Modification Of Functional Groups Research Articles

Photoinduced Electron Transfer in Multicomponent Truxene-Quinoxaline Metal-Organic Frameworks.

Metal-organic frameworks (MOFs) can respond to light in a number of interesting ways. Photochromism is observed when a structural change to the framework is induced by the absorption of light, which results in a color change. In this work, we show that introducing quinoxaline ligands to MUF-7 and MUF-77 (MUF = Massey University Framework) produces photochromic MOFs that change color from yellow to red upon the absorption of 405 nm light. This photochromism is observed only when the quinoxaline units are incorporated into the framework and not for the standalone ligands in the solid state. Electron paramagnetic resonance (EPR) spectroscopy shows that organic radicals form upon irradiation of the MOFs. The EPR signal intensities and longevity depend on the precise structural details of the ligand and framework. The photogenerated radicals are stable for long periods in the dark but can be switched back to the diamagnetic state by exposure to visible light. Single-crystal X-ray diffraction analysis reveals bond length changes upon irradiation that are consistent with electron transfer. The multicomponent nature of these frameworks allows the photochromism to emerge by allowing through-space electron transfer, precisely positioning the framework building blocks, and tolerating functional group modifications to the ligands.

Synthesis of the sialic acid-containing tetrasaccharide repeating unit corresponding to the cell wall O-antigen of Escherichia coli O131 strain

A concise synthetic strategy have been developed for the synthesis of the sialic acid-containing tetrasaccharide repeating unit of the cell wall O-antigen of Escherichia coli (E. coli) O131 strain using regio- and stereoselective (2 → 6)-α-glycosylations of judiciously protected sialic acid thioglycoside derivatives. Perchloric acid supported over silica (HClO4–SiO2) in combination with N-iodosuccinimide (NIS) has been used in the stereoselective activation of thioglycoside derivatives as well as used as a solid acid for the functional group modifications. Appropriate stereoselectivity was achieved in the glycosylation steps involved in the synthetic strategy.

Recycling light-emitting-diode waste quartz sand and stone sludge for the synthesis of amine grafted mesoporous humidity control material

This article proposes a cost-effective development method to recycle two types of waste material (i.e., light-emitting-diode (LED) waste quartz and stone sludge) to produce mesoporous materials. The proposed method is simple yet effective. Extraction of the precursor liquid from the silicon and aluminum sources respectively contained in the waste quartz and stone sludge is based on the alkali fusion method, and the mesoporous material is synthesized after the hydrothermal reaction. The novelty of this work lies in our functionalization of Mobil Composition of Matter No. 41 (MCM-41) through amine group grafting (AGG-MCM-41). The results show that the structure of the mesoporous MCM-41 grafted by the amine functional groups remains orderly. The 29Si nuclear magnetic resonance spectrum confirmed that the supported surface of the MCM-41 features a large number of silanol groups, which verifies that modification of the amine functional group improved the effect. The results show that when the addition amount of amine functional group is 5 vol% (when relative humidity = 95%), the highest equilibrium moisture content of the material is 26.5 kg/kg. The wet performance of the material was studied, and it was proved that 5.0-AGG-MCM-41 complies with the standard of Japanese Industrial Standard (JIS A 1475) (equilibrium moisture content>5 m3/m3). The research results also show that the optimal equilibrium moisture content is more than 44 times that of metal-organic frameworks humidity pump. Therefore, the synthesized AGG-MCM-41 offers excellent humidity control performance in the practical application of building materials as it narrows the indoor humidity fluctuation spontaneously without any energy consumption. This creates new opportunities for smart indoor humidity control. The amine-group-grafted MCM-41 effectively reduces the shortcomings of high energy consumption, high costs, and insufficient space caused by mechanical dehumidifiers. In addition, the production of AGG-MCM-41 from LED waste and stone sludge achieves 100% recycling. Transformation of two problematic industrial byproducts into humidity-conditioning materials with beneficial technical and environmental properties represents a significant contribution towards the goals of sustainable development.

