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1.
J Agric Food Chem ; 68(5): 1248-1256, 2020 Feb 05.
Artículo en Inglés | MEDLINE | ID: mdl-31927921

RESUMEN

Lipophenols are regarded as an emerging source of functional food ingredients. However, little is known about their in vivo digestion, absorption, and metabolism. Thus, the pharmacokinetic characteristics in rat and the gut microbial degradation of tyrosol acyl esters (TYr-Es) with fatty acids of C12:0, C18:0, and C18:2 were investigated for the first time. Major metabolites including tyrosol sulfate and tyrosol glucuronide, rather than the parent compounds, were detected in rat plasma after oral administration of TYr-Es. The increased plasma half-life (T1/2) and mean residence time demonstrated that TYr-Es display a longer duration of action in vivo than TYr, potentially leading to higher oral bioavailability. TYr-Es could be hydrolyzed by the gut microbiota to free TYr, which may result in the appearance of the second absorption peak in pharmacokinetic profiles. Therefore, TYr-Es exhibit improved bioavailability compared to that of TYr because of their prolonged duration of action.


Asunto(s)
Ésteres/farmacocinética , Alcohol Feniletílico/análogos & derivados , Animales , Disponibilidad Biológica , Ésteres/química , Ácidos Grasos/sangre , Ácidos Grasos/química , Cinética , Masculino , Alcohol Feniletílico/química , Alcohol Feniletílico/farmacocinética , Plasma/química , Ratas , Ratas Sprague-Dawley
2.
J Agric Food Chem ; 68(5): 1373-1381, 2020 Feb 05.
Artículo en Inglés | MEDLINE | ID: mdl-31927950

RESUMEN

Most of the microorganisms can form biofilms, which makes biofilms an abundant bioresource to be exploited. Due to the limitations of the application of current immobilization methods for biofilms, we developed an immobilization method called the biofilm polysaccharide display (BPD) strategy while maintaining the native biofilm structure and catalytic microenvironment of Clostridium acetobutylicum B3. Lipase Lip181 showed significant improvements in stability after chemical immobilization. For example, immobilized Lip181 retained 74.23% of its original activity after incubation for 14 days, while free Lip181 was totally deactivated. In addition, immobilized Lip181 maintained high residual activity (pH 5.0-11.0), which showed improved resistance to pH changes. Notably, this method did not decrease but slightly increased the relative activity of Lip181 from 6.39 to 6.78 U/mg. Immobilized Lip181 was used to prepare cinnamyl acetate, and it showed a maximum yield of 85.09%. Overall, this biofilm immobilization method may promote the development of biocatalytic and biofilm materials.


Asunto(s)
Materiales Biocompatibles/química , Biopelículas , Clostridium acetobutylicum/química , Lipasa/metabolismo , Polisacáridos/química , Biocatálisis , Clostridium acetobutylicum/fisiología , Estabilidad de Enzimas , Enzimas Inmovilizadas/química , Enzimas Inmovilizadas/metabolismo , Concentración de Iones de Hidrógeno , Cinética , Lipasa/química , Polisacáridos/metabolismo
3.
Chem Commun (Camb) ; 56(8): 1187-1190, 2020 Jan 25.
Artículo en Inglés | MEDLINE | ID: mdl-31922177

RESUMEN

Trimethylamine N-oxide is found to be effective in regulating the interaction between microtubules and kinesins over a wide temperature range. The lifetime of the motility of microtubules on kinesins at high temperatures is prolonged using trimethylamine N-oxide. The activation energy of microtubule motility is increased by trimethylamine N-oxide. Prolonged operation at high temperatures decreased the activation energy of MT motility despite the increase in concentration of trimethylamine N-oxide.


Asunto(s)
Cinesina/metabolismo , Metilaminas/farmacología , Microtúbulos/metabolismo , Temperatura Ambiental , Cinesina/química , Cinética , Metilaminas/química , Microtúbulos/química
4.
J Phys Chem Lett ; 11(3): 877-884, 2020 Feb 06.
Artículo en Inglés | MEDLINE | ID: mdl-31931562

RESUMEN

BODIPY chromophores can serve as organic-based triplet photosensitizers for a wide range of applications. To perform this function, the formation of the triplet state is critical, and a better understanding of how to modulate the formation of the triplet state could lead to further advances in BODIPY-based sensitizers for solar energy conversion and photodynamic therapy. In this work we investigate the ability of halogen bonding, a noncovalent solvent interaction, to facilitate intersystem crossing in a diiodo-BODIPY. Ultrafast transient absorption spectroscopy is applied to diiodo-BODIPY in the presence of pyridine-based halogen bonding solvent molecules to determine the rate constants for intersystem crossing. We find that halogen bonding facilitates the formation of the triplet state by increasing the intersystem crossing rate constant of diiodo-BODIPY. The results are interpreted in terms of the Marcus expression for intersystem crossing. Quantum chemical calculations show that halogen bonding acts to alter both the spin-orbit coupling terms and the relative energetics of the singlet and triplet states.


