A novel amphoteric granular lignin adsorbent(AGLA) was prepared using magnesium lignosulfonate as a raw material which was provided by a straw sulfite pulp mill in Guangdong Province, China. A reactive dye(red K-3B) w...A novel amphoteric granular lignin adsorbent(AGLA) was prepared using magnesium lignosulfonate as a raw material which was provided by a straw sulfite pulp mill in Guangdong Province, China. A reactive dye(red K-3B) was used as an adsorbate to investigate the adsorption behavior by static and mobile ways. The removal of reactive red K-3B was found to be initially pH and concentration dependent. Moreover, an increase of solution temperature ranging from 5℃ to 60℃ helped to enhance the rate of intraparticle diffusion of adsorbate and changes in the size of the pores of the adsorbent and thus to reduce the adsorption time. The total breakthrough adsorption capacity was 531 mg/g, and the saturated adsorption capacity was 560 mg/g, which prevailed over the activated carbons evidently. The reactive red K-3B adsorbed on AGLA could be recovered with a mixture of alcohol, NaCl and HCl aqueous solutions. The recovery percentage could reach 92.4%.展开更多
To reduce the energy consumption of the electrolytic hydrogen generation process, we propose a novel approach to generate hydrogen with acidic/alkaline amphoteric water electrolysis, wherein hydrogen is produced insid...To reduce the energy consumption of the electrolytic hydrogen generation process, we propose a novel approach to generate hydrogen with acidic/alkaline amphoteric water electrolysis, wherein hydrogen is produced inside an acidic solution and oxygen evolved under alkaline condition, and a membrane is employed in the middle of the electrolyzer to restrain neutralization. The electrode polarization is greatly reduced due to the specific arrangement of the acidic/alkaline amphoteric electrolyzer. The rate of hydrogen production achieves over four times higher than that of the alkaline aqueous solution at 2.2 V, and the energy consumption is reduced approximately 30% under the current density of 200 m A/cm ^2. The investigation of transmembrane potential drop indicates water splitting on the membrane surfaces, which compensates for acid or alkaline loss on-site and maintains the concentration approximately constant during electrolysis process. The acidic/alkaline amphoteric water electrolysis is promising as an energy saving, clean and sustainable hydrogen production technology.展开更多
The adsorption behavior ofp-aminobenzoic acid and o-aminobenzoic acid onto the different polymeric adsorbents was systematically investigated as a function of the solution concentration and temperature. Experimental r...The adsorption behavior ofp-aminobenzoic acid and o-aminobenzoic acid onto the different polymeric adsorbents was systematically investigated as a function of the solution concentration and temperature. Experimental results indicated that the equilibrium adsorption data of the four polymeric adsorbents fitted well in the Freundlich isotherm. The adsorption capacity of multi-functional polymeric adsorbent NJ-99 was the highest, which might be attributed to the strong hydrogen-bonding interaction between the amino groups on the resin and the carboxyl group of aminobenzoic acid. The adsorption capacity of o-aminobenzoic acid onto any adsorbent was higher than p-aminobenzoic acid. Thermodynamic studies suggested the exothermic, spontaneous physical adsorption process. Adsorption kinetics results showed that the adsorption followed the pseudo-second-order kinetics model and the intraparticle mass transfer process was the rate-controlling step.展开更多
A new amphoteric membrane was prepared by blending long-side-chain sulfonated poly(2,6-dimethyl-1,4-phenylene oxide)(S-L-PPO)and polybenzimidazole(PBI)for vanadium redox flow battery(VRFB)application.An acid-base pair...A new amphoteric membrane was prepared by blending long-side-chain sulfonated poly(2,6-dimethyl-1,4-phenylene oxide)(S-L-PPO)and polybenzimidazole(PBI)for vanadium redox flow battery(VRFB)application.An acid-base pair structure formed between the imidazole of PBI and sulfonic acid of S-L-PPO resulted in lowered swelling ratio.It favors to reduce the vanadium permeation.While,the increased sulfonic acid concentration ensured that proton conductivity was still at a high level.As a result,a better balance between the vanadium ion permeation(6.1×10^-9 cm^2·s^-1)and proton conductivity(50.8 m S·cm^-1)in the S-L-PPO/PBI-10%membrane was achieved.The VRFB performance with S-L-PPO/PBI-10%membrane exhibited an EE of 82.7%,which was higher than those of pristine S-L-PPO(81.8%)and Nafion 212(78.0%)at 120 m A·cm^-2.In addition,the S-LPPO/PBI-10%membrane had a much longer self-discharge duration time(142 h)than that of Nafion 212(23 h).展开更多
Metallic interface engineering is a promising strategy to stabilize Zn anode via promoting Zn^(2+) uniform deposition.However,strong interactions between the coating and Zn^(2+) and sluggish transport of Zn^(2+) lead ...Metallic interface engineering is a promising strategy to stabilize Zn anode via promoting Zn^(2+) uniform deposition.However,strong interactions between the coating and Zn^(2+) and sluggish transport of Zn^(2+) lead to high anodic polarization.Here,we present a bio-inspired silk fibroin(SF)coating with amphoteric charges to construct an interface reversible electric field,which manipulates the transfer kinetics of Zn^(2+) and reduces anodic polarization.The alternating positively and negatively charged surface as a build-in driving force can expedite and homogenize Zn^(2+) flux via the inter-play between the charged coating and adsorbed ions,endowing the Zn-SF anode with low polarization voltage and stable plating/stripping.Experimental analyses with theo-retical calculations suggest that SF can facilitate the desolvation of[Zn(H_(2)O)_(6)]^(2+) and provide nucleation sites for uniform deposition.Consequently,the Zn-SF anode delivers a high-rate performance with low voltage polarization(83 mV at 20 mA cm^(−2)) and excellent stability(1500 h at 1 mA cm^(−2);500 h at 10 mA cm^(−2)),realizing exceptional cumulative capacity of 2.5 Ah cm^(−2).The full cell coupled with Zn_(x)V_(2)O_(5)·nH_(2)O(ZnVO)cathode achieves specific energy of~270.5/150.6 Wh kg^(−1)(at 0.5/10 A g^(−1))with-99.8% Coulombic efficiency and retains~80.3%(at 5.0 A g^(−1))after 3000 cycles.展开更多
