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1.
Chemosphere ; 262: 127596, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-32791364

RESUMEN

Herein, we have designed and synthesized a metal-organic framework (MOF)-like lanthanum-methanoate (LaMe) nanocomplex for the remediation of arsenate (AsO43-) from aqueous environment, in which AsO43- replaces the formic acid from LaMe through ligand exchange, partially disintegrates the crystal lattice, and is re-precipitated as LaAsO4. Consequently, the sucrose-derived biomass carbon (SBC) was utilized as supporting material to develop nanohybrid of LaMe@SBC to inhibit the solubility of lanthanum from LaMe, and enhance the adsorption ability towards AsO43- from water. The maximum adsorption densities of AsO43- on SBC and LaMe were (0.059 and 0.793) mmol/g, respectively. On the other hand, the synergistically re-constructed LaMe@SBC nanohybrid possesses AsO43- adsorption density of 0.918 mmol/g at 25 °C. The studies, including contact time, solution pH, competitive anions, and initial AsO43- concentration, were optimized for maximum AsO43- removal. The adsorption density of the LaMe@SBC for AsO43- removal was pH-dependent, and possesses the maximum adsorption density at pH (4.0 and 5.0); moreover, the removal process was highly selective in the presence of common co-existing anions, except PO43- ion. The adsorption isotherm and kinetics of the LaMe@SBC nanohybrid closely fitted the Langmuir isotherm and pseudo-second-order kinetic models, respectively. The surface interactions among the LaMe@SBC nanohybrid and AsO43- were revealed through FTIR and PXRD analyses. The adsorption of AsO43- on the LaMe@SBC nanohybrid was primarily a chemisorption, namely ligand exchange and electrostatic interactions. The results reported in this research work highlight the feasibility of the LaMe@SBC nanohybrid as a real adsorbent for the removal of AsO43- from aqueous environment.


Asunto(s)
Arseniatos/química , Lantano/química , Contaminantes Químicos del Agua/química , Purificación del Agua/métodos , Adsorción , Arseniatos/análisis , Biomasa , Carbono , Concentración de Iones de Hidrógeno , Cinética , Sacarosa , Agua/química , Contaminantes Químicos del Agua/análisis
2.
Chemosphere ; 262: 127801, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-32791366

RESUMEN

In this study, cost-effective cellulosic biomass based activated wood charcoal was developed from Japanese Sugi tree (Cryptomeria japonica) by concentrated nitric acid modification for adsorption of Cs from contaminated water. The physicochemical properties of specimens were investigated using N2 adsorption-desorption isotherms (BET method), FESEM, FTIR, and XPS spectra analysis. The experimental results revealed that the surface area of the raw wood charcoal was significantly decreased after boiling nitric acid modification. However, several oxygen-containing acidic function groups (-COOH, -CO) were introduced on the surface. The adsorption study confirmed that the equilibrium contact time was 1 h, the optimum adsorption pH was neutral to alkaline and the suitable adsorbent dose was 1:100 (solid: liquid). The maximum Cs was removed when the concentration of Na and K were lower (5.0 mM) with Cs in solution. The Cs adsorption processes well approved by the Langmuir isotherm and pseudo-second-order kinetic models and the maximum adsorption capacity was 35.46 mgg-1. The Cs adsorption mechanism was clearly described and it was assumed that the adsorption was strongly followed by chemisorptions mechanism based on the adsorbent surface properties, kinetic model and Langmuir isotherm model. Most importantly, about 98% of volume reduction was obtained by burning (500 °C) the Cs adsorbed charcoal, which ensured safe storage and disposal of radioactive waste. Therefore, this study can offer a guideline to produce a functional adsorbent for effective Cs removal and safe radioactive waste disposal.


