CN) has been prepared via a Knoevenagel condensation reaction, followed by reduction using LiAlH₄ to form an amine-functionalized COF (COF-NH₂). The characterization results demonstrated that the crystal structure was maintained during the post-modification step. Isothermal and kinetic adsorption studies showed the higher affinity of COF-NH₂ toward PFASs. Based on density functional theory, the adsorption mechanism of the stable six-member-ring structure formed between COF-NH₂ and PFASs via hydrogen bonding was tentatively revealed. After optimizing the solid-phase microextraction parameters, legacy and emerging PFASs were efficiently extracted from fish using the COF-NH₂ coating, followed by detection using ultra-performance liquid chromatography-tandem mass spectrometry. The method exhibited ideal linearity, low limits of quantification, excellent precision, and high relative recoveries. Finally, the bioconcentration kinetics for goldfish was studied, which can provide a feasible platform for investigating the accumulate ion and toxicity of PFASs.

Study on the mechanism of anaerobic fluidized bed microbial fuel cell for coal chemical wastewater treatment

The coal chemical wastewater (CCW) was treated by anaerobic fluidized bed microbial fuel cell (AFB-MFC) with macroporous adsorptive resin (MAR) as fluidized particle. Isosteric heat calculation and molecular dynamics simulation (MDS) have been performed to study the interaction between organics of CCW and MAR. The isosteric heat of MAR to m-cresol was the largest at 65.4961 kJ/mol, followed by phenol. Similarly, the diffusion coefficient of m-cresol on MAR was the largest, which was 0.04350 Ų/ps, and the results were verified by the kinetic adsorption experiments. Microbial community analysis showed that the dominant bacteria in activated sludge of MFC fed with CCW were acinetobacter, aeromonas, pseudomonas and sulfurospirillum. The synergistic cooperation of bacteria contributed to improving CCW degradation and the power generation of MFC. Headspace-gas chromatography-mass spectrometry (HS-GC-MS) was used to detect intermediate of organics in CCW. It was proved that the intermediate of m-cresol degradation was 4-methyl-2-pentanone and acetic acid, and the intermediate of phenol degradation included cyclohexanone, hydroxyhexanedither and hydroxyacetic acid. Combined with the highest occupied molecular orbital (HOMO) analysis results of organic matter obtained by molecular simulation, the degradation pathway of organic matter in CCW was predicted. The energy of organics degradation pathway was analyzed by Materials Studio (MS) software, and the control step of organics degradation was determined.

NaCl template-assisted synthesis of self-floating COFs foams for the efficient removal of sulfamerazine

The preparation of hierarchical porous covalent organic frameworks (HP-COFs) is of great significance due to their inherent porosity and low density. However, it is still very challenging owing to the poor machinability of COFs. Herein, a simple and cost-efficient strategy for the synthesis of HP-COFs was proposed. In particular, p-toluenesulfonic acid and NaCl, both of which can be recycled, are utilized as catalyst and template, respectively. The resulting HP-TpBD-900 featuring abundant macropore and mesopore as well as large specific surface area (~700 m² g^-1) possessed self-floating ability and was turned out to be a promising adsorbent for the efficient removal of sulfamerazine (SMR) in aqueous solution. The maximum adsorption capacity is 168 mg g^-1, which is more than twice in comparison to that of material prepared without NaCl template. In addition, no significant decrease in adsorption capacity was observed after 5 cycles. Furthermore, the density functional theory (DFT) method was utilized to elucidate the adsorption mechanism, which could be dominated by hydrogen bonding and C-H···π interaction. This work not only provides a new strategy for the synthesis of HP-COFs, but also contributes to boosting the application of COFs in the field of wastewater treatment.

Covalent organic frameworks-based smart materials for mitigation of pharmaceutical pollutants from aqueous solution

Covalent organic frameworks (COFs) are an emergent group of crystalline porous materials that have gained incredible interest in recent years. With foreseeable controllable functionalities and structural configurations, the constructions and catalytic properties of these organic polymeric materials can be controlled to fabricate targeted materials. The specified monomer linkers and pre-designed architecture of COFs facilitate the post-synthetic modifications for introducing novel functions and useful properties. By virtue of inherent porosity, robust framework, well-ordered geometry, functionality, higher stability, and amenability to functionalization, COFs and COFs-based composites are regarded as prospective nanomaterials for environmental clean-up and remediation. This report spotlights the state-of-the-art advances and progress in COFs-based materials to efficiently mitigate pharmaceutical-based environmental pollutants from aqueous solutions. Synthesis approaches, structure, functionalization, and sustainability aspects of COFs are discussed. Moreover, the adsorptive and photocatalytic potential of COFs and their derived nanocomposites for removal and degradation of pharmaceuticals are thoroughly vetted. In addition to deciphering adsorption mechanism/isotherms, the stability, regeneratability and reproducibility are also delineated. Lastly, the outcomes are summed up, and new directions are proposed to widen the promise of COF-based smart materials in diverse fields.