Research on the Fluorescence Properties of Protoporphyrin-Modified Amphiphilic Polysilane

Polysilanes are polymers with unique luminescent properties, which will be enhanced by functional side group modifications. In this paper, amphiphilic functional polysilane is synthesized by Si-H addition reaction between Si-H and alkene bonds. Polymethylsilane is selected as matrix which is full of reactive Si-H groups and azobisisobutyronitrile is used as the initiator. The product shows good luminescence (emission band between 400-650 nm), good solubility (soluble in various solvents such as toluene, tetrahydrofuran, n-hexane, dimethyl sulfoxide, alcohol and water) and environmental friendliness, which can be applied to flexible luminescent devices and solvent-based fluorescence detection in the future.

Isolation and Identification of 3,4-Seco-Solanidine-3,4-dioic acid (SSDA) as a Urinary Biomarker of Cytochrome P450 2D6 (CYP2D6) Activity.

Cytochrome P450 2D6 (CYP2D6), is responsible for the metabolism and elimination of approximately 25% of clinically used drugs, including antidepressants and antipsychotics, and its activity varies considerably on a population basis primary due to genetic variation. CYP2D6 phenotype can be assessed in vivo following administration of an exogenous probe compound, such as dextromethorphan or debrisoquine, but use of a biomarker that does not require administration of an exogenous compound (i.e., drug) has considerable appeal for assessing CYP2D6 activity in vulnerable populations, such as children. The goal of this study was to isolate, purify and identify an "endogenous" urinary biomarker (M1; m/z 444.3102) of CYP2D6 activity reported previously. Several chromatographic separation techniques (reverse phase HPLC, cation exchange and analytical reverse phase UPLC) were used to isolate and purify 96 μg of M1 from 40 L of urine. Subsequently, 1D and 2D NMR, and functional group modification reactions were used to elucidate its structure. Analysis of mass spectrometry and NMR data revealed M1 to have similar spectroscopic features to the nitrogen-containing steroidal alkaloid, solanidine. 2D NMR characterization by HMBC, COSY, TOCSY, and HSQC-TOCSY proved to be invaluable in the structural elucidation of M1; derivatization of M1 revealed the presence of two carboxylic acid moieties. M1 was determined to be a steroidal alkaloid with a solanidine backbone that had undergone C-C bond scission to yield 3,4-seco-solanidine-3,4-dioic acid (SSDA). SSDA may have value as a dietary biomarker of CYP2D6 activity in populations where potato consumption is common. Significance Statement Endogenous biomarkers of processes involved in drug disposition and response may allow improved individualization of drug treatment, especially in vulnerable populations, such as children. Given that several CYP2D6 substrates are commonly used in pediatrics and the ubiquitous nature of potato consumption in western diets, SSDA has considerable appeal as non-invasive biomarker of CYP2D6 activity to guide treatment with CYP2D6 substrates in children and adults.

H2+CO2 Synergistic Plasma Positioning Carboxyl Defects in g-C3N4 with Engineered Electronic Structure and Active Sites for Efficient Photocatalytic H2 Evolution.