For improvement of vanadium redox flow battery (VRB) performance, novel amphoteric semi- interpenetrating membranes (ASIPN) were prepared using poly(ether ether ketone) (PEEK) and polysul- fone (PSf), the fo...For improvement of vanadium redox flow battery (VRB) performance, novel amphoteric semi- interpenetrating membranes (ASIPN) were prepared using poly(ether ether ketone) (PEEK) and polysul- fone (PSf), the former bearing sulfonic groups and the latter imidazolium. These two groups form ionic crosslinks between PEEK and PSf; meanwhile, covalent cross links were built between PSf chains with ad- dition of N-(3-aminopropyl)-imidazole. The amphoteric nature of the membrane allows facile proton and anion transport; the IPN structure and the presence of imidazolium cation effectively suppress vanadium ion crossover through the membrane. Therefore, the ASIPN based VRBs show higher Coulombic efficiency and energy efficiency than that assembled with pristine SPEEK and Nation 212 membranes. Our work demonstrates that the ASIPN membranes are promising for VRB applications.展开更多
Three new diterpene alkaloids,tangutidines A-C(1-3),and four known alkaloids(4-7)were isolated from the whole plant of Aconitum tanguticum,from which amphoteric diterpene alkaloids(1-3)were obtained for the first time...Three new diterpene alkaloids,tangutidines A-C(1-3),and four known alkaloids(4-7)were isolated from the whole plant of Aconitum tanguticum,from which amphoteric diterpene alkaloids(1-3)were obtained for the first time.The structures of 1-3 were elucidated by detailed interpretation of spectroscopic data,including MS and NMR data.All of them were evaluated for their cytotoxic activities.展开更多
New amphoteric hydrogels based on carboxyethylchitosans (CECH) with various degrees of substitution (DS) were prepared using different amounts of epichlorohydrin (ECH) as the crosslinking agent. The equilibrium swelli...New amphoteric hydrogels based on carboxyethylchitosans (CECH) with various degrees of substitution (DS) were prepared using different amounts of epichlorohydrin (ECH) as the crosslinking agent. The equilibrium swelling ratio (SW) was determined as functions of pH and salt concentration. The hydrogels show typical amphoteric character responding to pH change of the external medium. At isoelectric point (IEP), the hydrogels shrink. The DS value has important effect on the swelling properties of the hydrogels. When the DS of N-carboxyethylchitosan increases from 0.32 to 0.72, the equilibrium swelling ratio (SW) of the hydrogel changes from 76 to 290 at pH 7.3 and from 117 to 499 at pH 11.3. A marked volume decrease was observed in hydrogels with increasing salt concentration in the surrounding solution. The viscoelastic properties of the hydrogels were studied by oscillatory shear measurements under small-deformation conditions. The elastic modulus G' of all the samples has no dependence on frequency and is one order of magnitude larger than the loss modulus G '', corresponding to a strong gel behavior.展开更多
The interaction of an amphoteric surfactant, N-12alkylbetaine, and an acid dye in aqueous solution was studied by spectrophotometry. The results of the experiments show that the particle of dye interacts with one or s...The interaction of an amphoteric surfactant, N-12alkylbetaine, and an acid dye in aqueous solution was studied by spectrophotometry. The results of the experiments show that the particle of dye interacts with one or several N-12alkylbetaine molecules when the concentration of the surfactant is less than the CMC. The aggregated dyes are disintegrated when the surfactant concentration is more than the CMC, and the individual dye ion interacts with the suffactant micelle.展开更多
The electronic structure and bonding nature of adsorbing bonding complexes which consist of Amphoteric Collector-I and Mg^(2+), Ca^(2+), MgPO_4^-, CaPO_^-4, CaCO_3, as well aa MgCO_3, are studied using quantum chemist...The electronic structure and bonding nature of adsorbing bonding complexes which consist of Amphoteric Collector-I and Mg^(2+), Ca^(2+), MgPO_4^-, CaPO_^-4, CaCO_3, as well aa MgCO_3, are studied using quantum chemistry CNDO/2, It is predicted that magnesium salts are more liable to form adsorbing chelates with Amphoteric Collector-I than calcium salts, and all results coincide with that obtained in flotation.展开更多
As a novel class of porous crystalline solids,covalent organic frameworks(COFs)based electrolyte can combine the advantages of both inorganic and polymer electrolytes,leading to such as higher structural stability to ...As a novel class of porous crystalline solids,covalent organic frameworks(COFs)based electrolyte can combine the advantages of both inorganic and polymer electrolytes,leading to such as higher structural stability to inhibit lithium dendrites and better processing facility for improving interfacial contact.However,the ionic components of Li salt tend to be closely associated in the form of ion pairs or even ionic aggregates in the channel of COFs due to strong coulombic interactions,thus resulting in slow ionic diffusion dynamics and low ionic conductivity.Herein,we successfully designed and synthesized a novel single-ion conducting nitrogen hybrid conjugated skeleton(NCS)as all solid electrolyte,whose backbone is consisted with triazine and piperazine rings.A loose bonding between the triazine rings and cations would lower the energy barrier during ions transfer,and electrostatic forces with piperazine rings could“anchor”anions to increase the selectivity during ions transfer.Thus,the NCSelectrolyte exhibits excellent room temperature lithium-ion conductivity up to 1.49 mS·cm−1 and high transference number of 0.84 without employing any solvent,which to the best of our knowledge is one of the highest COF-based electrolytes so far.Moreover,the fabricated all-solid-state lithium metal batteries demonstrate highly attractive properties with quite stable cycling performance over 100 cycles with 82%capacity reservation at 0.5 C.展开更多
