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1.
Int J Biol Macromol ; 265(Pt 2): 130519, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38553393

RESUMEN

Peroxymonosulfate (PMS), which is dominated by non-free radical pathway, has a good removal effect on organic pollutants in complex water matrices. In this article, a biodegradable cobalt-based catalyst (Co3O4/MoS2@NCS) was synthesized by a simple hydrothermal method with chitosan (CS) as nitrogen­carbon precursor and doped with Cobaltic­cobaltous oxide (Co3O4) and Molybdenum disulfide (MoS2), and was used to activate PMS to degrade dye wastewater. Electrochemical tests showed that Co3O4/MoS2@NCS exhibited higher current density and cycling area than MoS2@NCS and MoS2. In the Co3O4/MoS2@NCS/PMS system, the degradation rate of 30 mg·L-1 rhodamine B (RhB) reached 97.75 % within 5 min, and kept as high as 94.34 % after 5 cycles. Its rate constant was 1.91 and 8.37 times that of MoS2@NCS/PMS and MoS2/PMS, respectively. It had good complex background matrices and acid-base anti-interference ability, and had good universality and reusability. The degradation rate of methyl orange (MO) and methylene blue (MB) were more than 91 % within 5 min at pH 4.8. The experimental results demonstrated that MoS2-modified CS as a carrier exposed a large number of active sites, which not only dispersed Co3O4 nanoparticles and improved the stability of the catalyst, but also provided abundant electron rich groups, and promoted the activation of PMS and the production of reactive oxygen species (ROS). PMS was effectively activated by catalytic sites (Co3+/Co2+, Mo4+/Mo5+/Mo6+, CO, pyridine N, pyrrole N, hydroxyl group and unsaturated sulfur), producing a large number of radicals that attack RhB molecules, causing chromophore cleavage, ring opening, and mineralization. Among them, non-free radical 1O2 was the main ROS for RhB degradation. This work is expected to provide a new idea for the design and synthesis of environmentally friendly and efficient MoS2-modified cobalt-based catalysts.


Asunto(s)
Carbono , Quitosano , Óxidos , Peróxidos , Carbono/química , Especies Reactivas de Oxígeno/química , Molibdeno/química , Cobalto/química
2.
Small ; : e2310894, 2024 Mar 03.
Artículo en Inglés | MEDLINE | ID: mdl-38431943

RESUMEN

A visible-light-driven CO2 reduction optical fiber is fabricated using graphene-like nitrogen-doped composites and hollow quartz optical fibers to achieve enhanced activity, selectivity, and light utilization for CO2 photoreduction. The composites are synthesized from a lead-based metal-organic framework (TMOF-10-NH2 ) and g-C3 N4 nanosheet (CNNS) via electrostatic self-assembly. The TMOF-10-NH2 /g-C3 N4 (TMOF/CNNS) photocatalyst with an S-type heterojunction is coated on optical fiber. The TMOF/CNNS coating, which has a bandgap energy of 2.15 eV, has good photoinduced capability at the coating interfaces, high photogenerated electron-hole pair yield, and high charge transfer rate. The conduction band potential of the TMOF/CNNS coating is more negative than that for CO2 reduction. Moreover, TMOF facilitates the CO desorption on its surface, thereby improving the selectivity for CO production. High CO2 photoreduction and selectivity for CO production is demonstrated by the TMOF/CNNS-coated optical fiber with the cladding/core diameter of 2000/1000 µm, 10 wt% TMOF in CNNS, coating thickness of 25 µm, initial CO2 concentration of 90 vol%, and relative humidity of 88% RH under the excitation wavelength of 380-780 nm. Overall, the photocatalytic hollow optical fiber developed herein provides an effective and efficient approach for the enhancement of light utilization efficiency of photocatalysts and selective CO2 reduction.

