Absorption of phenol, catechol and resorcinol. which vary in their ability to interact with the adsorbent through hydrogen bond, were used to investigate the adsorption mechanistic interaction. The adsorption enthalpi...Absorption of phenol, catechol and resorcinol. which vary in their ability to interact with the adsorbent through hydrogen bond, were used to investigate the adsorption mechanistic interaction. The adsorption enthalpies of the above mentioned compound onto the adsorbent were calculated and thermodynamic analysis was carried out. The results showed the adsorbent with the lowest adsorption enthalpies for the sorbate such as catechol with intermolecular hydrogen bond also display the lowest adsorption affinity On the other hand the more of the groups available for hydrogen bond interaction. the higher of the adsorption affinity These observations support the contention that phenol adsorption is driven predominantly by specific interaction of the solute with active sites on the surface of the adsorbent.展开更多
Polymers play an important role in hybrid enhanced oil recovery (EOR), which involves both a polymer and low-salinity water. Because the polymer commonly used for low-salinity polymer flooding (LSPF) is strongly sensi...Polymers play an important role in hybrid enhanced oil recovery (EOR), which involves both a polymer and low-salinity water. Because the polymer commonly used for low-salinity polymer flooding (LSPF) is strongly sensitive to brine pH, its efficiency can deteriorate in carbonate reservoirs containing highly acidic formation water. In this study, polymer efficiency in an acidic carbonate reservoir was investigated experimentally for different salinity levels and SO42− concentrations. Results indicated that lowering salinity improved polymer stability, resulting in less polymer adsorption, greater wettability alteration, and ultimately, higher oil recovery. However, low salinity may not be desirable for LSPF if the injected fluid does not contain a sufficient number of sulfate (SO42−) ions. Analysis of polymer efficiency showed that more oil can be produced with the same polymer concentration by adjusting the SO42− content. Therefore, when river water, which is relatively easily available in onshore fields, is designed to be injected into an acidic carbonate reservoir, the LSPF method proposed in this study can be a reliable and environmentally friendly method with addition of a sufficient number of SO42− ions to river water.展开更多
After a concise introduction of hydrogen bonding effects in solute-solute and solutesolvent bonding, the design of polymeric adsorbents based on hydrogen bonding, selectivity in adsorption through hydrogen bonding. an...After a concise introduction of hydrogen bonding effects in solute-solute and solutesolvent bonding, the design of polymeric adsorbents based on hydrogen bonding, selectivity in adsorption through hydrogen bonding. and characterization of hydrogen bonding in adsorption and separation were reviewed with 28 references.展开更多
A novel biomimetic protein-resistant modifier based on cellulose-based polymeric liquid crystals was described(PLCs). Two types of PLCs of propyl hydroxypropyl cellulose ester(PPC) and octyl hydroxypropyl cellulos...A novel biomimetic protein-resistant modifier based on cellulose-based polymeric liquid crystals was described(PLCs). Two types of PLCs of propyl hydroxypropyl cellulose ester(PPC) and octyl hydroxypropyl cellulose ester(OPC) were prepared by esterification from hydroxypropyl cellulose, and then were mixed with polyvinyl chloride and polyurethane to obtain composite films by solution casting, respectively. The surface morphology of PLCs and their composite films were characterized by polarized optical microscopy(POM) and scanning electron microscopy(SEM), suggesting the existence of microdomain separation with fingerprint texture in PLC composite films. Water contact angle measurement results indicated that hydrophilicity of PLC/polymer composite films was dependent on the type and content of PLC as well as the type of matrix due to their interaction. Using bovine serum albumin(BSA) as a model protein, protein adsorption results revealed that PLCs with protein-resistant property can obviously suppress protein adsorption on their composite films, probably due to their flexible LC state. Moreover, all PLCs and their composites exhibited non-toxicity by MTT assay, suggesting their safety for biomedical applications.展开更多
