Charge-assisted H-bonds Research Articles

Pore engineering in highly stable hydrogen-bonded organic frameworks for efficient CH4 purification

The unsatisfactory stability of hydrogen-bonded organic frameworks (HOFs) arising from the weakness and flexibility of hydrogen-bonding (H-bonding) has generally hindered their practical applications. By synergistically employing three key strategies: (Ⅰ) introducing charge-assisted H-bonding to increase the polarity of the framework, (Ⅱ) optimizing the length of the building unit by extending the core structure of the linker molecule, and (III) incorporating functional sites containing methoxy and trifluoromethyl, to increase the stability of HOFs and the adsorption affinity for gas molecules, we successfully synthesized three charge-assisted hydrogen-bonded HOFs (NKM-HOF-3, NKM-HOF-4, and NKM-HOF-5; NKM = Nankai Materials). These HOFs exhibit distinct space configurations of nonporous packing, discrete cavities or continuous one-dimensional channels. Notably, NKM-HOF-5 exhibits commendable thermal and chemical stability and can be readily regenerated by re-solvothermal reaction. The activated NKM-HOF-5a exhibits a low affinity for CH4 but captures C2H6 and C3H8 with a relatively high affinity. According to theoretical calculations, the suitable pore size, together with functionalized and polarized surface environments in NKM-HOF-5a contribute to the excellent selective gas adsorption performance of NKM-HOF-5a. Furthermore, the dynamic breakthrough experiments demonstrate the highly efficient separation performance of NKM-HOF-5a for C2H6/CH4, C3H8/CH4, and C3H8/C2H6/CH4.

Comparison of rhodamine B adsorption and desorption on the aged non-degradable and degradable microplastics: Effects of charge-assisted hydrogen bond and underline mechanism

The accumulation of microplastics (MPs) in the environment and their role as carriers for ionic organic pollutants are increasingly attracting attention. This study evaluated the adsorption-desorption characteristics of the cationic organic pollutant on virgin and UV-aged non-degradable polystyrene (PS) as well as degradable poly(butylene succinate) (PBS) and poly(butylene adipate-co-terephthalate) (PBAT) MPs. The results showed that aging treatment made the surface of MPs rougher and more porous, causing the adsorption to shift from monolayer to multilayer adsorption. Aging increased the oxygen-containing groups on MPs, significantly enhancing the H bond (HB) donor capabilities of degradable aged PBS and PBAT, thereby improving adsorption by more than 10 times. This significant increase in adsorption is mainly due to the combined effects of strong HB (including ordinary HB (OHB) and charge-assisted HB (CAHB)), electrostatic interactions, and π-π interactions. Notably, the stronger HB enabled aged PBS and PBAT to achieve efficient and stable adsorption of rhodamine B over a wide pH range, with significant desorption hysteresis (HI > 1.80). This indicates that degradable aged MPs can act as carriers for long-distance pollutant transport. The significant total desorption of cationic pollutants from aged PBS and PBAT in simulated animal gastrointestinal fluids confirmed the greater environmental hazards of degradable aged MPs. This work is the first to demonstrate that degradable aged MPs, as unique HB donors, can primarily adsorb ionic organic pollutants through strong HB (CAHB and OHB), which helps assess the environmental fate of biodegradable microplastics and pollutants in aquatic systems.

Orthogonal Postsynthetic Copolymerization of Hydrogen-Bonded Organic Frameworks into a PolyHOF Membrane.

Hydrogen-bonded organic frameworks (HOFs) have shown promise in various fields; however, the construction of HOF/polymer hybrid membranes that can maintain both structural and functional integrity remains challenging. In this study, we here fabricated a new HOF (HOF-50) with reserved polymerizable allyl group via charge-assisted H-bonds between the carboxylate anion and amidinium, and subsequently copolymerized the HOF with monomers to construct a covalently bonded HOF/polymer hybrid (polyHOF) membrane. The resulting polyHOF membrane not only exhibits customizable mechanical properties and extreme stability, but also shows an exceptional ratiometric luminescent temperature-sensing function with very high sensitivity and visibility even when the lanthanide content is two orders of magnitude lower than that of the reported mixed-lanthanide metal-organic frameworks (MOFs) and lanthanide-doped covalent organic frameworks (COFs). This orthogonal postsynthesis copolymerization strategy may provide a general approach for preparing covalently connected HOF/polymer hybrid membranes for diverse applications.

