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1.
Environ Sci Technol ; 51(1): 522-530, 2017 01 03.
Artigo em Inglês | MEDLINE | ID: mdl-27936649

RESUMO

Hyper-cross-linked polymeric resin (HPR) represents a class of predominantly microporous adsorbents and has good adsorption performance toward VOCs. However, adsorption equilibrium of VOCs onto HPR are limited. In this research, a novel method for predicting adsorption capacities of VOCs on HPR at environmentally relevant temperatures and concentrations using inverse gas chromatography data was proposed. Adsorption equilibrium of six VOCs (n-pentane, n-hexane, dichloromethane, acetone, benzene, 1, 2-dichloroethane) onto HPR in the temperature range of 403-443 K were measured by inverse gas chromatography (IGC). Adsorption capacities at environmentally relevant temperatures (293-328 K) and concentrations (P/Ps = 0.1-0.7) were predicted using Dubinin-Radushkevich (DR) equation based on Polany's theory. Taking consideration of the swelling properties of HPR, the volume swelling ratio (r) was introduced and r·Vmicro was used instead of Vmicro determined by N2 adsorption data at 77 K as the parameter q0 (limiting micropore volume) of the DR equation. The results showed that the adsorption capacities of VOCs at environmentally relevant temperatures and concentrations can be predicted effectively using IGC data, the root-mean-square errors between the predicted and experimental data was below 9.63%. The results are meaningful because they allow accurate prediction of adsorption capacities of adsorbents more quickly and conveniently using IGC data.


Assuntos
Cromatografia Gasosa , Temperatura , Adsorção , Benzeno , Polímeros/química
2.
Water Sci Technol ; 69(9): 1879-85, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24804663

RESUMO

A novel method was proposed for efficient co-removal of Cu (II) and phthalic acid (PA) using self-synthesized polyamine resin (R-NH(2)). The adsorption properties of R-NH(2) were thoroughly investigated by equilibrium, kinetic and dynamic tests in sole and binary systems at pH 5.0. The Freundlich model was a good fit for all the isotherm data, showing higher Kf values in the binary system than the sole system. The pseudo-second-order kinetic equation showed a better correlation to the experimental data in all cases and PA uptake was much faster than that of Cu (II). R-NH(2) showed highest adsorption capacities to both Cu (II) and PA among the five tested resins. Moreover, the presence of PA markedly enhanced the adsorption of Cu (II), being around 3.5 times of that of the sole system. The adsorption of PA was also slightly increased when Cu (II) was coexistent. Furthermore, using Fourier transform infrared spectrometry (FTIR) and species calculations, possible mechanisms were proposed that Cu (II) coordinated with -NH(2) and negative PA species interacted with -NH(3)(+) by electrostatic attraction. [Cu-PA] complex in the binary system possessed a much higher affinity than free Cu (II) to chelating with -NH(2), resulting in mutual enhancement.


Assuntos
Cobre/química , Ácidos Ftálicos/química , Poliaminas/química , Resinas Sintéticas/química , Poluentes Químicos da Água/química , Estereoisomerismo , Purificação da Água/métodos
3.
Environ Pollut ; 348: 123879, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38548161

RESUMO

Desorption is a critical process in the recovery or post-treatment of adsorbents saturated with volatile organic compounds (VOCs). In this study, the thermal desorption behaviors for eight VOCs on hypercrosslinked polymeric resin (HPR) and macroporous polymeric resin (MPR) were investigated through isothermal desorption and temperature programmed desorption (TPD). Compared with MPR, HPR with more micropores exhibited a lower desorption rate constant, lower desorption efficiency and higher desorption activation energy due to the strong binding energy generated between VOCs molecules and narrow micropores. As the polarizability of VOCs increased, the desorption rate constants on two porous polymeric resins decreased, while the desorption activation energy showed an incremental trend. Excellent linear correlations were observed between VOC polarizability and desorption rate constants (R2 = 0.957 for HPR and R2 = 0.940 for MPR) as well as between VOC polarizability and desorption activation energy (R2 = 0.981 for HPR and R2 = 0.969 for MPR). Furthermore, a polyparameter linear free energy relationship (PP-LFER) was developed to explore the influences of intermolecular interactions on desorption behaviors of VOCs on porous polymeric resins. The results indicated that the dispersive interaction, which is directly related to polarizability of VOCs, was the primary factor influencing the desorption activation energy of VOCs on porous polymeric resins. The find from this study helps evaluate fleetly and availably the desorption properties of VOCs based on their polarizability.


