Characterization of electric properties of nanomaterials usually involves fabricating field effect transistors （FET） and deriving materials properties from device performances. However, the quality of electrode cont...Characterization of electric properties of nanomaterials usually involves fabricating field effect transistors （FET） and deriving materials properties from device performances. However, the quality of electrode contacts in FET devices heavily influences the device performance, which makes it difficult to obtain the intrinsic electric properties of nanomaterials. Dielectric force microscopy （DFM）, a contactless method developed recently, can detect the low-frequency dielectric responses of nanomaterials without electric contact, which avoids the influence of electric contact and can be used to study the intrinsic conductivity of nanomaterials. Here we study the influences of surface adsorbates on the conductivity of ZnO nanowires （NWs） by using FET and DFM methods. The conductivity of ZnO NW is much larger in N2 atmosphere than that in ambient environment as measured by FET device, which is further proven by DFM measurement that the ZnO NW exhibits larger dielectric response in N2 environment, and the influence of electrode contacts on measurement can be ruled out. Based on these results, it can be concluded that the adsorbates on ZnO NW surface highly influence the conductivity of ZnO NW rather than the electrode contact. This work also verifies the capability of DFM in measuring electric properties of nanomaterials.展开更多
Despite substantial efforts in developing high-performance catalysts for the oxygen reduction reaction(ORR),the persistent challenge lies in the high onset overpotential of the ORR,and the effect of the elec-trolyte s...Despite substantial efforts in developing high-performance catalysts for the oxygen reduction reaction(ORR),the persistent challenge lies in the high onset overpotential of the ORR,and the effect of the elec-trolyte solution cannot be ignored.Consequently,we have systematically investigated the impact of adsorbate species and concentration,as well as solution pH,on the ORR activity on Pt(111)and Pt(poly)electrodes.The results all tend to establish a linear quantitative relationship between the onset potential for ORR and the adsorption equilibrium potential of the adsorbate.This finding indicates the decisive role of adsorbates in the onset potential for ORR,suggesting that the adsorption potential of adsorbates can serve as an intuitive criterion for ORR activity.Additional support for this conclusion is derived from experimental results obtained from the oxygen evolution reaction on Pt(poly)with different adsorbate species and from the hydrogen evolution reaction on Pt(111)with iodine adsorption.We further propose both an empirical equation for the onset potential for ORR and the concept of a potential-regulated adsor-bate shielding effect to elucidate the influence of adsorbates on ORR activity.This study provides new insights into the high onset overpotential of the ORR and offers potential strategies for predicting and enhancingORRactivity inthefuture.展开更多
The mass spectrometry of gold clusters stabilized by poly（N‐vinyl‐2‐pyrrolidone） （Au：PVP） re‐vealed the presence of Cl adsorbates derived from synthetic precursors, mainly on the Au34 and Au43 clusters. Chang...The mass spectrometry of gold clusters stabilized by poly（N‐vinyl‐2‐pyrrolidone） （Au：PVP） re‐vealed the presence of Cl adsorbates derived from synthetic precursors, mainly on the Au34 and Au43 clusters. Changes in the amount of Cl adsorbates on the Au clusters did not affect the catalytic prop‐erties for the aerobic oxidation of benzyl alcohol, suggesting that the Cl atoms were only weakly bound to the Au clusters. In contrast, the replacement of Cl with Br on the Au34 and Au43 clusters significantly suppressed activity, without any influence on the electronic structure. This result indi‐cated that the Br atoms were strongly bound to the Au clusters and sterically blocked their active sites. The substantial reduction of the catalytic activity by the Br adsorbates suggested that the Au34 and Au43 clusters made a major contribution to the catalytic activity of the Au：PVP.展开更多
The monolayer adsorbed Mo(001)surface is studied by the slab dynamical calculation by using the nearest and next nearest neighbour interactions.The phase diagram is obtained for light,heavy atom adsorbed and clean Mo(...The monolayer adsorbed Mo(001)surface is studied by the slab dynamical calculation by using the nearest and next nearest neighbour interactions.The phase diagram is obtained for light,heavy atom adsorbed and clean Mo(001)surface.The surface reconstruction induced by the interactions between adsorbed atoms is dicussed.展开更多
Amines in porous materials have been employed as active species for the selective CO_(2) adsorption from natural gas because of their target-specific interactions.Nevertheless,it is difficult to modulate such strong i...Amines in porous materials have been employed as active species for the selective CO_(2) adsorption from natural gas because of their target-specific interactions.Nevertheless,it is difficult to modulate such strong interactions to reach a high efficiency in the adsorption processes.Herein,we fabricated lightresponsive adsorbents with tunable adsorbent–adsorbate interactions for CO_(2) capture.The adsorbents were synthesized by introducing primary and secondary amines into a mesoporous silica that had been grafted with azobenzene groups on the surfaces.The target-specific amine sites render the adsorbents significantly selective in the uptake of CO_(2) over CH_(4),and the azobenzene groups were used as lightresponsive switches to influence the adsorbent–adsorbate interactions.The adsorbents can freely adsorb CO_(2) when the azobenzene groups are in the trans state.Ultraviolet-light irradiation makes the azobenzene groups transform to the cis configuration,which greatly hinders amines in the uptake of CO_(2).The caused difference of adsorption capacity can reach 34.9%.The alternative irradiation by ultravioletand visible-light can lead to a recyclable regulation on adsorption performance.The changes of the electrostatic potentials of amines are responsible for the light-induced regulation on adsorption.展开更多
Graphite has achieved widespread recognition as an effective solid lubricant due to its high functionality across diverse environmental conditions.Although superlubricity or ultra-low friction is readily observed at t...Graphite has achieved widespread recognition as an effective solid lubricant due to its high functionality across diverse environmental conditions.Although superlubricity or ultra-low friction is readily observed at the graphite basal plane,it has been reported that certain adsorbates from the surrounding environment can deteriorate this friction regime.Here,we conducted a fundamental analysis on the effect of phenol,pentanol,and water adsorbates on the friction of graphite-silica interfaces using molecular dynamics simulations with the reactive force field ReaxFF.First,we evaluated three ReaxFF parameter sets optimized using friction-pertinent properties.It was observed that the force field optimization objective played a major role in the calculated tribological properties.Secondly,parameters such as normal load and motion directionality were investigated.Additionally,adsorption,and binding energy calculations were performed to expand upon the hypothesis that friction may be directly correlated to the interfacial molecular structure rather than binding energy and adsorbate commensuration with graphene.By quantitatively representing the interfacial roughness of each adsorbate,the hypothesis was confirmed by unequivocally explaining the calculated friction coefficients.展开更多
