Azido chelating fiber: synthesis,characterization and adsorption performances towards Hg2+ and Pb2+ from water

Herein, we report the synthesis and adsorption property of a novel chelating fiber containing azido group. Firstly, the brominated fiber (PP‐St‐DVB‐Br) was obtained via the reaction of polypropylene‐(g)‐styrene‐divinylbenzene fiber (PP‐St‐DVB) with bromine in CH₂Cl₂ solution. Then, azido chelating fiber (PP‐St‐DVB‐N₃) was prepared by azidation of PP‐St‐DVB‐Br fiber. Its structure and properties were characterized by Fourier transform infrared, elemental analysis, thermogravimetric analysis, and chemical titration, respectively. The micromophology and functional group distribution in fibrous matrix were investigated by scanning electron microscopy‐energy dispersive spectroscopy. The results show that the chelating fiber has high functional group contents (2.11 mmol/g for PP‐St‐DVB‐N₃) and uniform distribution. Different from granulate chelating resin, the novel fibrous adsorbent possesses excellent adsorption ability for Hg(II) and Pb(II) ions (408.9 mg/g for Hg²⁺ and 334.4 mg/g for Pb²⁺), and the adsorption capacity of the fiber has no loss until five cycles. The novel absorbent material shows the potential application prospect in the treatment of heavy metal wastewater. Copyright © 2017 John Wiley & Sons, Ltd.     

Enhanced Electrocatalytic Performance of a Porous g‐C3N4/Graphene Composite as a Counter Electrode for Dye‐Sensitized Solar Cells

A porous graphitic carbon nitride (g‐C₃N₄)/graphene composite was prepared by a simple hydrothermal method and explored as the counter electrode of dye‐sensitized solar cells (DSCs). The obtained g‐C₃N₄/graphene composite was characterized by XRD, SEM, TEM, FTIR spectroscopy, and X‐ray photoelectron spectroscopy. The results show that incorporating graphene nanosheets into g‐C₃N₄ forms a three‐dimensional architecture with a high surface area, porous structure, efficient electron‐transport network, and fast charge‐transfer kinetics at the g‐C₃N₄/graphene interfaces. These properties result in more electrocatalytic active sites and facilitate electrolyte diffusion and electron transport in the porous framework. As a result, the as‐prepared porous g‐C₃N₄/graphene composite exhibits an excellent electrocatalytic activity. In I^?/I₃^? redox electrolyte, the charge‐transfer resistance of the porous g‐C₃N₄/graphene composite electrode is 1.8 Ω cm², which is much lower than those of individual g‐C₃N₄ (70.1 Ω cm²) and graphene (32.4 Ω cm²) electrodes. This enhanced electrocatalytic performance is beneficial for improving the photovoltaic performance of DSCs. By employing the porous g‐C₃N₄/graphene composite as the counter electrode, the DSC achieves a conversion efficiency of 7.13 %. This efficiency is comparable to 7.37 % for a cell with a platinum counter electrode.     

Enhanced specific energy of silver-doped MnO2/graphene oxide electrodes as facile fabrication symmetric supercapacitor device

The present work is about the preparation of silver (Ag)-doped manganese oxide (MnO₂)/graphene oxide (GO) composite thin films are deposited by a facile and binder-free successive ionic layer adsorption and reaction (SILAR) method for the first time. The Brunauer-Emmett-Teller (BET) study revealed the nanosheets of MnO₂–Ag3/GO exhibit high specific surface area of 192 m² g^?1. The tailored flower-like morphology and interconnected nanosheets of MnO₂–Ag3/GO electrodes achieved high electrochemical performance. The maximum specific capacitance (Cs) of 877 F g^?1 at the scan rate of 5 mV s^?1 is obtained for MnO₂–Ag3/GO electrode tested in 1 M sodium sulfate (Na₂SO₄) electrolyte with capacity retention of 94.57% after 5000 cycling stability. The MnO₂–Ag3/GO composite-based flexible solid state symmetric supercapacitor (FSS-SSC) device delivered Cs as 164 F g^?1 with specific energy of 57 Wh kg^?1 at specific power of 1.6 kW kg^?1 and capacitive retention of 94% after 10,000 cycles.     