Asunto(s)
Cesio/química , Contaminantes Químicos del Agua/química , Madera/química , Adsorción , Biomasa , Carbón Orgánico/química , Concentración de Iones de Hidrógeno , Cinética , Ácido Nítrico , Propiedades de Superficie , Contaminantes Químicos del Agua/análisis , Contaminación del Agua/análisis
3.
Chemosphere ; 262: 127797, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-32799143

RESUMEN

Paraquat (PQ) pollution has become an increasing seriously threat to the ecological environment. Thus, it is vital to study novel adsorption materials capable of removing PQ. Modified carbon tubes (MCT-600) were prepared by carbonizing the seed hair fibers of Metaplexis japonica at 600 °C and further modifying with nitric acid. The MCT-600 was found to possess a regular morphology, a good graphitization degree and an abundance of carboxyl functional groups. Moreover, this materil exhibits excellent adsorption performance for paraquat (PQ), such as a fast adsorption rate (adsorption equilibrium within 20 min), large adsorption capacity (218.61 mg g-1) and good regeneration ability (reused more than 5 times). The adsorption process for PQ onto MCT-600 was found to be well matched to a Langmuir isotherm and pseudo-second-order kinetics model. Owing to its unique surface properties, green raw material source and simple preparation process, MCT-600 shows potential as an outstanding candidate for PQ removal from water.


Asunto(s)
Carbono/química , Paraquat/química , Contaminantes Químicos del Agua/química , Adsorción , Biomasa , Cinética , Propiedades de Superficie , Agua , Contaminantes Químicos del Agua/análisis
4.
Chemosphere ; 262: 127895, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-32799151

RESUMEN

In order to improve the adsorption efficiency of ammonia nitrogen in low temperature wastewater, the modified activated carbon (Fe-AC) was prepared by impregnation-calcination modification of Fe(NO3)3. The characterization results indicated that the total pore volume, specific surface area and the point of zero charge of activated carbon increased after modification. A better adsorption effect was achieved under neutral condition than under alkaline or acidic condition. The effect of Ca2+ on competitive adsorption of NH4+ was greater than that of Na+ when both cations were present. Pseudo-first-order kinetic model was confirmed to be consistent with Fe-AC adsorption kinetic data, and Langmuir model was consistent with adsorption isotherm data. The adsorption thermodynamics demonstrated that the ammonia nitrogen adsorption process by Fe-AC was spontaneous and low-temperature was helpful to improve the adsorption capacity. The mechanism of adsorption of ammonia nitrogen by Fe-AC was the comprehensive effect of physical adsorption and chemical adsorption, which was the essential reason for improving the adsorption efficiency of ammonia nitrogen by Fe-AC at a low temperature. This research offered a new way for the modification of activated carbon and a new method for the removal of ammonia nitrogen at a low temperature.


Asunto(s)
Amoníaco/química , Carbón Orgánico/química , Aguas Residuales/química , Contaminantes Químicos del Agua/química , Adsorción , Frío , Hierro/química , Cinética , Nitrógeno/química , Temperatura , Termodinámica , Contaminantes Químicos del Agua/análisis
5.
Chemosphere ; 262: 127901, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-32805660

RESUMEN

In this work, Lysinibacillus sp. JLT12 was used to remove the Cr(VI)-induced passive layer on the magnetite. Mechanism study via dynamic kinetics, X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy analyses revealed that Lysinibacillus sp. JLT12 could remove the passive layer (lepidocrocite and goethite) to facilitate the further Cr(VI) reduction by magnetite. For large-scale applications, porous ceramsite (PC) was prepared with magnetite, kaolin, and fallen leaves. Lysinibacillus sp. was then immobilized on the holes in PC. Slow-released nutrients were added to immobilized porous ceramsite (IM-PC) at a ratio of 1.5:10 (g/g) to supply carbon, nitrogen, and phosphorus to Lysinibacillus sp. JLT12 with low secondary pollution. The performance of IM-PC was evaluated via a column experiment. The results indicate that, in the presence of Lysinibacillus, the break-through time and maximum adsorption ability of IM-PC were 11.67 h and 121.47 mg/g, respectively. These values are higher than those of PC. Additionally, break-through curves detected at 5, 10, and 15 days demonstrated that the usage life of IM-PC was significantly longer than that of PC.