Recent advances in porous organic frameworks for sample pretreatment of pesticide and veterinary drug residues: a review

Rapid and accurate detection of pesticide and veterinary drug residues is a continuing challenge because of the complex matrix effects. Thus, appropriate sample pretreatment is a crucial step for the effective extraction of the analytes and removal of the interferences. Recently, the development of nanomaterial adsorbents has greatly promoted the innovation of food sample pretreatment approaches. Porous organic frameworks (POFs), including polymers of intrinsic microporosity, covalent organic frameworks, hyper crosslinked polymers, conjugated microporous polymers, and porous aromatic frameworks, have been widely utilized due to their tailorable skeletons and pores as well as fascinating features. This review summarizes the recent advances for POFs to be utilized in adsorption and sample preparation of pesticide and veterinary drug residues. In addition, future prospects and challenges are discussed, hoping to offer a reference for further study on POFs in sample pretreatment.

Adsorptive removal of pharmaceutical pollutants by defective metal organic framework UiO-66: Insight into the contribution of defects

The development of defective structure in MOFs can offer a novel approach to tailor the properties of MOFs-type adsorbent for better adsorption performance. In this study, the contribution of defective structure in UiO-66 to the adsorptive removal of pharmaceutical pollutants from aqueous solution was investigated. The results showed that the controlled defects in UiO-66 greatly affected adsorption equilibrium time, adsorption capacity and adsorption selectivity. Slightly defected UiO-66 contained more open frameworks, and it exhibited faster adsorption equilibrium. However, a high degree of destruction to the amorphous state resulted in a longer equilibrium time, due to the interference in the diffusion process as the result of severe structural collapse and interpenetration. Moreover, a higher degree of structural damage of UiO-66 led to a higher adsorption capacity because of the increased active sites. The maximum adsorption capacity was 321 mg/g for the as-prepared defective UiO-66, which was much higher than that of perfective UiO-66 (54.5 mg/g). Furthermore, defective UiO-66 had a higher adsorption affinity for diclofenac sodium than other studied pharmaceutical pollutants. This study could provide insight into the relationship between defective property and adsorption performance. The results will deepen the understanding of the adsorption mechanism of MOFs-type adsorbents, and help the design of MOFs-type adsorbents with fast adsorption equilibrium, higher adsorption capacity and adsorption selectivity.

Study on the efficiency of a covalent organic framework as adsorbent for the screening of pharmaceuticals in estuary waters

Herein, we demonstrate, for the first time, that covalent organic frameworks (COFs) can be efficient adsorbents for the screening of pharmaceuticals in real water samples, obtaining highly representative data on their occurrence and avoiding the cost of carrying high volume samples and tedious and costly clean-up and preconcentration steps. Of the 23 pharmaceuticals found present in the water samples from the Tagus river estuary using state-of-the-art solid-phase extraction (SPE), 22 were also detected (adsorbed and recovered for analysis) using a COF as the adsorbent material with adsorption efficiency of over 80% for nearly all compounds. In specific cases, acidification of the water samples was identified to lead to a dramatic loss of adsorption efficiency, underlining the effect of sample pre-treatment on the results. The COF efficiently adsorbed (>80%) 19 pharmaceuticals without acid treatment of the sample, highlighting the potential of this class of materials for representative in situ passive adsorption of pharmaceuticals, making this material suitable for being used in water monitoring programs as a simple and cost-efficient sample preparation procedure. In the case of α-hydroxyalprazolam and diclofenac, the COF outperformed the SPE procedure in the recovery efficiency. Although further efforts should be made in tailoring the desorption of the pharmaceuticals from the COF by using different solvents or solvent mixtures, we propose COFs as convenient adsorbent for broad-scope screening and as an efficient adsorbent material to target specific classes of pharmaceuticals. To the best of our knowledge, this is the first study on the use of COFs for contaminant screening in real, naturally contaminated water samples.

