Decoration of Fe3+ on carboxyl microporous organic network to fabricate magnetic porous carbon for efficient adsorption and removal of cationic dyes

Integrated and confinable paper-based chip biosensor for all-in-one colorimetric detection of aflatoxin B1

This study presents the development of a rapid and highly sensitive colorimetric biosensor for the detection of aflatoxin B1 (AFB1), utilizing a peroxidase-mimetic nanozyme in combination with a membrane-confined signal amplification strategy. The biosensor platform incorporates AFB1-specific aptamer-labeled Fe3+-doped mesoporous carbon nanospheres, which hybridize with a complementary strand immobilized on paper nanofibers. Upon binding with AFB1, the nanozyme detaches and is subsequently removed through a washing step. The remaining nanozyme catalyzes the oxidation of 3,3',5,5'-tetramethylbenzidine in the presence of H2O2, generating a blue-colored signal. To facilitate real-time, quantitative signal analysis, a smartphone-based imaging strategy is employed. In contrast to conventional open-solution detection methods, this approach confines the catalytic reaction and its products within the membrane, thereby enhancing the signal intensity. The integration of the nanozyme's high catalytic efficiency with the signal amplification enabled by membrane confinement results in superior sensitivity, stability, and operational simplicity. The biosensor demonstrates a broad detection range from 0.01 to 1000 ng mL-1 and an exceptionally low detection limit of 3.9 pg mL-1, outperforming most analogous systems. Additionally, the biosensor exhibits excellent performance in complex sample matrices, such as chicken feed and traditional Chinese medicinal herbs. Through the combination of smartphone imaging for quantitative analysis and rapid, visual detection, this platform provides a versatile, user-friendly tool for real-time, on-site food safety monitoring and health surveillance.

Self-Assembly of Nanovesicles for Enhanced Adsorption and Efficient Photodegradation of 2,4,6-Trichlorophenol

The compound 2,4,6-trichlorophenol poses significant risks to both the aquatic environment and human health. Its inherent persistence and stability present challenges in achieving complete purification, thus warranting its inclusion as a priority pollutant. The present study reports the development of an amphiphilic small-molecule compound that self-assembles into nanovesicles exhibiting remarkable adsorption and photodegradation capabilities. Through the synergistic effects of hydrogen bonding, van der Waals forces, π-π interactions, and electrostatic interactions, these vesicles efficiently adsorb 2,4,6-trichlorophenol from aqueous solutions within 1 min while demonstrating exceptional environmental stability and broad applicability. Upon self-assembly into vesicles, not only are more adsorption sites exposed, but charge separation and migration within the vesicles are also facilitated. Through the synergistic effects of adsorption and photodegradation, complete removal of 2,4,6-trichlorophenol in aqueous solution can be achieved within 8 h while exhibiting excellent recycling capability. This approach offers a viable strategy for designing and synthesizing pure organic photodegradable materials.

Removal and detection of phenols through an SPE-HPLC method using microporous organic networks as adsorbent

The design and development of a facile synthesis approach to construct novel materials for the rapid adsorption and removal of environmental pollutants are of significant interest. In this work, we report the rational design and facile synthesis of magnetic core-shell-based microporous organic networks, Fe3O4@MON-TBPT-TEB (TTMON, achieved by reacting 2,4,6-tris(p-bromophenyl) triazine and 1,3,5-triethynylbenzene) and Fe3O4@MON-TBPM-DEBP (TDMON, achieved by reacting tetrakis (4-bromophenyl) methane and 4-4'-diethynylbiphenyl). These MONs possessed excellent dispersity, electrostatic attraction as well as plenty of π-π and hydrophobic interaction sites enabled them to efficiently absorb targeted environmental pollutants. TTMON and TDMON exhibited excellent adsorption capacities of 440 and 510 mg g-1, respectively, at 25 °C for 2,4,6-trichlorophenol (TCP). TCP, 2,4-dichlorophenol (DCP), 2-naphthol (2-NT) and 4-nitrophenol (4-NP) from aqueous solution were treated by both MONs, followed by their analysis with high-performance liquid chromatography (HPLC). For TDMON, the proposed SPE-HPLC-UV method showed an LOD of 0.03 μg L-1, LOQ of 0.11 μg L-1, and a wide linear range of 1-1000 μg L-1 for TCP. The adsorption kinetics, thermodynamics, isotherms, effect of pH and humic acid (HA), ionic strength, regeneration, and reusability of the MONs were also studied. The results revealed that the novel-designed MONs have potential applications as efficient adsorbents in sample pretreatment.