Asunto(s)
Cromo/química , Óxido Ferrosoférrico/química , Contaminantes Químicos del Agua/química , Adsorción , Bacillus , Biodegradación Ambiental , Carbono , Cromo/análisis , Compuestos Férricos , Concentración de Iones de Hidrógeno , Cinética , Espectroscopía de Fotoelectrones , Contaminantes Químicos del Agua/análisis , Difracción de Rayos X
6.
Chemosphere ; 262: 128322, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-32962838

RESUMEN

The presence of emerging contaminants such as pharmaceuticals in aquatic means presents as a serious threat, since their real consequences for the environment and human health are not well known. Therefore, this work consisted of preparing and characterize sludge-derived activated carbons (beverage sludge activated carbon - BSAC and acid-treated beverage sludge activated carbon - ABSAC) to investigate their use in the pharmaceuticals adsorption in aqueous media. The morphology study has demonstrated that ABSAC, unlike BSAC, exhibited an abundant porous structure, with smaller particles and bigger roughness. Adsorption results indicated that the ABSAC was more effective that BSAC, since it presented superior surface area (642 m2 g-1) and total pore volume (0.485 cm3 g-1) values. Pseudo-second-order kinetic model was more suitable to predict experimental data. Sips model best described the equilibrium data, with maximum adsorption capacities of 145, 105, and 57 mg g-1 for paracetamol, ibuprofen, and ketoprofen, respectively. Besides, the sludge-derived adsorbent was highly efficient in the treatment of a simulated drug effluent, removing 85.16% of the pharmaceutical compounds. Therefore, the material prepared in this work possesses intrinsic characteristics that make it a remarkable adsorbent to be applied in the treatment of pharmaceutical contaminants contained in industrial wastewater.


Asunto(s)
Acetaminofén/química , Antiinflamatorios no Esteroideos/química , Bebidas , Eliminación de Residuos Líquidos/métodos , Contaminantes Químicos del Agua/química , Adsorción , Carbón Orgánico/química , Humanos , Ibuprofeno/química , Cetoprofeno/química , Cinética , Aguas del Alcantarillado , Aguas Residuales , Agua , Contaminantes Químicos del Agua/análisis
7.
Food Chem ; 335: 127600, 2021 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-32736155

RESUMEN

Toosendanin (TSN), as an important Chinese traditional insecticide, has been registered and commercialized in China. In this report, the residual analytical methods, residue dynamics and final residues of TSN in tobacco, cabbage and soil under field condition were studied by IC-ELISA and HPLC. The sensitivity, precision and repeatability of IC-ELISA method were more suitable in comparison with HPLC for the demand of TSN residue analysis. Using IC-ELISA, the half-lives (t1/2) of TSN were found to be 1.30 days in cabbage, 1.70 days in tabacco and 0.71 days in soil, respectively. At the recommended dose, the final residues of TSN detection by IC-ELISA was 0.009 mg·kg-1 in cabbage and 0.043 mg·kg-1 in tobacco, as well as was not detected in soil. Therefore, TSN is easily degradable, and IC-ELISA could be a convenient and supplemental analytical tool for monitoring TSN residue in crops and environment.


Asunto(s)
Brassica/metabolismo , Medicamentos Herbarios Chinos/metabolismo , Ensayo de Inmunoadsorción Enzimática/métodos , Contaminantes del Suelo/metabolismo , Suelo/química , China , Cromatografía Líquida de Alta Presión/métodos , Semivida , Cinética , Residuos de Plaguicidas/análisis , Tabaco
8.
Sci Total Environ ; 751: 141623, 2021 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-32877793