A series of biodegradable amphoteric chitosan-based flocculants (3-chloro-2-hydroxypropyl trimethyl ammonium chloride (CTA) modified carboxymethyl chitosan, denoted as CMC-CTA) with different substitution degrees ...A series of biodegradable amphoteric chitosan-based flocculants (3-chloro-2-hydroxypropyl trimethyl ammonium chloride (CTA) modified carboxymethyl chitosan, denoted as CMC-CTA) with different substitution degrees of CTA were prepared successfully. The content of carboxymethyl groups in each CMC-CTA sample was kept almost constant. The solubility of the various flocculants showed that, higher cationic content of flocculants caused a better solubility. The flocculation experiments using kaolin suspension as synthetic water at the laboratory scale indicated that the substitution degree of CTA was one of the key factors for the flocculation properties. With the increase of cationic content, the flocculants were demonstrated better flocculation performance and lower dosage requirement. Flocculation kinetics model of particles collisions combining zeta potential and turbidity measurements was employed to investigate the effects of the cationic content of the flocculants on the flocculation properties from the viewpoint of flocculation mechanism in detail. Furthermore, flocculation performance using raw water from Zhenjiang part of Yangtze River at the pilot scale showed the similar effects to those at the laboratory scale.展开更多
Amphoteric polymer can be used as retanning agent in leather manufacture. It is particularly useful in chrome-free tanning systems since it can regulate the charge properties of chrome-free leather and enhance the fix...Amphoteric polymer can be used as retanning agent in leather manufacture. It is particularly useful in chrome-free tanning systems since it can regulate the charge properties of chrome-free leather and enhance the fixation of anionic post-tanning chemicals in leather. However, the aggregation and precipitation of amphoteric polymer retanning agents around the isoelectric point (pI) hinder their wide application. Herein, we synthesized five amphoteric acrylic polymers (AAPs) by free radical copolymerization with acrylic acid and five different cationic acrylic monomers. The effect of cationic monomer structure on the aggregation behavior of AAPs was investigated. The aggregation of AAPs in aqueous solution showed pH and concentration dependence. Light scattering analysis showed that Poly (AA-co-MAPTAC) and Poly (AA-co-DMAPMA) were in the shape of coiled linear flexible chains with small particle size (Rg 7.6 nm and 14.8 nm, respectively) near the pI. However, Poly (AA-co-DAC), Poly (AA-co-DMC) and Poly (AA-co- DMAEMA) were in the shape of hollow spheres and exhibited serious aggregation. Quantum chemical calculations suggested that the amide groups in the cationic monomers MAPTAC and DMAPMA enhanced the nucleophilicity of AAPs. Thus the corresponding AAPs could carry a large number of cationic charges to slow their aggregation when the pH just climbed over the pI. The results are expected to provide theoretical reference for the synthesis and widespread application of AAPs.展开更多
With the characteristics of controllable charge and environmental friendliness,amphoteric polymers can be used in post-tanning process to solve the problems that arise during leather making and are caused by the low a...With the characteristics of controllable charge and environmental friendliness,amphoteric polymers can be used in post-tanning process to solve the problems that arise during leather making and are caused by the low absorption rate of single-charge chemicals,incompatibility with new tanning methods,and complex operation process.In this review,the structure,performance,and preparation of amphoteric polymers are reported.Then,the charge change of collagen during different tanning and pH treatments is introduced.Finally,the application and development of amphoteric polymers during the post-tanning process of leather making are discussed.This review has certain guiding significance to the preparation and application of amphoteric polymers for tanning system.展开更多
Gelation adversely affects the aqueous adiabatic terpolymerization of acrylamide (AM), sodium acrylate (NaAA),and 2-methacryloyloxyethyl trimethylammonium chloride (DMC). Here, the mixed dispersants sorbitan monooleat...Gelation adversely affects the aqueous adiabatic terpolymerization of acrylamide (AM), sodium acrylate (NaAA),and 2-methacryloyloxyethyl trimethylammonium chloride (DMC). Here, the mixed dispersants sorbitan monooleate (Span80) and polyoxyethylene sorbitan monooleate (Tween 80) were introduced to the terpolymerization system in an attemptto mitigate the gel effect. This enabled the preparation of high-performance amphoteric polyacrylamides, which werecharacterized by Fourier-transform infrared spectroscopy and thermogravimetric analysis. The influences of the dispersanttype and content as well as the hydrophilic-lipophilic balance (HLB) on the gel effect were examined, and the mechanismunderlying the suppression of the gel effect was considered. The obtained results indicated that the gel effect can beeffectively mitigated using an aqueous adiabatic terpolymerization system containing mixed Span 80/Tween 80 dispersantsat various contents. In particular, mixed dispersant contents of 0.6%–0.8% with HLB values of 5.0–6.0 afforded the optimalperformance (e.g., high viscosity, fast aqueous dissolution time, and the like).展开更多
A novel low-temperature alkaline smelting process is proposed to convert and separate amphoteric metals in crushed metal enrichment originated from waste printed circuit boards. The central composite design was used t...A novel low-temperature alkaline smelting process is proposed to convert and separate amphoteric metals in crushed metal enrichment originated from waste printed circuit boards. The central composite design was used to optimize the operating parameters,in which mass ratio of Na OH-to-CME, smelting temperature and smelting time were chosen as the variables, and the conversions of amphoteric metals tin, lead, aluminum and zinc were response parameters. Second-order polynomial models of high significance and3 D response surface plots were constructed to show the relationship between the responses and the variables. Optimum area of80%-85% Pb conversion and over 95% Sn conversion was obtained by the overlaid contours at mass ratio of Na OH-to-CME of4.5-5.0, smelting temperature of 653-723 K, smelting time of 90-120 min. The models were validated experimentally in the optimum area, and the results demonstrate that these models are reliable and accurate in predicting the smelting process.展开更多