Asunto(s)
Compuestos de Boro/química , Halógenos/química , Cinética , Piridinas/química , Teoría Cuántica , Solventes/química
5.
Bioresour Technol ; 301: 122732, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-31972399

RESUMEN

In this work, the thermal degradation behaviors of two kinds of biomasses (pinewood and rice husk) with powder and pellet under three oxygen concentrations were investigated by a self-designed macro-thermogravimetric analyzer. An obvious hysteresis of thermal degradation of biomass pellets was observed under three conditions. The maximum activation energy of biomass pellets was significantly greater than that of biomass powders, while their average activation energies were almost equal based on distributed activation energy model. For the oxygen-rich combustion, the comprehensive combustion character index of powdered and pelletized biomasses ranged from 3.92 × 10-7 to 5.16 × 10-7%2·min-2·°C-3 and from 1.82 × 10-7 to 1.91 × 10-7%2·min-2·°C-3, respectively. Furthermore, the derived biochar of powdered biomass has a higher caloricity than that of pelletized biomass during combustion by TG-DSC analysis. The performances of thermal degradation observed by macro-thermogravimetric analyzer could factually reveal the influence of mass and heat transfer on the thermochemical conversion of powdered and pelletized biomasses.


Asunto(s)
Calor , Biomasa , Cinética , Polvos , Termogravimetría
6.
J Environ Manage ; 258: 110038, 2020 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-31929071

RESUMEN

Heavy metals are classified as persistent pollutants owing to their nature of bioaccumulation and affect human life and environment, even in minor concentrations. Divalent Cadmium (Cd2+) is one of the heavy metal pollutants that are highly toxic. The present study investigates the novel application of maghemite nanoparticles coated Bacillus subtilis for the removal of Cd2+ ions from its aqueous solution by batch adsorption studies. Surface characterization of the biosorbent done by Scanning Electron Microscope (SEM) and the presence of maghemite nanoparticle coat was confirmed. Parameters like pH, initial metal ion concentration, contact time, and temperature that affect the biosorption of cadmium ions are analyzed, and the equilibrium adsorption capacity expressed as a function of each of the parameters. The mechanism of biosorption was studied by plotting adsorption isotherms, and it follows pseudo-second-order kinetics. Thermodynamic studies showed the process to be spontaneous and endothermic. At optimum conditions of pH 4, 30 °C, 120 rpm, maximum removal percentage of 83.5%, which accounts for an equilibrium adsorption capacity of 32.6 mg/g of biosorbent. There was a recovery of 76.4% of the biosorbent after adsorption studies. Based on the adsorptive capacity and good recovery of the biosorbent, maghemite coated Bacillus subtilis proves to be an efficient adsorbent for the removal of Cd2+ ions from its aqueous solution.


Asunto(s)
Nanopartículas , Contaminantes Químicos del Agua , Adsorción , Bacterias , Cadmio , Compuestos Férricos , Concentración de Iones de Hidrógeno , Cinética , Temperatura Ambiental , Termodinámica
7.
Water Res ; 171: 115438, 2020 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-31896029

RESUMEN

Targeted inactivation of bacteria using bacteriophages has been proposed in applications ranging from bioengineering and biofuel production to medical treatments. The ability to differentiate between desirable and undesirable organisms, such as in targeting filamentous bacteria in activated sludge, is a potential advantage over conventional disinfectants. Like conventional disinfectants, bacteriophages exhibit non-linear concentration-time (Ct) dynamics in achieving bacterial inactivation. However, there is currently no workable model for predicting these observed non-linear inactivation rates. This work considers an approach to predicting bacteriophage-induced inactivation rates by utilizing classical particle aggregation theory. Bacteriophage-bacteria interactions are represented as a two-step process of transport by Brownian motion, differential settling, and shear, followed by attachment. Modifying classical expressions for particle-particle aggregation to include bacterial growth, death, and bacteriophage reproduction, the model was calibrated and validated using literature data. The calibrated model captures much of the observed non-linearity in inactivation rates and reasonably predicts the final host concentration. This model was shown to be most useful in systems more likely to reflect an industrial setting, where the initial multiplicity of infection, or MOI (the ratio of bacteriophage to host organisms), was 1 or greater. For systems of an initial MOI of less than 1 the model showed increased sensitivity to changes in input parameters and a less pronounced ability to reasonably predict inactivation rates.