RESUMEN

There is a growing interest in the use of adsorbent nanoparticles to mitigate the toxic effects of pollutants in natural matrices. However, due to their small size, nanoparticles have the potential to transport and disseminate contaminants adsorbed on their surfaces into environmental compartments with greater risk to human, animal, or plant health. This potential consequence of nanoparticle application remains largely unstudied. Here, we studied the application of three adsorbents, including zeolite (Z, micrometric size), nanomagnetite (Mt), and a nanomagnetite-zeolite composite (MtZ) intended to mediate arsenic toxicity in hydroponic tomato cultures. Adsorption studies showed an arsenate adsorption sequence of MtZ (6.2 mg g-1) ≥ Mt (4.7 mg g-1) â‰« Z (0.3 mg g-1). Tomatoes grown under the Mt condition demonstrated the lowest growth rate (4.2 cm), corresponding to a 45% decrease compared to the control (7.6 cm), as well as the highest oxidative stress level (0.024 µmol g-1) as indicated by malondialdehyde (MDA) concentration, almost twice the control (0.014 µg g-1). Tomatoes grown under MtZ conditions showed a 22% decreased growth (5.9 cm) but MDA levels (0.012 µmol g-1) were comparable to the control. Together, these results suggest that Mt at the nanometric size could obstruct channels in the plant and prevent absorption of water and nutrients. Anchoring nanomaterials in larger composites of micrometer size presents a promising alternative that would retain their super-adsorbent properties while avoiding toxicity due to nanometric size.


Asunto(s)
Arsénico , Lycopersicon esculentum , Contaminantes Químicos del Agua , Purificación del Agua , Zeolitas , Adsorción , Arsénico/análisis , Humanos , Concentración de Iones de Hidrógeno , Hidroponia , Cinética , Contaminantes Químicos del Agua/análisis
9.
Sci Total Environ ; 750: 141498, 2021 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-32882491

RESUMEN

This work examined the adsorption capacity of sugarcane bagasse (SB) for the removal of ciprofloxacin (CPX) from water using batch experiments and a fixed bed column and compared its adsorption performance with a powdered activated commercial carbon (PAC). Both adsorbents achieved a similar percentage removal of about 78% with doses of 3 g L-1 of SB and 0.3 g L-1 of PAC (20 mg L-1 initial CPX concentration at 30 °C). The maximum removal was obtained at a pH between 6 and 8. SB adsorption isotherms were fitted to the Langmuir, BET and Freundlich models showing a maximum adsorption capacity of 13.6 mg g-1. The kinetic data for both SB and PAC fitted the pseudo second-order model (R2 = 0.99). The adsorption process was faster on the SB (65% of elimination in the first 5 min) than on the PAC. The study of the adsorbent properties shows that SB is a macroporous solid with a specific surface area 250 times smaller than PAC. The thermodynamic results show that SB adsorption was physical and exothermic. The main suggested interactions between CPX and SB are electrostatic attraction, hydrogen bonding and dipole-dipole interactions. The experiments carried out in a fixed bed show that the adsorption capacity at breakthrough increases with the bed height. The adsorption capacity at saturation time was 9.47 mg g-1 at a flow rate of 3 mL min-1, a bed height of 14 cm, and a diameter of 1.5 cm. The experimental data were fitted to the Bohart-Adams model (R2 = 0.98). These results highlight the capacity of sugarcane bagasse to adsorb ciprofloxacin from water, illustrating its potential as a low-cost adsorbent.


Asunto(s)
Saccharum , Contaminantes Químicos del Agua , Purificación del Agua , Adsorción , Celulosa , Carbón Orgánico , Ciprofloxacino , Ecuador , Concentración de Iones de Hidrógeno , Cinética , Polvos
10.
Food Chem ; 335: 127642, 2021 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-32739814

RESUMEN

Spray drying is the most commonly used encapsulation technique to stabilize sensitive bioactive compounds and sometimes enhances their performance. Vitamin B12 and vitamin D3 deficiencies are reported worldwide and co-encapsulation can provide a combined solution to this problem. The present work aimed at encapsulation of vitamin B12 and D3 by spray drying using experimental design to optimize wall material combination. Optimized solution obtained from the experimental design (gum acacia : Hi-Cap® 100 : maltodextrin = 38:60:2) provided spherical particles with smooth surface and better stability of both the vitamins. In vitro release mechanism showed a slow release for both the vitamins after encapsulation. The optimized co-encapsulated microcapsules obtained in this work showed an improved bioavailability of 151% for vitamin B12 and 109% for vitamin D3 in comparison with the control. This study delivered a suitable medium to provide water soluble vitamin B12 and fat soluble vitamin D3 in single product.