Assuntos
Compostos Orgânicos Voláteis , Compostos Orgânicos Voláteis/química , Porosidade , Polímeros/química , Temperatura , Adsorção
4.
Environ Pollut ; 346: 123603, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38373622

RESUMO

Microplastics, ubiquitous anthropogenic marine pollutants, represent potential threats to coral-Symbiodiniaceae relationships in global reef ecosystems. However, the mechanism underlying the impacts of polystyrene microplastics (PS-MPs) on Symbiodiniaceae remains poorly understood. In this study, the cytological, physiological, and microbial responses of Symbiodinium tridacnidorum, a representative Symbiodiniaceae species, to varying concentrations of PS-MPs (0, 5, 50, 100, and 200 mg L-1) were investigated. The results revealed that microplastic exposure inhibited cell division, resulting in reduced cell density compared to control group. Furthermore, algal photosynthetic activity, as indicated by chlorophyll content, Fv/Fm, and net photosynthetic rate, declined with increasing microplastic concentration up to 50 mg L-1. Notably, elevated levels of microplastics (100 and 200 mg L-1) prompted a significant increase in cell size in S. tridacnidorum. Transmission electron microscopy and fluorescence microscopy indicated that hetero-aggregation was formed between high levels of PS-MPs and algal cells, ultimately causing damage to S. tridacnidorum. Moreover, the impact of PS-MPs exposure on the bacterial community associated with S. tridacnidorum was investigated. The results showed a reduction in alpha diversity of the bacterial community in groups exposed to 50, 100, and 200 mg L-1 of microplastics compared to those treated with 0 and 5 mg L-1. Additionally, the relative abundance of Marinobacter, Marivita, and Filomicrobium significantly increased, while Algiphilus and norank Nannocystaceae declined after microplastic exposure. These findings suggest that MPs can inhibit the growth of S. tridacnidorum and alter the associated bacterial community, posing a potential serious threat to coral symbiosis involving S. tridacnidorum.


Assuntos
Antozoários , Dinoflagellida , Poluentes Químicos da Água , Animais , Microplásticos , Plásticos , Ecossistema , Simbiose , Poluentes Químicos da Água/toxicidade , Poluentes Químicos da Água/análise , Fotossíntese , Poliestirenos , Dinoflagellida/fisiologia , Bactérias
5.
Environ Sci Technol ; 45(10): 4506-12, 2011 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-21488665

RESUMO

A hydrophobic hypercrosslinked polymer with poly (4-tert-butylstyrene-styrene-divinylbenzene) matrix (LC-1) was prepared as adsorbent for the removal of volatile organic compounds from gas streams. The content of oxygen-containing functional groups of LC-1 was about one-fourth that of commercial hypercrosslinked polymeric adsorbent (NDA-201). The results of the water vapor adsorption experiment indicated that LC-1 had a more hydrophobic surface than NDA-201. Three chlorinated volatile organic compounds (trichloroethylene, trichloromethane, and 1, 2-dichloroethane) were used to investigate the adsorption characteristics of LC-1 under dry and humid conditions. Equilibrium adsorption data in dry streams showed that LC-1 had good adsorption abilities for three chlorinated VOCs due to its abundant micropore structure. Moreover, the presence of water vapor in the gas stream had negligible effect on breakthrough time of three chlorinated VOCs adsorption onto LC-1 when values of relative humidity were equal to or below 50%; the breakthrough time of three chlorinated VOCs decreased less than 11% even if the relative humidity was 90%. Taken together, it is expected that LC-1 would be a promising adsorbent for the removal of VOCs vapor from the humid gas streams.


