The adsorption of Congo red (CR), an azo dye, from aqueous solution using free and immobilized agricultural waste biomass of
(lotus) has been studied separately in a continuous fixed-bed column ...operation. The
leaf powder adsorbent was immobilized in various polymeric matrices and the maximum decolorization efficiency (83.64%) of CR occurred using the polymeric matrix sodium silicate. The maximum efficacy (72.87%) of CR dye desorption was obtained using the solvent methanol. Reusability studies of free and immobilized adsorbents for the decolorization of CR dye were carried out separately in three runs in continuous mode. The % color removal and equilibrium dye uptake of the regenerated free and immobilized adsorbents decreased significantly after the first cycle. The decolorization efficiencies of CR dye adsorption were 53.66% and 43.33%; equilibrium dye uptakes were 1.179 mg g
and 0.783 mg g
in the third run of operation with free and immobilized adsorbent, respectively. The column experimental data fit very well to the Thomas and Yoon-Nelson models for the free and immobilized adsorbent with coefficients of correlation R
≥ 0.976 in various runs. The study concludes that free and immobilized
can be efficiently used for the removal of CR from synthetic and industrial wastewater in a continuous flow mode. It makes a substantial contribution to the development of new biomass materials for monitoring and remediation of toxic dye-contaminated water resources.
Circularly polarized luminescence (CPL) is useful for 3D optical imaging and optical storage, but it remains a big challenge to prepare chiral compounds with both strong emission and high-dissymmetry ...factor (glum). Here, we demonstrate that encapsulation of achiral dyes into hollow cages can inhibit the aggregation-caused quenching (ACQ) behavior and promote CPL induction and amplification. This leads to the synthesis of two chiral hexahedral Pd6L12 cages with crown ether or methoxymethyl moieties. Complexation of K+ with crown ethers allows inclusion of anionic achiral boron-dipyrromethene (BODIPY) dyes into the cage cavities to form stable host-guest complexes by cation-anion and host-guest interactions. Although both the cage and dyes exhibit no CPL, their host-guest complexes display strong CPL emissions with the glum factors in the order of 10−3 in solution. Upon crystallization, one order of magnitude amplification of the glum values in the cage-dye adducts (up to 2.4 × 10−2) is obtained.
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•Self-assembly of endohedrally functionalized chiral metal-organic cages•Aggregation-caused quenching inhibition, CPL induction, and amplification promotion•X-ray single-crystallographic analysis of both the cages and the host-dye adducts
Circularly polarized luminescence (CPL) is attractive in understanding the excited-state chirality and has wide applications in advanced chiroptical materials. Chiral organic molecules play an important role in generating CPL with high-quantum yield and tunable colors. However, their CPL performance is virtually limited by the small dissymmetric factor |glum| value and the aggregation-caused quenching issue in the solid state. To address this issue, various attempts have been made by assembling organic chromophores into copolymers, hybrid polymers, and supramolecular polymers, but a quenching of the fluorophore is hard to avoid. Here, we demonstrate a strategy that incorporates achiral dyes into chiral metal-organic cages to inhibit the aggregation-caused quenching effect and promote CPL induction and amplification. The results are of great importance to manipulate CPL signals and intensities of organic molecules for developing entirely new chiroptical materials.
Chiral organic dyes can show a strong luminescence, but they usually display small glum values and suffer from the aggregation-caused quenching (ACQ) effect. Encapsulation of anionic BODIPY dyes into chiral hexahedral Pd6L12 cages with their interior surfaces decorated with crown ether moieties can inhibit the ACQ behavior and significantly promote CPL induction and amplification while maintaining strong emissions.