Asunto(s)
Colecalciferol/química , Composición de Medicamentos/métodos , Vitamina B 12/química , Disponibilidad Biológica , Cápsulas/química , Goma Arábiga/química , Cinética
11.
Food Chem ; 335: 127633, 2021 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-32739813

RESUMEN

The influence of different fatty acid carbon chains on the kinetic interactions of nanocomplexes between esterified astaxanthin (E-Asta) and ß-lactoglobulin (ß-Lg) were investigated by multi-spectroscopy and molecular modeling techniques. We synthesized ten different E-Asta bound to ß-Lg and formed nanocomplexes (< 300 nm). Fluorescence spectroscopy showed moderate affinities (binding constants Ka = 103-104 M-1). Docosahexaenoic acid astaxanthin monoester (Asta-C22:6) had the strongest binding affinity towards ß-Lg (Ka = 3.77 × 104 M-1). The fluorescence quenching of ß-Lg upon binding of E-Asta displayed a static mechanism, with binding sites (n) equal to 1. Fourier transform infrared spectroscopy and ultraviolet-visible absorption spectroscopy revealed that E-Asta might enter the ß-Lg hydrophobic cavity, leading to unfolding of the peptide chain skeleton. In summary, ß-Lg and E-Asta can form stable nanocomplex emulsions to achieve an effective delivery process for E-Asta.


Asunto(s)
Ésteres/química , Lactoglobulinas/química , Nanoestructuras/química , Sitios de Unión , Interacciones Hidrofóbicas e Hidrofílicas , Cinética , Xantófilas/química
12.
Food Chem ; 337: 127759, 2021 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-32777568

RESUMEN

High-resolution ultrasonic spectroscopy (HR-US) was applied for real-time monitoring of ß-casein hydrolysis by trypsin at various conditions for the first time. The technique is based on the precision measurement of hydration changes proportional to the number of peptide bond hydrolyzed. As HR-US exhibits ultrasonic transparency for most solution, the analysis did not require optical transparency like for 2,4,6-trinitrobenzenesulfonic acid (TNBS) assay. Appropriate enzymatic models were fitted with degree of hydrolysis (dh) profiles to provide kinetic and mechanistic description of proteolysis in terms of initial hydrolysis rate, r0, and rate constant of hydrolysis, kh, and enzyme inactivation, kd. Maximal r0 and dh were obtained at 45 °C and pH 8. The exponential dependence of kinetic parameters allowed determination of the activation (EA = 50.3 ± 7 kJ/mol) and deactivation (ED = 62.23 ± 3 kJ/mol) energies of hydrolysis. The ultrasonic assay provided rapid detection of trypsin activity even at sub-nanomolar concentration.


Asunto(s)
Caseínas/metabolismo , Pruebas de Enzimas/métodos , Análisis Espectral , Tripsina/metabolismo , Ondas Ultrasónicas , Activación Enzimática , Hidrólisis , Cinética , Proteolisis , Soluciones
13.
Food Chem ; 337: 127757, 2021 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-32791430

RESUMEN

The effects of enzymatic free fatty acid reduction process (EFFARP) on the composition and phytochemicals of dewaxed and degummed rice bran oil (DDRBO) were investigated and compared with the effects observed using internal acyl acceptors. The acid value of DDRBO was effectively decreased from 16.99 mg KOH/g to approximately 0.36 mg KOH/g by EFFARP. EFFARP significantly decreased the moisture content and peroxide value of DDRBO and increased the induction period. The Sn-2 fatty acid comoposition of DDRBO after EFFARP was very reaching the total fatty acid composition. EFFARP significantly increased the triacylglycerol content compared to the control, while the oryzanol content was not obviously affected. The contents of free sterol, and total tocopherol and tocotrienol were increased slightly by EFFARP compared to the control. When conducted under vacuum with added nitrogen, EFFARP shows great application potential in the edible oil industry.