An unusual polycatenating network self‐assembled by the 2D → 2D parallel → 3D parallel interpenetration of coordinative and hydrogen‐bonded (6,3) motifs

In the title coordination compound, catena‐poly[[[bis[diaquacadmium(II)]‐μ₂‐trans‐1,2‐bis(4‐pyridyl)ethene]bis{μ₂‐2,2′‐[(5‐carboxymethoxy‐m‐phenylene)dioxy]diacetato}] trans‐1,2‐bis(4‐pyridyl)ethene solvate dihydrate], {[Cd₂(C₁₂H₁₀O₉)₂(C₁₂H₁₀N₂)(H₂O)₄]·C₁₂H₁₀N₂·2H₂O}_n, (I), each Cd^II centre adopts a pentagonal–bipyramidal coordination geometry. The incompletely deprotonated 2,2′‐[(5‐carboxymethoxy‐m‐phenylene)dioxy]diacetate (TCMB) ligands and trans‐1,2‐bis(4‐pyridyl)ethene (bpe) ligands both act as bidentate bridges, linking the Cd^II centres into one‐dimensional ladders, which are connected into an undulating two‐dimensional (6,3) layer through O—H...N hydrogen bonds between the carboxylate groups of the TCMB ligands and the N atoms of the uncoordinated bpe ligands. Each undulating layer polycatenates two other identical layers, exhibiting the unusual combination of both 2D → 2D parallel and 2D → 3D parallel interpenetration (2D and 3D are two‐ and three‐dimensional, respectively).     

Preparation of porous g‐C3N4/Ag/Cu2O: a new composite with enhanced visible‐light photocatalytic activity

From previous reports, graphitic carbon nitride (g‐C₃N₄) can be used as a photocatalyst, although the low efficiency of solar energy utilization, small specific surface area and high recombination rate of photogenerated electron–hole pairs limit its practical application. For the purpose of increasing photocatalytic activity, especially under irradiation of visible light, we successfully synthesized a new composite, namely porous g‐C₃N₄/Ag/Cu₂O, through chemical adsorption of Ag‐doped Cu₂O on porous g‐C₃N₄, which has not been investigated carefully worldwide. The composition, morphology and optical properties of the composite were investigated through methods including X‐ray diffraction, energy‐dispersive X‐ray, Fourier transform infrared, UV–visible and photoluminescence spectroscopies and transmission electron microscopy. Using rhodamine B as organic pollutant to be degraded under the irradiation of visible light, different mass ratios of Ag/Cu₂O doped on porous g‐C₃N₄ led to enhanced photocatalytic performance of the composite compared to pure porous g‐C₃N₄. When the mass ratio of Ag/Cu₂O is 15%, porous g‐C₃N₄/Ag/Cu₂O exhibits a degradation rate 2.015 times higher than that of pure porous g‐C₃N₄. The reasons for this phenomenon may be attributed to the increased utilization efficiency of visible light, high‐speed separation of photogenerated electron–hole pairs, accelerated interfacial transfer process of electrons and increased surface area of the composite. Copyright © 2016 John Wiley & Sons, Ltd.     

Construction of a 2D Graphene‐Like MoS2/C3N4 Heterojunction with Enhanced Visible‐Light Photocatalytic Activity and Photoelectrochemical Activity