We leveraged the power of ChatGPT and Bayesian optimization in the development of a multi-AI-driven system, backed by seven large language model-based assistants and equipped with machine learning ...algorithms, that seamlessly orchestrates a multitude of research aspects in a chemistry laboratory (termed the ChatGPT Research Group). Our approach accelerated the discovery of optimal microwave synthesis conditions, enhancing the crystallinity of MOF-321, MOF-322, and COF-323 and achieving the desired porosity and water capacity. In this system, human researchers gained assistance from these diverse AI collaborators, each with a unique role within the laboratory environment, spanning strategy planning, literature search, coding, robotic operation, labware design, safety inspection, and data analysis. Such a comprehensive approach enables a single researcher working in concert with AI to achieve productivity levels analogous to those of an entire traditional scientific team. Furthermore, by reducing human biases in screening experimental conditions and deftly balancing the exploration and exploitation of synthesis parameters, our Bayesian search approach precisely zeroed in on optimal synthesis conditions from a pool of 6 million within a significantly shortened time scale. This work serves as a compelling proof of concept for an AI-driven revolution in the chemistry laboratory, painting a future where AI becomes an efficient collaborator, liberating us from routine tasks to focus on pushing the boundaries of innovation.
Heavy oil is an abundant and important energy source that has the potential to meet the increasing energy demand of the world. However, its economic recovery is challenging and having a thorough ...molecular understanding of the heavy oil–rock interface will be advantageous. Here, we have used molecular dynamics simulations to probe the adhesion of heavy oil at commonly found carbonate (calcite), sandstone (silica), and clay (mica)-type rock reservoirs. The calcite surface has the highest adhesion energy with heavy oil followed by mica and silica surfaces. The dispersion interaction is dominant as compared to electrostatic interactions in calcite and silica systems. In contrast, an equal contribution of both interactions is found in the heavy oil–mica interface. The structure of heavy oil adjacent to the rock surface is characterized by a dense interfacial layer (IL) followed by a bulk zone. We found that the areal density of exposed atoms, roughness, and dipole moment of the rock surface has a significant effect on the structure of the IL and adhesion energy. A higher areal density of surface atoms coupled with low roughness leads to stronger adsorption of heavy oil molecules favored by dispersion interactions. The adsorption of aromatic carbons (from aromatic and resin fractions) of heavy oil is more than that of aliphatic carbons (from saturates) in the calcite and mica system, whereas a reverse trend is observed in the silica system. The charge distribution is non-uniform in the IL; however, the electrostatic interaction between the heavy oil and rock surface is dictated by the dipole moment of the rock surface.
The adsorption of Congo red (CR) dye from aqueous solutions is conducted in a continuous fixed-bed column by using agricultural biomass of Nelumbo nucifera leaf adsorbent. The column performance is ...evaluated by varying the adsorbent bed height (2.5‒5 cm), influent dye concentrations (10-50 mg L
−1
), and inlet flow rate (1‒5 mL min
−1
). Column experimental data confirmed that the breakthrough characteristics of the adsorption system are dependent on bed height, flow rate, and initial adsorbate concentration. The results show that the decolourisation efficiency and equilibrium uptake (q
e
) of CR decreases with increasing flow rate and increases with increasing bed height and influent adsorbate concentration. The maximum absorption efficiency (83.12%) was obtained using 5 cm bed height, 15 mg L
−1
inlet adsorbate concentration, and 1 mL min
−1
flow rate. The increased flow rate and initial adsorbate concentration lead to a shorter column exhaustion time. The length of mass transfer zone increased with increasing bed height. Various mathematical models are applied to column experimental data to predict the breakthrough curve and to evaluate the column capacity and kinetic constants of the models. The correlation between the experimental and theoretical data is quantified by calculating the regression coefficients for the Thomas and Yoon-Nelson models, an R
2
≥ 0.954 at various operating conditions was obtained, which shows that the trend of experimental data fits well and the overall system kinetics are limited by solid-liquid interphase mass transfer. The N. nucifera leaf fine powder adsorbent is proven to be capable of removing CR efficiently from aqueous solutions in continuous fixed-bed systems at low flow rate and higher bed depth and it can be used effectively in wastewater treatment.