Asunto(s)
Enzimas/metabolismo , Ácidos Grasos no Esterificados/química , Fitoquímicos/química , Aceite de Salvado de Arroz/química , Biocatálisis , Cinética
14.
Sci Total Environ ; 752: 141662, 2021 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-32889260

RESUMEN

This work aimed at the microwave-assisted production of activated carbon (AC) from primary paper mill sludge (PS) for the adsorption of antibiotics from water. Production conditions, namely pyrolysis temperature, pyrolysis time and activating agent (KOH):PS ratio, were optimized as a function of product yield, specific surface area (SBET), total organic carbon (TOC) content and adsorptive removal percentage of two target antibiotics (amoxicillin (AMX) and sulfamethoxazole (SMX)). Under the optimized conditions (pyrolysis at 800 °C during 20 min and a KOH:PS ratio of 1:5), a microporous AC (MW800-20-1:5, with SBET = 1196 m2 g-1, TOC = 56.2% and removal of AMX and SMX = 85% and 72%, respectively) was produced and selected for further kinetic and equilibrium adsorption studies. The obtained results were properly described by the Elovich reaction-based kinetic model and the Langmuir equilibrium isotherm, with maximum adsorption capacities of 204 ± 5 mg g-1 and 217 ± 8 mg g-1 for AMX and SMX, respectively. Considering the satisfactory comparison of these results with the performance of commercial and alternative AC produced by conventional pyrolysis, this work demonstrated the feasibility of the microwave-assisted production of environmentally and energetically sustainable waste-based AC to be applied in the efficient removal of antibiotics from water.


Asunto(s)
Carbón Orgánico , Contaminantes Químicos del Agua , Adsorción , Antibacterianos , Cinética , Microondas , Agua , Contaminantes Químicos del Agua/análisis
15.
Sci Total Environ ; 752: 141876, 2021 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-32889285

RESUMEN

Recent studies have shown that free nitrous acid (FNA, i.e., HNO2) is biocidal to many microorganisms, promoting the development of FNA-based technology in biological wastewater treatment. Suppression of nitrite-oxidizing bacteria (NOB) is a critical step for autotrophic nitrogen removal via anammox. In this study, the biocidal effect of FNA on NOB was determined by developing a model methodology combined with NOB incubation. Sixteen groups of FNA exposure tests were conducted at five different FNA concentrations from 0 to 4 mg HNO2-N/L, obtained from three pH values (5.0, 5.5 and 6.0) with nitrite ranged from 21 to 1680 mg NO2--N/L, with one as a control. Nitrate production curves were tracked during incubations of the FNA-exposed sludge, and then used to estimate active NOB concentrations by the kinetic model-based fitting. The results showed that with 24-hour exposure to FNA at a level of over 1 mg HNO2-N/L, the active NOB decreased around two orders of magnitude compared with that in the primordial sludge. The Weibull model can well describe the biocidal effect, which would be useful for the optimization of FNA conditions. The maximum NOB growth rate was increased after FNA exposure. This result suggests that long-term implementation of FNA-based technology can select fast-growing NOB in activated sludge, causing a 'NOB adaptation' issue.


Asunto(s)
Nitritos , Ácido Nitroso , Bacterias , Reactores Biológicos , Cinética , Oxidación-Reducción , Aguas del Alcantarillado
16.
Sci Total Environ ; 751: 141755, 2021 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-32889470

RESUMEN

An issue of significant importance worldwide is the contamination of water with antibiotics giving rise to antibiotic resistance in the environment. Antibiotics such as tetracycline are widely used in agriculture, as such they can pollute water courses, providing a means by which environmental bacteria can evolve antibiotic resistance genes. Biochar can form part of a solution as it is a well-known adsorbent. This material can be efficient in the adsorption of a wide range of pollutants and is inexpensive. An innovative heat pipe reactor was used to produce biochar from excess food and garden materials. This biochar was characterised using scanning electron microscopy with energy dispersive X-ray analyser (SEM-EDAX), Fourier transform infrared (FTIR) spectroscopy and Raman spectroscopy. The biochar produced had an adsorption capacity between 2.98 mg/g and 8.23 mg/g for initial tetracycline concentrations of 20 mg/l and 100 mg/l, respectively. The Freundlich isotherm provided the best fit to the experimental data. Kinetics examination revealed a rapid adsorption of tetracycline during the initial stages. The Elovich equation fitted the experimental data well. This adsorbent could therefore be produced at the site of an agricultural enterprise through the pyrolysis of agriculture waste and then used to reduce the infiltration of antibiotics into the environment.