Facile synthesis of uniform spherical covalent organic frameworks for determination of neonicotinoid insecticides

A uniform spherical structure covalent organic framework (TAPA-BPDA-COF) was prepared by a facile method at room temperature with tris(4-aminophenyl)amine (TAPA) and 4,4'-biphenyldicarboxaldehyde (BPDA) as building blocks. Based on the solid phase extraction with the TAPA-BPDA-COF as the sorbent and high performance liquid chromatography-diode array detection, a sensitive analytical method was established for the determination of four neonicotinoid insecticides from water and honey samples. Under the optimum conditions, good linear response for the quantification of the analytes was achieved in the range of 0.3-50.0 ng mL^-1 for water samples and in the range of 8.0-500.0 ng g^-1 for honey samples. The method recoveries fell in the range of 80.0-121.9% with RSDs less than 7.6%. The limits of detection at the signal to noise ratio of 3 were measured to be in the range of 0.08-0.12 ng mL^-1 for water samples and 2.6-3.3 ng g^-1 for honey samples, depending on compounds.

Sulfonic acid functionalized hierarchical porous covalent organic frameworks as a SALDI-TOF MS matrix for effective extraction and detection of paraquat and diquat

Design and construction of a matrix with specific adsorption on the target compounds can effectively reduce the detection limit of surface-assisted laser desorption/ionization time-of-flight mass spectrometry (SALDI-TOF MS) analysis. Sulfonic acid functionalized hierarchical porous covalent organic frameworks (H-COF-SO₃H) was synthesized by defect-structure and post-modification method, and then used as matrix and adsorbent for the determination of quaternary ammonium herbicides paraquat (PQ) and diquat (DQ). N₂ adsorption-desorption experiments confirmed that H-COF-SO₃H possesses hierarchical porosity with pore widths concentrated at 1.3,1.5, and 2.8 nm. The strong UV absorption at 200-450 nm and good thermal stability made H-COF-SO₃H being a promising matrix without background interference. H-COF-SO₃H can efficiently enrich PQ and DQ via electrostatic attraction, and the key role of -SO₃H group on specific adsorption was confirmed by density functional theory (DFT) calculations. The limits of detection (LODs) for PQ and DQ with H-COF-SO₃H enrichment were 0.5 and 0.1 ng·mL^-1, respectively, which were 20 and 60 times higher than those without H-COF-SO₃H enrichment, respectively. The spiked recoveries of PQ and DQ for the three food samples were 92.0-113.2% and 80.1-102.6% with RSDs of 2.2-9.2% and 2.0-8.7%, respectively. This work provides an analyte-oriented approach for fabricating SALDI-TOF MS matrix.

Efficient removal of bisphenol pollutants on imine-based covalent organic frameworks: adsorption behavior and mechanism

The extensive use of bisphenol analogues in industry has aggravated the contamination of the water environment, and how to effectively remove them has become a research hotspot. This study presents two imine-based covalent organic frameworks with different pore sizes (COFs) [TAPB (1,3,5-tris(4-aminophenyl)benzene)-Dva (2,5-divinylterephthaldehyde)-PDA (terephthalaldehyde) (COF-1), and TAPB (1,3,5-tris(4-aminophenyl)benzene)-Dva (2,5-divinylterephthaldehyde)-BPDA (biphenyl dialdehyde) (COF-2)], which have achieved the efficient adsorption of bisphenol S (BPS) and bisphenol A (BPA). The maximum adsorption capacity of COF-2 for BPS and BPA obtained from Langmuir isotherms were calculated as 200.00 mg g⁻¹ and 149.25 mg g⁻¹. Both hydrogen bonding and π–π interactions might have been responsible for the adsorption of BPS and BPA on the COFs, where the high adsorption capacity of COFs was due to their unique pore dimensions and structures. Different types of pharmaceutical adsorption studies indicated that COF-2 exhibited a higher adsorption performance for different types of pharmaceuticals than COF-1, and the adsorption capacity was ranked as follows: bisphenol pharmaceuticals > anti-inflammatory pharmaceuticals > sulfa pharmaceuticals. These results confirmed that COFs with larger pore sizes were more conducive to the adsorption of pollutants with smaller molecular dimensions. Moreover, COF-1 and COF-2 possessed excellent pH stability and recyclability, which suggested strong potential applications for these novel adsorbents in the remediation of organic pollutants in natural waterways and aqueous ecosystems.

Two imine-based covalent organic frameworks with different pore sizes were synthesized, and can be used as adsorbents for the removal of bisphenol pollutants, showing high affinity toward bisphenol S and bisphenol A.