3.
Langmuir ; 40(14): 7569-7580, 2024 Apr 09.
Artículo en Inglés | MEDLINE | ID: mdl-38544311

RESUMEN

A La-doped Ti/SnO2-Sb2O4 electrode with TiO2-NTs intermediate layer (Ti/TiO2-NTs/SnO2-Sb2O4-La) was created via the electrodeposition technique. The physicochemical and electrochemical properties of the electrode were analyzed through FESEM, XRD, XPS, CV, and LSV electrochemical tests. The results showed that TiO2-NTs were tightly packed on the surface of Ti substrate, thus improving the binding force of the SnO2-Sb2O4-La coating, offering greater specific surface area, more active spots, higher current response, and longer lifespan for the degradation of rhodamine B. The lifespan of the Ti/TiO2-NTs/SnO2-Sb2O4-La electrode reached 200 min (1000 mA cm-2, 1 M H2SO4), while the actual service life was up to 3699 h. Under the conditions of initial pH 3.0, Na2SO4 concentration of 0.1 M, current density of 30 mA cm-2, and initial rhodamine B concentration of 20 mg L-1, the color and TOC removal rate of rhodamine B reached 100% and 86.13% within 15 and 30 min, respectively. Rhodamine B was decomposed into acids, esters, and other molecular compounds under the action of •OH and SO4•- free radicals and electrocatalysis, and finally completely mineralized into CO2 and H2O. It is anticipated that this work will yield a novel research concept for producing DSA electrodes with superior catalytic efficacy and elevated stability.

4.
Environ Sci Pollut Res Int ; 31(14): 21632-21645, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38393556

RESUMEN

In this paper, La-doped Ti/SnO2-Sb2O4 electrode was prepared by electrodeposition and used for electrochemical degradation of rhodamine B. The optimum preparation conditions of the electrode were optimized as deposition time of 15 min and calcination at 500 ℃ for 2 h. The water treatment conditions were selected as initial pH 3.0, electrolyte Na2SO4 concentration 0.1 M, current density 30 mA cm-2, and initial rhodamine B concentration 20 mg L-1; the color and TOC removal of RhB reached 99.78% and 82.41% within 30 min. The FESEM, XRD, XPS, CV, LSV, and EIS characterization studies demonstrated that Ti/SnO2-Sb2O4-1%La electrode had a dense structure and the highest oxygen evolution potential (2.14 V) and lowest charge transfer resistance (0.198 Ω cm-2), indicating that doped La has lower energy consumption. Moreover, La doping can expand the specific surface area, active site, performance of pollutant degradation, and service life of the electrode. Especially, the service life of Ti/SnO2-Sb2O4-1%La is increased by three times, and the maximum life span reaches 90 min (1000 mA cm-2, 1 M H2SO4). Free radical quenching experiments show that ·OH plays a major role in the degradation of RhB. The Ti/SnO2-Sb2O4-1%La electrode prepared in this paper and its results will provide data support and reference for the design of efficient electrocatalytic electrode.


Asunto(s)
Titanio , Titanio/química , Oxidación-Reducción , Rodaminas , Electrodos
5.
Bioresour Technol ; 394: 130287, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38181998

RESUMEN

Microalgae biochar is potential adsorbents to remove heavy metals from wastewater due to abundant functional groups, high porosity and wide sources, but performance is not fully developed since it depends on microalgae species attributing to distinct morphology and biomass compositions. Here, two microalgae species Chlorella Pyrenoidosa and Scenedesmus Obliquus were used for biochar preparation via KOH-modification, biochar properties and their influences on Ni(II) adsorption were investigated. Ni(II) adsorption performances responding to biochar properties and operating conditions were upgraded via progressive optimization and response surface methodology. Together, adsorption isotherms and kinetics were analyzed to obtain significant factors for Ni(II) removal. As results, 100 % of Ni(II) removal was achieved under 100 mg/L initial Ni(II) concentration as pH was higher than the biochar zero-charge point of 6.87 with low biochar dosage (0.5 g/L), which provides an efficient approach for heavy metal removal from wastewater with microalgae biochar.