Thermally stable mesoporous silica and Ti-containing molecular sieves have been synthesized at mild temperature using low-cost and biodegradable --- amphoteric tetradecyl betaine as template. The physicochemical chara...Thermally stable mesoporous silica and Ti-containing molecular sieves have been synthesized at mild temperature using low-cost and biodegradable --- amphoteric tetradecyl betaine as template. The physicochemical characterizations proved that Ti(IV) could be incorporated in the mesoporous struture.展开更多
In the present study the adsorptive properties of p-aminobenzoic acid with hypercrosslinked and multi-functional polymeric adsorbents at different solution pHs were systematically investigated in accordance with the p...In the present study the adsorptive properties of p-aminobenzoic acid with hypercrosslinked and multi-functional polymeric adsorbents at different solution pHs were systematically investigated in accordance with the particular physicochemical characteristics of the aromatic amphoteric compound involving both Lewis acid and Lewis base functional groups. It was found that the equilibrium adsorption data of the three polymeric adsorbents fitted well in the Langmuir and Freundlich isotherm equations. Studies at various pH levels indicate that the capacity of the adsorbents for adsorption of the ionic forms of adsorbate is less than that for the corresponding neutral species. At pH 3.78, the adsorption capacities of the three adsorbents are the highest. Whereas the adsorption property of multi-functional polymeric adsorbent NJ-99 is the largest, which may be attributed to the strong hydrogen-bonding interaction between the amino groups on the resin and the carboxyl group of p-aminobenzoic acid. The trend of the adsorption capacities of the three adsorbents towards p-aminobenzoic acid with the solution pH is in accord with the dissociation curve of the neutral molecular p-aminobenzoic acid. The adsorption forces include π-π interaction, hydrogen-bonding interaction and electrostatic attraction or repulsion when there exist the molecular and ionic adsorbing species at different pHs in aqueous solution.展开更多
Lou soil was modified by amphoteric surfactant in column experiment which was conducted. This study attempts to explore the transport of phenol to unmodified and modified soil and inquire into the effect of concentrat...Lou soil was modified by amphoteric surfactant in column experiment which was conducted. This study attempts to explore the transport of phenol to unmodified and modified soil and inquire into the effect of concentrations, pH, and ionic strength on phenol migration in the soil column. The parameters and breakthrough curves (BTCs) of transport were fitted by using the CXTFIT (version 2.1) model. The result of Cl?’s BTCs for non-reactive by determining the equilibrium model (EM) showed the retardation factor which was smaller than 1. The result of phenol’s BTCs by determining non-equilibrium model (NEM) was shown that the R-value increased while modification ratio increased, and the R was in order of CK (1.337) < 50BS-12 (4.085) < 100BS-12 (7.048). The lower to higher concentration of phenol didn’t affect to CK and 100BS-12 was able to block higher concentration. The effect of pH on transport to CK and 100BS-12 didn’t react and the average pore water velocity was decreased at pH = 4. The decreasing ionic strength of phenol migration on CK and 100BS-12 had effect and the average pore water velocity and retardation factor also decreased. The residual retention in soil was in order of CK < 50BS-12 < 100BS-12, and 100BS-12 could hold the amount of phenol than CK 7.21 times. Thus, amphoteric modified lou soil definitely blocks phenol migration and controls groundwater pollution.展开更多
The intrinsic surface reaction constants, pKa1^int, pKa2^int, p^*KC^int and p^*KA^int , were evaluated by a modifieddouble extrapolation (MDE) for TiO2 without structural charge and Mg-Fe hydrotalcite-like compoun...The intrinsic surface reaction constants, pKa1^int, pKa2^int, p^*KC^int and p^*KA^int , were evaluated by a modifieddouble extrapolation (MDE) for TiO2 without structural charge and Mg-Fe hydrotalcite-like compounds (HTlc) with structural charge, respectively. The results of intrinsic surface reaction constants for TiO2 were compared with those obtained by class double extrapolation (CDE) in literature. Furthermore, the values of intrinsic surface reaction constants obtained by MDE were used to simulate the charging behaviors of the materials. The following conclusions were obtained. For TiO2 without structural charge, the pKa1^int and pKa2^int evaluated by MDE are equal to those by CDE, however the p^*KC^int and p^*KA^int evaluated by MDE are much different from those by CDE. In principle, the results of the p^*KC^int and p^*KA^int evaluated by MDE are more accurate than those by CDE. The values of intrinsic surface reaction constants obtained by MDE can excellently simulate the charging curves for TiO2 with the triple layer model (TLM). For HTlc with positive structural charge, the results of ^*KC^int=0 and ^*KA^int →∞ were obtained by MDE, which means the inert electrolyte chemical binding does not exist; the point of zero net charge (PZNC) of c-independence also exist as the same as solid without structural charge, and the PHPZNC obtained by the acid-base titration can excellently be simulated and the surface charging tendency can be simulated to a great extent using the pKa1^int and pKa2^int evaluated by MDE and the diffuse layer model (DLM).展开更多
文摘A novel amphoteric granular lignin adsorbent(AGLA) was prepared using magnesium lignosulfonate as a raw material which was provided by a straw sulfite pulp mill in Guangdong Province, China. A reactive dye(red K-3B) was used as an adsorbate to investigate the adsorption behavior by static and mobile ways. The removal of reactive red K-3B was found to be initially pH and concentration dependent. Moreover, an increase of solution temperature ranging from 5℃ to 60℃ helped to enhance the rate of intraparticle diffusion of adsorbate and changes in the size of the pores of the adsorbent and thus to reduce the adsorption time. The total breakthrough adsorption capacity was 531 mg/g, and the saturated adsorption capacity was 560 mg/g, which prevailed over the activated carbons evidently. The reactive red K-3B adsorbed on AGLA could be recovered with a mixture of alcohol, NaCl and HCl aqueous solutions. The recovery percentage could reach 92.4%.