Developing efficient electrocatalysts for the oxygen evolution reaction(OER)under neutral conditions is important for microbial electrolysis cells(MECs).However,the OER kinetics in neutral electrolytes at present are ...Developing efficient electrocatalysts for the oxygen evolution reaction(OER)under neutral conditions is important for microbial electrolysis cells(MECs).However,the OER kinetics in neutral electrolytes at present are extremely sluggish,resulting in high overpotentials that greatly limit the energy conversion efficiencies of MECs.Previous studies failed to probe the adsorbates on surface metal sites of catalysts at the atomic scale and elucidate their influence on the catalytic activities,which has impeded the rational design of efficient neutral OER catalysts with optimal surface structures.Here,using in situ transmission electron microscopy(TEM),in situ X-ray photoelectron spectroscopy(XPS)and in situ low-energy ion scattering studies,we have identified,for the first time,that the electrochemically activated adsorbates on surface metal sites play a critical role in boosting the neutral OER activities of Ru-Ir binary oxide(RuxIryO2)catalysts.The adsorbate-activated RuxIryO2on a glassy carbon electrode achieved a low overpotential of 324 m V at10 m A cm-2in neutral electrolyte,with a 36-fold improvement in turnover frequency compared with that of Ir O2benchmark.Upon application in an MEC system,the resulting full cell showed a decreased voltage of 1.8 V,200 m V lower than the best value reported to date,facilitating efficient synthesis of poly(3-hydroxybutyrate)from bioelectrochemical CO_(2)reduction.Density functional theory(DFT)studies revealed that the enhanced OER activity of RuxIryO2catalyst arose from local structural distortion of adjacent adsorbate-covered Ru octahedra at the catalyst surface and the consequently decreased adsorption energies of OER intermediates on Ir active center.展开更多
Up to now, there have been many indistinctive points in the image interpretation of scanning tunnelhng microscopy (STM) system, and the problems have attracted almost all STM scientists’ attention. In 1992, Kenkre pr...Up to now, there have been many indistinctive points in the image interpretation of scanning tunnelhng microscopy (STM) system, and the problems have attracted almost all STM scientists’ attention. In 1992, Kenkre proposed the new programme which describes the behaviour of the electrons moving in the STM tunnelling by the method of exciton dynamics, and the programme not only breaks through the restrictions of Tersoff-Hamann theory, but also can be applied conveniently to discussing the effects of the tip structure, adsorbate structure, substrate structure, temperature, tunneling voltage, and the degree of coherence of elec-展开更多
Lignin,the most abundant natural aromatic polymer globally,has garnered considerable interest due to its rich and diverse active functional groups and its antioxidant,antimicrobial,and adhesive properties.Recent resea...Lignin,the most abundant natural aromatic polymer globally,has garnered considerable interest due to its rich and diverse active functional groups and its antioxidant,antimicrobial,and adhesive properties.Recent research has significantly improved the performance of lignin-based hydrogels,suggesting their substantial potential in fields such as biomedicine,environmental science,and agriculture.This paper reviews the process of lignin extraction,systematically introduces synthesis strategies for preparing lignin-based hydrogels,and discusses the current state of research on these hydrogels in biomedical and environmental protection fields.It concludes by identifying the existing challenges in lignin hydrogel research and envisioning future prospects and development trends.展开更多
Hospital wastewater contains complex pollutants,including residual organic dyes and antibiotic-resistant pathogens,posing severe risks to ecosystems and human health.Conventional adsorbents,constrained by monopolar fu...Hospital wastewater contains complex pollutants,including residual organic dyes and antibiotic-resistant pathogens,posing severe risks to ecosystems and human health.Conventional adsorbents,constrained by monopolar functional groups and limited surface sites,fail to remove both pollutants simultaneously.Here,we report an intelligent responsive polyurethane microsphere adsorbent doped with diallyl dimethylammonium chloride modified carbon nanotubes,termed as PUCD microspheres.The PUCD integrates bipolar adsorption sites,tunable micrometer-scale pores,and a near-infrared(NIR)-triggered in situ capture mechanism within a single platform,which achieves up to 98.3%dye removal,maintains strong adsorption performance across a wide pH range and retains 83.3%efficiency for rhodamine B after five cycles.Notably,the PUCD employs a temperature-responsive phase transition:under NIR irradiation,the microspheres undergo shrinkage,reducing the pore size to generate a‘polymer trap',enabling in situ capture of bacteria with>99%efficiencies for both Staphylococcus aureus and Escherichia coli.By immobilizing live bacteria,the PUCD microspheres substantially reduces the risk of pathogen desorption and toxin release.This promising platform offers a safe,efficient,and single-stage strategy for hospital wastewater purification,enabling the simultaneous elimination of dyes and pathogenic bacteria.展开更多
The enormous number of combinations of adsorbing molecules and porous materials that exist is known as adsorption space.The adsorption space for microporous polymers has not yet been systematically explored,especially...The enormous number of combinations of adsorbing molecules and porous materials that exist is known as adsorption space.The adsorption space for microporous polymers has not yet been systematically explored,especially when compared with efforts for crystalline adsorbents.We report molecular simulation data for the adsorptive and structural properties of polymers of intrinsic microporosity with a diverse set of adsorbate species with 345 distinct adsorption isotherms and over 240,000 fresh and swollen structures.These structures and isotherms were obtained using a sorption-relaxation technique that accounts for the critical role of flexibility of the polymeric adsorbents.This enables us to introduce a set of correlations that can estimate adsorbent swelling and fractional free volume dilation as a function of adsorbate uptake based on readily characterized properties.The separation selectivity of the 276 distinct binary molecular pairs in our data is reported and high-performing adsorbent systems are identified.展开更多
Maintaining high metal dispersion of supported metal catalysts to achieve superior reactivity under harsh conditions poses one of the main challenges for their practical applications.Constructing and regulating the st...Maintaining high metal dispersion of supported metal catalysts to achieve superior reactivity under harsh conditions poses one of the main challenges for their practical applications.Constructing and regulating the strong metal-support interactions(SMSI)by diverse methodologies has emerged as one of the promising approaches to fabricating robust supported metal catalysts.In this study,we report an L-ascorbic acid(AA)-inducing strategy to generate SMSI on a titania-supported gold(Au)catalyst after high-temperature treatment in an inert atmosphere(600℃,N_(2)).The AA-induced SMSI can efficiently stabilize Au nanoparticles(NPs)and preserve their catalytic performance.The detailed study reveals that the key to realizing this SMSI is the generation of oxygen vacancies within the TiO_(2) support induced by the adsorbed AA,which drives the formation of the Ti Oxpermeable layer onto the Au NPs.The strategy could be extended to TiO_(2)-supported Au catalysts with different crystal phases and platinum group metals,such as Pt,Pd,and Rh.This work offers a promising novel route to design stable and efficient supported noble metal catalysts by constructing SMSI using simple reducing organic adsorbent.展开更多
