scholarly journals Enhanced photocatalytic degradation performance of bisphenol A over TiO2-SiO2 photocatalyst by improving specific surface area under simulation natural light

2020 ◽  
Vol 9 (4) ◽  
pp. 49-57
Author(s):  
Minh-Vien Le ◽  
Tai Huynh Huu ◽  
Oanh Nguyen Thi Kieu ◽  
Thang Ngo Manh ◽  
Suong Ho Thi Ngoc
Keyword(s):  
Bisphenol A ◽  
Specific Surface ◽  
Photocatalytic Degradation ◽  
Surface Area ◽  
Specific Surface Area ◽  
Organic Pollutant ◽  
Molar Ratio ◽  
Natural Light ◽  
Solution Ph ◽  
Initial Concentration

The application of natural light in photocatalytic process is a potential energy source. In this study, TiO2-SiO2 nanoparticles with outstandingly enhanced photocatalytic activity have been fabricated by sol-gel method. The prepared photocatalysts with different molar ratio of TiO2:SiO2 as 100:0; 95:5; 85:15 and 75:25 were denoted as TiO2, TS5, TS15 and TS25, respectively. Characterization of these photocatalysts was evaluated using transmission electron microscopy (TEM), X-ray diffraction (XRD), N2 Adsorption and Desorption isotherms method (Brunauer–Emmet–Teller, BET). The specific surface area was improved in TiO2-SiO2 photocatalyst namely 193.9 m2.g-1 (at molar ratio of TiO2:SiO2 of 95:5) compared to 33.6 m2.g-1 of TiO2. The crystallite size was calculated around 5 nm from XRD data and uniform particle size distribution was observed in TEM image. The photocatalytic experiments were performed with bisphenol A (BPA) as model compound of organic pollutant. The effect of various operation parameters such as initial concentration, initial solution pH and photocatalyst dosage has been investigated. The kinetic studies of the photocatalytic degradation BPA over TS5 followed the pseudo-first order (k=1.09×10-2 min-1) and degradation yield to be 82.4% BPA, at pH6.23, initial concentration to be 10 ppm and photocatalyst dosage to be 1.0 g.L-1. The photocatalyst TS5 maintained activity after four cycles and remained 78%. The TiO2-SiO2 composite photocatalyst has shown to be a promising heterogeneous photocatalyst for organic degradation.

Preparation of Sands Modified by Aluminous Salt and its Adsorption Capability of CD2+

2011 ◽  
Vol 130-134 ◽  
pp. 856-859
Author(s):  
Chun Sheng Ding ◽  
Yang Ping Fu ◽  
Qian Fen Zhu ◽  
Jing Fu
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Influencing Factors ◽  
Removal Efficiency ◽  
Specific Surface Area ◽  
Quartz Sand ◽  
Ph Value ◽  
Alkaline Condition ◽  
Initial Concentration ◽  
Adsorption Capability

In this experiment quartz sand was chosen as a carrier to be coated by aluminous salt under alkaline condition, and then the specific surface area was tested, and the adsorption capability and Cd2+ removal influencing factors of modified sand were studied. The investigation results showed that the specific surface area of modified sand was 75.244m2/g which was 9.38 times of that of original sand; the removal efficiency of Cd2+ by aluminous salt modified sand reached 59% contrast to 39% of original sand with pH 7.00. It was also found that the removal efficiency of Cd2+ by the aluminous salt modified sand was reduced with the increase of initial concentration of Cd2+ solution, and was enhanced with the increase of pH value, the Cd2+ removal efficiency was almost 71% with pH 9.0.

The Influence of Fe/Al Molar Ratio on Microreactor-Based Catalyst Preparation and Carbon Nanotube Preparation

2021 ◽  
Vol 1036 ◽  
pp. 130-136
Author(s):  
Ting Qun Tan ◽  
Lei Geng ◽  
Yan Lin ◽  
Yan He
Keyword(s):  
Carbon Nanotubes ◽  
Catalytic Activity ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Small Diameter ◽  
High Specific Surface Area ◽  
Detection Methods ◽  
Molar Ratio ◽  
High Catalytic Activity