Asunto(s)
Bacteriófagos , Desinfectantes , Escherichia coli , Cinética , Aguas del Alcantarillado
8.
Water Res ; 171: 115451, 2020 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-31901682

RESUMEN

Endoxifen is an effective metabolite of a common chemotherapy agent, tamoxifen. Endoxifen, which is toxic to aquatic animals, has been detected in wastewater treatment plant (WWTP) effluent. This research investigates ultraviolet (UV) radiation (253.7 nm) application to degrade (E)- and (Z)-endoxifen in water and wastewater and phototransformation by-products (PBPs) and their toxicity. The effects of light intensity, pH and initial concentrations of (E)- and (Z)-endoxifen on the photodegradation rate were examined. Endoxifen in water was eliminated ≥99.1% after 35 s of irradiation (light dose of 598.5 mJ cm-2). Light intensity and initial concentrations of (E)- and (Z)-endoxifen exhibited positive trends with the photodegradation rates while pH had no effect. Photodegradation of (E)- and (Z)-endoxifen in water resulted in three PBPs. Toxicity assessments through modeling of the identified PBPs suggest higher toxicity than the parent compounds. Photodegradation of (E)- and (Z)-endoxifen in wastewater at light doses used for disinfection in WWTPs (16, 30 and 97 mJ cm-2) resulted in reductions of (E)- and (Z)-endoxifen from 30 to 71%. Two of the three PBPs observed in the experiments with water were detected in the wastewater experiments. Therefore, toxic compounds are potentially generated at WWTPs by UV disinfection if (E)- and (Z)-endoxifen are present in treated wastewater.


Asunto(s)
Rayos Ultravioleta , Contaminantes Químicos del Agua , Animales , Cinética , Fotólisis , Tamoxifeno/análogos & derivados , Agua
9.
Pharm Res ; 37(2): 28, 2020 Jan 07.
Artículo en Inglés | MEDLINE | ID: mdl-31912250

RESUMEN

PURPOSE: This study aims to conduct an impact investigation in the hydrophobic-hydrophilic balance as an important factor for dissolution improvement of a hydrophilic carrier-based solid dispersion system. METHODS: Polymeric carriers with different hydrophobic to hydrophilic ratios were used to prepare several electrospun solid dispersion formulations. Physicochemical properties and surface morphology of the samples were assessed using Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR), polarized light microscopy, Differential Scanning Calorimetry (DSC), X-ray Powder Diffraction (XRPD) and Scanning Electron Microscopy (SEM). Dissolution study was conducted in a non-sink condition to assess the drug release. RESULTS: Incorporation of a higher amount of hydrophilic component showed an improvement in formulating a fully amorphous system based on XRPD, yet the dissolution rate increment showed no significant difference from the lower. Hence, the degree of crystallinity is proven not to be the crucial factor contributing to dissolution rate improvement. The presence of a concomitant hydrophobic component, however, showed ability in resisting precipitation and sustaining supersaturation. CONCLUSION: Hydrophobicity in a binary carrier system plays an important role in achieving and maintaining the supersaturated state particularly for an amorphous solid dispersion. Graphical Abstract.


Asunto(s)
Antimaláricos/química , Atovacuona/química , Portadores de Fármacos/química , Polivinilos/química , Povidona/química , Cristalización , Composición de Medicamentos , Liberación de Fármacos , Concentración de Iones de Hidrógeno , Interacciones Hidrofóbicas e Hidrofílicas , Cinética , Solubilidad , Solventes/química
10.
Pharm Res ; 37(2): 29, 2020 Jan 08.
Artículo en Inglés | MEDLINE | ID: mdl-31915934

