scholarly journals A new type of microphotoreactor with integrated optofluidic waveguide based on solid-air nanoporous aerogels

2018 ◽  
Vol 5 (11) ◽  
pp. 180802 ◽  
Author(s):  
Yaprak Özbakır ◽  
Alexandr Jonáš ◽  
Alper Kiraz ◽  
Can Erkey
Keyword(s):  
Methylene Blue ◽  
Total Internal Reflection ◽  
Incident Light ◽  
Liquid Core ◽  
Photochemical Reactions ◽  
Point Of View ◽  
Blue Dye ◽  
New Type ◽  
Aqueous Core ◽  
Low Refractive Index

In this study, we developed a new type of microphotoreactor based on an optofluidic waveguide with aqueous liquid core fabricated inside a nanoporous aerogel. To this end, we synthesized a hydrophobic silica aerogel monolith with a density of 0.22 g cm −3 and a low refractive index of 1.06 that—from the optical point of view—effectively behaves like solid air. Subsequently, we drilled an L-shaped channel within the monolith that confined both the aqueous core liquid and the guided light, the latter property arising due to total internal reflection of light from the liquid–aerogel interface. We characterized the efficiency of light guiding in liquid-filled channel and—using the light delivered by waveguiding—we carried out photochemical reactions in the channel filled with aqueous solutions of methylene blue dye. We demonstrated that methylene blue could be efficiently degraded in the optofluidic photoreactor, with conversion increasing with increasing power of the incident light. The presented optofluidic microphotoreactor represents a versatile platform employing light guiding concept of conventional optical fibres for performing photochemical reactions.

scholarly journals Highly Porous and Ultra-Lightweight Aero-Ga2O3: Enhancement of Photocatalytic Activity by Noble Metals

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1985
Author(s):  
Irina Plesco ◽  
Vladimir Ciobanu ◽  
Tudor Braniste ◽  
Veaceslav Ursaki ◽  
Florian Rasch ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Noble Metals ◽  
Hybrid Structures ◽  
Blue Dye ◽  
Light Illumination ◽  
Methylene Blue Dye ◽  
Visible Light Illumination ◽  
New Type ◽  
Highly Porous

A new type of photocatalyst is proposed on the basis of aero-β-Ga2O3, which is a material constructed from a network of interconnected tetrapods with arms in the form of microtubes with nanometric walls. The aero-Ga2O3 material is obtained by annealing of aero-GaN fabricated by epitaxial growth on ZnO microtetrapods. The hybrid structures composed of aero-Ga2O3 functionalized with Au or Pt nanodots were tested for the photocatalytic degradation of methylene blue dye under UV or visible light illumination. The functionalization of aero-Ga2O3 with noble metals results in the enhancement of the photocatalytic performances of bare material, reaching the performances inherent to ZnO while gaining the advantage of the increased chemical stability. The mechanisms of enhancement of the photocatalytic properties by activating aero-Ga2O3 with noble metals are discussed to elucidate their potential for environmental applications.

Control of Teflon AF 2400 Permeability in a Liquid-Core Waveguide by an Ultra-Thin Crosslinked Polyamide Coating

2002 ◽  
Vol 56 (5) ◽  
pp. 574-578 ◽  
Author(s):  
Obianuju Inya-Agha ◽  
Shona Stewart ◽  
Tincuta Veriotti ◽  
Merlin L. Bruening ◽  
Michael D. Morris
Keyword(s):  
Liquid Core ◽  
Detection Limits ◽  
Subsequent Treatment ◽  
Gas Chromatography Mass Spectrometry ◽  
Raman Spectroscopic ◽  
Teflon Af ◽  
Liquid Core Waveguide ◽  
Aqueous Core ◽  
Capillary Walls ◽  
Low Refractive Index

In the last few years Teflon AF has emerged as the leading material for implementing waveguiding with an aqueous core because of its low refractive index (nD = 1.29). This low index should make it possible for very low limits of detection to be achieved in Teflon AF as a result of the ability to excite with laser light over an increased area. Detection limits have remained high, however, due in part to the porosity of the material. In this communication we report a significant reduction in the permeability of Teflon AF 2400 capillary walls with the deposition and subsequent treatment of polyelectrolyte multilayers. Alternating layers of polycations and polyanions on a bare Teflon AF surface are sufficient to reduce its permeability to small molecules such as methanol and benzene. Crosslinking and deprotonation of these multilayers further reduces permeability to less than 10% of the permeability value through uncoated TAF. As a consequence, detection limits are reduced. Evidence of these results is presented with gas chromatography-mass spectrometry (GC/MS) and Raman spectroscopic measurements.