Activating both metal and lattice oxygen sites for efficient oxygen evolution reactions(OER)is a critical challenge.This study pioneers a novel approach,employing cobalt-nickel glycerate solid spheres(CoNi-G SSs)as se...Activating both metal and lattice oxygen sites for efficient oxygen evolution reactions(OER)is a critical challenge.This study pioneers a novel approach,employing cobalt-nickel glycerate solid spheres(CoNi-G SSs)as self-sacrificial templates to synthesize yolk-shell structured CoNi-G SSs@ZIF-67 nanospheres.The derived NiCo2S4@CoS2/MoS2 double-shelled hollow nanospheres integrate the adsorbate evolution mechanism(AEM)and lattice oxygen mechanism(LOM),enabling synergistic dual catalytic pathways.Nickel modulation facilitates active species reconstruction in NiCo_(2)S_(4),enhancing lattice oxygen activity and optimizing the LOM pathway.Characterization results indicate that anode activation triggered the redox processes of metal and lattice oxygen sites,involving the formation and re-filling of oxygen vacancies.Additionally,the CoS_(2)/MoS_(2) heterostructure enhances the AEM pathway,as supported by density functional theory calculations,which demonstrate optimized adsorption of intermediates for both hydrogen evolution reaction and OER.The assembled anion exchange membrane water splitting device can deliver a catalytic current of 500 mA cm^(-2) at 1.74 V under commercial catalytic operating conditions(1 mol L^(-1) KOH)for 150 h,with negligible degradation.This work provides important insights into the understanding of OER mechanisms and the design of high-performance water-splitting electrocatalysts,while also opening new avenues for developing multifunctional materials with multi-shell structures.展开更多
Platinum group alloys have an excellent electronic structure for oxidation of alcohols,but the active sites are more susceptible to deactivation by CO adsorbates(CO_(ads)).The precise integration of single-atom and al...Platinum group alloys have an excellent electronic structure for oxidation of alcohols,but the active sites are more susceptible to deactivation by CO adsorbates(CO_(ads)).The precise integration of single-atom and alloy structures is highly attractive for energy conversion but still a challenge.Here,we report an ionexchange coupled in situ reduction strategy to fabricate hollow PtPdTe alloy nanoreactors loaded with atomically dispersed Cu sites(Cu_(SA)/h-PtPdTe NRs).The planted oxyphilic Cu single sites and resulted compressive strains are conductive to modulating the electronic structure of the active sites,which changes the rate-determining step of the reaction while inhibiting the formation of CO_(ads)and modulating the adsorption of intermediates,resulting in the improved activity and stability.Specifically,the obtained Cu_(SA)/h-PtPdTe NRs exhibit an excellent oxidation performance of multiple alcohols,especially for methanol and ethanol,with 8.0 and 10.3 times of the mass activity higher than Pt/C,and the activity could be recovered by refreshing the electrolyte and could be sustained for 72,000 and 36,000 s,respectively.Meanwhile,Cu_(SA)/h-PtPdTe NRs show superior oxidation performance and durability to ethylene glycol and glycerol.This work pioneers the realization of precise modulation of catalytic sites using single atoms and provides an encouraging pathway for the design of efficient and stable electrocatalysts for the oxidation of multiple alcohols,which could broaden the range of options and sources of fuel cells.展开更多
Currently,the solid adsorbents with porous structure have been widely applied in CO_(2)capture.However,the unmodified MgO-ZrO_(2)adsorbents appeared to be low adsorption capacity of CO_(2).The solid adsorbent material...Currently,the solid adsorbents with porous structure have been widely applied in CO_(2)capture.However,the unmodified MgO-ZrO_(2)adsorbents appeared to be low adsorption capacity of CO_(2).The solid adsorbent materials were successfully synthesized by loading TEPA onto the pore MgO/ZrO_(2)carriers in the paper.The pore structure and surface characteristic of the samples were analyzed by using XRD,BET,FT-IR and SEM.The adsorbent materials exhibited microcrystalline state,and the crystallinity of all samples gradually decreased as the increase of TEPA content.The pore structure analysis indicated that the modification of MgO-ZrO_(2)adsorbents with TEPA led to the decrease of the specific surface areas,but the narrow micro-mesopore size distributions ranging from 1.8-12 nm in the adsorbents still were maintained.FT-IR spectrum results further verified the successful loading of TEPA.The adsorption capacity of the adsorbents for CO_(2)were tested by using an adsorption apparatus equipped with gas chromatography.The results indicated that when the TEPA loading reached 50%,the sample exhibited the maximum adsorption value for CO_(2),reaching 4.07 mmol/g under the operation condition of 75℃and atmospheric pressure.This result could be assigned to not only the base active sites but also the coexistence of both micropore and mesopore in the adsorbent.After three cycles tests for CO_(2)capture,the adsorption value of the sample for CO_(2)can also reached 95%of its original adsorption capacity,which verified the excellent cyclic operation stability.展开更多
Prediction of production decline and evaluation of the adsorbed/free gas ratio are critical for determining the lifespan and production status of shale gas wells.Traditional production prediction methods have some sho...Prediction of production decline and evaluation of the adsorbed/free gas ratio are critical for determining the lifespan and production status of shale gas wells.Traditional production prediction methods have some shortcomings because of the low permeability and tightness of shale,complex gas flow behavior of multi-scale gas transport regions and multiple gas transport mechanism superpositions,and complex and variable production regimes of shale gas wells.Recent research has demonstrated the existence of a multi-stage isotope fractionation phenomenon during shale gas production,with the fractionation characteristics of each stage associated with the pore structure,gas in place(GIP),adsorption/desorption,and gas production process.This study presents a new approach for estimating shale gas well production and evaluating the adsorbed/free gas ratio throughout production using isotope fractionation techniques.A reservoir-scale carbon isotope fractionation(CIF)model applicable to the production process of shale gas wells was developed for the first time in this research.In contrast to the traditional model,this model improves production prediction accuracy by simultaneously fitting the gas production rate and δ^(13)C_(1) data and provides a new evaluation method of the adsorbed/free gas ratio during shale gas production.The results indicate that the diffusion and adsorption/desorption properties of rock,bottom-hole flowing pressure(BHP)of gas well,and multi-scale gas transport regions of the reservoir all affect isotope fractionation,with the diffusion and adsorption/desorption parameters of rock having the greatest effect on isotope fractionation being D∗/D,PL,VL,α,and others in that order.We effectively tested the universality of the four-stage isotope fractionation feature and revealed a unique isotope fractionation mechanism caused by the superimposed coupling of multi-scale gas transport regions during shale gas well production.Finally,we applied the established CIF model to a shale gas well in the Sichuan Basin,China,and calculated the estimated ultimate recovery(EUR)of the well to be 3.33×10^(8) m^(3);the adsorbed gas ratio during shale gas production was 1.65%,10.03%,and 23.44%in the first,fifth,and tenth years,respectively.The findings are significant for understanding the isotope fractionation mechanism during natural gas transport in complex systems and for formulating and optimizing unconventional natural gas development strategies.展开更多
