scholarly journals New TiO2/DSAT Immobilization System for Photodegradation of Anionic and Cationic Dyes

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Wan Izhan Nawawi Wan Ismail ◽  
S. K. Ain ◽  
R. Zaharudin ◽  
Ali H. Jawad ◽  
M. A. M. Ishak ◽  
...  

A new immobilized TiO2technique was prepared by coating TiO2solution onto double-sided adhesive tape (DSAT) as a thin layer binder without adding any organic additives. Glass plate was used as support material to immobilized TiO2/DSAT. Two different charges of dyes were applied, namely, anionic reactive red 4 (RR4) and cationic methylene blue (MB) dyes. Photocatalytic degradation of RR4 and MB dyes was observed under immobilized TiO2/DSAT with the degradation rate slightly lower and higher, respectively, compared with TiO2in suspension mode. It was observed that DSAT is able to provide a very strong intact between glass and TiO2layers thus making the reusability of immobilized TiO2/DSAT be up to 30 cycles. In fact, a better photodegradation activity was observed by number of cycles due to increasing formation of pores on TiO2surface observed by SEM analysis.

2016 ◽  
Vol 835 ◽  
pp. 353-358 ◽  
Author(s):  
Wan Izhan Nawawi ◽  
S.K. Ain ◽  
R. Zaharudin ◽  
Sudirman Sahid

In this work, titanium dioxide (TiO2) photocatalyst was generally immobilized onto glass plate support material by employing double sided adhesive tape (DSAT) as a thin layer binder. The photocatalytic performance of this new non-additive immobilization system was observed under the degradation of two different charges of dyes namely anionic reactive red 4 (RR4) and cationic methylene blue (MB) dyes. Photocatalytic degradation of RR4 and MB dyes under immobilized TiO2/DSAT were compared with TiO2 in suspension mode respectively. Immobilized TiO2/DSAT was observed to have up to 30 cycles of reusability thanks to DSAT that is able to provide a very strong intact between the glass plate and TiO2 layers. In fact, a better photodegradation activity was observed by number of photocatalysis cycles due to increasing pores formation on TiO2 surface as observed by Scanning Electron Microscopy (SEM) analysis.


Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 558
Author(s):  
Wenhui Zhu ◽  
Caiyun Zhang ◽  
Yali Chen ◽  
Qiliang Deng

Photothermal materials are attracting more and more attention. In this research, we synthesized a ferrocene-containing polymer with magnetism and photothermal properties. The resulting polymer was characterized by Fourier-transform infrared (FT-IR), vibrating sample magnetometer (VSM), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). Its photo-thermocatalytic activity was investigated by choosing methylene blue (MB) as a model compound. The degradation percent of MB under an irradiated 808 nm laser reaches 99.5% within 15 min, and the degradation rate is 0.5517 min−1, which is 145 times more than that of room temperature degradation. Under irradiation with simulated sunlight, the degradation rate is 0.0092 min−1, which is approximately 2.5 times more than that of room temperature degradation. The present study may open up a feasible route to degrade organic pollutants.


Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1660
Author(s):  
Sevda Mihailova Yantcheva

The development of composite materials is subject to the desire to overcome polymerization shrinkage and generated polymerization stress. An indicator characterizing the properties of restorative materials, with specific importance for preventing secondary caries, is the integrity and durability of marginal sealing. It is a reflection of the effects of polymerization shrinkage and generated stress. The present study aimed to evaluate and correlate marginal integrity and micropermeability in second-class cavities restored with three different types of composites, representing different strategies to reduce polymerization shrinkage and stress: nanocomposite, silorane, and bulk-fill composite after a ten-month ageing period. Thirty standardized class ΙΙ cavities were prepared on extracted human molars. Gingival margins were 1 mm apical to the cementoenamel junction. Cavities were randomly divided into three groups, based on the composites used: FiltekUltimate-nanocomposite; Filtek Silorane LS-silorane; SonicFill-bulk-fill composite. All specimens were subjected to thermal cycles after that, dipped in saline for 10-mounds. After ageing, samples were immersed in a 2% methylene blue. Thus prepared, they were covered directly with gold and analyzed on SEM for assessment of marginal seal. When the SEM analysis was completed, the teeth were included into epoxy blocks and cut longitudinally on three slices for each cavity. An assessment of microleakage on stereomicroscope followed. Results were statistically analyzed. For marginal seal evaluation: F.Ultimate and F.Silorane differ statistically with more excellent results than SonicFill for marginal adaptation to the gingival margin, located entirely in the dentin. For microleakage evaluation: F.Ultimate and F.Silorane differ statistically with less microleakage than SonicFill. Based on the results obtained: a strong correlation is found between excellent results for marginal adaptation to the marginal gingival ridge and micropermeability at the direction to the axial wall. We observe a more significant influence of time at the gingival margin of the cavities. There is a significant increase in the presence of marginal fissures (p = 0.001). A significant impact of time (p < 0.000) and of the material (p < 0.000) was found in the analysis of the microleakage.