Adsorption of poly(L-lysine) on surface-attached poly(methacrylic acid) monolayers formed through in situ free radical polymerization was investigated. A strong "template effect" was observed for the adsorption ...Adsorption of poly(L-lysine) on surface-attached poly(methacrylic acid) monolayers formed through in situ free radical polymerization was investigated. A strong "template effect" was observed for the adsorption of poly(L-lysine) on poly(methacrylic acid) layers, which were perpendicularly grown from the surface of substrates. The adsorbed amount of poly(amino acid) increases linearly with the increase in initial layer thickness of poly(methacrylic acid) monolayers. In addition, the adsorbed poly(amino acid) is relatively stable in medium concentration of salt solution but can be completely released from the brush in high salt concentration.展开更多
The adsorption of linear poly(N-isopropylacrylamide) (PNIPAM) chains on surfactant-free polystyrene (PS) nanoparticles was used as a model system to study the hydrophobic adsorption of polymer on the surface, because ...The adsorption of linear poly(N-isopropylacrylamide) (PNIPAM) chains on surfactant-free polystyrene (PS) nanoparticles was used as a model system to study the hydrophobic adsorption of polymer on the surface, because the hydrophobility of PNIPAM can be continuously varied by a small temperature change. The adsorption was investigated by a combination of static and dynamic laser light scattering (LLS) measurements. In static LLS, the absolute excess scattered light intensity led to the amount of PNIPAM adsorbed on the surface. In dynamic LLS, the hydrodynamic thickness of the adsorbed PNIPAM layer was accurately measured. For a given particle concentration, the adsorption increases as the PNIPAM concentration and the incubation temperature increase. The average density of the adsorbed PNIPAM layer is reciprocally proportional to the number of the PNIPAM chains on the surface, revealing a simple scaling of the chain density distribution. The adsorption follows the Langmuir's isotherm. The enthalpy change estimated from the adsorption at 25 degrees C and 30 degrees C is slightly positive, indicating that the adsorption involves the coil-to-globule transition of the chains on the surface.展开更多
Molecular imprinted polymers (MIPs) are novel functional polymer materials and known as specific adsorbents for the template molecules. These novel functional polymers have promised potential applications in racemic r...Molecular imprinted polymers (MIPs) are novel functional polymer materials and known as specific adsorbents for the template molecules. These novel functional polymers have promised potential applications in racemic resolution, sensor, chromatography, adsorptive separation and other fields. This review exhibits the approach for preparing MIPs, the features of MIPs obtained by different routes and the characteristics of adsorptive separations with MIPs. The molecular recognition mechanism and the idea of the present possibilities and limitations of molecular imprinting polymerization are discussed as well.展开更多
By reacting alkynylthiacalix[4]arenes with polyethylene glycol azido compounds,a series of novel thiacalix[4]arene 1,2,3-triazole-polyethylene glycol netty polymers were conveniently prepared in good yields.Their stru...By reacting alkynylthiacalix[4]arenes with polyethylene glycol azido compounds,a series of novel thiacalix[4]arene 1,2,3-triazole-polyethylene glycol netty polymers were conveniently prepared in good yields.Their structures and morphologies were studied by ^1H NMR,IR.and elemental analysis and SEM images.On average,approximately 28-31 thiacalixarene units exist in each polymeric molecule.These novel polymers possess excellent adsorption ability for both cationic and anionic dyes.The saturation adsorption capacity for Congo red reached 1.3-1.4 mmol/g.They exhibit high and stable adsorption ability in the scope of pH 5-9,and maintain good properties in five cycles.展开更多
Natural organic matter(NOM), present in natural waters and wastewater, decreases adsorption of micropollutants, increasing treatment costs. This research investigated mechanisms of competition for non-imprinted poly...Natural organic matter(NOM), present in natural waters and wastewater, decreases adsorption of micropollutants, increasing treatment costs. This research investigated mechanisms of competition for non-imprinted polymers(NIPs) and activated carbon with humic acid and wastewater. Three different types of activated carbons(Norit PAC 200,Darco KB-M, and Darco S-51) were used for comparison with the NIP. The lower surface area and micropore to mesopore ratio of the NIP led to decreased adsorption capacity in comparison to the activated carbons. In addition, experiments were conducted for single-solute adsorption of Methylene Blue(MB) dye, simultaneous adsorption with humic acid and wastewater, and pre-loading with humic acid and wastewater followed by adsorption of MB dye using NIP and Norit PAC 200. Both the NIP and PAC 200 showed significant decreases of 27% for NIP(p = 0.087) and 29% for PAC 200(p = 0.096) during simultaneous exposure to humic acid and MB dye. There was no corresponding decrease for NIP or PAC 200 pre-loaded with humic acid and then exposed to MB. In fact, for PAC 200, the adsorption capacity of the activated carbon increased when it was pre-loaded with humic acid by 39%(p = 0.0005). For wastewater, the NIP showed no significant increase or decrease in adsorption capacity during either simultaneous exposure or pre-loading. The adsorption capacity of PAC 200 increased by 40%(p = 0.001) for simultaneous exposure to wastewater and MB. Pre-loading with wastewater had no effect on MB adsorption by PAC 200.展开更多
