scholarly journals Photocatalytic Porous Silica-Based Granular Media for Organic Pollutant Degradation in Industrial Waste-Streams

Catalysts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 258
Author(s):  
Hannah M. McIntyre ◽  
Megan L. Hart
Keyword(s):  
Methylene Blue ◽  
Organic Contaminants ◽  
Granular Media ◽  
Pore Space ◽  
Organic Pollutant ◽  
Salt Content ◽  
Porous Silica ◽  
Cost Effective ◽  
High Porosity ◽  
Activation Temperature

Photocatalytic treatment of organic contaminants in industrial wastewaters has gained interest due to their potential for effective degradation. However, photocatalytic slurry reactors are hindered by solution turbidity, dissolved salt content, and absorbance of light. Research presented here introduces the development and application of a novel, photocatalytic, porous silica-based granular media (SGM). SGM retains the cross-linked structure developed during synthesis through a combination of foaming agent addition and activation temperature. The resultant media has a high porosity of 88%, with a specific surface area of ~150 m2/gram. Photocatalytic capabilities are further enhanced as the resultant structure fixes the photocatalyst within the translucent matrix. SGM is capable of photocatalysis combined with diffusion of nucleophiles, electrophiles, and salts from pore space. The photocatalytic efficiencies of SGM at various silica contents were quantified in batch reactors using methylene blue destruction over time and cycles. Methylene blue concentrations of 10 mg/L were effectively degraded (>90%) within 40 min. This effectiveness was retained over multiple cycles and various methylene blue concentrations. SGM is a passive and cost-effective granular treatment system technology which can translate to other organic contaminants and industrial processes.

scholarly journals Electrochemical Degradation of Methylene Blue using a Ni-Co-oxide Anode

Catalysts ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 793
Author(s):  
Emmanuel Onyekachi Nwanebu ◽  
Xiaocheng Liu ◽  
Elmira Pajootan ◽  
Viviane Yargeau ◽  
Sasha Omanovic
Keyword(s):  
Methylene Blue ◽  
Organic Contaminants ◽  
Uv Spectroscopy ◽  
Organic Pollutant ◽  
Oxygen Demand ◽  
Active Species ◽  
Chloride Ions ◽  
Blue Dye ◽  
Electrochemical Degradation ◽  
Oxide Anode

The potential of using thermally prepared Ni0.6Co0.4-oxide for the electrochemical degradation of organic contaminants was investigated using methylene blue (MB) in an aqueous solution, as a model pollutant. The results of UV spectroscopy obtained during galvanostatic electrolyses at the anode indicated the complete removal of the methylene blue dye. The high removal of chemical oxygen demand (COD) and total organic carbon (TOC) suggested a high level of mineralization of its intermediates. It was found that the electrocatalytic performance of the electrode in the anodic degradation of the organic pollutant was significantly enhanced by the presence of chloride ions in the solution. The improvement in the degradation rate of MB was attributed to the in situ electrogeneration of chlorine active species. The results show that Ni0.6Co0.4-oxide anode can be employed as a stable energy-efficient electrocatalyst in the electrochemical purification of wastewater.

Thermocatalytic Degradation of Methylene Blue Using Negative Temperature Coefficient Resistor

2013 ◽  
Vol 726-731 ◽  
pp. 2036-2039 ◽  
Author(s):  
Si Zhao Zhang ◽  
Xue Gang Luo ◽  
Xiao Yan Lin
Keyword(s):  
Methylene Blue ◽  
Thermal Degradation ◽  
Temperature Coefficient ◽  
Organic Contaminants ◽  
Negative Temperature Coefficient ◽  
Adsorption Equilibrium ◽  
Organic Pollutant ◽  
Negative Temperature ◽  
Thermal Treatments ◽  
Degradation Tests

Thermal degradation of organic pollutant was investigated in the presence of negative temperature coefficient resistor (NTC) under thermal treatments of 30°C, 35°C, 40°C and 45°C, respectively. Methylene blue (MB) was used as a model pollutant in this study. The degradation efficiency of MB in aqueous solutions were monitored by UV-vis spectrometry. Catalysts were allowed to adsorb MB to reach adsorption equilibrium before the degradation experiments were started. The results of degradation tests indicated that the best thermocatalytic ability was up to 41.68% in the concentration of 40 mg/L at 35°C within 30 h. Herein the feasibility of thermocatalytic elimination for organic contaminants with heat excitation was successfully demonstrated and the effectiveness of thermal catalyst adopted was also confirmed.

