Light-Enhanced Adsorptive Desulfurization of Dibenzothiophene Using Supported TiO2-ZrO2

2019 ◽  
Vol 798 ◽  
pp. 391-396
Author(s):  
Sukanya Thepwatee ◽  
Nitipon Chekuntod ◽  
Atisayapan Chanchawee ◽  
Pawnprapa Pitakjakpipop

Combustion of diesel fuel containing sulfur compounds emits SOx into atmosphere causing acid rain and respiratory illness in human. Dibenzothiophene (DBT) is one of the most difficult sulfur compounds in diesel to be removed by hydrodesulfurization (HDS). To produce ultra-low sulfur diesel (<15 ppmw-S), severe operating condition is required. As a result, production cost is increase. In this work, we investigated an alternative method for sulfur removal called Light-enhanced Adsorptive Desulfurization or L-ADS using supported TiO2-ZrO2. The TiO2-ZrO2 was loaded on commercial γ-Al2O3, fumed silica (FS), silica gel (SG) and zeolite (Z30) by wet-impregnation method. Impact of these supports on DBT removal were focused. Characteristic of the supported TiO2-ZrO2 was analyzed by N2 adsorption-desorption, scanning electron microscopy equipped with energy dispersive spectroscopy (SEM-EDS), and UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS). The presence of TiO2-ZrO2 greatly enhanced DBT removal compared to TiO2 and ZrO2. SG promoted DBT removal by facilitating the adsorption of dibenzothiophene sulfone (DBTO2), a product of DBT photocatalytic oxidation. Using TiO2-ZrO2/SG, 86% of sulfur was removed from 50 ppmw-S DBT/C16 within 4 h.

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2209 ◽  
Author(s):  
Jing Liu ◽  
Xiao-Min Li ◽  
Jing He ◽  
Lu-Ying Wang ◽  
Jian-Du Lei

A core-shell Cu-benzene-1,3,5-tricarboxylic acid (Cu-BTC)@TiO2 was successfully synthesized for photocatalysis-assisted adsorptive desulfurization to improve adsorptive desulfurization (ADS) performance. Under ultraviolet (UV) light irradiation, the TiO2 shell on the surface of Cu-BTC achieved photocatalytic oxidation of thiophenic S-compounds, and the Cu-BTC core adsorbed the oxidation products (sulfoxides and sulfones). The photocatalyst and adsorbent were combined using a distinct core-shell structure. The morphology and structure of the fabricated Cu-BTC@TiO2 microspheres were verified by scanning electron microscopy, high-resolution transmission electron microscopy, energy-dispersive x-ray spectroscopy, X-ray powder diffraction, nitrogen adsorption-desorption and X-ray photoelectron spectroscopy analyses. A potential formation mechanism of Cu-BTC@TiO2 is proposed based on complementary experiments. The sulfur removal efficiency of the microspheres was evaluated by selective adsorption of benzothiophene (BT) and dibenzothiophene (DBT) from a model fuel with a sulfur concentration of 1000 ppmw. Within a reaction time of 20 min, the BT and DBT conversion reached 86% and 95%, respectively, and achieved ADS capacities of 63.76 and 59.39 mg/g, respectively. The BT conversion and DBT conversion obtained using Cu-BTC@TiO2 was 6.5 and 4.6 times higher, respectively, than that obtained using Cu-BTC. A desulfurization mechanism was proposed, the interaction between thiophenic sulfur compounds and Cu-BTC@TiO2 microspheres was discussed, and the kinetic behavior was analyzed.


2020 ◽  
Vol 21 (1) ◽  
pp. 23-31
Author(s):  
Hussam Jumaah Mousa ◽  
Hussein Qasim Hussein

The present research was conducted to reduce the sulfur content of Iraqi heavy naphtha by adsorption using different metals oxides over Y-Zeolite. The Y-Zeolite was synthesized by a sol-gel technique. The average size of zeolite was 92.39 nm, surface area 558 m2/g, and pore volume 0.231 cm3/g. The metals of nickel, zinc, and copper were dispersed by an impregnation method to prepare Ni/HY, Zn/HY, Cu/HY, and Ni + Zn /HY catalysts for desulfurization. The adsorptive desulfurization was carried out in a batch mode at different operating conditions such as mixing time (10,15,30,60, and 600 min) and catalyst dosage (0.2,0.4,0.6,0.8,1, and 1.2 g). The most of the sulfur compounds were removed at 10 min for all catalyst types. The maximum sulfur removal was 56% using (Ni+Zn)/HY catalyst at 1.2 g dose for 24 h. The adsorption kinetics and isotherm of sulfur removal were studied, and results indicated that desulfurization adsorption kinetic was 2nd order, and Temkin and Freundlich models were the best representation isotherm.