Asunto(s)
Chlorella , Metales Pesados , Microalgas , Contaminantes Químicos del Agua , Adsorción , Aguas Residuales , Carbón Orgánico/química , Cinética
6.
Environ Sci Pollut Res Int ; 31(2): 2228-2242, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38055169

RESUMEN

The Zn/Fe@N-doped porous graphitic carbon catalyst (Zn/Fe@PCN) was successfully produced through one-step pyrolysis of g-C3N4 and Zn/Fe-MOF and was used for the activation of persulfate (PS) for the degradation of RhB. The Zn/Fe@PCN/PS system was able to degrade 95.92% of RhB in 30 min at a rate of 0.6453 min-1 when RhB was concentrated at 50 mg L-1. The efficient degradation of RhB is primarily realized through the synergistic activation of PS by Zn, Fe, and N to produce reactive oxygen species 1O2, [Formula: see text], [Formula: see text], and ·OH. Zn0/Fe0 in Zn/Fe@PCN forms a galvanic cell with carbon to release electrons to join in the activation of PS. The doping of Zn not only provides sufficient electrons for the activation of PS but also promotes the effective reduction of Fe2+ and thus the Fe2+/Fe3+ cycle. The N doping accelerates the electron transfer during the reaction progress.


Asunto(s)
Estructuras Metalorgánicas , Rodaminas , Nitrógeno , Carbono , Zinc
7.
Int J Biol Macromol ; 239: 124266, 2023 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-37003391

RESUMEN

In order to improve the stability, electrostatic interaction and ion exchange ability of chitosan for Cr (VI) removal, it is an effective strategy to introduce polyvalent metal ions and polymers into chitosan molecular chain through crosslinking. In this paper, Zr4+ and glutaraldehyde crosslinked polyethyleneimine functionalized chitosan (CGPZ) composite was successfully synthesized and characterized by XRD, SEM, FTIR, BET, and XPS. The results showed that polyethyleneimine was successfully grafted onto chitosan by Schiff base reaction, while the appearance of ZrO and ZrN bonds verified the successful preparation of CGPZ. The monolayer maximum adsorption capacity of Cr(VI) by CGPZ was 593.72 mg g-1 at 298 K and t = 210 min. The removal efficiency of 100 mg L-1 Cr(VI) reached 95.7 %. The thermodynamic, isotherm and kinetic results show that the adsorption process of Cr (VI) by CGPZ is a spontaneous endothermic process controlled by entropy, which accords with Freundlich model and pseudo-second-order kinetic model. The regeneration experiments show that both HCl and NaOH can effectively desorb Cr(III) and Cr(VI) from the adsorbent surface, and the adsorbent has good acid-base resistance and regeneration performance. The removal of Cr(VI) mainly involves electrostatic attraction, ion exchange, reduction and complexation. CGPZ can synergistically adsorb Cr(VI) by electrostatic interaction of -NH2/-C=N and ion exchange of Cl- ion in the center of Zr, then reduce Cr(VI) to Cr(III) (45.4 % at pH = 2.0) by the -OH group on its surface, and chelate Cr(III) through COO- and -NH- groups.


Asunto(s)
Quitosano , Contaminantes Químicos del Agua , Purificación del Agua , Quitosano/química , Glutaral , Polietileneimina , Adsorción , Cromo/química , Iones , Cinética , Contaminantes Químicos del Agua/química , Concentración de Iones de Hidrógeno , Purificación del Agua/métodos
8.
Chemosphere ; 325: 138399, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-36925002

RESUMEN

In order to develop efficient photoanode to improve the performance of visible light responsive photocatalytic fuel cell (PFC), in this work, polyaniline/g-C3N4/Bi2O3/Ti photoanode was successfully prepared using silica-sol drop coating method, and assembled with Cu cathode to construct PFC to decompose rhodamine B and generate electricity simultaneously. The degradation rate, maximum photocurrent density and maximum power density of this PFC were 91.23%, 0.086 mA cm-2 and 4.78 µW cm-2, respectively, which were 1.4 and 1.8 times, 2.4 and 4.5 times, and 1.9 and 7.3 times those of the corresponding values of the PFCs with g-C3N4/Bi2O3/Ti and Bi2O3/Ti photoanodes, respectively. This is attributed to the type II heterojunction structure formed among polyaniline, g-C3N4 and Bi2O3 in the polyaniline/g-C3N4/Bi2O3/Ti photoanode. Among them, polyaniline has π-π conjugated structure, which can rapidly transfer the electronic charge between g-C3N4 and Bi2O3, thus enhancing the separation efficiency of photo-generated e--h+ pairs spatially and reducing their recombination, extending the visible light response wavelength of the photocatalyst, and finally improving its photocatalytic properties. This study can provide significant reference for the research of Bi2O3-based visible light responsive PFC.