RESUMEN

PURPOSE: To speed up the drug development process in the biopharmaceutical industry, high throughput methods are indispensable for assessing drug candidates and potential lead formulations, in particular during late stages of discovery and early phases of development. This study aimed to establish a bio-layer-interferometry based high throughput assay for assessing formulation dependent mAb self-interaction (SI-BLI) and to compare the results with kD values obtained by dynamic light scattering (DLS). METHODS: Self-interaction of proprietary and commercially available mAbs was analyzed by SI-BLI and dynamic light scattering (DLS). RESULTS: We found significant correlations of the SI-BLI results and kD-values obtained by DLS for both, different mAbs in one platform formulation and for mAbs formulated in several buffer compositions. In total, we assessed self-interaction propensity of different mAbs in 58 formulations and found significant Pearson correlation (p < 0.05) between kD and results of SI-BLI. CONCLUSIONS: The SI-BLI results correlate with kD and enable fast ranking of both different drug candidates and potential lead formulations. Thus, SI-BLI might decrease the risk to lose potent mAb candidates during transition from discovery to development, and help to accelerate the development of high concentration liquid formulations.


Asunto(s)
Adalimumab/química , Omalizumab/química , Composición de Medicamentos , Ensayos Analíticos de Alto Rendimiento , Humanos , Interferometría/métodos , Cinética , Unión Proteica , Conformación Proteica , Multimerización de Proteína
11.
Bioresour Technol ; 300: 122700, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-31918293

RESUMEN

The objective of this study was to evaluate pyrolysis and co-pyrolysis behavior of cellulose and poly(methyl methacrylate) (PMMA) and examine the kinetics of the processes by using thermogravimetric analysis (TGA) coupled with FT-IR spectrometry. For this purpose, non-isothermal experiments were carried out using different heating rates and three prominent iso-conversional methods were used to obtain kinetic parameters at various extents of conversions from 0.1 to 0.9. Blending PMMA with cellulose had a marked effect on the process. The results of co-pyrolysis using a blending ratio of 50 wt% PMMA indicated that the highest rate of pyrolytic transformation was achieved at a conversion degree of 0.5 while activation energy ranged from 188.1 to 364.3 kJ/mol. The most intensive gas release during cellulose pyrolysis was CO2. Co-pyrolysis was more complicated than that of pyrolysis of cellulose and PMMA due to depolymerization and radical interactions.


Asunto(s)
Celulosa , Polimetil Metacrilato , Cinética , Pirólisis , Espectroscopía Infrarroja por Transformada de Fourier , Termogravimetría
12.
Bioresour Technol ; 300: 122660, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-31918301

RESUMEN

In this study, anaerobic digestion (AD) of hazelnut (Corylus colurna) husks (HH) was investigated by NaOH pretreatment at 1-6% w/w concentrations. The highest methane yield was 278.45 ± 7.85 mL/g volatile solid (VS), and this was obtained in a 4% NaOH pretreated reactor. In this reactor, the methane yield increased by 162.2% compared to that in the control. The concentrations of volatile fatty acids (VFAs) varied during the digestion process according to the different NaOH pretreatment results. The highest lignosellulosic solubilizations were obtained in a 6% NaOH pretreated reactor. Furthermore, in the second part of kinetic studies, it was defined critical points for cumulative methane yield (CMY) in the Logistic model (LM). These points were the absolute acceleration point (PAA), maximum acceleration point (PAM), inflection point (PI), maximum deceleration point (PDM), and asymptotic deceleration point (PDA). Using these points on the CMY curves, the AD process of HH was mathematically interpreted and explained.


Asunto(s)
Corylus , Anaerobiosis , Biocombustibles , Cinética , Modelos Logísticos , Metano
13.
Bioresour Technol ; 300: 122630, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-31923874

RESUMEN

This study aimed to quantify the catalytic effects of CaO, Fe2O3, and their blend on the Lentinus edodes stipe (LES) and pileus (LEP) combustion performances, kinetics and emissions in bioenergy generation. Apparent activation energy (Ea) of LES and LEP increased with CaO, decreased with Fe2O3 and differed with their blend. The catalysts mainly affected the maximum intensity of volatiles combustion and partly the fixed carbon combustion. CaO, Fe2O3, and their blend decreased the release intensity of NOx from the LES combustion. Fe2O3 increased SO2 emission, while CaO, and the blend narrowed the emission temperature to the range of 200 to 450 °C. Kinetic triplets were estimated via the integral master-plots methods, and the best-fit reaction for the three sub-stages were obtained coupled with the model-free models. Our study provides a reference for the catalyzed biomass combustion in terms of pollution control, bioenergy generation, optimal design of incinerator, and industrial-scale application.