Assuntos
Poluentes Atmosféricos/química , Hidrocarbonetos Clorados/química , Polímeros/química , Compostos Orgânicos Voláteis/química , Gerenciamento de Resíduos/métodos , Adsorção , Poluentes Atmosféricos/análise , Poluição do Ar/prevenção & controle , Clorofórmio/análise , Clorofórmio/química , Reagentes de Ligações Cruzadas/química , Dicloretos de Etileno/análise , Dicloretos de Etileno/química , Umidade , Hidrocarbonetos Clorados/análise , Interações Hidrofóbicas e Hidrofílicas , Modelos Químicos , Tricloroetileno/análise , Tricloroetileno/química , Compostos Orgânicos Voláteis/análise
6.
J Hazard Mater ; 418: 126335, 2021 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-34329011

RESUMO

Water vapor is very common in contaminated streams, which has a great influence on the adsorption of low-concentration volatile organic compounds (VOCs) due to the competition between water and VOCs. Understanding adsorption mechanisms and predicting adsorption of VOCs under different relative humidity (RH) are of great importance to design effective adsorption unit. In this study, we comprehensively investigated the effects of RH on the surface properties of hyper-cross-linked polymeric resin (HPR) and adsorption of 18 VOCs at low concentration on HPR under five levels of RH using inverse gas chromatography (IGC). Further, a promising RH-dependent poly-parameter linear free energy relationships (PP-LFERs) model was developed. It was found that water vapor caused the decrease of surface free energy (γst) of HPR due to the occupation of active sites by water molecules, resulting in the decrease of adsorption partition coefficients (K). Moreover, the γst could accurately quantify the effects of RH on the surface properties of HPR. Therefore, the RH-dependent PP-LFERs model was established by correlating RH and γst. The developed model overcame the limited predictive ability of existing models only under a specific RH level, and excellently predicted the lnK values of VOCs (R2 = 0.944, RMSEt = 0.36 and RMSEv = 0.47) under various RH.


Assuntos
Compostos Orgânicos Voláteis , Adsorção , Cromatografia Gasosa , Umidade , Polímeros
7.
Water Res ; 171: 115437, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31893554

RESUMO

Despite plenty of literatures focused on the application of pre-ozonation prior to membrane, it was still unclear about the role of divalent cations (Ca2+ and Mg2+) in reverse osmosis (RO) membrane fouling mitigation. In this study, ozone pre-treatment (0.10, 0.25 and 0.50 mg O3/mg DOC (dissolved organic carbon)) was employed to oxidize model biopolymer, which was represented by bovine serum albumin (BSA) and sodium alginate (SA) in the presence of Ca2+ and Mg2+ (0.5, 1.0 and 2.0 mM). Cross-flow filtration was conducted to investigate RO membrane fouling by concentration mode. The results showed that at appropriate ozone dose there were measurable changes in physicochemical properties of BSA and SA, including increases in particle size, hydrophilicity, density of negative charge and carboxylic groups. Pre-ozonation markedly alleviated RO fouling by BSA at ozone dose of 0.25 mg O3/mg DOC when Ca2+ and Mg2+ concentrations raised from 0.5 to 2.0 mM since the increase in electrostatic (EL) repulsion and decrease in hydrophobic (HP) interaction compensated the increase in divalent cation bridging. Similar results were obtained for SA fouling in the presence of Mg2+. In contrast, the effect of pre-ozonation on SA fouling strongly depended on the concentration of Ca2+. In brief, it mitigated SA fouling at 0.5 mM Ca2+, whereas accelerated irreversible fouling at higher Ca2+ concentration (1.0 and 2.0 mM) due to the overwhelming effect of divalent cation bridging compared to EL and HP interactions, as revealed by adsorption experiments (in-situ streaming potential measurement). Pre-ozonation shifted the fouling layer from compact to porous and weakened the adhesion forces between foulants and membrane (foulants) except for SA containing 1.0 and 2.0 mM Ca2+. This study may provide the guidance for the application of pre-ozonation prior to RO filtration.