Analisis Variasi Temperatur Aktivasi Terhadap Daya Serap Arang Aktif Tandan Aren (Arenga Pinnata Merr) Dengan Agen Aktivasi Potassium Silicate(K2SiO3)

2020 ◽  
Vol 5 (3) ◽  
pp. 221
Author(s):  
Muhammad Azam ◽  
Muhammad Anas ◽  
Erniwati Erniwati
Keyword(s):  
Methylene Blue ◽  
Activated Carbon ◽  
Adsorption Capacity ◽  
Temperature Variation ◽  
Chemical Activation ◽  
Weight Ratio ◽  
Potassium Silicate ◽  
Physical Activation ◽  
Activation Temperature ◽  
Pyrolysis Reactor

This study aims to determine the effect of variation of activation temperature of activated carbon from sugar palm bunches of chemically activatied with the activation agent of potassium silicate (K2SiO3) on the adsorption capacity of iodine and methylene blue. Activated carbon from bunches of sugar palmacquired in four steps: preparationsteps, carbonizationstepsusing the pyrolysis reactor with temperature of 300 oC - 400 oC for 8 hours and chemical activation using of potassium silicate (K2SiO3) activator in weight ratio of 2: 1 and physical activation using the electric furnace for 30 minutes with temperature variation of600 oC, 650 oC, 700 oC, 750 oC and 800 oC. The iodine and methyleneblue adsorption testedby Titrimetric method and Spectrophotometry methodrespectively. The results of the adsorption of iodine and methylene blue activated carbon from sugar palm bunches increased from 240.55 mg/g and 63.14 mg/g at a temperature of 600 oC to achieve the highest adsorption capacity of 325.80 mg/g and 73.59 mg/g at temperature of 700 oC and decreased by 257.54 mg/g and 52.03 mg/g at a temperature of 800 oCrespectively.However, it does not meet to Indonesia standard (Standard Nasional Indonesia/SNI), which is 750 mg/g and 120 mg/g respectively.

scholarly journals A Novel Method for the Preparation of Fibrous CeO2–ZrO2–Y2O3 Compacts for Thermochemical Cycles

Crystals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 885
Author(s):  
Nicole Knoblauch ◽  
Peter Mechnich
Keyword(s):  
Large Scale ◽  
Preparation Method ◽  
Cost Effective ◽  
High Porosity ◽  
Thermochemical Cycles ◽  
Redox Cycles ◽  
Redox Kinetics ◽  
Direct Infiltration ◽  
Novel Method ◽  
Functional Components

Zirconium-Yttrium-co-doped ceria (Ce0.85Zr0.13Y0.02O1.99) compacts consisting of fibers with diameters in the range of 8–10 µm have been successfully prepared by direct infiltration of commercial YSZ fibers with a cerium oxide matrix and subsequent sintering. The resulting chemically homogeneous fiber-compacts are sinter-resistant up to 1923 K and retain a high porosity of around 58 vol% and a permeability of 1.6–3.3 × 10−10 m² at a pressure gradient of 100–500 kPa. The fiber-compacts show a high potential for the application in thermochemical redox cycling due its fast redox kinetics. The first evaluation of redox kinetics shows that the relaxation time of oxidation is five times faster than that of dense samples of the same composition. The improved gas exchange due to the high porosity also allows higher reduction rates, which enable higher hydrogen yields in thermochemical water-splitting redox cycles. The presented cost-effective fiber-compact preparation method is considered very promising for manufacturing large-scale functional components for solar-thermal high-temperature reactors.

scholarly journals Derivation of Luminescent Mesoporous Silicon Nanocrystals from Biomass Rice Husks by Facile Magnesiothermic Reduction

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 613
Author(s):  
Sankar Sekar ◽  
Sejoon Lee
Keyword(s):  
Brown Rice ◽  
Total Pore Volume ◽  
Cost Effective ◽  
High Porosity ◽  
Magnesiothermic Reduction ◽  
Rice Husks ◽  
Average Pore ◽  
Efficient Catalyst ◽  
Mesoporous Silicon ◽  
Si Nanocrystals