In order to prepare carbon nanotubes with high specific surface area, small diameter, low resistivity, high purity and high catalytic activity, the Fe-Mo/Al2O3 catalyst was prepared based on the microreactor. The influence of different Fe/Al molar ratios on the catalyst and the carbon nanotubes prepared was studied through BET, SEM, TEM and other detection methods. Studies have shown that the pore structure of the catalyst is dominated by slit pores at a lower Fe/Al molar ratio. The catalytic activity is the highest when the Fe/Al molar ratio is 1:1, reaching 74.1%. When the Fe/Al molar ratio is 1:2, the catalyst has a higher specific surface area, the maximum pore size is 8.63 nm, and the four-probe resistivity and ash content of the corresponding carbon nanotubes are the lowest. The higher the proportion of aluminum, the higher the specific surface area of the catalyst and the carbon nanotubes, and the finer the diameter of the carbon nanotubes, which gradually tends to relax. The results show that when the Fe/Al molar ratio is 1:2, although the catalytic activity of the catalyst is not the highest, the carbon nanotubes prepared have the best performance.

scholarly journals Adsorption of pharmaceuticals from aqueous solutions using biochar derived from cotton gin waste and guayule bagasse

Biochar ◽  
2020 ◽  
Author(s):  
Marlene C. Ndoun ◽  
Herschel A. Elliott ◽  
Heather E. Preisendanz ◽  
Clinton F. Williams ◽  
Allan Knopf ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Functional Groups ◽  
Specific Surface Area ◽  
High Surface ◽  
Strong Interactions ◽  
Solution Ph ◽  
Experimental Conditions ◽  
Cotton Gin Waste ◽  
Cotton Gin

Abstract Biochars produced from cotton gin waste (CG) and guayule bagasse (GB) were characterized and explored as potential adsorbents for the removal of pharmaceuticals (sulfapyridine-SPY, docusate-DCT and erythromycin-ETM) from aqueous solution. An increase in biochar pyrolysis temperature from 350 οC to 700 οC led to an increase in pH, specific surface area, and surface hydrophobicity. The electronegative surface of all tested biochars indicated that non-Coulombic mechanisms were involved in adsorption of the anionic or uncharged pharmaceuticals under experimental conditions. The adsorption capacities of Sulfapyridine (SPY), Docusate (DCT) and Erythromycin (ETM) on biochar were influenced by the contact time and solution pH, as well as biochar specific surface area and functional groups. Adsorption of these pharmaceutical compounds was dominated by a complex interplay of three mechanisms: hydrophobic partitioning, hydrogen bonding and π–π electron donor–acceptor (EDA) interactions. Despite weaker π–π EDA interactions, reduced hydrophobicity of SPY− and increased electrostatic repulsion between anionic SPY− and the electronegative CG biochar surface at higher pH, the adsorption of SPY unexpectedly increased from 40% to 70% with an increase in pH from 7 to 10. Under alkaline conditions, adsorption was dominated by the formation of strong negative charge-assisted H-bonding between the sulfonamide moiety of SPY and surface carboxylic groups. There seemed to be no appreciable and consistent differences in the extent of DCT and ETM adsorption as the pH changed. Results suggest the CG and GB biochars could act as effective adsorbents for the removal of pharmaceuticals from reclaimed water prior to irrigation. High surface area biochars with physico-chemical properties (e.g., presence of functional groups, high cation and anion exchange capacities) conducive to strong interactions with polar-nonpolar functionality of pharmaceuticals could be used to achieve significant contaminant removal from water. Graphic Abstract

Bi2WO6 Nanoparticles Prepared by Combustion Synthesis with Different Fuels and their Photocatalytic Activity

2014 ◽  
Vol 604 ◽  
pp. 93-101
Author(s):  
Maris Kodols ◽  
Sabine Didrihsone ◽  
Janis Grabis
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Citric Acid ◽  
Ethylene Glycol ◽  
Specific Surface ◽  
Crystallite Size ◽  
Combustion Synthesis ◽  
Surface Area ◽  
Specific Surface Area ◽  
Solution Ph