Assuntos
Ozônio , Purificação da Água , Biopolímeros , Membranas Artificiais , Osmose
8.
Water Sci Technol ; 60(6): 1607-14, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19759463

RESUMO

A spherical microporous carbon adsorbent (CR-1), which was developed by carbonization and activation of the waste polysulfonated cation-exchanger, was used to remove Dimethyl phthalate (DMP) and 2, 4-dichlorophenol (2, 4-DCP) as the model compounds of EDCs from the aqueous solution. Four adsorption isotherm models, Langmuir, Freundlich, Toth and Polanyi-Dubinin-Manes equations were tested to correlate the experimental data, Toth and Polanyi-Dubinin-Manes isotherms models provided the best correlation. The Henry's law constants calculated from Toth equation were found to be 705.957 and 6,724.713 L g(-1) for 2, 4-DCP and DMP at 298 K, respectively, and the larger exponents n of the Freundlich model were 9.011 and 9.93 for 2, 4-DCP and DMP at 298 K, respectively. The values of Henry's law constants and exponent n of the Freundlich suggested that CR-1 was an effective adsorbent for removal of low concentrations of DMP and 2, 4-DCP from aqueous solution. Moreover, the adsorption kinetics results showed that adsorption of 2, 4-DCP and DMP on CR-1 was a pseudo-second-order process controlled by intra-particle diffusion and that adsorption uptake reached quickly half of equilibrium capacities within 20 min.


Assuntos
Carbono/química , Disruptores Endócrinos/química , Disruptores Endócrinos/isolamento & purificação , Resinas de Troca Iônica/química , Polímeros/química , Água/química , Adsorção , Clorofenóis/química , Clorofenóis/isolamento & purificação , Difusão , Cinética , Modelos Químicos , Ácidos Ftálicos/química , Ácidos Ftálicos/isolamento & purificação , Porosidade
9.
J Colloid Interface Sci ; 319(1): 12-8, 2008 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-18082173

RESUMO

In this research, naphthalene was adopted as the representative model compound of PAHs, and static adsorption of naphthalene from aqueous solution onto three commercial polymeric adsorbents with different pore structure was investigated. Nonlinear isotherms models, i.e., Freundlich, Langmuir, and Polanyi-Dubinin-Manes (PDM) models were tested to fit experimental data, and the experimental data were found to fit well by the PDM model. Through both isotherm modeling and constructing "characteristic curve," Polanyi theory was useful to describe the adsorption process of naphthalene by polymeric adsorbents, providing evidence that a micropore filling phenomenon was involved during the adsorption process. In addition, a good linear correlation was obtained between the naphthalene adsorption capacities and the micropore volume of adsorbents (Vmicro), whereas no linear relationship was found between the naphthalene adsorption capacities and the specific surface area of adsorbents. Based on the PDM model, the micropore volumes of adsorbents was introduced to normalize the equilibrium adsorbed volume (qv), plots of qv/V(micro) vs adsorption potential density for naphthalene on three different polymeric adsorbents were collapsed to a single correlation curve, which would be of great benefit to predict the adsorption capacity of adsorbent for the purpose of adsorption engineering design.


Assuntos
Adsorção , Modelos Químicos , Naftalenos/química , Polímeros/química , Água/química , Soluções
10.
J Hazard Mater ; 150(3): 656-61, 2008 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-17570583

RESUMO

Polycyclic aromatic hydrocarbons (PAHs) are widespread environmental pollutants that can result in serious health problems and genetic defects in humans. In this research, a spherical microporous carbon adsorbent (CR-1) had been obtained by carbonization and activation of the waste polysulfonated cation exchange resin. Naphthalene was adopted as a model compound to examine the adsorption effectiveness for removing PAHs from the aqueous solution by CR-1. Nonlinear isotherms models, i.e., Freundlich, Langmuir, Brunauer-Emmett-Teller and Polanyi-Dubinin-Manes models were tested to fit experimental data. The adsorption equilibrium data of naphthalene on CR-1 was fitted well by the Polanyi-Dubinin-Manes model. Through both isotherm modeling and constructing "characteristic curve", Polanyi theory was useful to describe the adsorption process of naphthalene by CR-1, providing evidence that a micropore filling phenomenon is involved. In addition, among the tested kinetic models in this study (e.g., pseudo-first-order and pseudo-second-order equations), the pseudo-first-order equation successfully predicted the kinetic adsorption process.