A novel graphene‐like MoS₂/C₃N₄ (GL‐MoS₂/C₃N₄) composite photocatalyst has been synthesized by a facile ethylene glycol (EG)‐assisted solvothermal method. The structure and morphology of this GL‐MoS₂/C₃N₄ photocatalyst have been investigated by a wide range of characterization methods. The results showed that GL‐MoS₂ was uniformly distributed on the surface of GL‐C₃N₄ forming a heterostructure. The obtained composite exhibited strong absorbing ability in the ultraviolet (UV) and visible regions. When irradiated with visible light, the composite photocatalyst showed high activity superior to those of the respective individual components GL‐MoS₂ and GL‐C₃N₄ in the degradation of methyl orange. The enhanced photocatalytic activity of the composite may be attributed to the efficient separation of electron–hole pairs as a result of the matching band potentials between GL‐MoS₂ and GL‐C₃N₄. Furthermore, a photocatalytic mechanism for the composite material has been proposed, and the photocatalytic reaction kinetics has been measured. Moreover, GL‐MoS₂/C₃N₄ could serve as a novel sensor for trace amounts of Cu²⁺ since it exhibited good selectivity for Cu²⁺ detection in water.     

Photogenic MnO2/Ag metal nanocomposites and their dye adsorbing activities

• Manganese dioxide/silver (MnO₂/Ag) nanoparticles were fabricated by using KMnO₄-NaBH₄ redox reaction at room temperature. The optical and structural properties of MnO₂/Ag were determined using UV–visible and Fourier transform infrared spectroscopies. The morphology was established with scanning and transmission electron microcopies, and X-ray diffraction. MnO₂/Ag showed excellent adsorbing activity to the removal of Congo red. The various kinetic models were used to determine the rate of dye removal. Congo red adsorption onto MnO₂Ag proceeds through the pseudo-second-order kinetic model. Langmuir adsorption capacity (Q⁰_max = 97.1 mg/g), and sorption intensity (n = 1.6) were estimated with Langmuir and Freundlich adsorption isotherm models for 250 mg/L Congo red. Elovich model suggest the adsorption of Congo red with the MnO₂Ag proceeds through the film diffusion. The positive values of enthalpy changes (ΔH⁰), entropy changes (ΔS⁰), and negative Gibbs free energy changes (ΔG⁰) showed that the Congo red adsorption process was endothermic, spontaneous, and chemisorption process followed with physical mechanism. The results showed that the removal efficiency decreases from 98% to 89% after the six consecutive experiments.

     

3D hierarchical MnO2 aerogels with superhydrophobicity for selective oil–water separation

Inorganic nanowire aerogel with low density, high specific surface area and high porosity has received increasing attention in the field of materials physics and chemistry because of not only the unique structural and physical features of metallic oxide but also low cost, environmental friendliness and earth abundant of precursor materials. In this work, MnO₂ nanowire aerogels (MNA) with ultralow density, and stable 3D hierarchical structures was successfully fabricated by freeze‐drying processes using MnO₂ nanowire as building blocks. The length of MnO₂ nanowires exceeds 100 μm, making it easier to cross‐link and self‐assemble into a 3D network of aerogels, and the acid and alkali resistance of MnO₂ enables it to adapt to extreme environments. Simultaneously, the monodispersed MnO₂ nanowire was prepared by the hydrothermal method, followed by acid treatment. To obtain superhydrophobic properties and achieve selective oil adsorption, the surfaces of nanowire aerogels were grafted the hydrophobic groups with low surface energy via vapor deposition. It is indicated that the obtained 3D hierarchical MNA show both superhydrophobic and super‐lipophilic properties simultaneously with a high‐water contact angle of 156°  ±  2° and an oil contact angle of 0°. And the MNA exhibited a high oil adsorption capacity of 85–140 g/g, thereby indicating its potential applications in oil/water separation. More importantly, the resulting MNA can be recycled ten cycles without loss of oil absorption capacity (more than 120 g/g). The results presented in this work demonstrate that the as‐prepared nanowire aerogel may find applications in chemical separation and environmental remediation for large‐scale absorption of oils from water.     