Asunto(s)
Luz , Titanio , Titanio/química , Electricidad
9.
Environ Sci Ecotechnol ; 14: 100234, 2023 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-36685749

RESUMEN

Tetracyclines are refractory pollutants that cause persistent harm to the environment and human health. Therefore, it is urgently necessary to develop methods to promote the efficient degradation and conversion of tetracyclines in wastewater. This report proposes a photobiocatalytic synergistic system involving the coupling of GeO2/Zn-doped phosphotungstic acid hydrate/TiO2 (GeO2/Zn-HPW/TiO2)-loaded photocatalytic optical hollow fibers (POHFs) and an algal-bacterial biofilm. The GeO2/Zn-HPW/TiO2 photocatalyst exhibits a broad absorption edge extending to 1000 nm, as well as high-efficiency photoelectric conversion and electron transfer, which allow the GeO2/Zn-HPW/TiO2-coated POHFs to provide high light intensity to promote biofilm growth. The resulting high photocatalytic activity rapidly and stably reduces the toxicity and increases the biodegradability of tetracycline-containing wastewater. The biofilm enriched with Salinarimonas, Coelastrella sp., and Rhizobium, maintains its activity for the rapid photocatalytic degradation and biotransformation of intermediates to generate the O2 required for photocatalysis. Overall, the synergistic photocatalytic biofilm system developed herein provides an effective and efficient approach for the rapid degradation and conversion of water containing high concentrations of tetracycline.

10.
Environ Technol ; 44(6): 864-874, 2023 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-34661510

RESUMEN

Ni-EDTA is widely present in electroplating effluents. It cannot be effectively removed by traditional wastewater treatment methods due to its chemical stability. In this study, copper sulphide/cuprous sulphide doped zero-valent iron@carbon (ZVI@C/CuS/Cu2S) was prepared to active peroxymonsulphate (PMS) to decomposition Ni-EDTA. The ZVI@C/CuS/Cu2S + PMS process shows excellent performance under neutral or even alkaline conditions. This is due to the acceleration of ZVI electron transport by CuS/Cu2S, the autocatalysis of CuS/Cu2S itself, and the synergistic effect of CuS/Cu2S and Ni-EDTA. The removal efficiency of 50 ppm Ni-EDTA electroplating effluents reached 99.53% at 10 min, and the discharge water can meet the Chinese emission standard. The influences of the main parameters such as initial pH value, catalyst, PMS and initial Ni-EDTA concentration on removal efficiency was systematically investigated.


Asunto(s)
Eliminación de Residuos Líquidos , Contaminantes Químicos del Agua , Carbono , Cobre/química , Ácido Edético/química , Hierro/química , Sulfuros , Eliminación de Residuos Líquidos/métodos , Contaminantes Químicos del Agua/química
11.
Environ Sci Pollut Res Int ; 30(3): 5847-5860, 2023 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-35984560

RESUMEN

In this work, a magnetic core-shell composite zero-valent iron/copper-polyacrylate (ZVI/Cu-PAA) was synthesized by a simple liquid-phase reduction process and used for hexavalent chromium Cr(VI) removal from wastewater. The optimization experiments show that the optimal dosages of polyacrylate and Cu are 7.00 wt% and 8.25 wt%, respectively. The maximum adsorption capacity and removal rate of Cr(VI) by ZVI/Cu-PAA reached 106.12 mg g-1 and 99.05% at pH 5.5, respectively. Furthermore, the presence of coexisting ions such as Ca2+, Mg2+, Na+, and NO3- had no significant effect on its Cr(VI) removal performance. The excellent performance of ZVI/Cu-PAA is attributed to that the modification of polyacrylate can not only give more active sites but also inhibit agglomeration of nano-metallic particles, while Cu doping promotes the electron generation and transformation of Fe(III)/Fe(II) and Cu(II)/Cu(I) redox cycles. This makes ZVI/Cu-PAA has rich active sites and excellent stability, and has broad application prospects in the remediation of Cr (VI) polluted wastewater. The magnetic core-shell composite ZVI/Cu-PAA has excellent Cr (VI) removal performance because of its rich active sites and high electron transformation efficiency.