Asunto(s)
Contaminantes Atmosféricos , Hongos Shiitake , Catálisis , Incineración , Cinética , Temperatura Ambiental
14.
Bioresour Technol ; 300: 122705, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-31926472

RESUMEN

Adsorption is an efficient and low-cost technology used to purify volatile organic compounds (VOCs). In the current study, novel microbial adsorbents were synthesized using cells of lyophilized fungi (Ophiostoma stenoceras LLC) or bacteria (Pseudomonas veronii ZW) that were modified by aminomethylation. Based on the adsorption performance and structural characterization results, the modified fungal biosorbent was the best. Its maximum adsorption capacities for ethyl acetate, α-pinene, and n-hexane were 620, 454, and 374 mg·g-1, respectively, which were much higher than those of other synthesized biosorbents. The specific surface area of the fungal biosorbent was 20 m2·g-1, and most of the components were hydrocarbon compounds and polysaccharides. The VOC adsorption process on these synthesized biosorbents was in accordance with the Langmuir isothermal model and the pseudo-first-order kinetic model, thereby suggesting that physical adsorption was the dominant mechanism. The fungal biosorbent could be used for five consecutive VOC sorption-desorption cycles without any obvious decrease in adsorption capacity.


Asunto(s)
Compuestos Orgánicos Volátiles , Contaminantes Químicos del Agua , Adsorción , Biomasa , Hongos , Concentración de Iones de Hidrógeno , Cinética
15.
Bioresour Technol ; 300: 122707, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-31926473

RESUMEN

High concentrations of antibiotics in swine wastewater pose potentially serious risks to the environment, human and animal health. Identifying the mechanism for removing antibiotics during the anaerobic treatment of swine wastewater is essential for reducing the serious damage they do to the environment. In this study, batch experiments were conducted to investigate the biosorption and biodegradation of tetracycline and sulfonamide antibiotics (TCs and SMs) in anaerobic processes. Results indicated that the removal of TCs in the anaerobic reactor contributed to biosorption, while biodegradation was responsible for the SMs' removal. The adsorption of TCs fitted well with the pseudo-second kinetic mode and the Freundlich isotherm, which suggested a heterogeneous chemisorption process. Cometabolism was the main mechanism for the biodegradation of SMs and the process fitted well with the first-order kinetic model. Microbial activity in the anaerobic sludge might be curtailed due to the presence of high concentrations of SMs.


Asunto(s)
Aguas Residuales , Contaminantes Químicos del Agua , Adsorción , Anaerobiosis , Animales , Antibacterianos , Biodegradación Ambiental , Cinética , Aguas del Alcantarillado , Porcinos
16.
Bioresour Technol ; 300: 122708, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-31926474

RESUMEN

Microbially-aged hydrochar were prepared to investigate how aging affected their ability to remove Cd2+ from aqueous solutions. Based on aging time in an anaerobic fermenter, four samples were produced: HC, M20-HC, M40-HC, and M60-HC. Results indicated increases in specific surface area, pH, and negative charge on hydrochar surface with aging process. Also, there were a decrease in O/C and an increase in surface functional groups, such as -COOH. The adsorption experiments confirmed the positive correlation between aging time and adsorption performance. The 60-day-aged M60-HC treatment displayed the maximum adsorption capacity, which was 3.8 times higher than that of HC. The Langmuir and pseudo-second-order kinetic equations fitted well with isothermal and kinetic data, respectively. Thermodynamic study indicated that Cd2+ adsorption is dominated by chemisorption. This study showed that microbial aging process is an effective and promising measure to improve hydrochar adsorption capacity for Cd2+.


Asunto(s)
Cadmio , Contaminantes Químicos del Agua , Adsorción , Carbón Orgánico , Concentración de Iones de Hidrógeno , Cinética , Termodinámica
17.
Bioresour Technol ; 301: 122619, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-31931333

RESUMEN

This work studies the chemical kinetics of wood pyrolysis by comparing nine reduced reaction schemes against 22 microscale experiments of softwood and hardwood from the literature. The complexity of reaction schemes ranged from 1 to 12 reactions, with 2 to 7 species. Using multi-objective optimization for isothermal and non-isothermal conditions, the kinetic parameters for each reaction scheme were derived. It was found that the uncertainty of a prediction increases with the number of model parameters, but the accuracy does not always increase with the number of parameters. The appropriate reaction scheme for hardwood is three parallel reactions, as it presents the optimal balance between accuracy and uncertainty. For softwood, a higher complexity could be justified. This work shows the benefits of finding an appropriately complex kinetic scheme by building up complexity from simple schemes.