2015 ◽  
Vol 1107 ◽  
pp. 341-346
Author(s):  
Wan Nazwanie Wan Abdullah ◽  
Rusmidah Ali ◽  
Wan Azelee Wan Abu Bakar

Due to the low specifications for sulfur content in diesel, a lot of research work are been conducted to develop alternative method for desulfurization. Catalytic oxidative desulfurization (Cat-ODS) has been found to be an alternative method to replace a conventional method which is hydrodesulfurization.New catalyst formulation using tert-butyl hydroperoxide polymolybdate based catalyst system was investigated in this research utilizing tert-butyl hydroperoxide (TBHP) as oxidant and dimethylformamide (DMF) as solvent for extraction. A series of polymolybdate supported alumina catalysts were prepared using wet impregnation method, ageing at ambient room temperature for 24 hours and followed by calcination process. A commercial diesel with 440 ppmw of total sulfur was employed to evaluate the elimination of sulfur compounds. Besides, the percentage of sulfur removal was measured by gas chromatography-flame photometric detector (GC-FPD). The sulfur content in commercial diesel was successfully reduced from 440 ppmw to 35 ppmw under mild condition followed by solvent extraction. From catalytic testing, Mo-Al2O3 calcined at 500°C was revealed as the most potential catalyst which gave 92% of sulfur removal.


2013 ◽  
Vol 448-453 ◽  
pp. 169-173
Author(s):  
Chun Yan Yan ◽  
Wen Tao Yi

Pure and F, Fe-codoped TiO2 were prepared by sol-hydrothermal process, in which titanium (IV) n-butoxide, Fe (NO3)2·6H2O and NH4F were used as precursors. And the samples were characterized by X-ray diffraction (XRD), UV-vis diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM), and N2 adsorption-desorption method. The results showed that the F, Fe-codoped samples were principally single-phase anatase structures, and the particles possessed higher BET area than that of pure TiO2. The photocatalytic activity and reusability of the catalysts under UV light (365nm) was investigated with neutral red as the model compound. The results showed that F (2.0%), Fe (4.0%) codoped TiO2 had the highest photocatalytic activity among all as-prepared samples. The kinetic study showed that this photocatalytic process coincided with the Langmuir-Hinshelwood (L-H) pseudo first order reaction model.


2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Manuel Sánchez-Cantú ◽  
Clara Barcelos-Santiago ◽  
Claudia M. Gomez ◽  
Esthela Ramos-Ramírez ◽  
Ma. de Lourdes Ruiz Peralta ◽  
...  

Three hydrocalumite-like compounds in a Ca/Al ratio of 2 containing nitrate and acetate anions in the interlaminar region were prepared by a simple, economic, and environmentally friendly method. The solids were characterized by X-ray powder diffraction (XRD), thermogravimetric (TG) analysis, nitrogen adsorption-desorption at −196°C, scanning electron microscopy (SEM), infrared spectroscopy (FTIR), and UV-Vis Diffuse Reflectance Spectroscopy (DRS). The catalytic activity of the calcined solids at 700°C was tested in the photodegradation of 2,4-dichlorophenoxyacetic acid (2,4-D) where 57% degradation of 2,4-D (40 ppm) and a mineralization percentage of 60% were accomplished within 150 minutes. The photocatalytic properties were attributed to mayenite hydration, since the oxide ions in the cages are capable of reacting with water to form hydroxide anions capable of breaking down the 2,4-D molecules.


Author(s):  
S. Belaidi ◽  
L. Mammeri ◽  
H. Mechakra ◽  
W. Remache ◽  
K. Benhamouda ◽  
...  

Abstract In this study we demonstrate the efficiency of a natural mineral as a photocalyst. This natural mineral was provided from the iron ore deposit from Chaabet-El-Ballout which is located in North-East of Algeria. The characterization analysis of the mineral by the Energy-dispersive X-ray spectroscopy (EDX) revealed that the natural powder has a mixed elemental composition and consist mainly of iron oxide with 50 % of iron. In order to determine the crystal phase composition of the natural iron oxide (NIO), X-ray diffraction (DRX) measurement and infrared absorption spectroscopy (FTIR) were carried out. The results showed that the NIO has a mixed crystal structure composed mainly of hematite and lesser extent of goethite. The specific surface area and the total pore volume of the NIO were 79.015 m2g−1 and 0.0892 cm3g−1 respectively, measured by the Brunauer Emmett–Teller method (BET). The Raman spectrum of the NIO confirmed that the sample has seven characteristic peaks attributable to hematite. The optical properties of soil powder were examined by UV-vis diffuse reflectance spectroscopy (DRS). The pH of point of zero charge (pHpzc) of the adsorbent was determined, a value of 8.3 was found. The photocatalytic activity of the NIO particles was tested by the decomposition of aqueous solution of different class of compounds; phenolic compounds, pesticides and dyes due to their presence in many types of wastewaters. The sorption on the surface of the NIO with photocatalytic oxidation using oxalic acid and hydrogen peroxide would be an effective oxidation process for the removal of contaminants under UV and solar irradiation. High percentages of degradation of 1- Naphtol (1-NP) and Linuron were found about, 94.6 %, 97.2 % respectively, in presence of NIO and H2O2 under UV irradiation. The presence of oxalic acid with NIO enhanced the photodegradation of 2,6-dimethylphenol (2,6-DMP), 2-chlorophenol (2-CP) and Methylene blue (MB) with 72 %, 92 % and 100 % percentages of degradation respectively.