基金financial support provided by the National Natural Science Foundation of China(21776154)the National High Technology Research and Development Program 863 (2012AA051203)
文摘To reduce the energy consumption of the electrolytic hydrogen generation process, we propose a novel approach to generate hydrogen with acidic/alkaline amphoteric water electrolysis, wherein hydrogen is produced inside an acidic solution and oxygen evolved under alkaline condition, and a membrane is employed in the middle of the electrolyzer to restrain neutralization. The electrode polarization is greatly reduced due to the specific arrangement of the acidic/alkaline amphoteric electrolyzer. The rate of hydrogen production achieves over four times higher than that of the alkaline aqueous solution at 2.2 V, and the energy consumption is reduced approximately 30% under the current density of 200 m A/cm ^2. The investigation of transmembrane potential drop indicates water splitting on the membrane surfaces, which compensates for acid or alkaline loss on-site and maintains the concentration approximately constant during electrolysis process. The acidic/alkaline amphoteric water electrolysis is promising as an energy saving, clean and sustainable hydrogen production technology.
基金Project supported by the National Key Technology Research and Development Program of China(No.2006BAC02A15)Opening Foundation of Jiangsu Provincial Key Laboratory of Coastal Wetland Bioresources and Environmental Protection of China(No.JLCBE05006)the Qinglan Project of Jiangsu Province
文摘The adsorption behavior ofp-aminobenzoic acid and o-aminobenzoic acid onto the different polymeric adsorbents was systematically investigated as a function of the solution concentration and temperature. Experimental results indicated that the equilibrium adsorption data of the four polymeric adsorbents fitted well in the Freundlich isotherm. The adsorption capacity of multi-functional polymeric adsorbent NJ-99 was the highest, which might be attributed to the strong hydrogen-bonding interaction between the amino groups on the resin and the carboxyl group of aminobenzoic acid. The adsorption capacity of o-aminobenzoic acid onto any adsorbent was higher than p-aminobenzoic acid. Thermodynamic studies suggested the exothermic, spontaneous physical adsorption process. Adsorption kinetics results showed that the adsorption followed the pseudo-second-order kinetics model and the intraparticle mass transfer process was the rate-controlling step.
基金supported by the National Natural Science Foundation of China(U1808209)Fundamental Research Funds for the Central Universities(DUT18JC40)Liaoning Province Science and Technology Department(201601037)。
文摘A new amphoteric membrane was prepared by blending long-side-chain sulfonated poly(2,6-dimethyl-1,4-phenylene oxide)(S-L-PPO)and polybenzimidazole(PBI)for vanadium redox flow battery(VRFB)application.An acid-base pair structure formed between the imidazole of PBI and sulfonic acid of S-L-PPO resulted in lowered swelling ratio.It favors to reduce the vanadium permeation.While,the increased sulfonic acid concentration ensured that proton conductivity was still at a high level.As a result,a better balance between the vanadium ion permeation(6.1×10^-9 cm^2·s^-1)and proton conductivity(50.8 m S·cm^-1)in the S-L-PPO/PBI-10%membrane was achieved.The VRFB performance with S-L-PPO/PBI-10%membrane exhibited an EE of 82.7%,which was higher than those of pristine S-L-PPO(81.8%)and Nafion 212(78.0%)at 120 m A·cm^-2.In addition,the S-LPPO/PBI-10%membrane had a much longer self-discharge duration time(142 h)than that of Nafion 212(23 h).
基金This work is supported by the National Natural Science Foundation of China(Nos.22275066,521032089,21774046,51871107,52130101 and 52271217)Jilin Provincial Science and Technology Department(20210508046RQ and 20200801057GH)+1 种基金China Postdoctoral Science Foundation(2021T140253 and 2021M691188)the Applied Basic Research Program of Changchun Municipal Science and Technology Project(21ZY22).