Covalent/metal organic frameworks are highly attractive due to their tunable structure and properties,and broad applications in multiple fields.However,they still suffer from numbers of drawbacks including low solubil...Covalent/metal organic frameworks are highly attractive due to their tunable structure and properties,and broad applications in multiple fields.However,they still suffer from numbers of drawbacks including low solubility,harsh synthesis and fabrication,and low mechanical flexibility.Herein,we report a new organic framework consisting of macrocycles and organic frames in its periodic structure,and denote it as macrocycle organic polymer(MOP).The size-tunable macrocycles containing peripheral furan units are synthesized by anionic ring-opening polymerization,which undergo a reversible Diels-Alde reaction with bismaleimide to generate/degrade MOPs at given temperatures.Relying on above features,MOPs exhibit excellent flexibility,healable ability and recycle ability.Interestingly,owing to the“living”nature of anionic ring-opening polymerization,MOPs can self-grow into bigger sizes in the presence of monomer and catalysis,analogs to the living creatures.Moreover,their high porosity and rich thioether structure enable them as good metal ion absorbers and promising applications in wearable electronics.展开更多
Lanthanide-ion imprinted polymers(L-IIPs) were synthesized by stoichiometric amounts of rare earth ions and the cavities in the polymers were created for the corresponding lanthanide ions. The maximum sorption capac...Lanthanide-ion imprinted polymers(L-IIPs) were synthesized by stoichiometric amounts of rare earth ions and the cavities in the polymers were created for the corresponding lanthanide ions. The maximum sorption capacities were estimated to be 125.3, 126.5, 127.6, 128.2 and 129.1 mg/g for Pr, Nd, Sm, Eu and Gd, respectively at p H 6. In the selectivity study, the L-IIPs exhibited good selectivity to the specific rare earth ions in the presence of coexisting cations. The imprinting results were found to be excellent with some rare earth ions over other competitor rare earth ions with the same charges and close ionic radius.展开更多
Polyacrylamide/silica (PAM/SiO2) composite capsules were synthesized by inverse Pickering emulsion polymerization. Silica nanoparticles modified with methacryloxypropyltrimethoxysilane (MPS) were used as a stabili...Polyacrylamide/silica (PAM/SiO2) composite capsules were synthesized by inverse Pickering emulsion polymerization. Silica nanoparticles modified with methacryloxypropyltrimethoxysilane (MPS) were used as a stabilizer. Transmission electron microscopy (TEM), scanning electron microscopy (SEM). Fourier transform infrared (FTIR) spectroscopy, and thermal gravimetric analysis (TGA) were used to characterize the morphology and composition of the composite capsules. SEM and TEM images showed that capsules consisted of a particle shell and a polymer inner layer. The capsule size depends on the nanoparticle concentration in the continuous phase. The composite rigidity largely depends on the acrylamide concentration. FTIR and TGA results indicated the existence of polyacrylamide and SiO2 in the composite particles. Aqueous Hg(ll) removal testing by the PAM/SiO2 composite capsules indicated promising potential for removing heavy metal ions from wastewater.展开更多
The influence of superplasticizer on the yield stress of cement pastes with recycled powder(RP)was examined in the study.Four superplasticizers were used to obtain the similar fluidity by adjusting the dosage.The resu...The influence of superplasticizer on the yield stress of cement pastes with recycled powder(RP)was examined in the study.Four superplasticizers were used to obtain the similar fluidity by adjusting the dosage.The results show that the 10%RP decreases the yield stress of paste compared to the reference paste at the same fluidity,but 20%and 30%RP increases the yield stress,ranging from 11 to 599%.The superplasticizer with adsorptive group of phosphate-type minimizes the yield stress of paste than that of polycarboxylate-type,but it made a significant increment in yield stress as the incorporating of RP increased.Besides,the polycarboxylate superplasticizer with the higher molecular weight of side chain and charge density led to lower yield stress.Based on the Yodel model,the yield stress of paste with RP was analyzed by the polymer adsorption and particle packing density of particles to reveal the influence of RP with different superplasticizers on the colloidal interaction and contact network among the particles.The packing density of particles with recycled powder was a little higher than the reference paste,but the higher fraction of fine particles made a stronger PSD effect,which improved the particle contact interaction.On the other hand,due to the higher polymer adsorption of recycled powder than cement,especially for superplasticizer with phosphate group,the average surface coverage was increased,which extended the separation distance,so that colloidal interaction among particles was weaken.展开更多