Defective functional-group-endowed polymer semiconductors, which have unique photoelectric properties and rapid carrier separation properties, are an emerging type of high-performance photocatalyst for various energy and environmental applications. However, traditional oxidation etching chemical methods struggle to introduce defects or produce special functional group structures gently and controllably, which limits the implementation and application of the defective functional group modification strategy. Here, with the surface carboxyl modification of graphitic carbon nitride (g-C3N4) photocatalyst as an example, we show for the first time the feasibility and precise modification potential of the non-thermal plasma method. In this method, the microwave plasma technique is employed to generate highly active plasma in a combined H2+CO2 gas environment. The plasma treatment allows for scalable production of high-quality defective carboxyl group-endowed g-C3N4 nanosheets with mesopores. The rapid H2+CO2 plasma immersion treatment can precisely tune the electronic and band structures of g-C3N4 nanosheets within 10 min. This conjoint approach also promotes charge-carrier separation and accelerates the photocatalyst-catalyzed H2 evolution rate from 1.68 mmol h−1g−1 (raw g-C3N4) to 8.53 mmol h−1g−1 (H2+CO2-pCN) under Xenon lamp irradiation. The apparent quantum yield (AQY) of the H2+CO2-pCN with the presence of 5 wt.% Pt cocatalyst is 4.14% at 450 nm. Combined with density functional theory calculations, we illustrate that the synergistic N vacancy generation and carboxyl species grafting modifies raw g-C3N4 materials by introducing ideal defective carboxyl groups into the framework of heptazine ring g-C3N4, leading to significantly optimized electronic structure and active sites for efficient photocatalytic H2 evolution. The 5.08-times enhancement in the photocatalytic H2 evolution over the as-developed catalysts reveal the potential and maneuverability of the non-thermal plasma method in positioning carboxyl defects and mesoporous morphology. This work presents new understanding about the defect engineering mechanism in g-C3N4 semiconductors, and thus paves the way for rational design of effective polymeric photocatalysts through advanced defective functional group engineering techniques evolving CO2 as the industrial carrier gas.

Recent advances and challenges in graphene-based nanocomposite scaffolds for tissue engineering application.

Graphene-based nanocomposites have recently attracted increasing attention in tissue engineering because of their extraordinary features. These biocompatible substances, in the presence of an apt microenvironment, can stimulate and sustain the growth and differentiation of stem cells into different lineages. This review discusses the characteristics of graphene and its derivatives, such as their excellent electrical signal transduction, carrier mobility, outstanding mechanical strength with improving surface characteristics, self-lubrication, antiwear properties, enormous specific surface area, and ease of functional group modification. Moreover, safety issues in the application of graphene and its derivatives in terms of biocompatibility, toxicity, and interaction with immune cells are discussed. We also describe the applicability of graphene-based nanocomposites in tissue healing and organ regeneration, particularly in the bone, cartilage, teeth, neurons, heart, skeletal muscle, and skin. The impacts of special textural and structural characteristics of graphene-based nanomaterials on the regeneration of various tissues are highlighted. Finally, the present review gives some hints on future research for the transformation of these exciting materials in clinical studies.

Three-arm star-shaped aniline derivatives: Tunable photoluminescence, aggregation-induced emission and reversible acid-base vapor fluorescence response

The aggregation-induced emission (AIE) molecules demonstrate unique luminous performance in aggregation state, which shows great potential in optoelectronic devices, chemical sensors, bioimaging and so on. Linear aniline derivatives own excellent photoelectric properties, good processing properties, outstanding designability and pH sensitivity. Most reported linear aniline derivatives are typical aggregation caused quenching (ACQ) molecules. One commonly adopted strategy to achieve ACQ-AIE conversion of aniline derivatives is introducing functional groups onto the backbone of aniline chain, which requires multi-step synthesis and post-processing. Herein, we propose a novel “one-step” strategy to achieve the ACQ-AIE conversion of the aniline derivatives through varying the molecular geometry and modification of functional groups on the backbone of the aniline. A series of aniline derivatives in three-arm star-shaped structure was then designed by adjusting the position of aniline units. Furthermore, derivatives containing terminal groups with different electron-withdrawing abilities, including methoxy, bromine, phenyl and cyanophenyl groups, were synthesized in succession. The absorption and emission behaviors of the derivatives could be effectively adjusted. All the synthesized derivatives exhibit AIE behaviors, implying that the ACQ-AIE conversion of aniline derivatives through structural adjustment was feasible. Theoretical simulation was further used to calculate the electronic and geometric structures of the derivatives. The results proved that the distorted conformation was responsible for the AIE characteristics. In addition, the powder of four derivatives showed a reversible fluorescence response to acid-base vapor which indicated potential for anti-counterfeiting applications.