Orderly Porous Covalent Organic Frameworks-based Materials: Superior Adsorbents for Pollutants Removal from Aqueous Solutions

Covalent organic frameworks (COFs) are a new type of crystalline porous polymers known for chemical stability, excellent structural regularity, robust framework, and inherent porosity, making them promising materials for capturing various types of pollutants from aqueous solutions. This review thoroughly presents the recent progress and advances of COFs and COF-based materials as superior adsorbents for the efficient removal of toxic heavy metal ions, radionuclides, and organic pollutants. Information about the interaction mechanisms between various pollutants and COF-based materials are summarized from the macroscopic and microscopic standpoints, including batch experiments, theoretical calculations, and advanced spectroscopy analysis. The adsorption properties of various COF-based materials are assessed and compared with other widely used adsorbents. Several commonly used strategies to enhance COF-based materials' adsorption performance and the relationship between structural property and sorption ability are also discussed. Finally, a summary and perspective on the opportunities and challenges of COFs and COF-based materials are proposed to provide some inspiring information on designing and fabricating COFs and COF-based materials for environmental pollution management.

Ecotoxicological assessment of micropollutant Diclofenac biosorption on magnetic sawdust: Phyto, Microbial and Fish toxicity studies

Diclofenac (DCF), a persistent pharmaceutical micropollutant which occurs in the ecosystems causing adverse effects on aquatic as well as terrestrial organisms. In this study, magnetic sawdust (MSD) was prepared using co-precipitation method for biosorptive removal of DCF from water. The MSD was characterized using various analytical techniques like microscopic and spectroscopic analysis. Magnetometer study confirms the ferromagnetic behavior of the biosorbent which is a key advantage in the separation of MSD after biosorption. The effect of experimental parameters was optimized in batch mode with evaluated maximum efficiency of 86.12 % at pH 6, biosorbent dosage 25 mg for 50 mg/L of DCF. Ecotoxicological assessment has been performed for the treated and untreated sample using plant seeds, microbes and zebra fish to check the adverse effects of DCF on these organisms. Evaluation of toxicity studies revealed that inhibition concentration of DCF for various seeds (60.91 mg/L to 43.11 mg/L), E. coli (48.82 μg/mL) and B. subtilis (31.55 μg/mL). The lethal concentration of DCF on the Danio rerio was found to be 156.99 mg/L. In contrast, significant increase in both the concentration measures of DCF after biosorption was observed making this biosorbent a potent alternative to other available treatment measures.

Microwave-assisted synthesis of β-cyclodextrin functionalized celluloses for enhanced removal of Pb(II) from water: Adsorptive performance and mechanism exploration

Herein, β-cyclodextrin (β-CD) was efficiently grafted onto rice husk-based celluloses using different cross-linking agents of epichlorohydrin (EPI) and glutaraldehyde (GA). By feat of microwave irradiation, the functionalization procedure was completed in 17 min, and the synthesized RHEPIMWβ-CD and RHGAMWβ-CD exhibited fast adsorption equilibrium for Pb(II) within 20 min, excellent monolayer adsorption capacities of 216.06 and 279.08 mg g^-1 across an extensive pH scope of 3.0-6.0, unaffected affinity to Pb(II) during the existence of co-existing ions, superior reusability with over 81% and 87% of Pb(II) uptake sustained for four adsorption-desorption cycles. Thermodynamic parameters implied that the uptake process of Pb(II) occurred spontaneously (-ΔG⁰) with an endothermic characteristic (+ΔH⁰). Furthermore, electrostatic attraction and complexation were demonstrated to enhance the Pb(II) uptake onto the RHEPIMWβ-CD and RHGAMWβ-CD. In fix-bed columns, these two adsorbents also efficiently eliminated Pb(II) under various flow rates with experimental breakthrough curves well simulated by Thomas and Yoon-Nelson models. Significantly, the RHEPIMWβ-CD and RHGAMWβ-CD could effectively purify acid battery effluent containing Pb(II) for meeting regulatory requirement. Overall, the fast fabrication, excellent adsorption and recycling performance facilitate the development of tailored adsorbents for Pb(II) elimination in wastewater.