Asunto(s)
Nanopartículas , Contaminantes Químicos del Agua , Aguas Residuales , Compuestos Férricos , Hierro/química , Cromo/química , Adsorción , Contaminantes Químicos del Agua/análisis
12.
Carbohydr Polym ; 296: 119872, 2022 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-36087961

RESUMEN

The effective strategy to solve the problems of low mechanical strength, low adsorption efficiency and poor stability of chitosan is to modify it. In this work, Zr4+ cross-linked chitosan-thiourea (CS-thiourea-Zr) composite was synthesized for the first time and used to remove Cr(VI). CS, ZrO, CN bonds in FTIR spectrum and Zr, S elements in XPS spectrum, SEM-mapping and EDS results verify the successful preparation of CS-thiourea-Zr. The main mechanism of Cr(VI) removal by CS-thiourea-Zr includes electrostatic action, ion exchange, reduction and complexation. The adsorption of Cr(VI) is enhanced by electrostatic adsorption and ion exchange, 80.6 % of the adsorbed Cr(VI) is reduced to Cr(III) by -OH group, and the adsorption of Cr(III) is enhanced by COO- group and CS bond. The maximum adsorption capacity of CS-thiourea-Zr is 246.72 mg g-1 at 298 K and pH = 2.0. CS-thiourea-Zr has excellent acid-base resistance (suitable pH 2-12) and reusability.


Asunto(s)
Quitosano , Contaminantes Químicos del Agua , Purificación del Agua , Quitosano/química , Cromo , Concentración de Iones de Hidrógeno , Cinética , Tiourea , Agua , Contaminantes Químicos del Agua/química , Purificación del Agua/métodos
13.
Water Res ; 222: 118929, 2022 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-35970007

RESUMEN

Globally eruptive harmful algal blooms (HABs) have caused numerous negative effects on aquatic ecosystem and human health. Conversion of HABs into biohythane via dark fermentation (DF) is a promising approach to simultaneously cope with environmental and energy issues, but low HABs harvesting efficiency and biohythane productivity severely hinder its application. Here we designed a gradient electro-processing strategy for efficient HABs harvesting and disruption, which had intrinsic advantages of no secondary pollution and high economic feasibility. Firstly, low current density (0.888-4.444 mA/cm2) was supplied to HABs suspension to harvest biomass via electro-flocculation, which achieved 98.59% harvesting efficiency. A mathematic model considering coupling effects of multi-influencing factors on HABs harvesting was constructed to guide large-scale application. Then, the harvested HABs biomass was disrupted via electro-oxidation under higher current density (44.44 mA/cm2) to improve bioavailability for DF. As results, hydrogen and methane yields of 64.46 mL/ (g VS) and 171.82 mL/(g VS) were obtained under 6 min electro-oxidation, along with the highest energy yield (50.1 kJ/L) and energy conversion efficiency (44.87%). Mechanisms of HABs harvesting and disruption under gradient electro-processing were revealed, along with the conversion pathways from HABs to biohythane. Together, this work provides a promising strategy for efficient disposal of HABs with extra benefit of biohythane production.


Asunto(s)
Ecosistema , Floraciones de Algas Nocivas , Biomasa , Floculación , Humanos , Metano
14.
J Hazard Mater ; 425: 127967, 2022 Mar 05.
Artículo en Inglés | MEDLINE | ID: mdl-34915299

RESUMEN

The development of traditional photocatalytic fuel cell (PFC) is severely hindered by poor visible-light response and limited reaction space. In this study, a visible-light responsive PFC with g-C3N4/BiOI/Ti photoanode was proposed and applied to activate peroxymonosulfate (PMS) to degrade rhodamine B. The degradation rate, maximum power density and maximum photocurrent density of the PMS/PFC system were respectively 95.39%, 103.87 µW cm-2 and 0.62 mA cm-2, which was respectively 1.28, 2.18, and 1.98 times that of PFC. The excellent performance is attributed to the production of more reactive oxygen species and the extension of the reaction space range after the activation of PMS. The activation pathway of PMS and charge transfer pathway of the photoanode were discussed in detail, and it was proposed that PMS was activated by Z-scheme heterojunction g-C3N4/BiOI/Ti photoanode.