High-quality silicon (Si) nanocrystals that simultaneously had superior mesoporous and luminescent characteristics were derived from sticky, red, and brown rice husks via the facile and cost-effective magnesiothermic reduction method. The Si nanocrystals were confirmed to comprise an aggregated morphology with spherical nanocrystals (e.g., average sizes of 15–50 nm). Due to the surface functional groups formed at the nanocrystalline Si surfaces, the Si nanocrystals clearly exhibited multiple luminescence peaks in visible-wavelength regions (i.e., blue, green, and yellow light). Among the synthesized Si nanocrystals, additionally, the brown rice husk (BRH)-derived Si nanocrystals showed to have a strong UV absorption and a high porosity (i.e., large specific surface area: 265.6 m2/g, small average pore diameter: 1.91 nm, and large total pore volume: 0.5389 cm3/g). These are indicative of the excellent optical and textural characteristics of the BRH-derived Si nanocrystals, compared to previously reported biomass-derived Si nanocrystals. The results suggest that the biomass BRH-derived Si nanocrystals hold great potential as an active source material for optoelectronic devices as well as a highly efficient catalyst or photocatalyst for energy conversion devices.

scholarly journals Study on microcrystalline cellulose/chitosan blend foam gel material

2020 ◽  
Vol 27 (1) ◽  
pp. 424-432
Author(s):  
Hongkai Zhao ◽  
Kehan Zhang ◽  
Shoupeng Rui ◽  
Peipei Zhao
Keyword(s):  
Microcrystalline Cellulose ◽  
Raw Materials ◽  
Pore Space ◽  
Sodium Dodecyl ◽  
Cost Effective ◽  
High Water ◽  
Aldehyde Group ◽  
Sem Analysis ◽  
Present Contribution ◽  
Bet Analysis

AbstractIn the present contribution, an environmental-friendly and cost-effective adsorbent was reported for soil treatment and desertification control. A novel foam gel material was synthesized here by the physical foaming in the absence of catalyst. By adopting modified microcrystalline cellulose and chitosan as raw materials and sodium dodecyl sulfonate (SDS) as foaming agent, a microcrystalline cellulose/chitosan blend foam gel was synthesized. It is expected to replace polymers derived from petroleum for agricultural applications. In addition, a systematical study was conducted on the adsorbability, water holding capacity and re-expansion performance of foam gel in deionized water and brine under different SDS concentrations (2%–5%) as well as adsorption time. To be specific, the adsorption capacity of foam gel was up to 105g/g in distilled water and 54g/g in brine, indicating a high water absorption performance. As revealed from the results of Fourier transform infrared spectroscopy (FTIR) analysis, both the amino group of chitosan and the aldehyde group modified by cellulose were involved. According to the results of Scanning electron microscope (SEM) analysis, the foam gel was found to exhibit an interconnected pore network with uniform pore space. As suggested by Bet analysis, the macroporous structure was formed in the sample, and the pore size ranged from 0 to 170nm. The mentioned findings demonstrated that the foam gel material of this study refers to a potential environmental absorbent to improve soil and desert environments. It can act as a powerful alternative to conventional petroleum derived polymers.

Permeability-porosity transforms from small sandstone fragments

Geophysics ◽  
2006 ◽  
Vol 71 (1) ◽  
pp. N11-N19 ◽  
Author(s):  
Ayako Kameda ◽  
Jack Dvorkin ◽  
Youngseuk Keehm ◽  
Amos Nur ◽  
William Bosl
Keyword(s):  
Pore Space ◽  
Petroleum Industry ◽  
Rock Physics ◽  
Three Dimensions ◽  
Absolute Permeability ◽  
High Porosity ◽  
Drill Cuttings ◽  
Thin Sections ◽  
Numerical Experimentation ◽  
The Absolute

Numerical simulation of laboratory experiments on rocks, or digital rock physics, is an emerging field that may eventually benefit the petroleum industry. For numerical experimentation to find its way into the mainstream, it must be practical and easily repeatable — i.e., implemented on standard hardware and in real time. This condition reduces the size of a digital sample to just a few grains across. Also, small physical fragments of rock, such as cuttings, may be the only material available to produce digital images. Will the results be meaningful for a larger rock volume? To address this question, we use a number of natural and artificial medium- to high-porosity, well-sorted sandstones. The 3D microtomography volumes are obtained from each physical sample. Then, analogous to making thin sections of drill cuttings, we select a large number of small 2D slices from a 3D scan. As a result, a single physical sample produces hundreds of 2D virtual-drill-cuttings images. Corresponding 3D pore-space realizations are generated statistically from these 2D images; fluid flow is simulated in three dimensions, and the absolute permeability is computed. The results show that small fragments of medium– to high-porosity sandstones that are statistically subrepresentative of a larger sample will not yield the exact porosity and permeability of the sample. However, a significant number of small fragments will yield a site-specific permeability-porosity trend that can then be used to estimate the absolute permeability from independent porosity data obtained in the well or inferred from seismic techniques.