Room-temperature synthesis of magnetic covalent organic frameworks for analyzing trace benzoylurea insecticide residue in tea beverages

A novel magnetic covalent organic framework (NH₂-Fe₃O₄@COF) was prepared using a simple room-temperature synthesis in this study. These magnetic particles exhibited high adsorption performance with short adsorption time (10 min) for six benzoylurea insecticides (BUs) as magnetic solid-phase extraction (MSPE) adsorbents. Quantum chemistry calculation demonstrated that adsorption mechanism was primarily attributed to strong halogen bonds between electronegative O atoms of COF and electropositive F atoms of BUs as well as potential hydrophobic effect. Wide linearities (10-1000 ng·L^-1) and low limits of detection (0.06-1.65 ng·L^-1) for six analytes were obtained via liquid chromatography-tandem mass spectrometry. Applicability of the proposed method was further evaluated by analyzing four kinds of original tea beverages. Recoveries of six BUs in spiked samples ranged from 80.1% to 108.4%.

A new squaraine-triazine based covalent organic polymer as an electrode material with long life and high performance for supercapacitors

Reaction of squaric acid and melamine.

Hydroxyl modified hypercrosslinked polymers: targeting high efficient adsorption separation towards aniline

The removal of aniline from aqueous solution has a major environmental impact and attracted increasing attention in last few years.

Fabrication of edge-curled petals-like covalent organic frameworks and their properties for extracting indole alkaloids from complex biological samples

In this study, a functionalized covalent-organic framework (COF) was first synthesized using porphyrin as the fabrication unit and showed an edge-curled, petal-like and well-ordered structure. The synthesized COF was then introduced to prepare porous organic polymer monolithic materials (POPMs). Two composite POPM/COF monolithic materials with rod shapes, referred to as sorbent A and sorbent B, were prepared in stainless steel tubes using different monomers. Sorbents A and B exhibited relatively uniform porous structures and enhanced specific surface areas of 153.14 m²/g and 80.01 m²/g, respectively. The prepared composite monoliths were used as in-tube solid-phase extraction (SPE) sorbents combined with HPLC for the on-line extraction and quantitative analytical systems. Indole alkaloids (from Catharanthus roseus G. Don and Uncaria rhynchophylla (Miq.) Miq. Ex Havil.) contained in mouse plasma were extracted and quantitatively analyzed using the online system. The two composite multifunctional monoliths showed excellent clean-up ability for complex biological matrices, as well as superior selectivity for target indole alkaloids. Method validation showed that the RSD values of the repeatability (n=6) were ≤ 3.46%, and the accuracy expressed by the spiked recoveries was in the ranges of 99.38%–100.91% and 96.39%–103.50% for vinca alkaloids and Uncaria alkaloids, respectively. Furthermore, sorbents A and B exhibited strong reusability, with RSD values ≤ 5.32%, which were based on the peak area of the corresponding alkaloids with more than 100 injections. These results indicate that the composite POPM/COF rod-shaped monoliths are promising media as SPE sorbents for extracting trace compounds in complex biological samples.

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Edge-curled petals-like COF was synthesized using porphyrin as the fabrication unit.

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In-tube monolithic POMP/COF composite SPE sorbents with rod-shape were fabricated.

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The in-tube sorbents were used to extract hence indole alkaloids from complex samples.

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The two homemade sorbents show strong reusability of more than 100 times.

Introducing reticular chemistry into agrochemistry

For survival and quality of life, human society has sought more productive, precise, and sustainable agriculture. Agrochemistry, which solves farming issues in a chemical manner, is the core engine that drives the evolution of modern agriculture. To date, agrochemistry has utilized chemical technologies in the form of pesticides, fertilizers, veterinary drugs and various functional materials to meet fundamental demands from human society, while increasing the socio-ecological consequences due to inefficient use. Thus, more useful, precise, and designable scaffolding materials are required to support sustainable agrochemistry. Reticular chemistry, which weaves molecular units into frameworks, has been applied in many fields based on two cutting-edge porous framework materials, namely metal-organic frameworks (MOFs) and covalent-organic frameworks (COFs). With flexibility in composition, structure, and pore chemistry, MOFs and COFs have shown increasing functionalities associated with agrochemistry in the last decade, potentially introducing reticular chemistry as a highly accessible chemical toolbox into agrochemical technologies. In this critical review, we will demonstrate how reticular chemistry shapes the future of agrochemistry in the fields of farm sensing, agro-ecological preservation and reutilization, agrochemical formulations, smart indoor farming, agrobiotechnology, and beyond.