Comprehensive analysis of cationic dye removal from synthetic and industrial wastewater using a semi-natural curcumin grafted biochar/poly acrylic acid composite hydrogel.

Polymer composites offer a tailored framework as an exceptional candidate for water treatment due to their tunable chemical structure, porous 3D architecture, physiochemical stability, accessibility, pH-sensitivity and ease of use. In this study, curcumin-engineered biochar is embedded into a cross-linked polyacrylic acid hydrogel matrix using in situ polymerization for developing a semi-natural adsorbent for the removal of cationic dye from an aqueous solution. The physicochemical features of the generated composite hydrogel are significantly influenced by the implementation of curcumin-grafted biochar into the polyacrylic acid substrate. Comprehensive characteristic approaches were employed to explore all aspects of the adsorbent's properties, especially its removal efficacy. The methodical adsorption study was accomplished by monitoring dynamic factors such as pH, adsorbent content, time frame, and initial dye concentration. The presence of the porous aromatized structure of biochar, active oxygen-enrich functional groups (carboxyl, hydroxyl, keto, enol, ether) coupled with the conjugated curcumin structure facilitate the effective establishment of hydrogen bonds, electrostatic interactions, π-π interactions, electron donor-acceptor and charge-assisted H-bonding with the malachite green (MG) and rhodamine B (Rho) molecules. The highest adsorption capacities of MG and Rho reached 521 mg g-1 and 741 mg g-1 respectively, in the range of neutral pH, considering their molecular nature, functionalities, and unique adsorption mechanisms. The isothermal modeling was carried out with Henry, Langmuir, Jovanovic, Freundlich, Temkin, and Koble-Corrigan models to determine the adsorption system. Additionally, the kinetic data were assessed with Bangham, pseudo-first-order, pseudo-second-order, intra-particle, and liquid film diffusion models to ascertain the rate-limiting phase. The Koble-Corrigan and Langmuir isotherm models (R2 > 0.997) as well as pseudo-second-order (R2 > 0.998) and Elovich (R2 = 0.983 and 0.995) kinetics models provide a substantial level of concordance with empirical findings. The analysis of non-linear diffusion models revealed that the Bangham (R2 > 0.995) pore and liquid film diffusion (R2 > 0.960) models has major influence on the rate of the adsorption procedure. The binary adsorption test demonstrated higher efficacy of the synthesized adsorbent in the removal of malachite as compared to rhodamine. This study sheds light on the design of a cost-effective semi-natural polymeric composite for treating dye-polluted wastewaters, a major milestone toward environmental and ecological sustainability.

Hydrogen-Bonding Assembly Meets Anion Coordination Chemistry: Framework Shaping and Polarity Tuning for Xenon/Krypton Separation.

Hybrid hydrogen-bonded (H-bonded) frameworks built from charged components or metallotectons offer diverse guest-framework interactions for target-specific separations. We present here a study to systematically explore the coordination chemistry of monovalent halide anions, i.e., F- , Cl- , Br- , and I- , with the aim to develop hybrid H-bond synthons that enable the controllable construction of microporous H-bonded frameworks exhibiting fine-tunable surface polarity within the adaptive cavities for realistic xenon/krypton (Xe/Kr) separation. The spherical halide anions, especially Cl- , Br- , and I- , are found to readily participate in the charge-assisted H-bonding assembly with well-defined coordination behaviors, resulting in robust frameworks bearing open halide anions within the distinctive 1D pore channels. The activated frameworks show preferential binding towards Xe (IAST Xe/Kr selectivity ca. 10.5) because of the enhanced polarizability and the pore confinement effect. Specifically, dynamic column Xe/Kr separation with a record-high separation factor (SF=7.0) among H-bonded frameworks was achieved, facilitating an efficient Xe/Kr separation in dilute, CO2 -containing gas streams exactly mimicking the off-gas of spent nuclear fuel (SNF) reprocessing.