Asunto(s)
Contaminantes Químicos del Agua , Agua , Adsorción , Agricultura , Antibacterianos , Carbón Orgánico , Concentración de Iones de Hidrógeno , Cinética , Espectroscopía Infrarroja por Transformada de Fourier , Tetraciclina
17.
Food Chem ; 338: 127825, 2021 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-32810814

RESUMEN

Four soluble dietary fibers (SDFs) were fortified with corn starch (CS) at different concentrations to match the same viscosity equivalents. The mixtures were subjected to a simulated digestion procedure to study the effects of SDFs on viscosity properties and digestion kinetics of CS. Results showed that SDFs increased the hydration property and decreased the water mobility of digesta. During digestion process, SDFs increased the apparent viscosity of digesta to some extent, and showed significant difference to delay the decay of digesta viscosity (kv). The amylolysis inhibitory ability was similar when each SDF was present at the same viscosity equivalent, however, significant differences were found on the digestion rate constant of k2. Linear correlations between kv and k2 were established for 1 and 2 equivalent groups. These results demonstrated that SDFs could delay the digestion process as chemistry differences, which related to their ability on delaying the change of digesta viscosity.


Asunto(s)
Fibras de la Dieta/farmacología , Almidón/química , Almidón/farmacocinética , Animales , Digestión , Jugo Gástrico/efectos de los fármacos , Jugo Gástrico/metabolismo , Cinética , Mananos/química , Polisacáridos/química , Polisacáridos Bacterianos/química , Solubilidad , Viscosidad
18.
Food Chem ; 336: 127714, 2021 Jan 30.
Artículo en Inglés | MEDLINE | ID: mdl-32828014

RESUMEN

Five new flavonoids (1-5), along with 25 known compounds, were isolated from the rhizomes of Potentilla anserina L. and their structures were identified using spectroscopic and chemical evidence. The extract, all fractions, and all isolated compounds were evaluated for their antioxidant, α-glucosidase, and tyrosinase inhibitory activities, and their structure-activity relationship was interpreted. The biflavanols and quercetin-3-O-α-l-rhamnopyranoside-2″-gallate (14) exhibited significant antioxidant and α-glucosidase inhibition activities. In this study, anti-tyrosinase activity and its mechanism of active compounds (potenserin C (4), potenserin D (5), and quercetin-3-O-α-l-rhamnopyranoside-2″-gallate (14)) were explored by a combination of computational simulations and kinetic studies. Kinetic studies indicated that potenserin C (4) and quercetin-3-O-α-l-rhamnopyranoside-2″-gallate (14) inhibited tyrosinase in a competitive manner, whereas potenserin D (5) acted in a reversible noncompetitive manner. The molecular docking result indicated that the substitution of the glucose moiety with galloyl and the presence of 3', 4', 5'-OH in flavonoid aglycones played a crucial role for the tyrosinase inhibiting effect. Moreover, the presence of biflavanols increased the activity against tyrosinase because of strong hydrogen binding, π-alkyl binding, and electrostatic interaction. Thus, the presented experiments developed several new lead compounds that could act as antioxidants and α-glucosidase inhibitors. Furthermore, biflavanols and quercetin-3-O-α-l-rhamnopyranoside-2″-gallate played important roles in the anti-browning activity during food processing.