Syntheses and crystal structures of two heterometallic iodoplumbates containing mixed‐valence copper(I/II)

Mixed‐valence copper(I/II) atoms have been introduced successfully into a Pb/I skeleton to obtain two heterometallic iodoplumbates, namely poly[bis(tetra‐n‐butylammonium) [bis(μ₃‐dimethyldithiocarbamato)dodeca‐μ₃‐iodido‐hexa‐μ₂‐iodido‐tetracopper(I)copper(II)hexalead(II)]], {(C₁₆H₃₆N)₂[Cu₄^ICu^IIPb₆(C₃H₆NS₂)₂I₁₈]}_n , (I), and poly[[μ₃‐iodido‐tri‐μ₂‐iodido‐iodido[bis(1,10‐phenanthroline)copper(I)]copper(I)copper(II)lead(II)] hemiiodine], {[Cu^ICu^IIPbI₅(C₁₂H₈N₂)₂]·0.5I₂}_n , (II), under solution and solvothermal conditions, respectively. Compound (I) contains two‐dimensional anionic layers, which are built upon the linkages of Cu^II(S₂CNMe₂)₂ units and one‐dimensional anionic Pb/I/Cu^I chains. Tetra‐n‐butylammonium cations are located between the anionic layers and connected to them via C—H…I hydrogen‐bonding interactions. Compound (II) exhibits a one‐dimensional neutral structure, which is composed of [PbI₅] square pyramids, [Cu^II₄] tetrahedra and [Cu^IIN₄I] trigonal bipyramids. Face‐to‐face aromatic π–π stacking interactions between adjacent 1,10‐phenanthroline ligands stabilize the structure and assemble compound (II) into a three‐dimensional supramolecular structure. I₂ molecules lie in the voids of the structure.     

CdS nanospheres hybridized with graphitic C3N4 for effective photocatalytic hydrogen generation under visible light irradiation

Graphitic carbon nitride (g‐C₃N₄)‐based photocatalysts have received considerable attention in the field of photocatalysis, especially for photocatalytic H₂ evolution. However, the intrinsic disadvantages of g‐C₃N₄ seriously limit its practical application. Herein, CdS nanospheres with an average diameter of 135 nm prepared using a solvothermal method were used as co‐catalysts to form CdS/g‐C₃N₄ composites (CSCN) to enhance the photocatalytic activity. Various techniques were employed to characterize the structure, composition and optical properties of the as‐prepared samples. It was found that the CdS nanospheres were relatively uniformly dispersed on the surface of g‐C₃N₄. Moreover, the photocatalytic H₂ generation activity of the samples was evaluated using lactic acid as sacrificial reagent in water under visible light irradiation. When the amount of CdS nanospheres loaded in the hybridized composites was 5 wt%, the optimal H₂ evolution rate reached 924 μmol g^?1 h^?1, which was approximately 1.4 times higher than that (680 μmol g^?1 h^?1) of Pt/g‐C₃N₄ (3 wt%). Based on the results of analysis, a possible mechanism for the photocatalytic activity of CSCN is proposed tentatively.     

Structure Modification Function of g‐C3N4 for Al2O3 in the In Situ Hydrothermal Process for Enhanced Photocatalytic Activity

Heterojunctions of g‐C₃N₄/Al₂O₃ (g‐C₃N₄=graphitic carbon nitride) are constructed by an in situ one‐pot hydrothermal route based on the development of photoactive γ‐Al₂O₃ semiconductor with a mesoporous structure and a high surface area (188 m²g^?1) acting as electron acceptor. A structure modification function of g‐C₃N₄ for Al₂O₃ in the hydrothermal process is found, which can be attributed to the coordination between unoccupied orbitals of the Al ions and lone‐pair electrons of the N atoms. The as‐synthesized heterojunctions exhibit much higher photocatalytic activity than pure g‐C₃N₄. The hydrogen generation rate and the reaction rate constant for the degradation of methyl orange over 50 % g‐C₃N₄/Al₂O₃ under visible‐light irradiation (λ>420 nm) are 2.5 and 7.3 times, respectively, higher than those over pristine g‐C₃N₄. The enhanced activity of the heterojunctions is attributed to their large specific surface areas, their close contact, and the high interfacial areas between the components as well as their excellent adsorption performance, and efficient charge transfer ability.     