Contrasting impact of phosphorus dissolution on the sorption of bisphenol A and carbamazepine by phosphorus-rich chars

Phosphorus (P)-rich chars produced by phosphoric-acid-assisted pyrolysis are promising carbonaceous remediation agents for soil pollution. Nevertheless, the potential of P species dissolution from P-rich chars has been ignored, and the impact of P dissolution on the sorption of hydrophobic compounds remains greatly unaddressed to date. Herein, the P species dissolution from wood-, cellulose-, and lignin-derived P-rich chars at 200–650 °C were investigated. P release capacity ranged from 0.2 to 0.3 mg·g−1 through cyclic dissolution and the maximum release capacity was 1.6 mg·g−1 through continuous dissolution. Enhanced P dissolution in soil experiment implies that P-rich char can be a potential P source. After P species dissolution, bisphenol A (BPA) sorption increased and carbamazepine (CBZ) sorption decreased onto P-rich chars. The enhanced π-π interaction facilitated BPA sorption, while the declined double charge-assisted H-bond ((±)CAHB) weakened CBZ sorption. Combined with DFT calculations, the binding energy (ΔE) supported the contrasting interfacial sorption processes. Apart from micropore-filling, the contribution of sorption mechanisms followed the sequence of (±)CAHB > π-π interaction > H-bonding. This work not only reveals that P-rich char can serve as a promising phosphatic fertilizer for soil improvement but also casts new light on the sorption mechanisms for hydrophobic compounds.

Engineering mesoporous algal-based biochars for efficient remediation of norfloxacin pollution in marine environment

• Marine biomass was chosen as raw material for the synthesis of biochar. • An appropriate H 3 PO 4 ratio was more favorable for GAB x to remove NOR from seawater. • The excellent adsorption capability reaches as high as 166.48 mg/g. • The interaction mechanism between GABx and norfloxacin was clarified in seawater. Gelidium amansii -derived biochars (GAB) were synthesized through one-step H 3 PO 4 chemical activation at impregnation ratios of 1.5–5 and applied for norfloxacin (NOR) removal in the marine environment. The effects of contact time and initial concentration, especially the salinity and humic acid on NOR adsorption were emphasized. The results showed that the increased H 3 PO 4 impregnation ratio prompted the development of mesoporous and the elimination of oxygen-containing functional groups. Thus, GAB with an appropriate impregnation ratio of 3 (GAB3) exhibited the largest NOR adsorption capability (166.48 mg/g) compare to the others (105.71–159.49 mg/g). NOR adsorption capacity slightly decreased with the increase of salinity, while the adsorption was almost unaffected with the increase of humic acid concentration. The adsorption mechanisms of NOR on GAB in seawater were dominantly through pore-filling, electrostatic attraction, π-π electron donor-acceptor interaction, cation bridging, and negative charge-assisted H-bond. This study provides strategies for efficient remediation of antibiotic-contaminated seawater using algal-based biochars.

Effect of pH-Dependent Homo/Heteronuclear CAHB on Adsorption and Desorption Behaviors of Ionizable Organic Compounds on Carbonaceous Materials.