In this study, the potential of using dried coffee husk adsorbent is systematically evaluated by conducting batch studies involving various process parameters, such as initial pH, dye concentration, ...adsorbent dosage, particle size, electrolytes, and temperature for the removal of Congo red (CR) dye from aqueous solutions. The prepared adsorbent was characterised with Attenuated Total Reflection, Field Emission Scanning Electron Microscopy/Energy Dispersive X-ray Spectroscopy, thermogravimetric, particle size, zero-point charge, Brunauer-Emmett-Teller surface area, and pore volume analysis. The maximum adsorption efficiency is obtained at an initial pH, 6, dye concentration, 50 mg L
−1
, adsorbent dosage, 10.5 g L
−1
, and adsorbent particle size, 89 µm. The kinetic rate constants and isotherm parameters were determined using various kinetic and isotherm models, respectively. The pseudo-second-order kinetic model gave a good fit to the experimental data at various dye concentrations. The adsorption mechanisms were described by intra-particle diffusion and Boyd plots. The overall rate of adsorption is controlled by external film diffusion of dye molecules. The experimental equilibrium data fit the Langmuir isotherm model with a maximum monolayer adsorption capacity (q
max
) of 38.65 mg g
−1
at 303 K. Thermodynamic studies were performed to evaluate the change in Gibbs free energy (ΔG), change in enthalpy (ΔH), and change in entropy (ΔS) of the adsorption process. Based on the thermodynamic analysis, the adsorption was found to be endothermic in nature, and the process was chemisorption, spontaneous and favoured at high temperatures. Desorption studies were conducted with various desorbing reagents in various runs and the maximum desorption efficiency (60.36% in third run) was determined using the solvent methanol. Reusability studies demonstrated that the prepared adsorbent was effective up to three runs of operation. These results show that waste coffee husks are cost-effective, eco-friendly bio-sustainable materials, and can be used for the removal of colour from synthetic dye wastewater.
Asphaltenes are the heaviest component of crude oil, causing the formation of a stable oil–water emulsion. Even though asphaltenes are known to behave as an emulsifying agent for emulsion formation, ...their arrangement at the oil–water interface is poorly understood. We investigated the effect of asphaltene structure (island type vs archipelago type) and heteroatom type (Oxygen-O, Nitrogen-N, and Sulfur-S) on their structural behavior in the oil–water system. Out of six asphaltenes studied here, only three asphaltenes remain at the oil–water interface while others are soluble in the oil phase. Molecular orientation of asphaltene at the interface, position, and angle of asphaltene with the interface has also been determined. We observed that the N-based island type asphaltene is parallel, while the O-based island type asphaltene and N-based archipelago type are perpendicular to the interface. These asphaltene molecules are anchored at the interface by the heteroatom. The S-based asphaltenes (both island and archipelago type) and O-based archipelago type asphaltenes are soluble in the oil phase due to their inability to form a hydrogen bond with water and steric crowding near the heteroatom. This study will help in understanding the role of asphaltenes in oil–water emulsion formation based on its structure and how to avoid it.
We present a new framework integrating the AI model GPT‐4 into the iterative process of reticular chemistry experimentation, leveraging a cooperative workflow of interaction between AI and a human ...researcher. This GPT‐4 Reticular Chemist is an integrated system composed of three phases. Each of these utilizes GPT‐4 in various capacities, wherein GPT‐4 provides detailed instructions for chemical experimentation and the human provides feedback on the experimental outcomes, including both success and failures, for the in‐context learning of AI in the next iteration. This iterative human‐AI interaction enabled GPT‐4 to learn from the outcomes, much like an experienced chemist, by a prompt‐learning strategy. Importantly, the system is based on natural language for both development and operation, eliminating the need for coding skills, and thus, make it accessible to all chemists. Our collaboration with GPT‐4 Reticular Chemist guided the discovery of an isoreticular series of MOFs, with each synthesis fine‐tuned through iterative feedback and expert suggestions. This workflow presents a potential for broader applications in scientific research by harnessing the capability of large language models like GPT‐4 to enhance the feasibility and efficiency of research activities.