This paper demonstrates the strategic molecular design of functional polymer monoliths comprised of mesoporous fibers with stimuli-responsive Joule-heating properties for the rapid and efficient recovery of viscous fu...This paper demonstrates the strategic molecular design of functional polymer monoliths comprised of mesoporous fibers with stimuli-responsive Joule-heating properties for the rapid and efficient recovery of viscous fuel oil from water.The mesoporous fibers were composed of carefully selected monomers,which spontaneously entangled with each other to form a spongy monolith in a one-pot synthesis process.The subsequent addition of polypyrrole nanoparticles to the polymer produced superwettable intertwined fibers with strain-responsive conductivity,allowing the monolith to be used as a compressible,fibrous,and porous adsorbent with a high-flux separation capability and a tunable electrical heating effect.This adsorbent was demonstrated to successfully separate different types of low-viscosity oil from water in a continuous,highly efficient process.It also induced a rapid increase in the temperature during the recovery of marine fuel oil(MFO380),with a minimal compression of 3%under an external voltage.The proposed adsorbent can thus be used for the effective recovery of various fuel oils and improved further by incorporating other synergistic components for various water-treatment systems.展开更多
Lead(Pb)is a toxic metal found in wastewater,posing significant health risks to both humans and the environment.This study aimed to develop a novel adsorbent for lead removal from aqueous solutions.This adsorbent,a co...Lead(Pb)is a toxic metal found in wastewater,posing significant health risks to both humans and the environment.This study aimed to develop a novel adsorbent for lead removal from aqueous solutions.This adsorbent,a coffee husk extract-capped magnetite with pumice silica nanocomposite(CHE-capped M/PU/Si-NC),was synthesized using a completely green approach.The novelty of this study lies in the green synthesis of silica nanoparticles(SiO_(2)-NPs)throughout the process.Coffee husk extract(CHE)served as both a stabilizing and capping agent for the SiO_(2)-NPs,which were synthesized from sodium silicate(Na_(2)SiO_(3))extracted from bagasse ash(BA).Subsequently,the CHE-capped silica was co-precipitated with phyto-fabricated magnetite and integrated into a pumice matrix to produce the final CHE-capped M/PU/Si-NC adsorbent.The CHE-capped M/PU/Si-NC was characterized using SEM,XRF,FTIR,BET,XRD,TGA,and zeta potential analysis.The surface area of the CHE-capped M/PU/Si-NC was determined to be 313 m^(2)·g^(-1),and TGA results indicated good thermal stability up to 690℃.The zeta potential was measured at-37.7 mV.XRD analysis of CHE-capped M/PU/Si-NC confirmed the formation of magnetite and revealed its crystal structure.The maximum adsorption performance of this material was observed to be 95%at an adsorbent dosage of 2 g·L^(-1) and an initial Pb^(2+)concentration of 100 g·L^(-1).The adsorption kinetics were best described by the pseudo-second-order kinetic model.The Langmuir isotherm provided a good fit with a maximum adsorption capacity of 150 mg·g^(-1)(R^(2)=0.99).Regeneration studies demonstrated that the adsorbent maintained its high Pb^(2+) uptake capacity for up to five cycles.Overall,these findings suggest that this adsorbent is a promising candidate for the removal of Pb^(2+) from water and wastewater.展开更多
Per-and polyfluoroalkyl substances(PFAS)are persistent environmental contaminants that often show an adverse impact on human health.Rational design of porous adsorbents for selective and reversible removal of PFAS,suc...Per-and polyfluoroalkyl substances(PFAS)are persistent environmental contaminants that often show an adverse impact on human health.Rational design of porous adsorbents for selective and reversible removal of PFAS,such as perfluorooctane sulfonate(PFOS),is imperative and challenging.Herein,a Janus strategy based on an ionic covalent organic framework(iCOF-DGCl)composed of the alternately hydrophobic aromatic domains and hydrophilic guanidinium moieites has been proposed to meet the requirement of high-performance adsorbents.iCOF-DGCl shows fast adsorption kinetics(970.9 mg g^(−1)min^(−1))and ultrahigh uptake capacity(2491 mg g^(−1))toward PFOS,making it one of the most effective materials among the reported PFOS adsorbents.Moreover,the PFOS removal by iCOF-DGCl remains highly selective in the presence of disturbing anions,and the adsorbent could be well recovered for reuse.Mechanism studies have demonstrated that the Janus structure units of iCOF-DGCl form both hydrophobic and electrostatic interactions with the amphiphilic PFOS,thus achieving cooperative adsorption of PFOS.This work provides a facile approach based on Janus structure of COFs adsorbent for wastewater remediation.展开更多
Boron adsorbents with high adsorption capacities have long been a focus of research for a long time.This study used small molecular polyols with different hydroxyl groups as functional monomers and as end-capping agen...Boron adsorbents with high adsorption capacities have long been a focus of research for a long time.This study used small molecular polyols with different hydroxyl groups as functional monomers and as end-capping agents,functional dendritic polyurethanes with nano structure were successfully prepared by one-pot method.The single molecule size and surface morphology were characterized by dynamic light scattering,transmission electron microscopy and scanning electron microscopy,and the molecular size in the dry state was 11 to 18 nm.The prepared materials were used as the boron adsorbents,and the effects of pH,time,boron solution concentration and temperature on the adsorption were studied.The results showed that the capacity of adsorbed boron could reach 110-130 mg·g^(-1).Adsorption was a homogeneous monolayer adsorption controlled by chemisorption,and adsorption thermodynamics showed that was a spontaneous endothermic process.Adsorption behavior was best described by the pseudo-second-order kinetic model and the Langmuir isotherm.This study also showed that it was difficult for ortho/meta-hydroxyl groups to chelate with H_(3)BO_(3) and other polyborates,and the chelates mainly had good chelating properties with B(OH)_(4)^(-),and the chelates formed had large steric hindrance.At the same time,increasing the number of hydroxyl groups of functional monomers was beneficial to increase the adsorption capacity of materials.In addition,the cyclic adsorption/desorption experiments showed that DPUs have good cyclic stability.At the same time,the adsorption results of the original salt lake brine showed that other metal ions in the brine had little effect on the adsorption of boron,and the adsorption capacity was as high as52.93 mg·g^(-1),and the maximum adsorption capacity was obtained by Adams-Bohart model to58.80 mg·g^(-1).The outstanding selectivity and adsorption capacity of these materials have broad potential application,and are expected to be used for the efficient adsorption and removal in boroncontaining water bodies.展开更多
文摘Characterization of electric properties of nanomaterials usually involves fabricating field effect transistors （FET） and deriving materials properties from device performances. However, the quality of electrode contacts in FET devices heavily influences the device performance, which makes it difficult to obtain the intrinsic electric properties of nanomaterials. Dielectric force microscopy （DFM）, a contactless method developed recently, can detect the low-frequency dielectric responses of nanomaterials without electric contact, which avoids the influence of electric contact and can be used to study the intrinsic conductivity of nanomaterials. Here we study the influences of surface adsorbates on the conductivity of ZnO nanowires （NWs） by using FET and DFM methods. The conductivity of ZnO NW is much larger in N2 atmosphere than that in ambient environment as measured by FET device, which is further proven by DFM measurement that the ZnO NW exhibits larger dielectric response in N2 environment, and the influence of electrode contacts on measurement can be ruled out. Based on these results, it can be concluded that the adsorbates on ZnO NW surface highly influence the conductivity of ZnO NW rather than the electrode contact. This work also verifies the capability of DFM in measuring electric properties of nanomaterials.