Herein, the adsorption/desorption behaviors of benzoic acid (BA) and phthalic acid (PA) on three functionalized carbon nanotubes (CNTs) at various pH were investigated, and the charge-assisted H-bond (CAHB) was verified by DFT and FTIR analyses to play a key role. The results indicated that the adsorption order of BA and PA on CNTs was different from Kow of that at pH 2.0, 4.0, and 7.0 caused by the CAHB interaction. The strength of homonuclear CAHB (≥78.96 kJ·mol−1) formed by BA/PA on oxidized CNTs is stronger than that of heteronuclear CAHB formed between BA/PA and amino-functionalized CNTs (≤51.66 kJ·mol−1). Compared with the heteronuclear CAHB (Hysteresis index, HI ≥ 1.47), the stronger homonuclear CAHB leads to clearly desorption hysteresis (HI ≥ 3.51). Additionally, the contribution of homonuclear CAHB (≥52.70%) was also greater than that of heteronuclear CAHB (≤45.79%) at pH 7.0. These conclusions were further confirmed by FTIR and DFT calculation, and the crucial evidence of CAHB formation in FTIR was found. The highlight of this work is the identification of the importance and difference of pH-dependent homonuclear/heteronuclear CAHB on the adsorption and desorption behaviors of ionizable organic compounds on carbonaceous materials, which can provide a deeper understanding for the removal of ionizable organic compounds by designed carbonaceous materials.

Metal-organic hybrids based on [VO2(L)]− tecton with cations of imidazole and its derivative: Synthesis, single-crystal structures and molecular docking studies

New vanadium Schiff base complexes [VO2(L)]ImH 1 and [VO2(L)]m-ImH 2 (where L = (Z)-N'-(2-hydroxy-3-methoxybenzylidene)acetohydrazide, ImH = Imidazole and m-ImH = methylimidazole) were prepared. These were characterized using various techniques and structures were determined using single-crystal X-ray diffraction analysis. In these complexes, the three-dimensional structures are assembled via the columbic interactions between [VO2(L)]− anions and imidazolium ions supported through charge-assisted H-bonding between protonated imidazolium NH and CH of L2−. Hirshfeld surface analysis was also performed to investigate the mode of non-covalent interactions. Electrochemical measurements were carried out to explore the redox properties of complexes using cyclic voltammetry and differential pulse voltammetry. Computational studies have been carried out to verify the molecular structures of the complexes. Global reactivity parameters were also derived. The molecular interactions in complexes with the α-amylase and α-glucosidase proteins with a co-crystallized ligand were investigated using in silico docking.

Biochar composite derived from cellulase hydrolysis apple branch for quinolone antibiotics enhanced removal: Precursor pyrolysis performance, functional group introduction and adsorption mechanisms

In this study, magnetic biochar (MAB) and humic acid (HA)-coated magnetic biochar produced from apple branches without and after cellulase hydrolysis (HMAB and CHMAB, respectively) were prepared and tested as adsorbents of enrofloxacin (ENR) and moxifloxacin (MFX) in aqueous solution. Compared with MAB and HMAB, novel adsorbent CHMAB possessed a superior mesoporous structure, greater graphitization degree and abundant functional groups. When antibiotic solutions ranged from 2 to 20 mg L−1, the theoretical maximum adsorption capacities of CHMAB for ENR and MFX were 48.3 and 61.5 mg g−1 at 35 °C with adsorbent dosage of 0.4 g L−1, respectively, while those of MAB and HMAB were 39.6 and 54.4 mg g−1, and 44.7 and 59.0 mg g−1, respectively. The pseudo-second-order kinetic model and Langmuir model presented a better fitting to the spontaneous and endothermic adsorption process. The maximum adsorption capacity of ENR and MFX onto CHMAB was achieved at initial pH values of 5 and 8, respectively. Additionally, the adsorption capacity of ENR and MFX decreased with increasing concentrations of K+ and Ca2+ (0.02–0.1 mol L−1). Synergism between the pore-filling effect, π-π electron-donor-acceptor interactions, regular and negative charge-assisted H-bonding, surface complexation, electrostatic interactions and hydrophobic interactions may dominate the adsorption process. This study demonstrated that a novel magnetic biochar composite prepared through pyrolysis of agricultural waste lignocellulose hydrolyzed by cellulase in combination with HA coating was a promising adsorbent for eliminating quinolone antibiotics from aqueous media.