Hydrogen‐bonded networks in 5‐chloropyridin‐2‐amine–fumaric acid (2/1) and 2‐aminopyridinium dl‐malate

Crystals of 5‐chloropyridin‐2‐amine–(2E)‐but‐2‐enedioate (2/1), 2C₅H₅ClN₂·C₄H₄O₄, (I), and 2‐aminopyridinium dl ‐3‐carboxy‐2‐hydroxypropanoate, C₅H₇N₂⁺·C₄H₅O₅⁻, (II), are built from the neutral 5‐chloropyridin‐2‐amine molecule and fumaric acid in the case of (I) and from ring‐N‐protonated 2‐aminopyridinium cations and malate anions in (II). The fumaric acid molecule lies on an inversion centre. In (I), the neutral 5‐chloropyridin‐2‐amine and fumaric acid molecules interact via hydrogen bonds, forming two‐dimensional layers parallel to the (100) plane, whereas in (II), oppositely charged units interact via ionic and hydrogen bonds, forming a three‐dimensional network.     

Assembled synthesis of luminescent mono/double‐layered 2D and 3D Zn (II)‐based coordination polymers tuned by flexible bis (pyridyl)propane‐1,2‐diamines and diverse organic dicarboxylates

Six mono/double‐layered 2D and three 3D coordination polymers were synthesized by a self‐assembly reaction of Zn (II) salts, organic dicarboxylic acids and L1/L2 ligands. These polymeric formulas are named as [Zn(L1)(C₄H₂O₄)_0.5 (H₂O)]_n·0.5n(C₄H₂O₄)·2nH₂O ( 1 ), [Zn₂(L2)(C₄H₂O₄)₂]_n·2nH₂O ( 2 ), [Zn(L1)(m‐BDC)]_n ( 3 ), [Zn₂(L2)(m‐BDC)₂]_n·2nH₂O ( 4 ), [Zn₃(L1)₂(p‐BDC)₃(H₂O)₄]_n·2nH₂O ( 5 ), [Zn₂(OH)(L2) (p‐BDC)_1.5]_n ( 6 ), [Zn₂(L1)(p‐BDC)₂]_n·5nH₂O ( 7 ), [Zn₂(L2)(p‐BDC)₂]_n·3nH₂O ( 8 ) and [Zn₂(L1)(C₄H₄O₄)_1.5(H₂O)]_n·n(ClO₄)·nH₂O ( 9 ) [L1 = N,N′‐bis (pyridin‐4‐ylmethyl)propane‐1,2‐diamine, L2 = N,N′‐bis (pyridin‐3‐ylmethyl)propane‐1,2‐ diamine, m‐BDC^2? = m‐benzene dicarboxylate, p‐BDC^2? = p‐benzene dicarboxylate]. Meanwhile, these polymers have been characterized by elemental analysis, infrared, thermogravimetry (TG), photoluminescence, powder and single‐crystal X‐ray diffraction. Polymers 1–6 present mono‐ and double (4,4)‐layer motifs accomplished by L1/L2 ligands with diverse conformations and organic dicarboxylates, and the layer thickness locates in the range of 5.8–15.0 Å. In three 3D polymers, the L1 and L2 molecules adopt the same cis‐conformations and join adjacent Zn (II) cations together with p‐BDC^2? or succinate, giving rise to different binodal (4,4)‐c nets with (4.5².8³)(4.5³.7²) ( 7 ), pts ( 8 ) topology and twofold interpenetrated binodal (5,5)‐c nets with (3².4⁴.5².6²)(3.4³.5².6⁴) ( 9 ). Therefore, the diverse conformations of the two bis (pyridyl)‐propane‐1,2‐diamines and the feature of different organic dicarboxylate can effectively influence the architectures of these polymers. Powder X‐ray diffraction patterns demonstrate that these bulk solid polymers are pure phase. TG analyses indicate that these polymers have certain thermal stability. Luminescent investigation reveals that the emission maximum of these polymers varies from 402 to 449 nm in the solid state at room temperature. Moreover, 1 , 3 and 5–8 show average luminescence lifetimes from 8.81 to 16.30 ns.     