The purpose of this work is to remove Pb(II) from the aqueous solution using a type of hydrogel composite. A hydrogel composite consisting of waste linear low density polyethylene, acrylic acid, starch, and organo-m...The purpose of this work is to remove Pb(II) from the aqueous solution using a type of hydrogel composite. A hydrogel composite consisting of waste linear low density polyethylene, acrylic acid, starch, and organo-montmorillonite was prepared through emulsion polymerization method. Fourier transform infrared spectroscopy(FTIR), Solid carbon nuclear magnetic resonance spectroscopy(CNMR)), silicon-29 nuclear magnetic resonance spectroscopy(Si NMR)), and X-ray diffraction spectroscope((XRD) were applied to characterize the hydrogel composite. The hydrogel composite was then employed as an adsorbent for the removal of Pb(II) from the aqueous solution. The Pb(II)-loaded hydrogel composite was characterized using Fourier transform infrared spectroscopy(FTIR)),scanning electron microscopy(SEM)), and X-ray photoelectron spectroscopy((XPS)). From XPS results, it was found that the carboxyl and hydroxyl groups of the hydrogel composite participated in the removal of Pb(II). Kinetic studies indicated that the adsorption of Pb(II)followed the pseudo-second-order equation. It was also found that the Langmuir model described the adsorption isotherm better than the Freundlich isotherm. The maximum removal capacity of the hydrogel composite for Pb(II) ions was 430 mg/g. Thus, the waste linear low-density polyethylene-g-poly(acrylic acid)-co-starch/organo-montmorillonite hydrogel composite could be a promising Pb(II) adsorbent.展开更多
基金Supported by the National Natural Science Foundation of China !(Grant No. 29574164 and 29974015)
文摘Absorption of phenol, catechol and resorcinol. which vary in their ability to interact with the adsorbent through hydrogen bond, were used to investigate the adsorption mechanistic interaction. The adsorption enthalpies of the above mentioned compound onto the adsorbent were calculated and thermodynamic analysis was carried out. The results showed the adsorbent with the lowest adsorption enthalpies for the sorbate such as catechol with intermolecular hydrogen bond also display the lowest adsorption affinity On the other hand the more of the groups available for hydrogen bond interaction. the higher of the adsorption affinity These observations support the contention that phenol adsorption is driven predominantly by specific interaction of the solute with active sites on the surface of the adsorbent.
基金supported by the Energy Efficiency&Resources(No.20212010200010)the“Development of Intelligential Diagnosis,Abandonment Process and Management Technology for Decrepit Oil and Gas Wells”(No.20216110100010)of the Korea Institute of Energy Technology EvaluationPlanning(KETEP)grant funded by the Korean Government Ministry of Trade,Industry&Energy.
文摘Polymers play an important role in hybrid enhanced oil recovery (EOR), which involves both a polymer and low-salinity water. Because the polymer commonly used for low-salinity polymer flooding (LSPF) is strongly sensitive to brine pH, its efficiency can deteriorate in carbonate reservoirs containing highly acidic formation water. In this study, polymer efficiency in an acidic carbonate reservoir was investigated experimentally for different salinity levels and SO42− concentrations. Results indicated that lowering salinity improved polymer stability, resulting in less polymer adsorption, greater wettability alteration, and ultimately, higher oil recovery. However, low salinity may not be desirable for LSPF if the injected fluid does not contain a sufficient number of sulfate (SO42−) ions. Analysis of polymer efficiency showed that more oil can be produced with the same polymer concentration by adjusting the SO42− content. Therefore, when river water, which is relatively easily available in onshore fields, is designed to be injected into an acidic carbonate reservoir, the LSPF method proposed in this study can be a reliable and environmentally friendly method with addition of a sufficient number of SO42− ions to river water.