Comprehensively understanding the natures of crystal structure and magnetic behavior of a radical salt with regular mixed anion-cation stacks

In this study, the ionic crystals of [TTF][Au(mnt)2] (1; mnt2− ​= ​maleonitriledithiolate) have been grown using solvent diffusion method, and characterized by microanalysis, IR and Raman spectra, TG and powder X-ray diffraction (PXRD) techniques. Crystal of 1 belongs to triclinic space P−1 with Z ​= ​1 and both planar TTF+ and [Au(mnt)2]− locate at an inversion center, respectively. Cation (C) and anion (A) form uniform … CACA … mixed stack along [1 0 0] direction, and the charge-assisted H-bonds form between neighboring mixed stacks. 1 features an S ​= ​½ Heisenberg uniform antiferromagnetic (AFM) chain with J/kB ​= ​−2.08(1) K with g ​= ​2.0085 fixed, and absent spin-Peierls transition above 1.9 ​K, however, with long-range AFM ordering below 1.9 ​K. Additionally, 1 displays different style of mixed stack from [TTF][M(mnt)2] (M ​= ​Pd or Pt; … C2A2C2A2 … manner mixed stack) owing to strong AFM couplings (−J/kB ​> ​1000 ​K) in a [M(mnt)2]22− dimer.

Adsorption of pharmaceuticals from aqueous solutions using biochar derived from cotton gin waste and guayule bagasse

Biochars produced from cotton gin waste (CG) and guayule bagasse (GB) were characterized and explored as potential adsorbents for the removal of pharmaceuticals (sulfapyridine-SPY, docusate-DCT and erythromycin-ETM) from aqueous solution. An increase in biochar pyrolysis temperature from 350 οC to 700 οC led to an increase in pH, specific surface area, and surface hydrophobicity. The electronegative surface of all tested biochars indicated that non-Coulombic mechanisms were involved in adsorption of the anionic or uncharged pharmaceuticals under experimental conditions. The adsorption capacities of Sulfapyridine (SPY), Docusate (DCT) and Erythromycin (ETM) on biochar were influenced by the contact time and solution pH, as well as biochar specific surface area and functional groups. Adsorption of these pharmaceutical compounds was dominated by a complex interplay of three mechanisms: hydrophobic partitioning, hydrogen bonding and π–π electron donor–acceptor (EDA) interactions. Despite weaker π–π EDA interactions, reduced hydrophobicity of SPY− and increased electrostatic repulsion between anionic SPY− and the electronegative CG biochar surface at higher pH, the adsorption of SPY unexpectedly increased from 40% to 70% with an increase in pH from 7 to 10. Under alkaline conditions, adsorption was dominated by the formation of strong negative charge-assisted H-bonding between the sulfonamide moiety of SPY and surface carboxylic groups. There seemed to be no appreciable and consistent differences in the extent of DCT and ETM adsorption as the pH changed. Results suggest the CG and GB biochars could act as effective adsorbents for the removal of pharmaceuticals from reclaimed water prior to irrigation. High surface area biochars with physico-chemical properties (e.g., presence of functional groups, high cation and anion exchange capacities) conducive to strong interactions with polar-nonpolar functionality of pharmaceuticals could be used to achieve significant contaminant removal from water.Graphic

Unveiling the correlation of Fe3O4 fractions upon the adsorption behavior of sulfamethoxazole on magnetic activated carbon

Magnetic particles (MPs) assisted powdered activated carbon (PAC) is a promising composite material for adsorption removal of micropollutants. The fractional amount of Fe3O4 impacts the balance between adsorption capacity and magnetic property of magnetic activated carbons (MPACs), and therefore it affects the extent of sulfamethoxazole (SMX) removal. Here, five MPACs with different mass ratios of Fe3O4: PAC (1:1, 1:2, 1:4, 1:6, and 1:8) were prepared using a hydrothermal method and characterized by various spectroscopic methods. The spherical shaped MPs were monolayerly deposited on PAC with fewer pores blocked when the mass ratio of Fe3O4 was comparatively low (≤ 20%). MPAC6 (14.3 wt% of Fe3O4) had the best overall performance, with good Langmuir adsorption capacities for SMX (173.0 mg g−1) and excellent magnetic properties (9.0 emu g−1). Corresponding adsorption kinetics fitted well with the pseudo second-order kinetic model. The negative ΔG0 (−25.6 to −27.2 KJ mol−1) and ΔH0 (−9.14 KJ mol−1), and positive ΔS0 (0.55 KJ mol−1 K−1) properties indicated the spontaneous and exothermic nature of the adsorption process accompanied by an increase in entropy. The strong cation-assisted electron donor-acceptor and hydrophobic interactions were contributed to a high extent of SMX removal in the pH range of 2–4. Formation of negative charge-assisted H-bonds was responsible for the adsorption of hydrophilic SMX− on negatively charged MPAC6 in alkaline solution. Desorption and regeneration experiments showed SMX removal was still 92.3% in the 5th cycle. These findings give valuable insights into the interactions between SMX and MPACs and guide for choosing sustainable magnetic adsorbents for environmental applications.