2012 ◽  
Vol 584 ◽  
pp. 396-400 ◽  
Author(s):  
Aravind Naga Revuru ◽  
Nagarajan Padmavathy ◽  
Angappan Sheela ◽  
Swamiappan Sasikumar

The major cause of surface and ground water contamination is due to effluent from dyeing industries. The discharged effluent chemicals inhibit light penetration into water bodies and some are considered to be carcinogenic. In this study, the photocatalytic decomposition of the synthetic dye, methylene blue was investigated in the presence of activated TiO2. The TiO2 sample was characterized by using XRD to analyze the presence of anatase and rutile phases. The dye degradation was monitored as a change in absorbance by UV-Visible spectrophotometer. The contributing factors towards dye degradation include both the dye concentration as well as the quantity of TiO2 used. Different quantities of TiO2 in anatase phase was taken and activated under UV radiation for 15 min. and subsequently coated on to TLC plates using 5% polyvinyl alcohol as a binding agent. This photocatalytic plate was kept in the methylene blue dye solution and exposed to sunlight. The results shows that 57% of the 30ppm methylene blue dye gets degraded within 75min., when exposed to UV activated TiO2 in presence of natural sunlight.


2020 ◽  
Vol 148 ◽  
pp. 01003
Author(s):  
Sarah Aphirta ◽  
Prayatni Soewondo ◽  
Nida Maisa Zakiyya ◽  
Dyah Wulandari Putri ◽  
Barti Setiani Muntalif

Artificial support material was examined to determine the removal capacity of organic pollutants and nutrients on laboratory scale using PFR system. The experiment was performed using artificial water with similar characteristics to Cikapayang River in three PFRs of 10.78 L. The PFRs were made of PVC pipes filled with an inert chemical substrate as an artificial support material. The process of pollutants removal in the PFR relies on a biological layer (biofilm) grown on the surface of the material support. Three type of C:N:P ratio used in this study were 30:15:1, 75:25:2, and 180:35:3. The results showed that the maximum removal efficiency of TSS, TN, TP, and COD in the preliminary tests were 85%, 87%, 71% and 79%, respectively. Moreover, the maximum water absorption capacity result was up to 30.8%. Organic substrate removal rate compared with first order and Strover-Kincannon substrate removal models prediction. The best fit model for this experiment was Stover-Kincannon model, with the average correlation coefficient up to 90% for all of the three reactors. SEM analysis shown that the microorganisms shape is coccus with the average size of 5 µm.


2020 ◽  
Vol 62 ◽  
pp. 87-95
Author(s):  
Hichem Farh ◽  
Abdelouahab Noua ◽  
Rebai Guemini ◽  
Djamal Eldine Guitoume ◽  
Oussama Zaoui

In this work, we studied the ZnO film thickness effect on the photocatalytic performance of n-ZnO/p-NiO heterostructures. The ZnO and NiO films were prepared by sol-gel dip-coating technique and the thickness of the ZnO film was varied by changing the number of coatingsfrom 2 to12. The formation of the p-NiO/n-ZnO heterostructure was confirmed by X ray diffraction (XRD). The obtained ZnO films present a wurtzite structure with a preferred orientation along (002) direction while the NiO film present a cubic structure highly oriented along (200) direction. UV-visible transmittance spectra of the prepared heterostructures revealed a good transparency in the visible region. The photocatalytic propertiesof the n-ZnO/p-NiO heterostructures were investigated by measuring the degradation rate of methylene blue. All the samples exhibit a good photocatalytic activity under solar light irradiation. The photocatalytic activity of p-NiO/n-ZnO heterostructureswas strongly correlated with the number of ZnO coatings. The highest photocatalytic activity was obtained at 6 coatings with a degradation rate of methylene blue equal to 98.67% for 4.5h of irradiation.