Using of modified-bentonite as low-cost sorbent for removal of methylene blue dye from aqueous solution

2020 ◽  
Vol 27 (2) ◽  
pp. 45-54
Author(s):  
Saraa Muwafaq Ibrahim ◽  
Ziad T. Abd Ali
Keyword(s):  
Aqueous Solution ◽  
Methylene Blue ◽  
Silanol Group ◽  
Infrared Spectrometry ◽  
Blue Dye ◽  
Ammonium Bromide ◽  
Vibration Band ◽  
Order Kinetic ◽  
Methylene Blue Dye ◽  
Modified Bentonite

Batch experiments have been studied to remove methylene blue dye (MB) from aqueous solution using modified bentonite. The modified bentonite was synthesized by replacing exchangeable calcium cations in natural bentonite with cationic surfactant cetyl trimethyl ammonium bromide (CTAB). The characteristics of modified bentonite were studied using different analysis such as Scanning electronic microscopy (SEM), Fourier transform infrared spectrometry (FTIR) and surface area. Where SEM shows the natural bentonite has a porous structure, a rough and uneven appearance with scattered and different block structure sizes, while the modified bentonite surface morphology was smooth and supplemented by a limited number of holes. On other hand, (FTIR) analysis that proved NH group aliphatic and aromatic group of MB and silanol group are responsible for the sorption of contaminate. The organic matter peaks at 2848 and 2930 cm-1 in the spectra of modified bentonite which are sharper than those of the natural bentonite were assigned to the CH2 scissor vibration band and the symmetrical CH3 stretching absorption band, respectively, also the 2930 cm-1 peak is assigned to CH stretching band. The batch study was provided the maximum removal efficiency (99.99 % MB) with a sorption capacity of 129.87 mg/g at specified conditions (100 mg/L, 25℃, pH 11 and 250rpm). The sorption isotherm data fitted well with the Freundlich isotherm model. The kinetic studies were revealed that the sorption follows a pseudo-second-order kinetic model which indicates chemisorption between sorbent and sorbate molecules.

Adsorption Studies of Methylene Blue Dye using Biosorbents

2018 ◽  
Vol 8 (3) ◽  
pp. 502-513
Author(s):  
Saravanan Narayanan ◽  
Rathika Govindasamy
Keyword(s):  
Methylene Blue ◽  
Blue Dye ◽  
Methylene Blue Dye ◽  
Adsorption Studies

The use of insoluble matter of Moroccan oil shale for removal of dyes from aqueous solution

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Methylene Blue ◽  
Oil Shale ◽  
Heating Temperature ◽  
Blue Dye ◽  
Adsorption Capacities ◽  
Experimental Parameters ◽  
Initial Ph ◽  
New Material ◽  
Activating Agent ◽  
Moderate Cost

The study aims to use an adsorbent natural based of Moroccan oil shale of Timahdit area (Y layer) in a physical-chemical adsorption process for treating industrial discharges colorful. The used adsorbent is the insoluble party of the sub-critical extraction of decarbonized oil shale of Timahdit. The tests performed on the methylene blue (MB), showed a strong elimination in the first 10 minutes. The influences of various experimental parameters were studied: mass ratio of adsorbent, time and temperature of thermal treatment, contact time, pH of MB and heating temperature of solution on the parameters of material were studied. The experimental results have shown that the adsorption of methylene blue dye by the adsorbent is more than 90% at initial pH a range 6-7 at room temperature for 30 minutes. The process is simple and the adsorbent produced is a new material with interesting adsorption capacities of moderate cost which does not require an activating agent and can be used as industrial adsorbent for the decontamination of effluents containing organic pollutants.

scholarly journals Characterization and use of a lignin sample extracted from Eucalyptus grandis sawdust for the removal of methylene blue dye

2021 ◽  
Vol 170 ◽  
pp. 375-389
Author(s):  
Alexandra Cemin ◽  
Fabrício Ferrarini ◽  
Matheus Poletto ◽  
Luis R. Bonetto ◽  
Jordana Bortoluz ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Eucalyptus Grandis ◽  
Blue Dye ◽  
Methylene Blue Dye
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