Asunto(s)
Antioxidantes/farmacología , Inhibidores de Glicósido Hidrolasas/farmacología , Monofenol Monooxigenasa/antagonistas & inhibidores , Potentilla/química , Relación Estructura-Actividad , Antioxidantes/química , Evaluación Preclínica de Medicamentos , Flavonoides/química , Flavonoides/farmacología , Inhibidores de Glicósido Hidrolasas/química , Glicósidos/química , Glicósidos/farmacología , Cinética , Simulación del Acoplamiento Molecular , Monofenol Monooxigenasa/metabolismo , Extractos Vegetales/química , Quercetina/análogos & derivados , Quercetina/química , Quercetina/farmacología , Rizoma/metabolismo
19.
Sci Total Environ ; 751: 142293, 2021 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-33181995

RESUMEN

The harm done to the environment by coal gangue was very serious, and it is urgent to adopt effective methods to dispose of coal gangue in order to prevent further environmental damage. Co-pyrolysis experiments of coal gangue (CG) and peanut shell (PS) were carried out using thermogravimetry-Fourier transform infrared spectroscopy (TG-FTIR) under nitrogen atmosphere. The heavy metal was detected using the inductively coupled plasma-optical emission spectroscopy (ICP-OES). CG and PS were mixed according to the mass ratio of 1:0, 3:1, 1:1, 1:3 and 0:1. The samples were heated to 1000 °C at the heating rate of 10 °C/min, 20 °C/min and 30 °C/min. The comprehensive pyrolysis index (CPI) of CG, C3P1, C1P1, C1P3 and PS is 0.17 × 10-8, 9.75 × 10-8, 35.47 × 10-8, 100.94 × 10-8 and 192.72 × 10-8%2 ·min-2·°C-3. The kinetic parameters were calculated by model-free methods (Flynn-Wall-Ozawa and Kissinger-Akahira-Sunose). The gas products generated at different temperatures during the pyrolysis experiment were detected by Fourier transform infrared spectrometer. The heating rate, temperature and mixing ratio are the input parameters of artificial neural network (ANN), and the remaining mass percentage of sample during the pyrolysis is the output parameter. The ANN model was established and used to predict thermogravimetric experimental data. The ANN18 model is the best model for predicting the co-pyrolysis of CG and PS.


Asunto(s)
Carbón Mineral , Pirólisis , Biomasa , Carbón Mineral/análisis , Cinética , Redes Neurales de la Computación , Espectroscopía Infrarroja por Transformada de Fourier
20.
Sci Total Environ ; 750: 142370, 2021 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-33182210

RESUMEN

Plastic debris is ubiquitous in aquatic systems and has been proven vehicles for the transport of various pollutants including trace organic compounds. Nanoplastics have large specific surface area and hydrophobic characteristics and therefore are capable of adsorbing other organic or inorganic chemicals from the environment. Antibiotics, as another class of emerging contaminants, have raised significant research concern in recent years as they pose threats to the ecosytems and human health. Nevertheless, little information is available on the adsorption behaviors of antibiotics onto nano-sized plastics. The toxicity of combined nanoplastics and antibiotics is also largely unknown. In this study, the physicochemical and thermodynamic interactions between representative nanoplastics, which containing a carboxyl functional group of polystyrene nanoplastics (PS-COOH), and typical antibiotic, i.e., ciprofloxacin (CIP) were investigated in a batch adsorption experiment. The specific thermodynamic correlation function of PS-COOH combined with CIP was obtained through isothermal titration microcalorimetry (ITC) analysis. The adsorption kinetics and isotherm of CIP on PS-COOH closely fit the pseudo-second-order kinetic model (r2 = 0.99) and Freundlich isotherm (r2 = 0.99). The ITC results showed that the adsorption reaction of PS-COOH with CIP was a spontaneous exothermic reaction. The adsorption of antibiotics on nanoplastics may aggravate the negative impacts of these two pollutants on aqueous ecosystems, and we hypothesized that would be reflected in the survival rate of model organism of Caenorhabditis elegans when exposed to this combination. This work used a mechanistic approach to unravel the adsorption behavior of antibiotics on nanoplastics and shed light on their potential impact on aquatic ecosystems.


Asunto(s)
Plásticos , Contaminantes Químicos del Agua , Adsorción , Ciprofloxacino/toxicidad , Ecosistema , Cinética , Plásticos/toxicidad , Poliestirenos , Contaminantes Químicos del Agua/análisis , Contaminantes Químicos del Agua/toxicidad
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