Adsorption, desorption and coadsorption behaviors of sulfamerazine, Pb(II) and benzoic acid on carbon nanotubes and nano-silica

In this study, nano-silica (Nano-SiO2), oxidized (O-CNTs) and graphitized multi-walled carbon nanotubes (G-CNTs) were applied as model adsorbents to study the adsorption, desorption and coadsorption behaviors of sulfamerazine (SMR), Pb(II) and benzoic acid (BA). The results showed that charge assisted H-bond (CAHB) formation played an important role in adsorption of SMR and BA on O-riched nanomaterials. The adsorption capacities of Pb(II) on CNTs were 21.46– 26.77 times higher than that on Nano-SiO2, which was mainly attributed to surface complexation and cation-π interaction. The fraction of Pb2+ adsorbed in the inside channel of CNTs should not be ignored. In coexisting systems, the absolute sorption inhibition of the SMR (ΔQeSMR) was compared with the amount of competitor adsorbed. Competitive sorption was observed as indicated by adding Pb(II) decreased adsorption of SMR on Nano-SiO2 (ΔQeSMR > 0), but hardly affected SMR adsorption on CNTs (ΔQeSMR ≈ 0) which was attributed to cation-π interaction. In addition, CAHB formed between SMR and Nano-SiO2 (ΔpKa ≈ 4.34) was weaker than that formed between SMR and O-CNTs (ΔpKa ≈ 3.15), which also consequently resulted in stronger competition of Pb(II) to SMR on Nano-SiO2 than that on O-CNTs. Moreover, coexisting BA increased adsorption of SMR on Nano-SiO2 and G-CNTs (ΔQeSMR < 0), but did not result in an apparent competition on SMR adsorption by O-CNTs (ΔQeSMR ≈ 0). These results emphasize that the environmental behaviors of a certain pollutant should be assessed carefully by considering the presence of other pollutants.

Charge-assisted hydrogen bond and nitrile⋯nitrile interaction directed supramolecular associations in Cu(ii) and Mn(ii) coordination complexes: anticancer, hematotoxicity and theoretical studies

Charge-assisted H-bonds and nitrile⋯nitrile interactions directed assemblies in Cu(ii) and Mn(ii) complexes have been analyzed by MEP surface and NCI plot index. Anticancer activities and hematotoxictiy have been investigated.

The promoted dissolution of copper oxide nanoparticles by dissolved humic acid: Copper complexation over particle dispersion.

Humic substances are the dominant dissolved organic matter fraction in the aqueous phase of environmental media. They would inevitably react with chemicals released into the environment. The influence of dissolved humic acid (DHA) on the dissolution and dispersion of copper oxide nanoparticles (CuO NPs, 50nm, 49.57mgL-1) was therefore investigated in the present study. In addition to dispersing CuO NPs and reducing the size of the aggregates, the amount of released Cu from CuO NPs was found to increase over time with increasing concentrations of DHA, 96% of which was present as organic complexes after 72h. At DHA concentrations exceeding 16.09mgC L-1, the complexation coefficients of DHA with Cu and the adsorptivity of CuO NPs to DHA were both reduced due to increased homo-conjugation of DHA as promoted by negative charge-assisted H-bond. Although the adsorption capacity of DHA kept increasing up to 57.07mgC L-1, the hydrodynamic diameter and ζ-potential were similar and the percentages of total released Cu continued to increase linearly to 4.92% at higher levels of DHA (30.13-57.07mgC L-1). Thereupon, DHA promoted the dissolution of CuO NPs in a concentration-dependent fashion. The driving force was complexation of Cu by DHA, rather than the balancing between the exposed and the covered surface area of the CuO NPs due to DHA adsorption. Our findings facilitate understanding the underlying mechanisms on how DHA impacts the CuO NPs environmental behavior (or fate) as well as on their kinetics.