Surface modification of date palm activated carbonaceous materials for heavy metal removal and CO2 adsorption

In this study, high surface area activated carbon (AC) was prepared from a local palm tree (Phoenix Dactylifera) using a variety of metal carbonates activators and finally achieved an excellent S_BET of 2700 m²/g when Cs₂CO₃ was used as an activating agent at a temperature of 600 °C. Surface modification of AC was carried out using various nitrogen transporting agents, resulting in N-doped ACs with nitrogen content varying from 4.0 to 11.4 %, depending on the functionalizing agents and activators used. The bimodal (presence of micro- as well as meso-porosity) ACs with such excellent surface properties were studied for their CO₂ uptake capacity at two different temperatures (0 and 25 °C) by isotherms recorded at pressure 1 bar and showed a remarkable uptake ability of 3.52 mmol/g (at 25 °C) and 5.6 mmol/g (at 0 °C), respectively. Also, batch experiments with variable pH, contact time, adsorbate concentrations, adsorbent dose, and temperatures were evaluated to understand the mechanism of sorption phenomena of Cr(VI) and Pb(II) achieving > 99.9 % removal capacity by the prepared ACs. Depending on the heavy metal ions being investigated, it was revealed that the pH of the solution and the amount of adsorbent had a direct impact on the total adsorption ability. Nitrogen atoms doped into the carbon frameworks were found to enhance the adsorption in the case of Pb(II) while the removal of Cr(VI) appeared to be unaffected. Maximum adsorption for Cr(VI) was observed at pH 2 and was determined to follow Freundlich isotherm while that of Pb(II) was observed at pH 7 and follows Langmuir isotherm. Best adsorption was found at an adsorbate concentration of 10 ppm and an adsorbent dose of 10 g/L. Kinetic modeling parameters showed the applicability of pseudo-second-order model perfectly.     

Water Transport with Ultralow Friction through Partially Exfoliated g‐C3N4 Nanosheet Membranes with Self‐Supporting Spacers

Two‐dimensional (2D) graphitic carbon nitride (g‐C₃N₄) nanosheets show brilliant application potential in numerous fields. Herein, a membrane with artificial nanopores and self‐supporting spacers was fabricated by assembly of 2D g‐C₃N₄ nanosheets in a stack with elaborate structures. In water purification the g‐C₃N₄ membrane shows a better separation performance than commercial membranes. The g‐C₃N₄ membrane has a water permeance of 29 L m⁻² h⁻¹ bar⁻¹ and a rejection rate of 87 % for 3 nm molecules with a membrane thickness of 160 nm. The artificial nanopores in the g‐C₃N₄ nanosheets and the spacers between the partially exfoliated g‐C₃N₄ nanosheets provide nanochannels for water transport while bigger molecules are retained. The self‐supported nanochannels in the g‐C₃N₄ membrane are very stable and rigid enough to resist environmental challenges, such as changes to pH and pressure conditions. Permeation experiments and molecular dynamics simulations indicate that a novel nanofluidics phenomenon takes place, whereby water transport through the g‐C₃N₄ nanosheet membrane occurs with ultralow friction. The findings provide new understanding of fluidics in nanochannels and illuminate a fabrication method by which rigid nanochannels may be obtained for applications in complex or harsh environments.     

Construction of hydroxyethyl cellulose/silica/graphitic carbon nitride solid foam for adsorption and photocatalytic degradation of dyes