文摘Metallic interface engineering is a promising strategy to stabilize Zn anode via promoting Zn^(2+) uniform deposition.However,strong interactions between the coating and Zn^(2+) and sluggish transport of Zn^(2+) lead to high anodic polarization.Here,we present a bio-inspired silk fibroin(SF)coating with amphoteric charges to construct an interface reversible electric field,which manipulates the transfer kinetics of Zn^(2+) and reduces anodic polarization.The alternating positively and negatively charged surface as a build-in driving force can expedite and homogenize Zn^(2+) flux via the inter-play between the charged coating and adsorbed ions,endowing the Zn-SF anode with low polarization voltage and stable plating/stripping.Experimental analyses with theo-retical calculations suggest that SF can facilitate the desolvation of[Zn(H_(2)O)_(6)]^(2+) and provide nucleation sites for uniform deposition.Consequently,the Zn-SF anode delivers a high-rate performance with low voltage polarization(83 mV at 20 mA cm^(−2)) and excellent stability(1500 h at 1 mA cm^(−2);500 h at 10 mA cm^(−2)),realizing exceptional cumulative capacity of 2.5 Ah cm^(−2).The full cell coupled with Zn_(x)V_(2)O_(5)·nH_(2)O(ZnVO)cathode achieves specific energy of~270.5/150.6 Wh kg^(−1)(at 0.5/10 A g^(−1))with-99.8% Coulombic efficiency and retains~80.3%(at 5.0 A g^(−1))after 3000 cycles.
基金the financial supports from the National Key Research and Development Program of China (2016YFB0101203)China MOST (Ministry of Science and Technology) Innovation Team in Key Area (2016RA4053)+2 种基金the National Natural Science Foundation of China (21276252)Natural Science Foundation of Liaoning Province (2015020630)State Key Laboratory of Fine Chemicals (Panjin) (JH2014009)
文摘For improvement of vanadium redox flow battery (VRB) performance, novel amphoteric semi- interpenetrating membranes (ASIPN) were prepared using poly(ether ether ketone) (PEEK) and polysul- fone (PSf), the former bearing sulfonic groups and the latter imidazolium. These two groups form ionic crosslinks between PEEK and PSf; meanwhile, covalent cross links were built between PSf chains with ad- dition of N-(3-aminopropyl)-imidazole. The amphoteric nature of the membrane allows facile proton and anion transport; the IPN structure and the presence of imidazolium cation effectively suppress vanadium ion crossover through the membrane. Therefore, the ASIPN based VRBs show higher Coulombic efficiency and energy efficiency than that assembled with pristine SPEEK and Nation 212 membranes. Our work demonstrates that the ASIPN membranes are promising for VRB applications.
基金the Second Tibetan Plateau Scientific Expedition and Research(STEP)program(2019QZKK0502)the National Natural Science Foundation of China(No.81673329)Authors are grateful for Dr.Ming Zhang from northwest institute of plateau biology,Chinese Academy of Sciences,for the assistance for obtaining plant materials.
文摘Three new diterpene alkaloids,tangutidines A-C(1-3),and four known alkaloids(4-7)were isolated from the whole plant of Aconitum tanguticum,from which amphoteric diterpene alkaloids(1-3)were obtained for the first time.The structures of 1-3 were elucidated by detailed interpretation of spectroscopic data,including MS and NMR data.All of them were evaluated for their cytotoxic activities.
文摘New amphoteric hydrogels based on carboxyethylchitosans (CECH) with various degrees of substitution (DS) were prepared using different amounts of epichlorohydrin (ECH) as the crosslinking agent. The equilibrium swelling ratio (SW) was determined as functions of pH and salt concentration. The hydrogels show typical amphoteric character responding to pH change of the external medium. At isoelectric point (IEP), the hydrogels shrink. The DS value has important effect on the swelling properties of the hydrogels. When the DS of N-carboxyethylchitosan increases from 0.32 to 0.72, the equilibrium swelling ratio (SW) of the hydrogel changes from 76 to 290 at pH 7.3 and from 117 to 499 at pH 11.3. A marked volume decrease was observed in hydrogels with increasing salt concentration in the surrounding solution. The viscoelastic properties of the hydrogels were studied by oscillatory shear measurements under small-deformation conditions. The elastic modulus G' of all the samples has no dependence on frequency and is one order of magnitude larger than the loss modulus G '', corresponding to a strong gel behavior.
文摘The interaction of an amphoteric surfactant, N-12alkylbetaine, and an acid dye in aqueous solution was studied by spectrophotometry. The results of the experiments show that the particle of dye interacts with one or several N-12alkylbetaine molecules when the concentration of the surfactant is less than the CMC. The aggregated dyes are disintegrated when the surfactant concentration is more than the CMC, and the individual dye ion interacts with the suffactant micelle.
文摘The electronic structure and bonding nature of adsorbing bonding complexes which consist of Amphoteric Collector-I and Mg^(2+), Ca^(2+), MgPO_4^-, CaPO_^-4, CaCO_3, as well aa MgCO_3, are studied using quantum chemistry CNDO/2, It is predicted that magnesium salts are more liable to form adsorbing chelates with Amphoteric Collector-I than calcium salts, and all results coincide with that obtained in flotation.
基金We thank the financial support from the Natural Science Foundation of Shandong(Nos.ZR2020JQ21 and ZR2021ZD24)National Natural Science Foundation of China(Nos.51873231 and 22138013)+1 种基金Taishan Scholar Project(No.tsqn201909062)the Technology Foundation of Shandong Energy Group Co.,LTD.(YKZB2020-176,YKKJ2019AJ08JG-R63)。
文摘As a novel class of porous crystalline solids,covalent organic frameworks(COFs)based electrolyte can combine the advantages of both inorganic and polymer electrolytes,leading to such as higher structural stability to inhibit lithium dendrites and better processing facility for improving interfacial contact.However,the ionic components of Li salt tend to be closely associated in the form of ion pairs or even ionic aggregates in the channel of COFs due to strong coulombic interactions,thus resulting in slow ionic diffusion dynamics and low ionic conductivity.Herein,we successfully designed and synthesized a novel single-ion conducting nitrogen hybrid conjugated skeleton(NCS)as all solid electrolyte,whose backbone is consisted with triazine and piperazine rings.A loose bonding between the triazine rings and cations would lower the energy barrier during ions transfer,and electrostatic forces with piperazine rings could“anchor”anions to increase the selectivity during ions transfer.Thus,the NCSelectrolyte exhibits excellent room temperature lithium-ion conductivity up to 1.49 mS·cm−1 and high transference number of 0.84 without employing any solvent,which to the best of our knowledge is one of the highest COF-based electrolytes so far.Moreover,the fabricated all-solid-state lithium metal batteries demonstrate highly attractive properties with quite stable cycling performance over 100 cycles with 82%capacity reservation at 0.5 C.