Assuntos
Resinas de Troca de Cátion/química , Naftalenos/química , Poluentes Químicos da Água/química , Purificação da Água/métodos , Adsorção , Carbono/química , Cinética , Poliestirenos/química , Compostos de Vinila/química
11.
Environ Sci Pollut Res Int ; 24(19): 16253-16262, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28540548

RESUMO

Reverse osmosis (RO) is a promising technology for treating and reusing textile secondary effluent (SE). To better understand the effect of membrane surface properties on membrane fouling, the performances of three commercial polyamide thin-film composite RO membranes (BW30-4040, CPA2-4040, and RE-4040-FEN) with different roughness and hydrophilicity were investigated for treating textile SE. The RO membranes were characterized by ATR-FTIR, SEM, AFM, and contact angle, respectively. The results showed that the flux increased with an increase in the surface hydrophilicity of membrane. CPA2-4040 had the highest hydrophilic surface and thus the largest initial flux. There was a strong correlation between the membrane fouling and the surface roughness; the fouling increased with an increase in the surface roughness. The roughest surface of CPA2-4040 led to the most significantly flux decline. However, the fouling reversibility was not related directly to surface roughness. BW30-4040 with the secondary roughness and the most hydrophobic surface had the highest fouling reversibility. This was mainly due to the primary hydrophilicity of textile SE in nature. Fluorescence excitation-emission matrix (EEM) showed that hydrophilic neutral protein-like matters and soluble microbial products (SMP) were the main foulants, thus stronger affinity with hydrophilic surface of membrane. Graphical abstract ᅟ.


Assuntos
Membranas Artificiais , Indústria Têxtil , Purificação da Água , Filtração , Osmose , Propriedades de Superfície
12.
Plast Reconstr Surg ; 139(6): 1305e-1314e, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28538572

RESUMO

BACKGROUND: Decellularized cadaveric tendons are a potential source for reconstruction. Reseeding to enhance healing is ideal; however, cells placed on the tendon surface result in inadequate delivery. The authors used an injection technique to evaluate intratendinous cell delivery. METHODS: Decellularized tendons were reseeded with adipose-derived stem cells in culture, and injected with fetal bovine serum or hydrogel. PKH26-stained cells in cross-section were quantified. To evaluate cell viability, the authors delivered luciferase-labeled cells and performed bioluminescent imaging. To evaluate synthetic ability, the authors performed immunohistochemistry of procollagen. Adipose-derived stem cells' ability to attract tenocytes was assessed using transwell inserts. Cell-to-cell interaction was assessed by co-culturing, measuring proliferation and collagen production, and quantifying synergy. Finally, tensile strength was tested. RESULTS: Both fetal bovine serum (p < 0.001) and hydrogel (p < 0.001) injection led to more cells inside the tendon compared with culturing. Hydrogel injection initially demonstrated greater bioluminescence than culturing (p < 0.005) and fetal bovine serum injection (p < 0.05). Injection groups demonstrated intratendinous procollagen staining correlating with the cells' location. Co-culture led to greater tenocyte migration (p < 0.05). Interaction index of proliferation and collagen production assays were greater than 1 for all co-culture ratios, demonstrating synergistic proliferation and collagen production compared with controls (p < 0.05). There were no differences in tensile strength. CONCLUSIONS: Hydrogel injection demonstrated the greatest intratendinous seeding efficiency and consistency, without compromising tensile strength. Intratendinous cells demonstrated synthetic capabilities and can potentially attract tenocytes inside the tendon, where synergy would promote intrinsic tendon healing. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, V.