The influence of glycine, glycerine, ethylene glycol and citric acid fuel and their ratio to NO3- on formation and dispersity of Bi2WO6 nanoparticles prepared by combustion synthesis has been studied. The pure crystalline Bi2WO6 with specific surface area 24,8 m2/g and crystallite size of 28 nm was obtained by using glycerine as fuel at its ratio to NO3- of 0,67. The photocatalytic activity of the prepared Bi2WO6 in degradation of methylene blue depended on its specific surface area of samples and solution pH.

scholarly journals Photocatalytic degradation of metoxuron in aqueous suspensions ofTiO2. Analytical and kinetic studies

2002 ◽  
Vol 4 (4) ◽  
pp. 147-151 ◽  
Author(s):  
Amina Amine Khodja ◽  
Bernadette Lavedrine ◽  
Claire Richard ◽  
Tahar Sehili
Keyword(s):  
Photocatalytic Activity ◽  
Specific Surface ◽  
Photocatalytic Degradation ◽  
Surface Area ◽  
Specific Surface Area ◽  
Kinetic Studies ◽  
Photocatalytic Efficiency ◽  
Aqueous Suspensions ◽  
Degussa P25 ◽  
Ring Hydroxylation

The photocatalytic degradation of metoxuron [3-(3-chloro-4-methoxyphenyl)-1,1-dimethylurea] in aqueous suspensions ofTiO2was investigated. Several intermediate photoproducts were identified using NMR and MS techniques. Oxidation or removal of the methyl of terminal nitrogen and ring hydroxylation were found to occur. 2-Propanol was shown to decrease the rate of photocatalytic degradation, inhibiting partly ring hydroxylation and completely reactions on terminal nitrogen. In contrast, basification of the suspensions accelerated the degradation significantly. Degussa P25TiO2was found to exhibit a higher photocatalytic activity than MillenniumTiO2in spite of a generally smaller specific surface area. Within the MillenniumTiO2series, the photocatalytic efficiency increased with the specific surface area.

Effect of pH, Molar Ratio of Fuel to Nitrates and Calcination Temperature on the Glycine-Nitrate Synthesis of Nano CoAl2O4

2010 ◽  
Vol 68 ◽  
pp. 176-181 ◽  
Author(s):  
Seyyed Hamid Jazayeri ◽  
Federica Bondioli ◽  
Shiva Salem ◽  
Ali Allahverdi ◽  
Mansoor Shirvani ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Calcination Temperature ◽  
Specific Surface Area ◽  
Precursor Solution ◽  
Molar Ratio ◽  
Effect Of Ph ◽  
Molar Ratios ◽  
Metal Nitrates ◽  
Powder Characteristics

In this research, solution-based combustion synthesis is applied to prepare the spinel CoAl2O4 pigment from precursor solution of Al(NO3)3 .9H2O, Co(NO3)2 .6H2O and glycine. Effect of pH values (2.5, 7, 10.5), molar ratio of fuel to metal nitrates in the precursor solutions (1.5, 2) and subsequent calcination temperature (800, 1000, 1200 °C) on the powder characteristics are described. Gel formation, morphologies, specific surface area and colour of the powder are characterized using DTA/TG, XRD, TEM, BET and UV-Vis. The results indicate that the crystalline spinel CoAl2O4 is formed at all different Gl/(metal nitrates) molar ratios, pH and temperatures and higher temperature promote the increase of the crystallite size. According to TEM figures most of the particles calcined at 800 and 1000 °C has sizes less than 50 and 100 nm, respectively. Corresponding to results of BET experiment, specific surface area has its maximum values at pH 7 and decreases with increasing of temperature. Finally, colorability test indicates the complete stability of the synthesized powder in the glass matrix.

Preparation and Characterization of Ultralow Density Silica Aerogels by Acetonitrile Supercritical Drying

2012 ◽  
Vol 519 ◽  
pp. 83-86 ◽  
Author(s):  
Guang Wu Liu ◽  
Xing Yuan Ni ◽  
Bin Zhou ◽  
Qiu Jie Yu
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Silica Aerogel ◽  
Sol Gel ◽  
Supercritical Drying ◽  
Silica Aerogels ◽  
High Specific Surface Area ◽  
Molar Ratio ◽  
Sol Gel Process

This paper deals with the synthesis of ultralow density silica aerogels using tetramethyl orthosilicate (TMOS) as the precursor via sol-gel process followed by supercritical drying using acetonitrile solvent extraction. Ultralow density silica aerogels with 6 mg/cc of density was made for the molar ratio by this method. The microstructure and morphology of the ultralow density silica aerogels was characterized by the specific surface area, SBET, SEM, and the pore size distribution techniques. The results show that the ultralow density silica aerogel has the high specific surface area of 812m2/g. Thermal conductivities at desired temperatures were analyzed by the transient plane heat source method. Thermal conductivity coefficients of silica aerogel monoliths changed from 0.024 to 0.043W/ (m K) as temperature increased to 400°C, revealed an excellent heat insulation effect during thermal process.