15.
Water Sci Technol ; 83(9): 2218-2231, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33989188

RESUMEN

To improve the efficiency of the Fe(II)/Fe(III) cycle and continuous reactivity of pyrite, a pyrite/H2O2/hydroxylamine (HA) system was proposed to treat rhodamine B (RhB). The results showed that near-complete decolorization and 52.8% mineralization 50 mg L-1 RhB were achieved under its optimum conditions: HA 0.8 mM, H2O2 1.6 mM, pyrite 0.4 g L-1, and initial pH 4.0. The degradation reaction was dominated by an •OH radical produced by the reaction of Fe2+ with H2O2 in solution. HA primarily had two roles: in solution, HA could accelerate the Fe(II)/Fe(III) cycle through its strong reducibility to enhance RhB decolorization; on the pyrite surface, HA could improve the continuous reactivity of pyrite by inhibiting the oxidation of pyrite. In addition, the dosing manner of HA had a significant effect on RhB decolorization. In addition, the high decolorization and mineralization efficiency of other dye pollutants suggested that the pyrite/H2O2/HA system might be widely used in textile wastewater treatment.


Asunto(s)
Peróxido de Hidrógeno , Contaminantes Químicos del Agua , Compuestos Férricos , Hidroxilamina , Hidroxilaminas , Hierro , Oxidación-Reducción , Rodaminas , Sulfuros , Contaminantes Químicos del Agua/análisis
16.
Appl Opt ; 59(19): 5708-5713, 2020 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-32609694

RESUMEN

A simple U-shaped plastic optical fiber evanescent-wave sensor was fabricated for temperature-independent highly sensitive detection of humidity. The sensing region of the sensor was subjected to five cycles of heating-cooling to improve temperature independence. The effects of the polyimide (PI) coating thickness, number of graphene oxide (GO) coating layers, and alternate PI-GO coating sequence were investigated to optimize sensitivity. The fabricated sensor exhibited high-temperature independence and good sensitivity of 0.17×10-2 (% relative humidity)-1 in the temperature range of 10°C to 70°C.

17.
J Phys Chem A ; 124(14): 2854-2862, 2020 Apr 09.
Artículo en Inglés | MEDLINE | ID: mdl-32202105

RESUMEN

Herein, we reported a simple solvothermal and chemical oxidation method to synthesize a magnetic core-shell composite (Fe3O4@UiO-66@PANI) for Cr(VI) removal from wastewater. Due to the porosity and stability of UiO-66 and stability, high acid resistance, and multiple active (reducing and chelating) groups of polyaniline (PANI), Fe3O4@UiO-66@PANI exhibited excellent efficiency, regeneration, and reusability performance for Cr(VI) removal. Its maximum adsorption capacity and removal rate were 474.42 mg·g-1 and 99.90%, respectively. The effects of initial pH values, contact time, and initial Cr(VI) concentration on Cr(VI) removal were investigated. The fitted data showed that the adsorption process was consistent with the pseudo-second-order kinetic model and Langmuir isothermal model. The study of the mechanism shows that the excellent efficiency of Fe3O4@UiO-66@PANI is due to the electrostatic adsorption and reduction of Cr(VI) and the chelation of Cr3+. The results demonstrate that Fe3O4@UiO-66@PANI is a promising adsorbent for the Cr(VI) removal.