基金supported by the National Natural Science Foundation of China(no.22372154,21972131).
文摘Despite substantial efforts in developing high-performance catalysts for the oxygen reduction reaction(ORR),the persistent challenge lies in the high onset overpotential of the ORR,and the effect of the elec-trolyte solution cannot be ignored.Consequently,we have systematically investigated the impact of adsorbate species and concentration,as well as solution pH,on the ORR activity on Pt(111)and Pt(poly)electrodes.The results all tend to establish a linear quantitative relationship between the onset potential for ORR and the adsorption equilibrium potential of the adsorbate.This finding indicates the decisive role of adsorbates in the onset potential for ORR,suggesting that the adsorption potential of adsorbates can serve as an intuitive criterion for ORR activity.Additional support for this conclusion is derived from experimental results obtained from the oxygen evolution reaction on Pt(poly)with different adsorbate species and from the hydrogen evolution reaction on Pt(111)with iodine adsorption.We further propose both an empirical equation for the onset potential for ORR and the concept of a potential-regulated adsor-bate shielding effect to elucidate the influence of adsorbates on ORR activity.This study provides new insights into the high onset overpotential of the ORR and offers potential strategies for predicting and enhancingORRactivity inthefuture.
基金supported by the Elements Strategy Initiative for Catalysts and Batteries (ESICB)a Grant-in-Aid for Scientific Research (26248003, 15H01042) from the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan
文摘The mass spectrometry of gold clusters stabilized by poly（N‐vinyl‐2‐pyrrolidone） （Au：PVP） re‐vealed the presence of Cl adsorbates derived from synthetic precursors, mainly on the Au34 and Au43 clusters. Changes in the amount of Cl adsorbates on the Au clusters did not affect the catalytic prop‐erties for the aerobic oxidation of benzyl alcohol, suggesting that the Cl atoms were only weakly bound to the Au clusters. In contrast, the replacement of Cl with Br on the Au34 and Au43 clusters significantly suppressed activity, without any influence on the electronic structure. This result indi‐cated that the Br atoms were strongly bound to the Au clusters and sterically blocked their active sites. The substantial reduction of the catalytic activity by the Br adsorbates suggested that the Au34 and Au43 clusters made a major contribution to the catalytic activity of the Au：PVP.
文摘The monolayer adsorbed Mo(001)surface is studied by the slab dynamical calculation by using the nearest and next nearest neighbour interactions.The phase diagram is obtained for light,heavy atom adsorbed and clean Mo(001)surface.The surface reconstruction induced by the interactions between adsorbed atoms is dicussed.
基金supported by the National Natural Science Foun-dation of China(22078155,21808110,21878149,and 21676138)China Postdoctoral Science Foundation(2020M681567)。
文摘Amines in porous materials have been employed as active species for the selective CO_(2) adsorption from natural gas because of their target-specific interactions.Nevertheless,it is difficult to modulate such strong interactions to reach a high efficiency in the adsorption processes.Herein,we fabricated lightresponsive adsorbents with tunable adsorbent–adsorbate interactions for CO_(2) capture.The adsorbents were synthesized by introducing primary and secondary amines into a mesoporous silica that had been grafted with azobenzene groups on the surfaces.The target-specific amine sites render the adsorbents significantly selective in the uptake of CO_(2) over CH_(4),and the azobenzene groups were used as lightresponsive switches to influence the adsorbent–adsorbate interactions.The adsorbents can freely adsorb CO_(2) when the azobenzene groups are in the trans state.Ultraviolet-light irradiation makes the azobenzene groups transform to the cis configuration,which greatly hinders amines in the uptake of CO_(2).The caused difference of adsorption capacity can reach 34.9%.The alternative irradiation by ultravioletand visible-light can lead to a recyclable regulation on adsorption performance.The changes of the electrostatic potentials of amines are responsible for the light-induced regulation on adsorption.
基金funded by PPG Industries through a project under Cooperative Agreement 2021072-142118 from The National Center for Manufacturing Sciences(NCMS)and the US DoD。
文摘Graphite has achieved widespread recognition as an effective solid lubricant due to its high functionality across diverse environmental conditions.Although superlubricity or ultra-low friction is readily observed at the graphite basal plane,it has been reported that certain adsorbates from the surrounding environment can deteriorate this friction regime.Here,we conducted a fundamental analysis on the effect of phenol,pentanol,and water adsorbates on the friction of graphite-silica interfaces using molecular dynamics simulations with the reactive force field ReaxFF.First,we evaluated three ReaxFF parameter sets optimized using friction-pertinent properties.It was observed that the force field optimization objective played a major role in the calculated tribological properties.Secondly,parameters such as normal load and motion directionality were investigated.Additionally,adsorption,and binding energy calculations were performed to expand upon the hypothesis that friction may be directly correlated to the interfacial molecular structure rather than binding energy and adsorbate commensuration with graphene.By quantitatively representing the interfacial roughness of each adsorbate,the hypothesis was confirmed by unequivocally explaining the calculated friction coefficients.