Assuntos
Hidrogel de Polietilenoglicol-Dimetacrilato/farmacologia , Traumatismos dos Tendões/cirurgia , Tendões/efeitos dos fármacos , Tendões/transplante , Engenharia Tecidual/métodos , Adipócitos/citologia , Animais , Bovinos , Sobrevivência Celular , Técnicas de Cocultura , Humanos , Injeções Intralesionais , Ratos , Procedimentos de Cirurgia Plástica/métodos , Sensibilidade e Especificidade , Células-Tronco/citologia , Tendões/citologia , Resistência à Tração , Alicerces Teciduais
13.
J Environ Sci (China) ; 14(4): 457-63, 2002 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-12491718

RESUMO

Adsorption equilibrium isotherms of phenolic compounds, phenol, p-cresol, p-chlorophenol and p-nitrophenol, from aqueous solutions by Amberlite XAD-4 polymeric adsorbent and its acetylized derivative MX-4 within temperature range of 283-323K were obtained and fitted to the Freundlich isotherms. The capacities of equilibrium adsorption for all four phenolic compounds from their aqueous solutions increased around 20% on the acetylized resin, which may be contributed to the specific surface area and the partial polarity on the network. Estimations of the isosteric enthalpy, free energy, and entropy for the adsorption process were reported.


Assuntos
Fenóis/química , Poliestirenos/química , Polivinil/química , Poluentes Químicos da Água , Purificação da Água/métodos , Acetilação , Adsorção , Temperatura , Termodinâmica
14.
Environ Sci Pollut Res Int ; 21(5): 3756-63, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24281677

RESUMO

The emission of gasoline vapors is becoming a significant environmental problem especially for the population-dense area and also results in a significant economic loss. In this study, adsorption equilibrium and dynamics of gasoline vapors onto macroporous and hypercrosslinked polymeric resins at 308 K were investigated and compared with commercial activated carbon (NucharWV-A 1100). The results showed that the equilibrium and breakthrough adsorption capacities of virgin macroporous and hypercrosslinked polymeric resins were lower than virgin-activated carbon. Compared with origin adsorbents, however, the breakthrough adsorption capacities of the regenerated activated carbon for gasoline vapors decreased by 58.5 % and 61.3 % when the initial concentration of gasoline vapors were 700 and 1,400 mg/L, while those of macroporous and hypercrosslinked resins decreased by 17.4 % and 17.5 %, and 46.5 % and 45.5 %, respectively. Due to the specific bimodal property in the region of micropore (0.5-2.0 nm) and meso-macropore (30-70 nm), the regenerated hypercrosslinked polymeric resin exhibited the comparable breakthrough adsorption capacities with the regenerated activated carbon at the initial concentration of 700 mg/L, and even higher when the initial concentration of gasoline vapors was 1,400 mg/L. In addition, 90 % of relative humidity had ignorable effect on the adsorption of gasoline vapors on hypercrosslinked polymeric resin. Taken together, it is expected that hypercrosslinked polymeric adsorbent would be a promising adsorbent for the removal of gasoline vapors from gas streams.


Assuntos
Poluentes Atmosféricos/química , Gasolina , Polímeros/química , Adsorção , Poluição do Ar/prevenção & controle , Carbono/química , Umidade , Volatilização
15.
J Hazard Mater ; 203-204: 251-6, 2012 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-22204838

RESUMO

A novel hypercrosslinked polymeric adsorbent (HY-1) with high surface area and specific bimodal pore size distribution in the regions of micropore (0.5-2.0 nm) and meso-macropore (30-70 nm) was prepared. Adsorption properties of benzene and methyl ethyl ketone (MEK) vapors onto HY-1 were investigated and compared with a commercial microporous activated carbon (m-GAC). The equilibrium adsorption data showed that the adsorption capacities of benzene and MEK on HY-1 were larger than those of m-GAC at the higher relative pressure. The Dubinin-Radushkevich (D-R) equation was found to fit the experimental data well. The isosteric enthalpy of adsorption for benzene and MEK were calculated. The m-GAC exhibited much higher values of ΔH(st) for the VOCs than HY-1 at the whole loading studied, which can lead to significant temperature rises during the adsorption step. The results of dynamic experiments revealed that HY-1 had a good dynamic adsorption capacity with a longer breakthrough time and shorter length of mass transfer zone due to its specific bimodal property. Therefore, HY-1 will be a particularly efficient and competitive adsorbent for VOCs recovery, especially at medium-high concentrations.