Hydrothermal synthesis of Sm-doped Bi2WO6 flower-like microspheres for photocatalytic degradation of rhodamine B

CrystEngComm ◽  
2019 ◽  
Vol 21 (41) ◽  
pp. 6208-6218 ◽  
Author(s):  
Xianghui Zhang ◽  
Mingming Zhang ◽  
Kaixuan Cao
Keyword(s):  
Hydrothermal Synthesis ◽  
Optical Absorption ◽  
Specific Surface ◽  
Photocatalytic Degradation ◽  
Surface Area ◽  
Specific Surface Area ◽  
Rhodamine B

Sm-doped Bi2WO6 with 3D flower-like microspheres structure shows extremely high photodegradation activity and superior stability and reusability because of the optimum optical absorption activity and the larger specific surface area.

scholarly journals Adsorption of Cr(VI) Ions using Activated Carbon Produced from Indian Water Chestnut (Trapa natans) Peel Powder

2020 ◽  
Vol 32 (4) ◽  
pp. 876-880
Author(s):  
Maninder Singh ◽  
D. P. Tiwari ◽  
Mamta Bhagat
Keyword(s):  
Heavy Metals ◽  
Metal Ions ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Metal Ion ◽  
Ion Concentration ◽  
Solution Ph ◽  
Indian Water ◽  
Trapa Natans

The indiscriminate discharge of heavy metals into water and soil from anthropogenic practices is becoming prominent threat to the environment. Heavy metals like chromium, cadmium, lead, arsenic, nickel etc. are heavily toxic and carcinogenic in nature. This study emphasizes the adequacy of activated water chest nut (Trapa natans) peel powder as a new adsorbent material for removal of chromium(VI) metal ions. Adsorption experiments were performed in batch process. Various process parameters like contact time, temperature, solution pH, dose of adsorbent, metal ion concentration etc. were optimized. The physico-chemical properties of adsorbent material were characterized by FTIR and XRD. The morphology, topology of adsorbent surface was characterized by scanning electron microscopy (SEM) and Brunauer, Emmett and Teller (BET) which revealed a highly porous structure and available specific surface area. The adsorption capacity (maximum) was counted as 59.17 mg/g and specific surface area was found 23.467 m2/g at a pH 7. The adsorption process for Cr(VI) ions was in a good agreement with Langmuir isotherm. The process also followed pseudo second order kinetics. The obtained result shows that activated water chest nut (Trapa natans) peel powder (AWCPP) can be a hopeful low-cost and eco-friendly bio-adsorbent for removal of Cr(VI) metal ions and also better adsorbent than other various reported adsorbents.

Visible light responsive mesoporous graphene–Eu2O3/TiO2 nanocomposites for the efficient photocatalytic degradation of 4-chlorophenol

RSC Advances ◽  
2016 ◽  
Vol 6 (41) ◽  
pp. 35024-35035 ◽  
Author(s):  
Mallanaicker Myilsamy ◽  
Mani Mahalakshmi ◽  
Nallasivam Subha ◽  
Ariyamuthu Rajabhuvaneswari ◽  
Velayutham Murugesan
Keyword(s):  
Charge Transfer ◽  
Visible Light ◽  
Specific Surface ◽  
Photocatalytic Degradation ◽  
Surface Area ◽  
Specific Surface Area ◽  
Red Shift ◽  
Transfer Efficiency ◽  
Co Doped

Graphene and europium co-doped on TiO2 nanocomposites synergistically enhanced the photocatalytic degradation of 4-chlorophenol under visible light due to the enhanced specific surface area with red shift and improved charge transfer efficiency.

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