Straightforward Synthesis of Functionalized 4,5,6,7‐Tetrahydro‐pyrazolo[1,5‐a]pyrazines – Important Building Blocks for Medicinal Chemistry

AbstractA set of building blocks based on the 4,5,6,7‐tetrahydro‐pyrazolo[1,5‐a]pyrazine scaffold is synthesized in a multigram scale in a cost‐efficient manner. The possibility of the introduction of different substituents, neutral or functionalized in different positions of pyrazole and/or piperazine rings, is shown. The efficacy of using NH‐pyrazole carbonic acids as a key intermediate of the process is demonstrated. The regioselectivity for direct insertion of the substituent to the 4,5,6,7‐tetrahydro‐pyrazolo[1,5‐a]pyrazine core is discussed. The synthetic perspectives for using the functionalized 4,5,6,7‐tetrahydro‐pyrazolo[1,5‐a]pyrazine as a bifunctional scaffold is discussed. The utilizing of building blocks obtained for the different region‐ and/or stereoselective synthesis, including sole transformations or modifications of functional groups, is demonstrated. The advantages of the proposed approach are proven compared with the other known methodologies.

Surface Functional Groups Effect on the Absorption Spectrum of Carbon Dots: Initial TD-DFT Study

Carbon dots (CDs) have attracted considerable interest due to their remarkable performance, low cost and ease of preparation, and wide range of potential applications. Surface engineering, including modifying the surface functional group and subsequent chemical modification, is preferable to achieve the requirement of the specific application. Oxygen and Nitrogen-based surface functional groups are two common functionalizations on CDs that are subsequently generated during the synthetic process. In this study, we elucidate the optical properties of oxygen and nitrogen-functionalized CDs using time-dependent density functional theory (TD-DFT). Both considered functional groups, the carbon-oxygen double bond (-C=O) and amino groups (-NH2), are quite favourable to tailor the optical properties of CDs, especially in enhancing its absorption spectrum. Moreover, the carbonyl (-C=O) and amino (-NH2) functional groups effectively serve a new absorption peak in the first near-infrared window (650-900 nm). Our results suggest the potential application of the amino and carbonyl functionalized CDs as a photothermal agent in photothermal cancer therapy.

Crosslinker-free collagen gelation for corneal regeneration

Development of an artificial cornea can potentially fulfil the demand of donor corneas for transplantation as the number of donors is far less than needed to treat corneal blindness. Collagen-based artificial corneas stand out as a regenerative option, having promising clinical outcomes. Collagen crosslinked with chemical crosslinkers which modify the parent functional groups of collagen. However, crosslinkers are usually cytotoxic, so crosslinkers need to be removed from implants completely before application in humans. In addition, crosslinked products are mechanically weak and susceptible to enzymatic degradation. We developed a crosslinker free supramolecular gelation strategy using pyrene conjugated dipeptide amphiphile (PyKC) consisting of lysine and cysteine; in which collagen molecules are intertwined inside the PyKC network without any functional group modification of the collagen. The newly developed collagen implants (Coll-PyKC) are optically transparent and can effectively block UV light, are mechanically and enzymatically stable, and can be sutured. The Coll-PyKC implants support the growth and function of all corneal cells, trigger anti-inflammatory differentiation while suppressing the pro-inflammatory differentiation of human monocytes. Coll-PyKC implants can restrict human adenovirus propagation. Therefore, this crosslinker-free strategy can be used for the repair, healing, and regeneration of the cornea, and potentially other damaged organs of the body.