Assuntos
Benzeno/isolamento & purificação , Butanonas/isolamento & purificação , Carbono/química , Polímeros/química , Compostos Orgânicos Voláteis/química , Adsorção , Termodinâmica
16.
J Hazard Mater ; 193: 149-55, 2011 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-21831521

RESUMO

A copper (II)-bound polymeric ligand exchanger named WH-425-Cu was prepared by loading Cu(2+) onto poly (4-vinylpyridine) resin. The performance of WH-425-Cu as the ligand exchanger to remove arsenate [As (V)] from aqueous solution was also investigated by using static equilibrium and dynamic adsorption experiments. Results of static experiments indicated that WH-425-Cu had higher adsorption selectivity for As (V) than other ubiquitous anions in nature water body such as SO(4)(2-), Cl(-), SiO(3)(2-), and PO(4)(3-). The optimal pH for adsorption of As (V) on WH-425-Cu was in the range of 6.0-8.0. The As (V) adsorbed on WH-425-Cu could be easily eluted with 7 BV of 6% NaCl solution (at pH = 9.0) with elution efficiency above 99%. The prepared WH-425-Cu could be used as a highly selective and reusable ligand exchanger for selective removal of As (V) from water.


Assuntos
Arseniatos/isolamento & purificação , Cobre/química , Polímeros/química , Poluentes Químicos da Água/isolamento & purificação , Adsorção , Concentração de Íons de Hidrogênio , Ligantes
17.
Huan Jing Ke Xue ; 32(9): 2805-9, 2011 Sep.
Artigo em Zh | MEDLINE | ID: mdl-22165255

RESUMO

The dynamic adsorption of trichloroethylene (TCE), 1,2-dichloroethane (DCE) and trichloromethane (TCM) vapors onto hydrophobic hypercrosslinked polymeric resin (LC-1) were investigated using the fixed-bed adsorption method. The results indicated that the breakthrough time decreased and the height of mass transfer zone increased with the elevated initial concentration, gas flow rate and adsorption temperature. The gas flow rate had the wost significant influence on breakthrough time and height of mass transfer zone among the three factors. In addition, a simple semi-empirical mathematic model developed by Yoon and Nelson was applied to investigate the breakthrough behavior, and all correlation coefficients R2 were greater than 0.994.


Assuntos
Poluentes Atmosféricos/isolamento & purificação , Hidrocarbonetos Clorados/isolamento & purificação , Resinas Sintéticas/química , Adsorção , Reagentes de Ligações Cruzadas , Polímeros , Volatilização
18.
J Hazard Mater ; 175(1-3): 111-6, 2010 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-19879689

RESUMO

In the present study, the performance, behavior and mechanism of synthetic poly(2-vinylpyridine) resin (WH-225) adsorbing 5-sodiosulfoisophthalic acids (SIPA) from the aqueous solution were investigated, and two commercial adsorbents, namely, hypercrosslinked adsorbent NDA-100 and macroporous adsorbent XAD-4 were employed as reference. Compared to NDA-100 and XAD-4, WH-225 has the highest capacity for adsorbing SIPA from the aqueous solution, which is verified by the related adsorption experiments. The investigation indicated that electrostatic interaction is an important factor in affecting the adsorption behavior of WH-225. The Freundlich isotherm equation was successfully applied to describe the adsorption isotherms. The negative values of the adsorptive enthalpy changes indicate an exothermic process for WH-225, and the absolute values (<43 kJ mol(-1)) further manifest a physical adsorption process. The column adsorption and desorption tests further proved WH-225 is a promising adsorbent for field applications to remove and recover aromatic acids (e.g. SIPA) from aqueous solution.