In the present study, novel hydroxyethyl cellulose/silica/graphitic carbon nitride (HEC/SiO₂/C₃N₄) solid foams with hierarchical porous structure have been successfully fabricated with gas bubbles template combination with freeze-drying method. Compared with HEC/SiO₂/C₃N₄-50 without gas foaming, the HEC/SiO₂/C₃N₄-80 with air bubbles template had larger pore volume and higher porosity and specific surface area, which not only exhibited faster adsorption rate, but also presented higher saturated adsorption capacity towards methylene blue (MB) and methyl violet (MV). From the experimental results, it was found that HEC/SiO₂/C₃N₄-80 had high adsorption capacities of 132.45 mg/g and 206.62 mg/g for MB and MV, respectively, and the adsorption process fitted the Langmuir adsorption isotherm and pseudo-second-order rate equation. Additionally, benefiting from its higher adsorption capacity and light-harvesting capability, HEC/SiO₂/C₃N₄-80 exhibited relatively higher photocatalytic degradation efficiencies against MB and MV under visible light irradiation than HEC/SiO₂/C₃N₄-50. More importantly, compared with the bare g-C₃N₄ powder, the HEC/SiO₂/C₃N₄ solid foams could be more easily separated from the treated water, which facilitated their recycle and reuse. Therefore, the good adsorption capacity, high photocatalytic degradation activity and recyclability of the HEC/SiO₂/C₃N₄ solid foam made it a promising candidate for the removal of organic dyes from wastewater.     

Synthesis of nitrogen doped activated carbon/polyaniline material for CO2 adsorption

The equilibrium adsorption isotherms of carbon dioxide and nitrogen on the nitrogen doped activated carbon (NAC) prepared by the chemical activation of a pine cone‐based char/polyaniline composite were measured using a volumetric technique. CO₂ and N₂ adsorption experiments were done at three different temperatures (298, 308, and 318 K) and pressures up to 16 bar, and correlated with the Langmuir, Freundlich, and Sips models. The Sips isotherm model presented the best fit to the experimental data. The N‐doped adsorbent showed CO₂ and N₂ adsorption capacity of 3.96 mmol·g⁻¹ and 0.86 mmol·g⁻¹, respectively, at 298 K and 1 bar. The selectivity predicted by ideal adsorbed solution theory (IAST) model was achieved 47.17 for NAC at 1 bar and y_N2 = 0.85 which is a composition similar to flue gas. The results showed that NAC adsorbent has a high CO₂‐over‐N₂ selectivity in a binary mixture. The relatively fast sorption rate of CO₂ on NAC compared to N₂ indicates the stronger affinity between CO₂ and amine groups. The isosteric heat of adsorption of CO₂ by the NAC demonstrated the physico‐chemical adsorption of CO₂ on the adsorbent surface. These data showed that prepared NAC could be successfully applied in separation of CO₂ from N₂.     

Post Synthetic Modification of NH2-(Zr-MOF) via Rapid Microwave-promoted Synthesis for Effective Adsorption of Pb(II) and Cd(II)

Excessive heavy metals in the water constitute a health hazard to humans, yet it may be efficiently purified using adsorbents. Herein, for the first time, UiO-66-NH₂ was modified by Glycidyl methacrylate (GMA) via microwave heating method to investigate its potential for adsorption of Pb(II) and Cd(II) metal ions. Synthesized MOF was characterized by TGA, XRD, BET, FE-SEM-EDX, and FTIR. The MOF has a huge surface area of 1144 m²/g, a mean pore diameter of 2.84 nm, and a total pore volume of 0.37 cm³/g. The effect of UiO-66-GMA performance was evaluated by investigating the impact of pH (1–9), contact time (0–200 min), initial metal ions concentration (20–1000 mg/L), temperature (25–55 °C), adsorbent dosage (0.5–3 g/L), and co existences of other metals was investigated on Pb(II) and Cd(II) percentage removal. Following an analysis of the adsorption isotherms, kinetics, and thermodynamics, the Temkin isothermal model showed an excellent fit with the adsorption data (R² = 0.99). The adsorption process was a spontaneous endothermic reaction and kinetically followed the pseudo-second-order kinetics model. Microwave heating method produced highly crystalline small Zr-MOF nanoparticles with a short reaction time. It promoted the simple yet highly efficient synthesis of Zr-based MOFs, as shown by the reaction mass space-time yield. The adsorption capability of Pb to the presence of several polar functional groups, including as primary and secondary amines, ester, alkene, and hydroxyl groups. This adsorbent is a potential candidate for wastewater treatment due to its outstanding structural stability in acidic and basic solutions, high removal efficiency, and recyclability.     