Unveiling the cooperative roles of pyrrolic-N and carboxyl groups in biomass-derived hierarchical porous carbon nanosheets for high energy-power Zn-ion hybrid supercapacitors

The low energy density of Zn-ion hybrid supercapacitors (ZHSCs) remains to be one of the key challenges against its commercialization due to the lack of cathode materials with high capacity, particularly at high current density. Herein, biomass-derived hierarchical porous carbon nanosheets functionalized with oxygen groups and nitrogen dopants used as the cathode for ZHSCs are synthesized via a consecutive two-step pyrolysis-activation strategy, which manifest a high capacity of 220.1 mAh g−1 at 0.2 A g−1, and maintain 118.2 mAh g−1 when the current density increases 100 times to 20 A g−1. Benefitting from the promising performance of the as-obtained cathode materials, the ZHSC finally demonstrates an ultra-high energy density of 181.6 Wh kg−1 at the power density of 165.0 W kg−1, which surpasses the vast majority of state-of-the-art reported ZHSCs. Accordingly, the experimental results and theoretical calculations reveal that the hierarchically porous ultrathin nanosheet architecture with macro-, meso- and micropores is favorable for boosting the physical adsorption of Zn2+, while the introduction of surface pyrrolic-N and carboxyl (–COOH) groups synergistically boosts the chemical adsorption of Zn2+. The present work provides insights into the synergistic effect of nitrogen doping and oxygen functional groups modification hierarchical porous carbon for Zn-ion storage.

Electrochemical synthesis of Ni doped carbon quantum dots for simultaneous fluorometric determination of Fe3+ and Cu2+ ion facilely

A novel Ni doped carbon quantum dots (Ni-CQDs) fluorescence probe was synthesized by facile electrolysis of monoatomic Ni dispersed porous carbon (Ni–N–C). The obtained Ni-CQDs showed a high quantum yield of 6.3% with the strongest excitation and emission peaks of 360 nm and 460 nm, and maintained over 90% of the maximum fluorescence intensity in a wide pH range of 3–12. The metal ions detectability of Ni-CQDs was enhanced by Ni doping and functional groups modification, and the rapid and selective detection of Fe3+ and Cu2+ ions was achieved with Ni-CQDs through dynamic and static quenching mechanism, respectively. On one hand, the energy band gap of Ni-CQDs was regulated by Ni doping, so that excited electrons in Ni-CQDs were able to transfer to Fe3+ easily. On the other hand, the abundant functional groups promoted the generation of static quenching complexation between Cu2+ and Ni-CQDs. In metal ions detection, the linear quantitation range of Fe3+ and Cu2+ were 100–1000 μM (R2 = 0.9955) and 300–900 μM (R2 = 0.9978), respectively. The limits of detection (LOD) were calculated as 10.17 and 7.88 μM, respectively. Moreover, the fluorescence quenched by Cu2+ could be recovered by EDTA2− due to the destruction of the static quenching complexation. In this way, Ni-CQDs showed the ability to identify the two metal ions to a certain degree under the condition of Fe3+ and Cu2+ coexistent. This work paves the way of facile multiple metal ion detection with high sensitivity.

"VALORIZATION OF RICE STRAW VIA PRODUCTION OF MODIFIED XYLANS AND XYLOOLIGOSACCHARIDES FOR THEIR POTENTIAL APPLICATION IN FOOD INDUSTRY "

The present study attempted to valorise rice straw, one of the most abundant, renewable and economic agricultural wastes, via production of modified xylans and xylooligosaccharides (XOS), which were evaluated for their total antioxidant capacity. The percent contents of extractives, cellulose, hemicelluloses, lignin and ash (silica) in rice straw were found to be 20, 41, 24, 9 and 6, respectively. Hemicellulosic xylan was extracted from straw by reaction with 11% (w/v) sodium hydroxide for about 3 h at 80 °C, so that a yield of about 19.4% was obtained, followed by spectral and thermal analyses. Xylan was then subjected to chemical modifications using acetic anhydride, benzyl chloride and sodium monochloroacetate, and the modifications of functional groups were confirmed by FT-IR and NMR spectral techniques. Controlled acid hydrolysis of xylan was carried out using dilute sulphuric acid (0.1, 0.25, 0.5 and 1.0M) at 121 °C, 15 psi for 10 min to produce XOS-rich hydrolysate. Xylan, modified xylans and XOS exhibited significant concentration dependent AAE values, XOS exhibiting the highest AAE value, followed by xylan, benzylated xylan, carboxymethylated xylan and acetylated xylan. Therefore, rice straw based modified xylans and XOS with potential antioxidant properties may serve as potential candidates for use in food industries as packaging films and functional food ingredients.