基金Supported by the National Natural Science Foundation of China! (Grant No. 29574164 and 29974015)
文摘After a concise introduction of hydrogen bonding effects in solute-solute and solutesolvent bonding, the design of polymeric adsorbents based on hydrogen bonding, selectivity in adsorption through hydrogen bonding. and characterization of hydrogen bonding in adsorption and separation were reviewed with 28 references.
基金Funded by the National Natural Science Foundation of China(Nos.31170911 and 31040027)the Research Development and Innovation Fund of Jinan University(No.21611410)+1 种基金the Open Fund of the First Affiliated Hospital,Jinan University,Guangzhou(No.511005024)the Macao Science and Technology Development Fund(No.064/2013/A2)
文摘A novel biomimetic protein-resistant modifier based on cellulose-based polymeric liquid crystals was described(PLCs). Two types of PLCs of propyl hydroxypropyl cellulose ester(PPC) and octyl hydroxypropyl cellulose ester(OPC) were prepared by esterification from hydroxypropyl cellulose, and then were mixed with polyvinyl chloride and polyurethane to obtain composite films by solution casting, respectively. The surface morphology of PLCs and their composite films were characterized by polarized optical microscopy(POM) and scanning electron microscopy(SEM), suggesting the existence of microdomain separation with fingerprint texture in PLC composite films. Water contact angle measurement results indicated that hydrophilicity of PLC/polymer composite films was dependent on the type and content of PLC as well as the type of matrix due to their interaction. Using bovine serum albumin(BSA) as a model protein, protein adsorption results revealed that PLCs with protein-resistant property can obviously suppress protein adsorption on their composite films, probably due to their flexible LC state. Moreover, all PLCs and their composites exhibited non-toxicity by MTT assay, suggesting their safety for biomedical applications.
基金Funded by the National Natural Science Foundation of China(21576216)
文摘Adsorption of poly(L-lysine) on surface-attached poly(methacrylic acid) monolayers formed through in situ free radical polymerization was investigated. A strong "template effect" was observed for the adsorption of poly(L-lysine) on poly(methacrylic acid) layers, which were perpendicularly grown from the surface of substrates. The adsorbed amount of poly(amino acid) increases linearly with the increase in initial layer thickness of poly(methacrylic acid) monolayers. In addition, the adsorbed poly(amino acid) is relatively stable in medium concentration of salt solution but can be completely released from the brush in high salt concentration.
文摘The adsorption of linear poly(N-isopropylacrylamide) (PNIPAM) chains on surfactant-free polystyrene (PS) nanoparticles was used as a model system to study the hydrophobic adsorption of polymer on the surface, because the hydrophobility of PNIPAM can be continuously varied by a small temperature change. The adsorption was investigated by a combination of static and dynamic laser light scattering (LLS) measurements. In static LLS, the absolute excess scattered light intensity led to the amount of PNIPAM adsorbed on the surface. In dynamic LLS, the hydrodynamic thickness of the adsorbed PNIPAM layer was accurately measured. For a given particle concentration, the adsorption increases as the PNIPAM concentration and the incubation temperature increase. The average density of the adsorbed PNIPAM layer is reciprocally proportional to the number of the PNIPAM chains on the surface, revealing a simple scaling of the chain density distribution. The adsorption follows the Langmuir's isotherm. The enthalpy change estimated from the adsorption at 25 degrees C and 30 degrees C is slightly positive, indicating that the adsorption involves the coil-to-globule transition of the chains on the surface.
文摘Molecular imprinted polymers (MIPs) are novel functional polymer materials and known as specific adsorbents for the template molecules. These novel functional polymers have promised potential applications in racemic resolution, sensor, chromatography, adsorptive separation and other fields. This review exhibits the approach for preparing MIPs, the features of MIPs obtained by different routes and the characteristics of adsorptive separations with MIPs. The molecular recognition mechanism and the idea of the present possibilities and limitations of molecular imprinting polymerization are discussed as well.