Assuntos
Ácidos Ftálicos/química , Polivinil/química , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos , Adsorção , Físico-Química/métodos , Reagentes de Ligações Cruzadas/química , Relação Dose-Resposta a Droga , Modelos Químicos , Nitrogênio/química , Polímeros/química , Eletricidade Estática , Propriedades de Superfície , Termodinâmica , Poluentes Químicos da Água/química
19.
J Hazard Mater ; 166(1): 46-51, 2009 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-19095353

RESUMO

In this research, the adsorption equilibria of trichloroethylene (TCE) and benzene vapors onto hypercrosslinked polymeric resin (NDA201) were investigated by the column adsorption method in the temperature range from 303 to 333 K and pressures up to 8 kPa for TCE, 12 kPa for benzene. The Toth and Dubinin-Astakov (D-A) equations were tested to correlate experimental isotherms, and the experimental data were found to fit well by them. The good fits and characteristic curves of D-A equation provided evidence that a pore-filling phenomenon was involved during the adsorption of TCE and benzene onto NDA-201. Moreover, thermodynamic properties such as the Henry's constant and the isosteric enthalpy of adsorption were calculated. The isosteric enthalpy curves varied with the surface loading for each adsorbate, indicating that the hypercrosslinked polymeric resin has an energetically heterogeneous surface. In addition, a simple mathematic model developed by Yoon and Nelson was applied to investigate the breakthrough behavior on a hypercrosslinked polymeric resin column at 303 K and the calculated breakthrough curves were in high agreement with corresponding experimental data.


Assuntos
Benzeno/isolamento & purificação , Resíduos Industriais/prevenção & controle , Resinas Sintéticas/química , Tricloroetileno/isolamento & purificação , Adsorção , Gases , Modelos Teóricos , Polímeros/química , Pressão , Temperatura , Termodinâmica , Volatilização
20.
J Hazard Mater ; 167(1-3): 589-96, 2009 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-19264406

RESUMO

N,N'-di (carboxymethyl) dithiocarbamate chelating resin (PSDC) was synthesized by anchoring the chelating agent of N,N'-di (carboxymethyl) dithiocarbamate to the chloromethylated PS-DVB (Cl-PS-DVB) matrix, as a new adsorbent for removing divalent heavy metal ions from waste-stream. The physicochemical structures of Cl-PS-DVB and PSDC were elaborately characterized using Fourier transform infrared spectroscopy (FT-IR), elemental analysis (EA), and were further morphologically characterized using BET and BJH methods. The adsorption performances of PSDC towards heavy metals such as Cu(II), Pb(II) and Ni(II) were systematically investigated, based upon which the adsorption mechanisms were deeply exploited. For the above target, the classic batch adsorption experiments were conducted to explore the kinetics and isotherms of the removal processes with pH-value, initial concentration, temperature, and contact time as the controlling parameters. The kinetic and isotherm data could be well elucidated with Lagergren-second-order equation and Langmuir model respectively. The strong affinity of PSDC toward these target soft acids could be well demonstrated with the electrostatic attraction and chelating interaction caused by IDA moiety and sulphur which were namely soft bases on the concept of hard and soft acids and bases (HASB). Thermodynamic parameters, involving DeltaH(o), DeltaS(o) and DeltaG(o) were also calculated from graphical interpretation of the experimental data. The standard heats of adsorption (DeltaH(o)) were found to be endothermic and the entropy change values (DeltaS(o)) were calculated to be positive for the adsorption of Cu(II), Pb(II) and Ni(II) ions onto the tested adsorbents. Negative values of DeltaG(o) indicated that adsorption processes for all tested metal ions onto PSDC were spontaneous.


Assuntos
Cátions Bivalentes/isolamento & purificação , Dimetilditiocarbamato/análogos & derivados , Metais Pesados/isolamento & purificação , Purificação da Água/métodos , Adsorção , Quelantes/química , Dimetilditiocarbamato/química , Concentração de Íons de Hidrogênio , Cinética , Resinas Sintéticas/química , Temperatura , Termodinâmica , Poluentes da Água/isolamento & purificação
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