基金supported by the Key Natural Science Foundation of China (No. 51073077,50938004,50825802)the Research Project of Ministry of Housing and Urban-Rural Development of China (No. 2009-K7-11)+2 种基金the Open Fund from State Key Laboratory of Pollution Control and Resource Reuse of Nanjing University (No.PCRRF11004)the Fundamental Research Funds for the Central Universities (No. 1105020504,1116020510)the Scientific Research Foundation of Graduate School of Nanjing University (No. 2012CL06)
文摘A series of biodegradable amphoteric chitosan-based flocculants (3-chloro-2-hydroxypropyl trimethyl ammonium chloride (CTA) modified carboxymethyl chitosan, denoted as CMC-CTA) with different substitution degrees of CTA were prepared successfully. The content of carboxymethyl groups in each CMC-CTA sample was kept almost constant. The solubility of the various flocculants showed that, higher cationic content of flocculants caused a better solubility. The flocculation experiments using kaolin suspension as synthetic water at the laboratory scale indicated that the substitution degree of CTA was one of the key factors for the flocculation properties. With the increase of cationic content, the flocculants were demonstrated better flocculation performance and lower dosage requirement. Flocculation kinetics model of particles collisions combining zeta potential and turbidity measurements was employed to investigate the effects of the cationic content of the flocculants on the flocculation properties from the viewpoint of flocculation mechanism in detail. Furthermore, flocculation performance using raw water from Zhenjiang part of Yangtze River at the pilot scale showed the similar effects to those at the laboratory scale.
基金the Tianfu Ten-thousand Talents Program of Sichuan Province and the National Key R&D Program(2017YFB0308500).
文摘Amphoteric polymer can be used as retanning agent in leather manufacture. It is particularly useful in chrome-free tanning systems since it can regulate the charge properties of chrome-free leather and enhance the fixation of anionic post-tanning chemicals in leather. However, the aggregation and precipitation of amphoteric polymer retanning agents around the isoelectric point (pI) hinder their wide application. Herein, we synthesized five amphoteric acrylic polymers (AAPs) by free radical copolymerization with acrylic acid and five different cationic acrylic monomers. The effect of cationic monomer structure on the aggregation behavior of AAPs was investigated. The aggregation of AAPs in aqueous solution showed pH and concentration dependence. Light scattering analysis showed that Poly (AA-co-MAPTAC) and Poly (AA-co-DMAPMA) were in the shape of coiled linear flexible chains with small particle size (Rg 7.6 nm and 14.8 nm, respectively) near the pI. However, Poly (AA-co-DAC), Poly (AA-co-DMC) and Poly (AA-co- DMAEMA) were in the shape of hollow spheres and exhibited serious aggregation. Quantum chemical calculations suggested that the amide groups in the cationic monomers MAPTAC and DMAPMA enhanced the nucleophilicity of AAPs. Thus the corresponding AAPs could carry a large number of cationic charges to slow their aggregation when the pH just climbed over the pI. The results are expected to provide theoretical reference for the synthesis and widespread application of AAPs.
基金National Key Research and Development Program of China(2017YFB0308500)National Natural Science Foundation of China(22078183).
文摘With the characteristics of controllable charge and environmental friendliness,amphoteric polymers can be used in post-tanning process to solve the problems that arise during leather making and are caused by the low absorption rate of single-charge chemicals,incompatibility with new tanning methods,and complex operation process.In this review,the structure,performance,and preparation of amphoteric polymers are reported.Then,the charge change of collagen during different tanning and pH treatments is introduced.Finally,the application and development of amphoteric polymers during the post-tanning process of leather making are discussed.This review has certain guiding significance to the preparation and application of amphoteric polymers for tanning system.
基金the Project of Science and Technology Program of Guangzhou City of China(Project Nol.201604020004)for the financial support to this research.
文摘Gelation adversely affects the aqueous adiabatic terpolymerization of acrylamide (AM), sodium acrylate (NaAA),and 2-methacryloyloxyethyl trimethylammonium chloride (DMC). Here, the mixed dispersants sorbitan monooleate (Span80) and polyoxyethylene sorbitan monooleate (Tween 80) were introduced to the terpolymerization system in an attemptto mitigate the gel effect. This enabled the preparation of high-performance amphoteric polyacrylamides, which werecharacterized by Fourier-transform infrared spectroscopy and thermogravimetric analysis. The influences of the dispersanttype and content as well as the hydrophilic-lipophilic balance (HLB) on the gel effect were examined, and the mechanismunderlying the suppression of the gel effect was considered. The obtained results indicated that the gel effect can beeffectively mitigated using an aqueous adiabatic terpolymerization system containing mixed Span 80/Tween 80 dispersantsat various contents. In particular, mixed dispersant contents of 0.6%–0.8% with HLB values of 5.0–6.0 afforded the optimalperformance (e.g., high viscosity, fast aqueous dissolution time, and the like).