Review on covalent organic frameworks and derivatives for electrochemical and photocatalytic CO2 reduction

With increasing potential for environmental volatility in the wake of increasing atmospheric pollutants, the need for sustainable approaches towards renewable energy and pollution reduction is ever-expanding. In recent years, research has geared towards utilizing carbon dioxide, which is seen as the largest threat of climate change, to produce various other useful chemicals while decreasing carbon dioxide levels. Considering this recent research, covalent organic frameworks (COFs) have jumped into the spotlight as promising and exciting new catalysts development to drive efforts towards easing climate change. As a relatively new class of materials, COFs are high surface area crystalline networks with a large degree of fine-tunable chemistry and the capability of metallic hybridization and functional group modifications. This review is a comprehensive and detailed discussion of the recent research accomplishments and goals of both photocatalytic and electrocatalytic carbon dioxide reduction using COFs as catalysts. Recent COF electrochemical catalysis is thoroughly discussed through different metal-based and pristine COFs along with the material design principles necessary to reduce carbon dioxide effectively and selectively. COF photocatalysis is discussed namely on the remarkable ability of irradiation-induced carbon dioxide reduction for pristine metal-free, metalated, and hybrid COFs along with the ability of photocoupled electrocatalytic reduction. Additionally, final conclusions on the state of COF research are provided along with future suggestions towards expanding and improving the investigation and application of COFs for CO2 reduction.

Cl-based functional group modification MIL-53(Fe) as efficient photocatalysts for degradation of tetracycline hydrochloride

MIL-53(Fe) catalyst has been widely used to treat the pollutants in water. However, the limited number of electrons in MIL-53(Fe) catalyst has always affected the rate at which Fe3+ can be reduced to Fe2+. We modulated iron-based metal–organic frameworks (MOFs) using organic ligands modified with chlorine functional groups. The characterization results indicate that the 2Cl-MIL-53(Fe) catalyst exhibited the optimal photoelectric properties while maintaining the original structural characteristics. The experimental analyses and the first-principles study suggest that the introduction of a chlorine functional group not only reduced the band gap width and enhanced the visible-light absorption capacity, but also significantly enhanced the electron cloud density of Fe–O clusters. This could further accelerate the redox cycle of Fe(III)/Fe(II), beneficial for H2O2 activation. The constructed Cl-MIL-53(Fe) catalyst exhibited a 3.8 times higher reaction rate constant than pure MIL-53(Fe) catalyst. The specific TCH degradation pathway and mechanism of 2Cl-MIL-53(Fe) treatment are proposed. This study provides a new strategy for iron-based MOFs as a heterogeneous photo-Fenton catalyst to degrade pollutants in water.

Polydopamine Coating Doped with Graphene Oxide Enhances Enantioseparation of Capillary Column.

How to improve the enantiomer separation efficiency of drugs is a hot topic. In this paper, polydopamine (PDA) coating doped with graphene oxide (GO) by physical adsorption was used to modify the capillary column to enhance the enantioseparation efficiency of the drugs. In the capillary electrochromatography (CEC) system, the novel capillary column with carboxymethyl-β-cyclodextrin (CM-β-CD) as a chiral selector has completed the enantioseparation of four basic drugs (propranolol, metoprolol, amlodipine and chlorpheniramine). The optimum separation conditions were obtained by optimizing the pH of the buffer, the concentration of organic modifier, the concentration of the chiral selector and the voltage, and the resolution and peak shape were significantly improved compared with uncoated bare-fused column. The stability and reproducibility of the new capillary column were satisfactory and the relative standard deviation of intra-day and inter-day was <3.2%, and of column-to-column was <4.8%. The rich functional groups of GO are key factors to improve the enantioseparation efficiency, which also indicates that nanomaterials with easy modification of functional groups and large specific surface area are excellent resources for capillary modification applications.