Covalent Organic Framework Composites: Synthesis and Analytical Applications

In the recent years, composite materials containing covalent organic frameworks (COFs) have raised increasing interest for analytical applications. To date, various synthesis techniques have emerged that allow for the preparation of crystalline and porous COF composites with various materials. Herein, we summarize the most common methods used to gain access to crystalline COF composites with magnetic nanoparticles, other oxide materials, graphene and graphene oxide, and metal nanoparticles. Additionally, some examples of stainless steel, polymer, and metal-organic framework composites are presented. Thereafter, we discuss the use of these composites for chromatographic separation, environmental remediation, and sensing.

Adsorption isotherm models: Classification, physical meaning, application and solving method

Adsorption is widely applied separation process, especially in environmental remediation, due to its low cost and high efficiency. Adsorption isotherm models can provide mechanism information of the adsorption process, which is important for the design of adsorption system. However, the classification, physical meaning, application and solving method of the isotherms have not been systematical analyzed and summarized. In this paper, the adsorption isotherms were classified into adsorption empirical isotherms, isotherms based on Polanyi's theory, chemical adsorption isotherms, physical adsorption isotherms, and the ion exchange model. The derivation and physical meaning of the isotherm models were discussed in detail. In addition, the application of the isotherm models were analyzed and summarized based on over 200 adsorption equilibrium data in literature. The statistical parameters for evaluating the fitness of the models were also discussed. Finally, a user interface (UI) was developed based on Excel software for solving the isotherm models, which was provided in supplemental material and can be easily used to model the adsorption equilibrium data. This paper will provide theoretical basis and guiding methodology for the selection and use of the adsorption isotherms.

Use of a magnetic covalent organic framework material with a large specific surface area as an effective adsorbent for the extraction and determination of six fluoroquinolone antibiotics by HPLC in milk sample

A magnetic covalent organic framework material was synthesized with a core-shell structure using a simple solvothermal method. It was prepared with Fe₃ O₄ as the magnetic core, covalent organic framework as the shell, which synthesized from 1,3,5-triformylphloroglucinol and p-phenylenediamine by Schiff base reaction. Transmission electron microscopy, Fourier transform infrared spectroscopy, powder X-ray diffraction, vibrating sample magnetometry, and nitrogen adsorption-desorption were used to characterize magnetic adsorbent. It has showed a large specific surface area (505.6 m² /g), which can provide many adsorption sites. Moreover, the saturation magnetization value was 48.4 emu/g enough to be separated by external magnet. Six kinds of fluoroquinolones (enoxacin, fleroxacin, ofloxacin, norfloxacin, pefloxacin, and lomefloxacin) were extracted by magnetic solid phase extraction with the magnetic adsorbent. High-performance liquid chromatography detects the entire adsorption and desorption process to further evaluate the optimal extraction and desorption conditions. Under the optimal chromatographic conditions, this method showed a low detection limit (0.05 to 0.20 μg/L), good linearity in the range of 0.5 to 200 μg/L, and the enrichment factor reaches 115.5-127.3. The spiked recovery of the fluoroquinolones in milk sample ranged from 90.4 to 101.2%.

Removal of pharmaceutical compounds from aqueous solution by novel activated carbon synthesized from lovegrass (Poaceae)

In this work, lovegrass (Cpa), an abundant grass of the Poaceae family, was employed as feedstock for the production of activated carbon in a conventional furnace using ZnCl₂ as a chemical activator. The prepared material (Cpa-AC) was characterized by pH of the point of zero charges (pH_pzc), Boehm's titration method, CHN/O elemental analysis, ATR-FTIR, N₂ adsorption/desorption curves, and SEM. This carbon material was used for adsorption of acetylsalicylic acid (ASA) and sodium diclofenac (DFC). FTIR analysis identified the presence of O-H, N-H, O-C=O), C-O, and aromatic ring bulk and surface of (Cpa-AC) adsorbent. The quantification of the surface functional groups showed the presence of a large amount of acidic functional groups on the surface of the carbon material. The isotherms of adsorption and desorption of N₂ confirm that the Cpa-AC adsorbent is mesopore material with a large surface area of 1040 m² g^-1. SEM results showed that the surface of Cpa-AC is rugous. The kinetic study indicates that the system followed the pseudo-second-order model (pH 4.0). The equilibrium time was achieved at 45 (ASA) and 60 min (DCF). The Liu isotherm model best fitted the experimental data. The maxima sorption capacities (Q_max) for ASA and DFC at 25 °C were 221.7 mg g^-1 and 312.4 mg g^-1, respectively. The primary mechanism of ASA and DFC adsorption was justified considering electrostatic interactions and π-π interactions between the Cpa-AC and the adsorbate from the solution.