基金supported by the Ministry of Science and Technology(2016YFA0203302)the National Natural Science Foundation of China(21875042,21634003,51573027 and 11227902)+3 种基金Science and Technology Commission of Shanghai Municipality(16JC1400702 and 18QA1400800)Shanghai Municipal Education Commission(2017-01-07-00-07-E00062)Yanchang Petroleum Groupthe Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learning。
文摘Developing efficient electrocatalysts for the oxygen evolution reaction(OER)under neutral conditions is important for microbial electrolysis cells(MECs).However,the OER kinetics in neutral electrolytes at present are extremely sluggish,resulting in high overpotentials that greatly limit the energy conversion efficiencies of MECs.Previous studies failed to probe the adsorbates on surface metal sites of catalysts at the atomic scale and elucidate their influence on the catalytic activities,which has impeded the rational design of efficient neutral OER catalysts with optimal surface structures.Here,using in situ transmission electron microscopy(TEM),in situ X-ray photoelectron spectroscopy(XPS)and in situ low-energy ion scattering studies,we have identified,for the first time,that the electrochemically activated adsorbates on surface metal sites play a critical role in boosting the neutral OER activities of Ru-Ir binary oxide(RuxIryO2)catalysts.The adsorbate-activated RuxIryO2on a glassy carbon electrode achieved a low overpotential of 324 m V at10 m A cm-2in neutral electrolyte,with a 36-fold improvement in turnover frequency compared with that of Ir O2benchmark.Upon application in an MEC system,the resulting full cell showed a decreased voltage of 1.8 V,200 m V lower than the best value reported to date,facilitating efficient synthesis of poly(3-hydroxybutyrate)from bioelectrochemical CO_(2)reduction.Density functional theory(DFT)studies revealed that the enhanced OER activity of RuxIryO2catalyst arose from local structural distortion of adjacent adsorbate-covered Ru octahedra at the catalyst surface and the consequently decreased adsorption energies of OER intermediates on Ir active center.
文摘Up to now, there have been many indistinctive points in the image interpretation of scanning tunnelhng microscopy (STM) system, and the problems have attracted almost all STM scientists’ attention. In 1992, Kenkre proposed the new programme which describes the behaviour of the electrons moving in the STM tunnelling by the method of exciton dynamics, and the programme not only breaks through the restrictions of Tersoff-Hamann theory, but also can be applied conveniently to discussing the effects of the tip structure, adsorbate structure, substrate structure, temperature, tunneling voltage, and the degree of coherence of elec-
基金supported by the National Natural Science Foundation of China(21706052,22278114)Natural Science Foundation of Henan Province(242300421575).
文摘Lignin,the most abundant natural aromatic polymer globally,has garnered considerable interest due to its rich and diverse active functional groups and its antioxidant,antimicrobial,and adhesive properties.Recent research has significantly improved the performance of lignin-based hydrogels,suggesting their substantial potential in fields such as biomedicine,environmental science,and agriculture.This paper reviews the process of lignin extraction,systematically introduces synthesis strategies for preparing lignin-based hydrogels,and discusses the current state of research on these hydrogels in biomedical and environmental protection fields.It concludes by identifying the existing challenges in lignin hydrogel research and envisioning future prospects and development trends.
基金financially supported by the National Natural Science Foundation of China(Nos.52473139 and U21A2098)。
文摘Hospital wastewater contains complex pollutants,including residual organic dyes and antibiotic-resistant pathogens,posing severe risks to ecosystems and human health.Conventional adsorbents,constrained by monopolar functional groups and limited surface sites,fail to remove both pollutants simultaneously.Here,we report an intelligent responsive polyurethane microsphere adsorbent doped with diallyl dimethylammonium chloride modified carbon nanotubes,termed as PUCD microspheres.The PUCD integrates bipolar adsorption sites,tunable micrometer-scale pores,and a near-infrared(NIR)-triggered in situ capture mechanism within a single platform,which achieves up to 98.3%dye removal,maintains strong adsorption performance across a wide pH range and retains 83.3%efficiency for rhodamine B after five cycles.Notably,the PUCD employs a temperature-responsive phase transition:under NIR irradiation,the microspheres undergo shrinkage,reducing the pore size to generate a‘polymer trap',enabling in situ capture of bacteria with>99%efficiencies for both Staphylococcus aureus and Escherichia coli.By immobilizing live bacteria,the PUCD microspheres substantially reduces the risk of pathogen desorption and toxin release.This promising platform offers a safe,efficient,and single-stage strategy for hospital wastewater purification,enabling the simultaneous elimination of dyes and pathogenic bacteria.
基金This work was supported by the U.S.Department of Energy,Office of Science,Basic Energy Sciences,under Award DE-FG02-17ER16362as part of the ComputationalChemical Sciences Program.Simulations were carried out on the University of Florida's high-performance computing system HiPerGator 2.0.
文摘The enormous number of combinations of adsorbing molecules and porous materials that exist is known as adsorption space.The adsorption space for microporous polymers has not yet been systematically explored,especially when compared with efforts for crystalline adsorbents.We report molecular simulation data for the adsorptive and structural properties of polymers of intrinsic microporosity with a diverse set of adsorbate species with 345 distinct adsorption isotherms and over 240,000 fresh and swollen structures.These structures and isotherms were obtained using a sorption-relaxation technique that accounts for the critical role of flexibility of the polymeric adsorbents.This enables us to introduce a set of correlations that can estimate adsorbent swelling and fractional free volume dilation as a function of adsorbate uptake based on readily characterized properties.The separation selectivity of the 276 distinct binary molecular pairs in our data is reported and high-performing adsorbent systems are identified.
基金supported by the National Natural Science Foundation of China(NSFC)the Japan Society for the Promotion of Science(JSPS)under the Joint Research Program(Nos.NSFC21961142006 and JPJSJRP20191804)+3 种基金NSFC(Nos.U22A20394 and 22375200)the DICP.CAS-Cardiff Joint Research Units(No.121421ZYLH20230008)the International Partnership Program of Chinese Academy of Sciences(No.028GJHZ2023097GC)the China Postdoctoral Science Foundation(No.2022M723086)。
文摘Maintaining high metal dispersion of supported metal catalysts to achieve superior reactivity under harsh conditions poses one of the main challenges for their practical applications.Constructing and regulating the strong metal-support interactions(SMSI)by diverse methodologies has emerged as one of the promising approaches to fabricating robust supported metal catalysts.In this study,we report an L-ascorbic acid(AA)-inducing strategy to generate SMSI on a titania-supported gold(Au)catalyst after high-temperature treatment in an inert atmosphere(600℃,N_(2)).The AA-induced SMSI can efficiently stabilize Au nanoparticles(NPs)and preserve their catalytic performance.The detailed study reveals that the key to realizing this SMSI is the generation of oxygen vacancies within the TiO_(2) support induced by the adsorbed AA,which drives the formation of the Ti Oxpermeable layer onto the Au NPs.The strategy could be extended to TiO_(2)-supported Au catalysts with different crystal phases and platinum group metals,such as Pt,Pd,and Rh.This work offers a promising novel route to design stable and efficient supported noble metal catalysts by constructing SMSI using simple reducing organic adsorbent.