Asunto(s)
Pirólisis , Madera , Cinética
18.
J Environ Manage ; 256: 109943, 2020 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-31989978

RESUMEN

Magnetic graphene oxide-titanate composites (MGO@TNs) were synthesized via growing titanate nanosheets on the graphene oxide sheets with magnetite nanoparticles anchored on. The as-prepared MGO@TNs showed a hierarchical structure and large specific surface area (193.4 m2/g), which were suitable for rapid and effective adsorption of Pb(II) from wastewater. Moreover, the loaded magnetite nanoparticles guaranteed the effective magnetic separation of MGO@TNs, avoiding secondary pollution. The adsorption mechanism were illuminated to be ion exchange and surface complexation. Batch adsorption experiments showed the maximum adsorption capacity of MGO@TNs reached 322.7 mg/g for Pb(II) removal. The removal efficiency retained 89.6% after six adsorption-desorption cycles. In addition, the efficiency reached up to 99.8% when applying MGO@TNs for removal of Pb(II) from simulated realistic battery wastewater, ensuring the safe discharge of treated water. The good adsorption performance, recyclability and easy magnetic separation ability made sure that the MGO@TNs has great potential for purification of Pb(II) contaminated wastewater.


Asunto(s)
Contaminantes Químicos del Agua , Purificación del Agua , Adsorción , Grafito , Cinética , Plomo , Fenómenos Magnéticos , Aguas Residuales
19.
J Environ Manage ; 256: 109959, 2020 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-31989982

RESUMEN

Cd2+ pollution in aquatic environments can pose a serious threat to human health. Biochar can remove Cd2+ from aquatic environments, but the Cd2+adsorption capacity of conventional biochar is low, therefore, we focused on exploring the Cd2+ adsorption capacity of modified biochar. In this study, KMnO4 was used to modify vermicompost biochar (VBC), and static adsorption tests for Cd2+ were carried out. The biochar properties and its adsorption efficiency toward Cd2+ before and after modification were studied by kinetics and isotherm model fitting, scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS), Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). Additionally, an adsorption mechanism was discussed. The results showed that the KMnO4-modification resulted in a successful loading of the vermicompost biochar with MnO2, which greatly improved its adsorption capacity for Cd2+. The adsorption of Cd2+ by VBC and MVBC was a spontaneous, endothermic, and monolayer chemical adsorption process. Mineral precipitation mechanism accounted for the largest proportion, and CdCO3 was the main precipitate. After modification the proportion of surface precipitation and other mechanisms (π-electron coordination and the inner/outer sphere surface coordination) increased,while adsorption via cation exchange, oxygen-containing functional groups, physical adsorption and electrostatic attraction reduced. Hence, KMnO4 modification has a significant effect on the Cd2+ adsorption behavior of vermicompost biochar.


Asunto(s)
Cadmio , Contaminantes Químicos del Agua , Adsorción , Carbón Orgánico , Cinética , Compuestos de Manganeso , Óxidos , Espectroscopía Infrarroja por Transformada de Fourier
20.
J Environ Manage ; 256: 109969, 2020 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-31989986

RESUMEN

This study reports a new inorganic-organic composite membrane fabricated by an electrostatic self-assembling method. The low-cost and eco-friendly porous geopolymer (PG) was chosen as a support, on which chitosan (CS), a "green" biomaterial, was used to form an active layer. With optimum dosage of CS (2.0 mL of 1.0% CS solution), the obtained CS/PG membrane exhibited a high porosity of 50.97% with an average pore diameter of 13.93 nm as well as a high water flux of 1663.82 ± 22.46 L/m2·h·bar. The effects of initial concentration, pH, flow rate and temperature of the feed solution on crystal violet (CV) removal by the CS/PG were evaluated in a continuous mode. The results indicated ~95% CV could be removed from water during continuous treating of 14 h. The effectiveness in CV removal by the CS/PG membrane was attributed to the synergistic effect of rejection and adsorption. Furthermore, the composite membrane could be easily regenerated for prolonged use. Overall, this work opens a new possibility of building cost-saving and eco-friendly composite membranes for practical applications in water purification.


Asunto(s)
Quitosano , Contaminantes Químicos del Agua , Purificación del Agua , Adsorción , Concentración de Iones de Hidrógeno , Cinética
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