基金Financial support from the National Natural Science Foundation of China(No:21406036)Fujian Natural Science Foundation of China(No.2014J01034)+1 种基金Project of Fujian provincial department of education(Nos.JA11044,JA10056,JB13011)the Program for Innovative Research Team in Science and Technology in Fujian Province University were greatly acknowledged
文摘By reacting alkynylthiacalix[4]arenes with polyethylene glycol azido compounds,a series of novel thiacalix[4]arene 1,2,3-triazole-polyethylene glycol netty polymers were conveniently prepared in good yields.Their structures and morphologies were studied by ^1H NMR,IR.and elemental analysis and SEM images.On average,approximately 28-31 thiacalixarene units exist in each polymeric molecule.These novel polymers possess excellent adsorption ability for both cationic and anionic dyes.The saturation adsorption capacity for Congo red reached 1.3-1.4 mmol/g.They exhibit high and stable adsorption ability in the scope of pH 5-9,and maintain good properties in five cycles.
基金funded by the Natural Sciences and Engineering Council of Canada (NSERC RGPIN 06246-2016) under the Discovery Grant program
文摘Natural organic matter(NOM), present in natural waters and wastewater, decreases adsorption of micropollutants, increasing treatment costs. This research investigated mechanisms of competition for non-imprinted polymers(NIPs) and activated carbon with humic acid and wastewater. Three different types of activated carbons(Norit PAC 200,Darco KB-M, and Darco S-51) were used for comparison with the NIP. The lower surface area and micropore to mesopore ratio of the NIP led to decreased adsorption capacity in comparison to the activated carbons. In addition, experiments were conducted for single-solute adsorption of Methylene Blue(MB) dye, simultaneous adsorption with humic acid and wastewater, and pre-loading with humic acid and wastewater followed by adsorption of MB dye using NIP and Norit PAC 200. Both the NIP and PAC 200 showed significant decreases of 27% for NIP(p = 0.087) and 29% for PAC 200(p = 0.096) during simultaneous exposure to humic acid and MB dye. There was no corresponding decrease for NIP or PAC 200 pre-loaded with humic acid and then exposed to MB. In fact, for PAC 200, the adsorption capacity of the activated carbon increased when it was pre-loaded with humic acid by 39%(p = 0.0005). For wastewater, the NIP showed no significant increase or decrease in adsorption capacity during either simultaneous exposure or pre-loading. The adsorption capacity of PAC 200 increased by 40%(p = 0.001) for simultaneous exposure to wastewater and MB. Pre-loading with wastewater had no effect on MB adsorption by PAC 200.
基金Financial support from the National Natural Science Foundation of China(22275193)the Natural Science Foundation of Fujian Province(E131AJ0101)+2 种基金Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China(2021ZR115)STS Project of Putian-CAS(2020HJSTS001)Fujian Institute of Research on the Structure of Matter,Chinese Academy of Sciences(E055AJ01)is gratefully acknowledged.
文摘Covalent/metal organic frameworks are highly attractive due to their tunable structure and properties,and broad applications in multiple fields.However,they still suffer from numbers of drawbacks including low solubility,harsh synthesis and fabrication,and low mechanical flexibility.Herein,we report a new organic framework consisting of macrocycles and organic frames in its periodic structure,and denote it as macrocycle organic polymer(MOP).The size-tunable macrocycles containing peripheral furan units are synthesized by anionic ring-opening polymerization,which undergo a reversible Diels-Alde reaction with bismaleimide to generate/degrade MOPs at given temperatures.Relying on above features,MOPs exhibit excellent flexibility,healable ability and recycle ability.Interestingly,owing to the“living”nature of anionic ring-opening polymerization,MOPs can self-grow into bigger sizes in the presence of monomer and catalysis,analogs to the living creatures.Moreover,their high porosity and rich thioether structure enable them as good metal ion absorbers and promising applications in wearable electronics.