18.
Anal Chem ; 91(23): 15155-15162, 2019 12 03.
Artículo en Inglés | MEDLINE | ID: mdl-31663721

RESUMEN

Simple D-type plastic optical fiber (POF) probes (i.e., sensor, reference, and photochemical probes) were created to accurately monitor the progression and phenol degradation of a Chlorella vulgaris biofilm. The sensor and reference probes were used to monitor the biofilm growth (thickness). The sensor probe, which consisted of a D-shaped POF and Canada balsam doped with GeO2 (CBG) coating, was developed to monitor the biofilm growth and change in the liquid-phase composition and its concentration inside the biofilm. The reference probe, which comprised a D-shaped POF, CBG coating, and glass fiber membrane (to separate the liquids from Chlorella vulgaris), was used to measure the response to changes in the liquid phase. A model was developed to demonstrate the accurate measurement of the biofilm thickness. The photochemical POF probe was coupled with a high-permselectivity phenol polymer membrane to monitor the phenol concentration and analyze the degradation time of 50 mg/L phenol with microalgal biofilms. A fixed relationship was obtained between the biofilm sensor output information and biofilm thickness for a biofilm thickness range of 0-290 µm with a periodic supply of 50 mg/L phenol solution. The highest phenol degradation rate occurred at a biofilm thickness of 191-222 µm. The proposed system can be used to investigate microalgal biomass and can provide a promising avenue for research on renewable resources and pollutant degradation.


Asunto(s)
Biopelículas/crecimiento & desarrollo , Tecnología de Fibra Óptica , Microalgas/metabolismo , Fenol/metabolismo , Tecnología de Fibra Óptica/instrumentación , Fenol/química
19.
Environ Sci Pollut Res Int ; 26(23): 23981-23993, 2019 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-31222649

RESUMEN

In order to improve the adsorption efficiency of the adsorbent and solve the problem of separation difficulty, a novel superparamagnetic micro-nano-bio-adsorbent (PDA/Fe3O4/BC) was prepared by in situ self-assembly of polydopamine (PDA). The results of scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier transform infrared spectrometer (FT-IR), X-ray photoelectron spectrometer (XPS), and vibrating sample magnetometer (VSM) characterization showed that the size of bio-adsorbent was about 200 nm. PDA and Fe3O4 modifications increased the specific surface area of adsorbent, changed the surface functional group of biochar (BC), and made the adsorbent have super-high magnetization (294.76 emu g-1). PDA/Fe3O4/BC was applied to treat Cr wastewater. The results show that the adsorption of Cr by PDA/Fe3O4/BC includes single-layer and multilayer adsorption. The adsorption follows the pseudo-second-order kinetic model. The adsorption is spontaneous and endothermic, and its maximum adsorption capacity and activation energy are 25.25 mg g-1 at 318 K and 23.108 kJ mol-1, respectively. After adsorption treatment, PDA/Fe3O4/BC still possesses high magnetization (233.04 emu g-1). PDA/Fe3O4/BC can treat actual electroplating wastewater with Cr(VI) concentration from 20 mg L-1 to less than 0.2 mg L-1, which met the PRC discharge standard (GB/21900-2008) of electroplating pollutants. Graphical abstract.


Asunto(s)
Galvanoplastia , Eliminación de Residuos Líquidos/métodos , Aguas Residuales/química , Contaminantes Químicos del Agua/química , Adsorción , Carbón Orgánico , Cromo , Concentración de Iones de Hidrógeno , Indoles , Iones , Cinética , Nanopartículas de Magnetita/química , Espectroscopía de Fotoelectrones , Polímeros , Espectroscopía Infrarroja por Transformada de Fourier , Contaminantes Químicos del Agua/análisis , Difracción de Rayos X
20.
Appl Opt ; 58(8): 2091-2099, 2019 Mar 10.
Artículo en Inglés | MEDLINE | ID: mdl-30874074

RESUMEN

A photochemical fiber-optic sensor was developed by integrating a plastic optical fiber (POF), polymer membrane, gold mirror, and TiO2-based composite, and was shown to sensitively and selectively detect phenol in aqueous solution. The sensing element consisted of a thinned POF and visible-light-driven SiO2/N-doped TiO2 coating. The gold mirror was used to develop a reflective POF probe. The polymer membrane with high phenol permselectivity was employed to form a micro-channel between the membrane and probe. Our findings highlight the sensor's capability of phenol detection in aqueous solutions with high sensitivity of 0.294×10-3 (mg·L-1)-1, pH immunity ranging from 2.0 to 14.0, and high selectivity with a limit of detection of 30 µg·L-1.

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