Adsorption behavior and mechanism of sulfonamides on phosphonic chelating cellulose under different pH effects

Phosphonic chelating fiber (PCCSF) as a novel adsorbent was produced through alkalization, etherification, amination and phosphonation, and then it was applied to adsorb sulfonamides (SAs), such as sulfadiazine (SD), sulfamonomethoxine (SMM) and sulfamethoxazole (SMZ). Specially, their adsorption behavior at different pH values was studied. As a result, PCCSF was provided with amino (NH2 or NH) and PO(OH)2 (PO) groups, and its equilibrium data were generally represented by both Langmuir and Freundlich models. Combining adsorbent-to-solution distribution coefficients (Kd) values and the effect of pH, the primary mechanism suggested that adsorption capacity of PCCSF was lower in strong acid and alkali solution, due to the electrostatic repulsion and hydrophobic interactions. By contrast, its adsorption affinity became more excellent at 3 < pH < 9 owing to the π-π electron-donor-acceptor (EDA) charge-assisted H-bond, Lewis acid-base interaction and charge-assisted H-bond (CAHB).

Enhanced adsorption of bisphenol A and sulfamethoxazole by a novel magnetic CuZnFe2O4–biochar composite

The widespread occurrence of endocrine-disrupting compound and pharmaceutical active compounds such as bisphenol A (BPA) and sulfamethoxazole (SMX) in natural freshwater resources can cause serious environmental problems even at low exposure levels. In this work, in order to remove BPA and SMX from aqueous solutions, a novel biochar-supported magnetic CuZnFe2O4 composite (CZF–biochar) was synthesized by a facile one-pot hydrothermal process. After characterization studies, the key factors affecting BPA and SMX adsorption on CZF–biochar were comprehensively investigated. The primary mechanisms for BPA and SMX adsorption included charge-assisted H-bonding, hydrophobic, and π–π electron donor–acceptor interactions. In summary, considering the fast kinetics, high adsorption properties, easy magnetic separation, and recyclability for multiple reuses, the CZF–biochar composite has potential for the removal of BPA, SMX, and potentially other emerging organic contaminants from contaminated soil and water.

Metalo Hydrogen-Bonded Organic Frameworks (MHOFs) as New Class of Crystalline Materials for Protonic Conduction.

Recently, proton conduction has been a thread of high potential owing to its wide applications in fuel-cell technology. In the search for a new class of crystalline materials for protonic conductors, three metalo hydrogen-bonded organic frameworks (MHOFs) based on [Ni(Imdz)6 ]2+ and arene disulfonates (MHOF1 and MHOF2) or dicarboxylate (MHOF3) have been reported (Imdz=imidazole). The presence of an ionic backbone with charge-assisted H-bonds, coupled with amphiprotic imidazoles made these MHOFs protonic conductors, exhibiting conduction values of 0.75×10-3 , 3.5×10-4 and 0.97×10-3 S cm-1 , respectively, at 80 °C and 98 % relative humidity, which are comparable to other crystalline metal-organic framework, coordination polymer, polyoxometalate, covalent organic framework, and hydrogen-bonded organic framework materials. This report initiates the usage of MHOF materials as a new class of solid-state proton conductors.

UNAM-1: a robust CuIand CuIIcontaining 3D-hydrogen-bonded framework with permanent porosity and reversible SO2sorption

[CuIICuI12(HL)12]10−and [Me2NH2]+ions assemble into a unique 3D hydrogen-bonded framework.