文摘Activating both metal and lattice oxygen sites for efficient oxygen evolution reactions(OER)is a critical challenge.This study pioneers a novel approach,employing cobalt-nickel glycerate solid spheres(CoNi-G SSs)as self-sacrificial templates to synthesize yolk-shell structured CoNi-G SSs@ZIF-67 nanospheres.The derived NiCo2S4@CoS2/MoS2 double-shelled hollow nanospheres integrate the adsorbate evolution mechanism(AEM)and lattice oxygen mechanism(LOM),enabling synergistic dual catalytic pathways.Nickel modulation facilitates active species reconstruction in NiCo_(2)S_(4),enhancing lattice oxygen activity and optimizing the LOM pathway.Characterization results indicate that anode activation triggered the redox processes of metal and lattice oxygen sites,involving the formation and re-filling of oxygen vacancies.Additionally,the CoS_(2)/MoS_(2) heterostructure enhances the AEM pathway,as supported by density functional theory calculations,which demonstrate optimized adsorption of intermediates for both hydrogen evolution reaction and OER.The assembled anion exchange membrane water splitting device can deliver a catalytic current of 500 mA cm^(-2) at 1.74 V under commercial catalytic operating conditions(1 mol L^(-1) KOH)for 150 h,with negligible degradation.This work provides important insights into the understanding of OER mechanisms and the design of high-performance water-splitting electrocatalysts,while also opening new avenues for developing multifunctional materials with multi-shell structures.
基金supported by the National Natural Science Foundation of China(22102132)the Funds for Basic Scientific Research in Central Universities+2 种基金the Scientific Research Foundation of Qingdao UniversityTaishan Scholar Program(NO.tsqnz20231213)sponsored by the Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University(CX2024101)。
文摘Platinum group alloys have an excellent electronic structure for oxidation of alcohols,but the active sites are more susceptible to deactivation by CO adsorbates(CO_(ads)).The precise integration of single-atom and alloy structures is highly attractive for energy conversion but still a challenge.Here,we report an ionexchange coupled in situ reduction strategy to fabricate hollow PtPdTe alloy nanoreactors loaded with atomically dispersed Cu sites(Cu_(SA)/h-PtPdTe NRs).The planted oxyphilic Cu single sites and resulted compressive strains are conductive to modulating the electronic structure of the active sites,which changes the rate-determining step of the reaction while inhibiting the formation of CO_(ads)and modulating the adsorption of intermediates,resulting in the improved activity and stability.Specifically,the obtained Cu_(SA)/h-PtPdTe NRs exhibit an excellent oxidation performance of multiple alcohols,especially for methanol and ethanol,with 8.0 and 10.3 times of the mass activity higher than Pt/C,and the activity could be recovered by refreshing the electrolyte and could be sustained for 72,000 and 36,000 s,respectively.Meanwhile,Cu_(SA)/h-PtPdTe NRs show superior oxidation performance and durability to ethylene glycol and glycerol.This work pioneers the realization of precise modulation of catalytic sites using single atoms and provides an encouraging pathway for the design of efficient and stable electrocatalysts for the oxidation of multiple alcohols,which could broaden the range of options and sources of fuel cells.
基金supported by Shanxi Provincial Key Research and Development Project(202102090301026)Graduate Education Innovation Project of Taiyuan University of Science and Technology(SY2023024)。
文摘Currently,the solid adsorbents with porous structure have been widely applied in CO_(2)capture.However,the unmodified MgO-ZrO_(2)adsorbents appeared to be low adsorption capacity of CO_(2).The solid adsorbent materials were successfully synthesized by loading TEPA onto the pore MgO/ZrO_(2)carriers in the paper.The pore structure and surface characteristic of the samples were analyzed by using XRD,BET,FT-IR and SEM.The adsorbent materials exhibited microcrystalline state,and the crystallinity of all samples gradually decreased as the increase of TEPA content.The pore structure analysis indicated that the modification of MgO-ZrO_(2)adsorbents with TEPA led to the decrease of the specific surface areas,but the narrow micro-mesopore size distributions ranging from 1.8-12 nm in the adsorbents still were maintained.FT-IR spectrum results further verified the successful loading of TEPA.The adsorption capacity of the adsorbents for CO_(2)were tested by using an adsorption apparatus equipped with gas chromatography.The results indicated that when the TEPA loading reached 50%,the sample exhibited the maximum adsorption value for CO_(2),reaching 4.07 mmol/g under the operation condition of 75℃and atmospheric pressure.This result could be assigned to not only the base active sites but also the coexistence of both micropore and mesopore in the adsorbent.After three cycles tests for CO_(2)capture,the adsorption value of the sample for CO_(2)can also reached 95%of its original adsorption capacity,which verified the excellent cyclic operation stability.
基金supported by the Natural Science Foundation of China(Grant No.42302170)National Postdoctoral Innovative Talent Support Program(Grant No.BX20220062)+3 种基金CNPC Innovation Found(Grant No.2022DQ02-0104)National Science Foundation of Heilongjiang Province of China(Grant No.YQ2023D001)Postdoctoral Science Foundation of Heilongjiang Province of China(Grant No.LBH-Z22091)the Natural Science Foundation of Shandong Province(Grant No.ZR2022YQ30).
文摘Prediction of production decline and evaluation of the adsorbed/free gas ratio are critical for determining the lifespan and production status of shale gas wells.Traditional production prediction methods have some shortcomings because of the low permeability and tightness of shale,complex gas flow behavior of multi-scale gas transport regions and multiple gas transport mechanism superpositions,and complex and variable production regimes of shale gas wells.Recent research has demonstrated the existence of a multi-stage isotope fractionation phenomenon during shale gas production,with the fractionation characteristics of each stage associated with the pore structure,gas in place(GIP),adsorption/desorption,and gas production process.This study presents a new approach for estimating shale gas well production and evaluating the adsorbed/free gas ratio throughout production using isotope fractionation techniques.A reservoir-scale carbon isotope fractionation(CIF)model applicable to the production process of shale gas wells was developed for the first time in this research.In contrast to the traditional model,this model improves production prediction accuracy by simultaneously fitting the gas production rate and δ^(13)C_(1) data and provides a new evaluation method of the adsorbed/free gas ratio during shale gas production.The results indicate that the diffusion and adsorption/desorption properties of rock,bottom-hole flowing pressure(BHP)of gas well,and multi-scale gas transport regions of the reservoir all affect isotope fractionation,with the diffusion and adsorption/desorption parameters of rock having the greatest effect on isotope fractionation being D∗/D,PL,VL,α,and others in that order.We effectively tested the universality of the four-stage isotope fractionation feature and revealed a unique isotope fractionation mechanism caused by the superimposed coupling of multi-scale gas transport regions during shale gas well production.Finally,we applied the established CIF model to a shale gas well in the Sichuan Basin,China,and calculated the estimated ultimate recovery(EUR)of the well to be 3.33×10^(8) m^(3);the adsorbed gas ratio during shale gas production was 1.65%,10.03%,and 23.44%in the first,fifth,and tenth years,respectively.The findings are significant for understanding the isotope fractionation mechanism during natural gas transport in complex systems and for formulating and optimizing unconventional natural gas development strategies.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(no.2022R1C1C1003149 and 2020R1A5A8018367)by the Korea Institute of Marine Science&Technology Promotion(KIMST)funded by the Ministry of Oceans and Fisheries,Korea(00254781)This research was alsosupported by Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(no.RS-202400345266)。
文摘This paper demonstrates the strategic molecular design of functional polymer monoliths comprised of mesoporous fibers with stimuli-responsive Joule-heating properties for the rapid and efficient recovery of viscous fuel oil from water.The mesoporous fibers were composed of carefully selected monomers,which spontaneously entangled with each other to form a spongy monolith in a one-pot synthesis process.The subsequent addition of polypyrrole nanoparticles to the polymer produced superwettable intertwined fibers with strain-responsive conductivity,allowing the monolith to be used as a compressible,fibrous,and porous adsorbent with a high-flux separation capability and a tunable electrical heating effect.This adsorbent was demonstrated to successfully separate different types of low-viscosity oil from water in a continuous,highly efficient process.It also induced a rapid increase in the temperature during the recovery of marine fuel oil(MFO380),with a minimal compression of 3%under an external voltage.The proposed adsorbent can thus be used for the effective recovery of various fuel oils and improved further by incorporating other synergistic components for various water-treatment systems.