Nanomaterials ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 53 ◽  
Author(s):  
Yuanyuan Li ◽  
Xiaofang Tian ◽  
Yaoqiong Wang ◽  
Qimei Yang ◽  
Yue Diao ◽  
...  

Using solar energy to remove antibiotics from aqueous environments via photocatalysis is highly desirable. In this work, a novel type-II heterojunction photocatalyst, MgSn(OH)6/SnO2, was successfully prepared via a facile one-pot in situ hydrothermal method at 220 °C for 24 h. The obtained heterojunctions were characterized via powder X-ray diffraction, Fourier-transform infrared spectroscopy, transmission electron microscopy, and ultraviolet-visible diffuse reflectance spectroscopy. The photocatalytic performance was evaluated for photodegradation of tetracycline solution under ultraviolet irradiation. The initial concentration of tetracycline solution was set to be 20 mg/L. The prepared heterojunctions exhibited superior photocatalytic activity compared with the parent MgSn(OH)6 and SnO2 compounds. Among them, the obtained MgSn(OH)6/SnO2 heterojunction with MgCl2·6H2O:SnCl4·5H2O = 4:5.2 (mmol) displayed the highest photocatalytic performance and the photodegradation efficiency conversion of 91% could be reached after 60 min under ultraviolet irradiation. The prepared heterojunction maintained its performance after four successive cycles of use. Active species trapping experiments demonstrated that holes were the dominant active species. Hydroxyl radicals and superoxide ions had minor effects on the photocatalytic oxidation of tetracycline. Photoelectrochemical measurements were used to investigate the photocatalytic mechanism. The enhancement of photocatalytic activity could be assigned to the formation of a type-II junction photocatalytic system, which was beneficial for efficient transfer and separation of photogenerated electrons and holes. This research provides an in situ growth strategy for the design of highly efficient photocatalysts for environmental restoration.


2019 ◽  
Vol 948 ◽  
pp. 221-227
Author(s):  
Latifah Hauli ◽  
Karna Wijaya ◽  
Ria Armunanto

Catalyst of Chromium (Cr) metal supported on sulfated zirconia (SZ) was prepared by wet impregnation method. This study aim to determine the optimal concentration of Cr metal that impregnated on SZ catalyst. Preparation of catalyst was conducted at different concentrations of Cr metal (0.5%, 1%, 1.5% (w/w)), impregnated on SZ catalyst, then followed by the calcinationand reduction process. Catalysts were charaterized by FTIR, XRD, XRF, SAA, TEM, and acidity test. The results showed the Cr/SZ 1% had the highest acidity value of 8.22 mmol/g which confirmed from FTIR spectra. All the crystal phase of these catalysts were in monoclinic. The specific surface area increased with the increasing of Cr metal concentration on SZ catalyst and the isotherm adsorption-desorption of N2 gas observed all the catalysts as mesoporous material. The impregnation process formed particles agglomeration.


Nanomaterials ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2139 ◽  
Author(s):  
Chukwuka Bethel Anucha ◽  
Ilknur Altin ◽  
Zekeriya Biyiklioglu ◽  
Emin Bacaksiz ◽  
Ismail Polat ◽  
...  

ZnWO4MnPc was synthesized via a hydrothermal autoclave method with 1 wt.% manganese (iii) phthalocyanine content. The material was characterized for its structural and morphological features via X-ray diffraction (XRD) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, transmission emission microscopy (TEM), scanning electron microscopy-Energy dispersive X-ray spectroscopy (SEM-EDX), N2 adsorption–desorption at 77K, X-ray photoelectron spectroscopy (XPS), and UV-visible/diffuse reflectance spectroscopy(UV-vis/DRS). ZnWO4MnPc photocatalytic performance was tested on the degradation of bisphenol A (BPA). The ZnWO4MnPc material removed 60% of BPA after 4 h of 365 nm UV irradiation. Degradation process improved significantly to about 80% removal in the presence of added 5 mM H2O2 after 4 h irradiation. Almost 100% removal was achieved after 30 min under 450 nm visible light irradiation in the presence of same concentration of H2O2. The effect of ions and humic acid (HA) towards BPA removal was also investigated.


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