Using chitosan nanofibers to simultaneously improve the toughness and sensing performance of chitosan-based ionic conductive hydrogels

Conductive hydrogels, especially polysaccharide-based ionic conductive hydrogels, have received increasing interest in the field of wearable sensors due to their similarity to human skin. Nevertheless, it is still a challenging task to simultaneously prepare a self-healed and adhesive conductive hydrogel with good toughness, temperature tolerance and high sensing performance, especially with high sensitivity and a low detection limit. Herein, we developed a new strategy to improve the toughness and sensing performance of a multifunctional conductive hydrogel by simultaneously using dissolved chitosan (CS) and solid chitosan nanofibers (CSFs) to induce the formation of hierarchical polymeric networks in the hydrogel. The tensile strength and elongation at break of the hydrogel could be improved from 70.3 kPa and 1005 % to 173.9 kPa and 1477 %, respectively, simply by introducing CSFs to the hydrogel, and its self-healing, adhesive and antibacterial properties were effectively retained. When serving as a resistive sensing material, the introduction of CSFs increased the gauge factor of the hydrogel-based strain sensor from 8.25 to 14.27. Moreover, the hydrogel-based strain sensor showed an ultralow detection limit of 0.2 %, excellent durability and stability (1000 cycles) and could be used to detect various human activities. In addition, the hydrogel prepared by using a water-glycerol binary solvent system showed temperature-tolerant performance and possessed adequate sensitivity when serving as a resistive sensing material. Therefore, this work provides a new way to prepare multifunctional conductive hydrogels with good toughness, sensing performance and temperature tolerance to expand the application range of hydrogel-based strain sensors.

Facile synthesis of triazine-based microporous organic network for high-efficient adsorption of flumequine and nadifloxacin: A comprehensive study on adsorption mechanisms and practical application potentials

Flumequine (FLU) and nadifloxacin (NAD), as emerging contaminants, have received extensive attention recently. In this study, a triazine-based microporous organic network (TMON) was synthetized and developed as an excellent adsorbent for FLU and NAD. The adsorption behavior and influence factors were investigated in both single and binary systems. Insight into the adsorption mechanisms were conducted through experiments, models, and computational studies, from macro and micro perspectives including functional groups, adsorption sites, adsorption energy and frontier molecular orbital. The results showed that the maximum adsorption capacities of TMON for FLU and NAD are 325.27 and 302.28 mg/g under 30 °C higher than records reported before. TMON exhibits the better adaptability and anti-interference ability for influence factors, leading to the preferable application effect in kinds of real water samples. TMON also shows the application potentials for the adsorption of other quinolone antibiotics and CO₂ capture. Hydrogen-bonding interaction played the most critical role compared to π-π stacking effect, π-π electron-donor-acceptor interaction, CH-π interaction, and hydrophobic interaction during the adsorption. TMON could be regarded as a promising environmental adsorbent for its large surface area, stable physical and chemical properties, excellent recyclability, and wide range of applications.

Synthesis of reusable and renewable microporous organic networks for the removal of halogenated contaminants

Microporous organic networks (MONs) have shown great potential in the removal of environmental contaminants. However, all studies have focused on the design and construction of novel and efficient adsorbents, and the recycling and reuse of adsorbates were disregarded. In this study, we report a feasible approach to synthesize renewable and reusable MONs by using target halogenated contaminants such as tetrabromobisphenol A (TBBPA), 2,3-dichlorophenol (2,3-DCP), and 2,4,6-trichlorophenol (2,4,6-TCP) as starting monomers. TBBPA, 2,3-DCP, and 2,4,6-TCP acted as hazardous contaminants and starting monomers for MONs, leading to the recycling of both adsorbents and adsorbates. The obtained TBBPA-MON, 2,3-DCP-MON, and 2,4,6-TCP-MON not only offered good reusability and large adsorption capacity for their elimination but also provided good adsorption for other phenolic contaminants relying on multiple interactions. Density functional theory calculation indicated the dominant role of π-π and hydrophobic interactions and the secondary role of hydrogen bonding interactions during the adsorption process. The used TBBPA-MON could be reused and the eluted TBBPA could be recycled and renewed for the construction of fresh MONs. This study provided a feasible approach to design and synthesize renewable MONs for environmental contaminants.

Modification of cyclodextrin and use in environmental applications

Water pollution, which has become a global problem in parallel with environmental pollution, is a problem that needs to be solved urgently, considering the gradual depletion of water resources. The inadequacy of the water treatment methods and the materials used somehow directed the researchers to look for dual character structures such as biocompatible and biodegradable β-cyclodextrin (β-CD). β-CD, which is normally insoluble in water, is used in demanding wastewater applications by being modified with the help of different agents to be water soluble or transformed into polymeric adsorbents as a result of co-polymerization via cross-linkers. In this way, in addition to the host-guest interactions offered by β-CD, secondary forces arising from these interactions provide advantages in terms of regeneration and reusability. However, the adsorption efficiency and synthesis steps need to be improved. Based on the current studies presented in this review, in which cross-linkers and modification methods are also mentioned, suggestions for novel synthesis methods of new-generation β-CD-based materials, criticisms, and recent methods of removal of micropollutants such as heavy metals, industrial dyes, harmful biomolecules, and pharmaceutics wastes are mentioned.