2011 ◽  
Vol 287-290 ◽  
pp. 1735-1743 ◽  
Author(s):  
Yi Dong Shi ◽  
Qiong Guo ◽  
Yuan Song Xie

The C, N, S tri-doped TiO2 with high visible-light photo-catalysis effect was successfully prepared by mixing thiourea with the self-prepared TiO2 powder through calcining for 2h at 450°C. The TiO2 powder was obtained by homogeneous precipitation method using the metatitanic acid instead of expensive chemical reagents contained Ti as raw material. The effect of doping materials and methods on the photo-degradation rate of methylene blue and dyes was studied. The characterizations of the doped TiO2 were analyzed using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and UV-visible absorption spectra (UV-vis). The results showed that this sample was the anatase TiO2 and contained elements C, N, S. The sample exhibited a significant response to ultraviolet and visible light. In the photo-degradation experiment, the C, N, S, tridoped-TiO2 could decolorize methylene blue and textile dyes quickly, and the photo-degradation rate of methylene blue could reach upward 98% after 3 hours under the different light sources.


2012 ◽  
Vol 610-613 ◽  
pp. 3247-3251 ◽  
Author(s):  
Xian Guang Zeng ◽  
Jia Zhuang ◽  
Min Gong ◽  
Xing Wen Zheng ◽  
Ming Tian Li

A new hydrothermal method was introduced to prepare TiO2 films. The films were prepared by using tetrabutyl titanate as precursor, toluene as solvent and hydrochloric acid as the inhibitor via a facile hydrothermal method. XRD, SEM, AFM, and TG-DSC were used to characterize phase structure and morphology of TiO2 thin films. XRD analysis showed that crystal phase of as- prepared films were anatase entirely,and its average size was 9 nm. AFM and SEM analysis indicated that films had nanocrystallines,and it was homogenous,dense and crack- free. Photocatalytic properties of TiO2 film were estimated by degradation of methylene blue . The result shows that the degradation rate of 40mL methylene blue solution with initial concentration 10 mg/L reaches to 52.8 % after irradiated for 120 min under 35W ultraviolet lamp ,and as-prepared TiO2 film has better photocatalytic property.


2015 ◽  
Vol 69 (7) ◽  
Author(s):  
Mohammad Peydayesh ◽  
Mojgan Isanejad ◽  
Toraj Mohammadi ◽  
Seyed Mohammad Reza Seyed Jafari

AbstractMethylene blue (MB) removal using eco-friendly, cost-effective, and freely available Urtica was investigated. The morphology of the adsorbent surface and the nature of the possible Urtica and MB interactions were examined using SEM analysis and the FTIR technique, respectively. Various factors affecting MB adsorption such as adsorption time, initial MB concentration, temperature, and solution pH were investigated. The adsorption process was analysed using different kinetic models and isotherms. The results showed that the MB adsorption kinetic follows a pseudo-second-order kinetic model and the isotherm data fit the Langmuir isotherm well. Thermodynamic parameters, such as ΔG°, ΔH°, and ΔS°, were also evaluated, and the results indicated that the adsorption process is endothermic and spontaneous in nature. The MB adsorption capacity of Urtica was found to be as high as 101.01 mg g


2011 ◽  
Vol 332-334 ◽  
pp. 1040-1044 ◽  
Author(s):  
Qiu Mei Wang ◽  
Lei Tan ◽  
Rong Wen Zhou ◽  
Zhi Wei Zou ◽  
Xue Mei Xu

In this paper, the photocatalytic degradation of methylene blue solution by photocatalysis bamboo charcoal fiber knitted fabric was studied. The relationships were analyzed between the photocatalytic degradation rate and the reaction time, the initial concentration, pH of methylene blue solution, and the distance between the UV light centre and liquid level. The results indicates that there is an remarkable photocatalytic degradation effect of methylene blue solution by photocatalysis bamboo charcoal fiber knitted fabric under UV-irradiation, even the degradation rate could reach to 67.02%. The degradation effect was better with lower initial concentration of methylene blue solution, higher initial pH,and the shorter distance between light centre and liquid level.


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