A Novel Molecularly Imprinted Photoelectrochemical Sensor Based on g‐C3N4‐AuNPs for the Highly Sensitive and Selective Detection of Triclosan

A novel molecularly imprinted polymer (MIP) photoelectrochemical sensor was fabricated for the highly sensitive and selective detection of triclosan. The MIP photoelectrochemical sensor was fabricated using graphite‐like carbon nitride (g‐C₃N₄) and gold nanoparticles (AuNPs) as photoelectric materials. The MIP/g‐C₃N₄‐AuNPs sensor used photocurrent as the detection signal and was triggered by ultraviolet light (UV‐Light 365 nm). g‐C₃N₄‐AuNPs was immobilized on indium tin oxide electrodes to produce the photoelectrochemically responsive electrode of the MIP/g‐C₃N₄‐AuNPs sensor. A MIP layer of poly‐o‐phenylenediamine was electropolymerized on the g‐C₃N₄‐AuNPs‐modified electrode to act as the recognition element of the MIP/g‐C₃N₄‐AuNPs sensor and to enable the selective adsorption of triclosan to the sensor through specific binding. Under optimal experimental conditions, the designed MIP/g‐C₃N₄‐AuNPs sensor presented high sensitivity for triclosan with a linear range of 2×10⁻¹² to 8×10⁻¹⁰ M and a limit of detection of 6.01×10⁻¹³ M. Moreover, the MIP/g‐C₃N₄‐AuNPs sensor showed excellent selectivity. The sensor had been successfully applied in the analysis of toothpaste samples.     

Synthesis and characterization of Ni (II), Cu (II), Fe (II) and Fe3O4 nanoparticle complexes with tetraaza macrocyclic Schiff base ligand for antimicrobial activity and cytotoxic activity against cancer and normal cells

This work describes a simple synthesis of complexes of the type [M(C₃₂H₂₈N₄)Cl₂], where M = Ni (II), Cu (II) and Fe (II) and a novel complex of magnetite nanoparticle (Fe₃O₄NP) inside (INS) tetraaza macrocyclic Schiff base ligand (C₃₂H₂₈N₄): [Fe₃O₄NP‐INS‐(C₃₂H₂₈N₄)], which was prepared by using a novel co‐precipitation method of coordinated ferric ion (Fe³⁺) in the complex [Fe(C₃₂H₂₈N₄)Cl₂] under mild conditions. The synthesized compounds were characterized and compared with a various physic‐chemical techniques like: Fourier transform infrared (FT‐IR), ultraviolet–visible spectroscopic techniques (UV–Vis), 1‐dimensional (1D) ¹H‐NMR, ¹³C‐NMR spectroscopic techniques, mass spectra, Powder X‐ray diffraction (PXRD), Vibrating sample magnetometer (VSM), Scanning electron microscopy (SEM), elemental analysis and molar conductance measurements. Furthermore, the highest saturation magnetization was 26.56 emu.g^?1 obtained from [Fe₃O₄NP‐INS‐(C₃₂H₂₈N₄)] (diameter of Fe₃O₄NPs~20.87 nm) that prove easy separation by an external magnetic field. In vitro screening of all the compounds against different species of bacteria and fungi shows that [Fe₃O₄NP‐INS‐(C₃₂H₂₈N₄)] is effective against the tested strains as compared to the tetraaza macrocyclic ligand and selected complexes. The cytotoxic activity of the all compounds was also examined in 3 human tumor cell lines as U87, MDA‐MB‐231 and LS‐174. The complex [Fe₃O₄NP‐INS‐(C₃₂H₂₈N₄)] shows moderate and strong cytotoxic activity against brain cancer, colon cancer and breast cancer (U87, MDA‐MB‐231 and LS‐174 respectively), without showing cytotoxicity towards peripheral blood mononucleocyte (PBMC) cells.