The power of using artificial intelligence (AI)‐human collaboration to advance reticular chemistry is shown. Through iterative learning, the GPT‐4 Reticular Chemist indicates instructions while evolving based on the feedback from a human researcher. It results in the innovative discovery of a series of isoreticular metal–organic frameworks (MOFs), and suggests an approach for using large language models in experimental scientific research.
Metal–organic framework nanoparticles (nanoMOFs) have been widely studied in biomedical applications. Although substantial efforts have been devoted to the development of biocompatible approaches, ...the requirement of tedious synthetic steps, toxic reagents, and limitations on the shelf life of nanoparticles in solution are still significant barriers to their translation to clinical use. In this work, we propose a new postsynthetic modification of nanoMOFs with phosphate-functionalized methoxy polyethylene glycol (mPEG–PO3) groups which, when combined with lyophilization, leads to the formation of redispersible solid materials. This approach can serve as a facile and general formulation method for the storage of bare or drug-loaded nanoMOFs. The obtained PEGylated nanoMOFs show stable hydrodynamic diameters, improved colloidal stability, and delayed drug-release kinetics compared to their parent nanoMOFs. Ex situ characterization and computational studies reveal that PEGylation of PCN-222 proceeds in a two-step fashion. Most importantly, the lyophilized, PEGylated nanoMOFs can be completely redispersed in water, avoiding common aggregation issues that have limited the use of MOFs in the biomedical field to the wet forma critical limitation for their translation to clinical use as these materials can now be stored as dried samples. The in vitro performance of the addition of mPEG–PO3 was confirmed by the improved intracellular stability and delayed drug-release capability, including lower cytotoxicity compared with that of the bare nanoMOFs. Furthermore, z-stack confocal microscopy images reveal the colocalization of bare and PEGylated nanoMOFs. This research highlights a facile PEGylation method with mPEG–PO3, providing new insights into the design of promising nanocarriers for drug delivery.
Metal–organic polyhedra featuring non-Archimedean/Platonic architectures with multiple kinds of vertices have aroused great attention for their fascinating structures and properties but are yet ...challenging to achieve. Here, we report a combinatorial strategy to make such nonclassic polyhedral cages by combining kinetically labile metal ions with non-planar organic linkers instead of the usual only inert metal centers and planar ligands. This facilitates the synthesis of an enantiopure twisted tetra(3-pyridyl)-based TADDOL (TADDOL = tetraaryl-1,3-dioxolane-4,5-dimethanol) ligand (L) capable of binding Ni(II) ions to produce a regular convex cage, Ni6 L 8, with two mixed metal/organic vertices and three rarely reported concave cages Ni14 L 8, Ni18 L 12, and Ni24 L 16 with three or four mixed vertices. Each of the cages has an amphiphilic cavity decorated with chiral dihydroxyl functionalities and packs into a three-dimensional structure. The enantioselective adsorption and separation performances of the cages are strongly dependent on their pore structure features. Particularly, Ni14 L 8 and Ni18 L 12 with wide openings can be solid adsorbents for the adsorptive and solid-phase extractive separation of a variety of racemic spirodiols with up to 98% ee, whereas Ni6 L 8 and Ni24 L 16 with smaller pore apertures cannot adsorb the racemates. The combination of single-crystal X-ray diffraction analysis of the host–guest adduct and GCMC simulation indicates that the enantiospecific recognition capabilities originate from the well-organized chiral inner sphere as well as multiple interactions within the chiral microenvironment. This work therefore provides an attractive strategy for the rational design of polyhedral cages, showing geometrically fascinating structures with properties different from those of classic assemblies.
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