scholarly journals Transformation of Glass Fiber Waste into Mesoporous Zeolite-Like Nanomaterials with Efficient Adsorption of Methylene Blue

2021 ◽  
Vol 13 (11) ◽  
pp. 6207
Author(s):  
Cheng-Kuo Tsai ◽  
Jao-Jia Horng
Keyword(s):  
Methylene Blue ◽  
Glass Fiber ◽  
Environmental Concern ◽  
Cost Effective ◽  
Environmentally Benign ◽  
Mesoporous Zeolite ◽  
Trace Metal Ions ◽  
Langmuir Adsorption ◽  
Ceramic Ring ◽  
Cost Effective Method

Recycling and reusing glass fiber waste (GFW) has become an environmental concern, as the means of disposal are becoming limited as GFW production increases. Therefore, this study developed a novel, cost-effective method to turn GFW into a mesoporous zeolite-like nanomaterial (MZN) that could serve as an environmentally benign adsorbent and efficient remover of methylene blue (MB) from solutions. Using the Taguchi optimizing approach to hydrothermal alkaline activation, we produced analcime with interconnected nanopores of about 11.7 nm. This MZN had a surface area of 166 m2 g−1 and was negatively charged with functional groups that could adsorb MB ranging from pH 2 to 10 and all with excellent capacity at pH 6.0 of the maximum Langmuir adsorption capacity of 132 mg g−1. Moreover, the MZN adsorbed MB exothermically, and the reaction is reversible according to its thermodynamic parameters. In sum, this study indicated that MZN recycled from glass fiber waste is a novel, environmentally friendly means to adsorb cation methylene blue (MB), thus opening a gateway to the design and fabrication of ceramic-zeolite and tourmaline-ceramic balls and ceramic ring-filter media products. In addition, it has environmental applications such as removing cation dyes and trace metal ions from aqueous solutions and recycling water.

scholarly journals A Review of Composite Phase Change Materials Based on Porous Silica Nanomaterials for Latent Heat Storage Applications

Molecules ◽  
2021 ◽  
Vol 26 (1) ◽  
pp. 241
Author(s):  
Raul-Augustin Mitran ◽  
Simona Ioniţǎ ◽  
Daniel Lincu ◽  
Daniela Berger ◽  
Cristian Matei
Keyword(s):  
Phase Change ◽  
Latent Heat ◽  
Phase Change Materials ◽  
Heat Storage ◽  
Porous Silica ◽  
Lessons Learned ◽  
High Porosity ◽  
Storage Materials ◽  
Silica Nanomaterials ◽  
Heat Storage Materials

Phase change materials (PCMs) can store thermal energy as latent heat through phase transitions. PCMs using the solid-liquid phase transition offer high 100–300 J g−1 enthalpy at constant temperature. However, pure compounds suffer from leakage, incongruent melting and crystallization, phase separation, and supercooling, which limit their heat storage capacity and reliability during multiple heating-cooling cycles. An appropriate approach to mitigating these drawbacks is the construction of composites as shape-stabilized phase change materials which retain their macroscopic solid shape even at temperatures above the melting point of the active heat storage compound. Shape-stabilized materials can be obtained by PCMs impregnation into porous matrices. Porous silica nanomaterials are promising matrices due to their high porosity and adsorption capacity, chemical and thermal stability and possibility of changing their structure through chemical synthesis. This review offers a first in-depth look at the various methods for obtaining composite PCMs using porous silica nanomaterials, their properties, and applications. The synthesis and properties of porous silica composites are presented based on the main classes of compounds which can act as heat storage materials (paraffins, fatty acids, polymers, small organic molecules, hydrated salts, molten salts and metals). The physico-chemical phenomena arising from the nanoconfinement of phase change materials into the silica pores are discussed from both theoretical and practical standpoints. The lessons learned so far in designing efficient composite PCMs using porous silica matrices are presented, as well as the future perspectives on improving the heat storage materials.

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