基金Projects(51074190,51234009)supported by the National Natural Science Foundation of ChinaProject(2014DFA90520)supported by International Cooperation Program of Ministry of Science of ChinaProject(20110162110049)supported by the Doctoral Scientific Fund Project of the Ministry of Education of China
文摘A novel low-temperature alkaline smelting process is proposed to convert and separate amphoteric metals in crushed metal enrichment originated from waste printed circuit boards. The central composite design was used to optimize the operating parameters,in which mass ratio of Na OH-to-CME, smelting temperature and smelting time were chosen as the variables, and the conversions of amphoteric metals tin, lead, aluminum and zinc were response parameters. Second-order polynomial models of high significance and3 D response surface plots were constructed to show the relationship between the responses and the variables. Optimum area of80%-85% Pb conversion and over 95% Sn conversion was obtained by the overlaid contours at mass ratio of Na OH-to-CME of4.5-5.0, smelting temperature of 653-723 K, smelting time of 90-120 min. The models were validated experimentally in the optimum area, and the results demonstrate that these models are reliable and accurate in predicting the smelting process.
文摘Thermally stable mesoporous silica and Ti-containing molecular sieves have been synthesized at mild temperature using low-cost and biodegradable --- amphoteric tetradecyl betaine as template. The physicochemical characterizations proved that Ti(IV) could be incorporated in the mesoporous struture.
基金This work was supported by the Opening Foundation of Jiangsu Provincial Key Laboratory of Coastal Wetland Bioresources and Environmental Protection of China (No. JLCBE05006).
文摘In the present study the adsorptive properties of p-aminobenzoic acid with hypercrosslinked and multi-functional polymeric adsorbents at different solution pHs were systematically investigated in accordance with the particular physicochemical characteristics of the aromatic amphoteric compound involving both Lewis acid and Lewis base functional groups. It was found that the equilibrium adsorption data of the three polymeric adsorbents fitted well in the Langmuir and Freundlich isotherm equations. Studies at various pH levels indicate that the capacity of the adsorbents for adsorption of the ionic forms of adsorbate is less than that for the corresponding neutral species. At pH 3.78, the adsorption capacities of the three adsorbents are the highest. Whereas the adsorption property of multi-functional polymeric adsorbent NJ-99 is the largest, which may be attributed to the strong hydrogen-bonding interaction between the amino groups on the resin and the carboxyl group of p-aminobenzoic acid. The trend of the adsorption capacities of the three adsorbents towards p-aminobenzoic acid with the solution pH is in accord with the dissociation curve of the neutral molecular p-aminobenzoic acid. The adsorption forces include π-π interaction, hydrogen-bonding interaction and electrostatic attraction or repulsion when there exist the molecular and ionic adsorbing species at different pHs in aqueous solution.
文摘Lou soil was modified by amphoteric surfactant in column experiment which was conducted. This study attempts to explore the transport of phenol to unmodified and modified soil and inquire into the effect of concentrations, pH, and ionic strength on phenol migration in the soil column. The parameters and breakthrough curves (BTCs) of transport were fitted by using the CXTFIT (version 2.1) model. The result of Cl?’s BTCs for non-reactive by determining the equilibrium model (EM) showed the retardation factor which was smaller than 1. The result of phenol’s BTCs by determining non-equilibrium model (NEM) was shown that the R-value increased while modification ratio increased, and the R was in order of CK (1.337) < 50BS-12 (4.085) < 100BS-12 (7.048). The lower to higher concentration of phenol didn’t affect to CK and 100BS-12 was able to block higher concentration. The effect of pH on transport to CK and 100BS-12 didn’t react and the average pore water velocity was decreased at pH = 4. The decreasing ionic strength of phenol migration on CK and 100BS-12 had effect and the average pore water velocity and retardation factor also decreased. The residual retention in soil was in order of CK < 50BS-12 < 100BS-12, and 100BS-12 could hold the amount of phenol than CK 7.21 times. Thus, amphoteric modified lou soil definitely blocks phenol migration and controls groundwater pollution.
基金Project supported by the National Key Basic Research Program of China (No. 2004CB418504), the National Natural Science Foundation of China (Nos. 20273041 and 20573065) and the Natural Science Foundation of Shandong Province of China (No. Z2005B02).
文摘The intrinsic surface reaction constants, pKa1^int, pKa2^int, p^*KC^int and p^*KA^int , were evaluated by a modifieddouble extrapolation (MDE) for TiO2 without structural charge and Mg-Fe hydrotalcite-like compounds (HTlc) with structural charge, respectively. The results of intrinsic surface reaction constants for TiO2 were compared with those obtained by class double extrapolation (CDE) in literature. Furthermore, the values of intrinsic surface reaction constants obtained by MDE were used to simulate the charging behaviors of the materials. The following conclusions were obtained. For TiO2 without structural charge, the pKa1^int and pKa2^int evaluated by MDE are equal to those by CDE, however the p^*KC^int and p^*KA^int evaluated by MDE are much different from those by CDE. In principle, the results of the p^*KC^int and p^*KA^int evaluated by MDE are more accurate than those by CDE. The values of intrinsic surface reaction constants obtained by MDE can excellently simulate the charging curves for TiO2 with the triple layer model (TLM). For HTlc with positive structural charge, the results of ^*KC^int=0 and ^*KA^int →∞ were obtained by MDE, which means the inert electrolyte chemical binding does not exist; the point of zero net charge (PZNC) of c-independence also exist as the same as solid without structural charge, and the PHPZNC obtained by the acid-base titration can excellently be simulated and the surface charging tendency can be simulated to a great extent using the pKa1^int and pKa2^int evaluated by MDE and the diffuse layer model (DLM).