基金Project supported by the Ministry of Science,Technology and Innovation,Malaysia(RDU130505,SBK0260-ST-2016)
文摘Lanthanide-ion imprinted polymers(L-IIPs) were synthesized by stoichiometric amounts of rare earth ions and the cavities in the polymers were created for the corresponding lanthanide ions. The maximum sorption capacities were estimated to be 125.3, 126.5, 127.6, 128.2 and 129.1 mg/g for Pr, Nd, Sm, Eu and Gd, respectively at p H 6. In the selectivity study, the L-IIPs exhibited good selectivity to the specific rare earth ions in the presence of coexisting cations. The imprinting results were found to be excellent with some rare earth ions over other competitor rare earth ions with the same charges and close ionic radius.
文摘Polyacrylamide/silica (PAM/SiO2) composite capsules were synthesized by inverse Pickering emulsion polymerization. Silica nanoparticles modified with methacryloxypropyltrimethoxysilane (MPS) were used as a stabilizer. Transmission electron microscopy (TEM), scanning electron microscopy (SEM). Fourier transform infrared (FTIR) spectroscopy, and thermal gravimetric analysis (TGA) were used to characterize the morphology and composition of the composite capsules. SEM and TEM images showed that capsules consisted of a particle shell and a polymer inner layer. The capsule size depends on the nanoparticle concentration in the continuous phase. The composite rigidity largely depends on the acrylamide concentration. FTIR and TGA results indicated the existence of polyacrylamide and SiO2 in the composite particles. Aqueous Hg(ll) removal testing by the PAM/SiO2 composite capsules indicated promising potential for removing heavy metal ions from wastewater.
基金supported by a Youth Program of National Natural Science Foundation of China(Grant No:52008190).
文摘The influence of superplasticizer on the yield stress of cement pastes with recycled powder(RP)was examined in the study.Four superplasticizers were used to obtain the similar fluidity by adjusting the dosage.The results show that the 10%RP decreases the yield stress of paste compared to the reference paste at the same fluidity,but 20%and 30%RP increases the yield stress,ranging from 11 to 599%.The superplasticizer with adsorptive group of phosphate-type minimizes the yield stress of paste than that of polycarboxylate-type,but it made a significant increment in yield stress as the incorporating of RP increased.Besides,the polycarboxylate superplasticizer with the higher molecular weight of side chain and charge density led to lower yield stress.Based on the Yodel model,the yield stress of paste with RP was analyzed by the polymer adsorption and particle packing density of particles to reveal the influence of RP with different superplasticizers on the colloidal interaction and contact network among the particles.The packing density of particles with recycled powder was a little higher than the reference paste,but the higher fraction of fine particles made a stronger PSD effect,which improved the particle contact interaction.On the other hand,due to the higher polymer adsorption of recycled powder than cement,especially for superplasticizer with phosphate group,the average surface coverage was increased,which extended the separation distance,so that colloidal interaction among particles was weaken.
基金supported by the USM short-term grant (Ac No.: 8044043)by the USM fellowship scheme for PhD study (to M. Irani)Water Program at University of Wyoming
文摘The purpose of this work is to remove Pb(II) from the aqueous solution using a type of hydrogel composite. A hydrogel composite consisting of waste linear low density polyethylene, acrylic acid, starch, and organo-montmorillonite was prepared through emulsion polymerization method. Fourier transform infrared spectroscopy(FTIR), Solid carbon nuclear magnetic resonance spectroscopy(CNMR)), silicon-29 nuclear magnetic resonance spectroscopy(Si NMR)), and X-ray diffraction spectroscope((XRD) were applied to characterize the hydrogel composite. The hydrogel composite was then employed as an adsorbent for the removal of Pb(II) from the aqueous solution. The Pb(II)-loaded hydrogel composite was characterized using Fourier transform infrared spectroscopy(FTIR)),scanning electron microscopy(SEM)), and X-ray photoelectron spectroscopy((XPS)). From XPS results, it was found that the carboxyl and hydroxyl groups of the hydrogel composite participated in the removal of Pb(II). Kinetic studies indicated that the adsorption of Pb(II)followed the pseudo-second-order equation. It was also found that the Langmuir model described the adsorption isotherm better than the Freundlich isotherm. The maximum removal capacity of the hydrogel composite for Pb(II) ions was 430 mg/g. Thus, the waste linear low-density polyethylene-g-poly(acrylic acid)-co-starch/organo-montmorillonite hydrogel composite could be a promising Pb(II) adsorbent.