文摘Lead(Pb)is a toxic metal found in wastewater,posing significant health risks to both humans and the environment.This study aimed to develop a novel adsorbent for lead removal from aqueous solutions.This adsorbent,a coffee husk extract-capped magnetite with pumice silica nanocomposite(CHE-capped M/PU/Si-NC),was synthesized using a completely green approach.The novelty of this study lies in the green synthesis of silica nanoparticles(SiO_(2)-NPs)throughout the process.Coffee husk extract(CHE)served as both a stabilizing and capping agent for the SiO_(2)-NPs,which were synthesized from sodium silicate(Na_(2)SiO_(3))extracted from bagasse ash(BA).Subsequently,the CHE-capped silica was co-precipitated with phyto-fabricated magnetite and integrated into a pumice matrix to produce the final CHE-capped M/PU/Si-NC adsorbent.The CHE-capped M/PU/Si-NC was characterized using SEM,XRF,FTIR,BET,XRD,TGA,and zeta potential analysis.The surface area of the CHE-capped M/PU/Si-NC was determined to be 313 m^(2)·g^(-1),and TGA results indicated good thermal stability up to 690℃.The zeta potential was measured at-37.7 mV.XRD analysis of CHE-capped M/PU/Si-NC confirmed the formation of magnetite and revealed its crystal structure.The maximum adsorption performance of this material was observed to be 95%at an adsorbent dosage of 2 g·L^(-1) and an initial Pb^(2+)concentration of 100 g·L^(-1).The adsorption kinetics were best described by the pseudo-second-order kinetic model.The Langmuir isotherm provided a good fit with a maximum adsorption capacity of 150 mg·g^(-1)(R^(2)=0.99).Regeneration studies demonstrated that the adsorbent maintained its high Pb^(2+) uptake capacity for up to five cycles.Overall,these findings suggest that this adsorbent is a promising candidate for the removal of Pb^(2+) from water and wastewater.
基金the financial support from National Key Research and Development Program(2019YFA0210403)National Natural Science Foundation of China(22001178,21975259)+1 种基金Natural Science Foundation of Hebei Province(B2021202077,B2022202039,C20220313)S&T Program of Hebei(236Z4308G).The authors extend their gratitude to Shiyanjia Lab(www.shiyanjia.com)for XPS measurement.
文摘Per-and polyfluoroalkyl substances(PFAS)are persistent environmental contaminants that often show an adverse impact on human health.Rational design of porous adsorbents for selective and reversible removal of PFAS,such as perfluorooctane sulfonate(PFOS),is imperative and challenging.Herein,a Janus strategy based on an ionic covalent organic framework(iCOF-DGCl)composed of the alternately hydrophobic aromatic domains and hydrophilic guanidinium moieites has been proposed to meet the requirement of high-performance adsorbents.iCOF-DGCl shows fast adsorption kinetics(970.9 mg g^(−1)min^(−1))and ultrahigh uptake capacity(2491 mg g^(−1))toward PFOS,making it one of the most effective materials among the reported PFOS adsorbents.Moreover,the PFOS removal by iCOF-DGCl remains highly selective in the presence of disturbing anions,and the adsorbent could be well recovered for reuse.Mechanism studies have demonstrated that the Janus structure units of iCOF-DGCl form both hydrophobic and electrostatic interactions with the amphiphilic PFOS,thus achieving cooperative adsorption of PFOS.This work provides a facile approach based on Janus structure of COFs adsorbent for wastewater remediation.
基金financially supported by Applied Basic Research Project of Qinghai province(2023-ZJ-774)。
文摘Boron adsorbents with high adsorption capacities have long been a focus of research for a long time.This study used small molecular polyols with different hydroxyl groups as functional monomers and as end-capping agents,functional dendritic polyurethanes with nano structure were successfully prepared by one-pot method.The single molecule size and surface morphology were characterized by dynamic light scattering,transmission electron microscopy and scanning electron microscopy,and the molecular size in the dry state was 11 to 18 nm.The prepared materials were used as the boron adsorbents,and the effects of pH,time,boron solution concentration and temperature on the adsorption were studied.The results showed that the capacity of adsorbed boron could reach 110-130 mg·g^(-1).Adsorption was a homogeneous monolayer adsorption controlled by chemisorption,and adsorption thermodynamics showed that was a spontaneous endothermic process.Adsorption behavior was best described by the pseudo-second-order kinetic model and the Langmuir isotherm.This study also showed that it was difficult for ortho/meta-hydroxyl groups to chelate with H_(3)BO_(3) and other polyborates,and the chelates mainly had good chelating properties with B(OH)_(4)^(-),and the chelates formed had large steric hindrance.At the same time,increasing the number of hydroxyl groups of functional monomers was beneficial to increase the adsorption capacity of materials.In addition,the cyclic adsorption/desorption experiments showed that DPUs have good cyclic stability.At the same time,the adsorption results of the original salt lake brine showed that other metal ions in the brine had little effect on the adsorption of boron,and the adsorption capacity was as high as52.93 mg·g^(-1),and the maximum adsorption capacity was obtained by Adams-Bohart model to58.80 mg·g^(-1).The outstanding selectivity and adsorption capacity of these materials have broad potential application,and are expected to be used for the efficient adsorption and removal in boroncontaining water bodies.