Computational Screening of Newly Designed Compounds against Coxsackievirus A16 and Enterovirus A71.

Outbreaks of hand, foot, and mouth disease (HFMD) that occur worldwide are mainly caused by the Coxsackievirus-A16 (CV-A16) and Enterovirus-A71 (EV-A71). Unfortunately, neither an anti-HFMD drug nor a vaccine is currently available. Rupintrivir in phase II clinical trial candidate for rhinovirus showed highly potent antiviral activities against enteroviruses as an inhibitor for 3C protease (3Cpro). In the present study, we focused on designing 50 novel rupintrivir analogs against CV-A16 and EV-A71 3Cpro using computational tools. From their predicted binding affinities, the five compounds with functional group modifications at P1′, P2, P3, and P4 sites, namely P1′-1, P2-m3, P3-4, P4-5, and P4-19, could bind with both CV-A16 and EV-A71 3Cpro better than rupintrivir. Subsequently, these five analogs were studied by 500 ns molecular dynamics simulations. Among them, P2-m3, the derivative with meta-aminomethyl-benzyl group at the P2 site, showed the greatest potential to interact with the 3Cpro target by delivering the highest number of intermolecular hydrogen bonds and contact atoms. It formed the hydrogen bonds with L127 and K130 residues at the P2 site stronger than rupintrivir, supported by significantly lower MM/PB(GB)SA binding free energies. Elucidation of designed rupintrivir analogs in our study provides the basis for developing compounds that can be candidate compounds for further HFMD treatment.

Selective adsorption of Ba2+ using chemically modified alginate beads with enhanced Ba2+ affinity and its application to 131Cs production

The 131Cs radioisotope with a short half-life time and high average radiation energy can treat the cancer effectively in prostate brachytherapy. The typical 131Cs production processes have a separation step of the cesium from 131Ba to obtain a high specific radioactivity. Herein, we suggested a novel 131Cs separation method based on the Ba2+ adsorption of alginate beads. It is necessary to reduce the affinity of alginate beads to cesium ions for a high production yield. The carboxyl group of the alginate beads was replaced by a sulfonate group to reduce the cesium affinity while reinforcing their affinity to barium ions. The modified beads exhibited superior Ba2+ adsorption performances to native beads. In the fixed-bed column tests, the saturation time and adsorption capacity could be estimated with the Yoon-Nelson model in various injection flow rates and initial concentrations. In terms of the Cs elution, the modified alginate showed better performance (i.e., an elution over 88%) than the native alginate (i.e., an elution below 10%), indicating that the functional group modification was effective in reducing the affinity to cesium ions. Therefore, the separation of cesium from the barium using the modified alginate is expected to be an additional option to produce 131Cs.

Functional group modified 1D interpenetrated metal-organic frameworks on perfluorooctanoic acid adsorption: Experimental and theoretical calculation study

Functional groups modified metal-organic frameworks (MOFs) was synthesized via a pre-tailor method and served as an adsorbent for perfluorooctanoic acid (PFOA) removal. The material was characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction and N2 sorption-desorption. Monte Carlo simulation and molecular dynamics are derived to predict the possible molecular packing and adsorption mechanism. The Hirshfeld surface with reduced density gradient analysis demonstrates that PFOA is adsorbed on MOF-X mainly affected by van der Waals interactions and steric effects. Adsorption kinetics and isotherms were investigated on the basis of a static experiment. The pseudo-second-order kinetic model and Langmuir isotherm were fitted well to characterize adsorption process. Hereinto, amino-modified MOFs reached the highest adsorption efficiency and the maximum capacity was 185.6 mg/g. Combing the experimental data with theoretical simulation, results indicated that functional group modification is an effective approach to alter the crystal structure and then affect the adsorptive properties of MOFs.