Showing 7 results for Tio2
M Shirzad Siboni, M. T Samadi, A.r Rahmani, A.r Khataee, M Bordbar, M.r Samarghandi,
Volume 3, Issue 3 (10-2010)
Abstract
Backgrounds and Objectives: Industrial wastewater included the heavy metal is one of the important sources of environmental pollution. Hexavalent chromiumand divalent nickel are founded in plating wastewater which is harmful for human health and environment. Therefore, the purpose of this research is investigation of photocatalytic removal of hexavalent chromium and divalent nickel from aqueous solution using UV/TiO2 process in a batch system.
Materials andMethods: At first, reactor was designed. Then, optimumdosage of TiO2 was obtained equal to 1 g/L, with variation TiO2 dosage at constant pH and initial concentrations of hexavalent chromium and divalent nickel. The effect of pH, contact time and initial concentration of hexavalent chromium was studied at the constant amount of TiO2 (1gr/L).
Results: The result showed that photocatalytic removal efficiency increased with increasing reaction time and TiO2 dosage. In addition, it was found that removal efficiency of hexavalent chromium was decreased by increasing initial chromium concentration and pH. But, photocatalytic removal efficiency of nickel ion was increased and decreased by increasing of pH and initial nickel concentration, respectively.
Conclusion: The results showed that UV/TiO2 was an effective method in removal of hexavalent chromium and divalent nickel from aqueous solutions
S Hemmati Borji, S Nasseri, R Nabizadeh Nodehi, A.h Mahvi, A.h Javadi,
Volume 3, Issue 4 (1-2011)
Abstract
Backgrounds and Objectives: Phenol and phenolic compounds are widely used in industry and daily liFe, and are of high interest due to stability in the environment, dissolution ability in water and health problems. In this regard, phenol removal from water is of high importance. The purpose of this study was to investigate the efficiency of photodegradation process for removal of phenol from aqueous system by use of Fe-doped TiO2 nanoparticles prepared by sol-gel method.
Materials and Methods: Phenol concentrations of 5, 10, 50 and 100 mg/L were prepared and exposed to UV and Fe-doped TiO2, separately and simultaneously. Also the effect of initial phenol concentration, Fe-doped TiO2 loading and pH were studied. Various doses of photocatalist investigated for Fe- doped TiO2 were 0.25, 0.5 and 1 g/L. pH was studied at three ranges, acidic (pH=3), neutral (pH=7) and alkaline (pH=11).
Results: Maximum degradation was obtained at acidic pH, 0.5 g/L of Fe-doped TiO2 for all of phenol concentrations. With increasing initial concentration of phenol, photocatalytic degradation decreased. In comparison with Fe-doped TiO2/UV process, efficiency of UV radiation alone was low in phenol degradation (% 64.5 at 100 mg/l of phenol concentration). Also the amount of phenol adsorbed on the Fe-doped TiO2 was negligible at dark conditions.
Conclusion: Results of this study showed that Fe(III)- doped TiO2 nanoparticles had an important effect on photocatalytic degradation of high initial phenol concentration when Fe(III)-doped TiO2/ UV process applied.
A Khodadadi, H Ganjidoust, H Ijad Panah,
Volume 4, Issue 4 (3-2012)
Abstract
Background and Objectives: Many industrial effluent plants contain amounts of hard biodegradable compounds such as β-naphthol which can be removed by conventional treatment systems. The objective of this research is to treat wastewater containing naphthalene by nano titanium oxide coated on activated carbon.
Materials and Methods: Photocatalytic experiments were carried out for different concentrations of β-naphthol using time and pH as dependent factors. Nano TiO2 coated on activated carbone in one liter batch reactor and the resultants compounds' concentration were measured in a photocatalytic reactor with UV-C of 12 Watt.
Results: The experimental results indicated that UV/ nano TiO2 coated on activated carbone removed 92% of β-naphthol with concentrations of 100 mg/L within an overall elapsed time of three hours. β-naphthol total removal with concenteration of 25 mg/L was observed in two hours.
Conclusions: UV/ nano TiO2 process is very fast and effective method for removal of β-naphthol and pH 11 was indicated as the optimum pH.
Saeed Parastar, Simin Nasseri, Amir Hossein Mahvi, Mitra Gholami, Amir Hossein Javadi, Saeedeh Hemmati,
Volume 5, Issue 3 (10-2012)
Abstract
Background and Objectives: Pollution of water resources to nitrate is an
environmental problem in many parts of the world. This problem possibly causes
diseases such as methemoglobinemia, lymphatic system cancer and Leukemia.
Hence, nitrate control and removal from water resources is necessary.
Considering that application of nanomaterials in treatment of environmental pollutants
has become an interesting method, in this research use of Ag-doped TiO2 nanoparticles synthesized through photodeposition produced under UV irradiation
was studied for removal of nitrate from aqueous solutions.
Materials and Methods: Three nitrate concentrations of 20, 50, and 100 mg/L were considered. In order
to determine the effect of Ag-doped TiO2 nanoparticles on nitrate removal, dosages of 0.1, 0.4, 0.8 and 1.2 g/L nanoparticles were
used pH range of 5-9 was also considered. The effect of Ag-doped TiO2 nanoparticles both in darkness and under UV irradiation was studied. Moreover,
the presence of chloride and sulfate anions on the system removal efficiency
was investigated.
Results: The optimum
performance of nitrate removal (95.5%) was obtained using nitrate concentration
of 100 mg/L, in acidic pH and 0.8 g/L Ag-TiO2. Increase of
nanoparticle dosage up to 0.8 g/L, increased the removal efficiency, but for
1.2 g/L dosage of nanoparticles, the removal efficiency decreased. Maximum
reduction performance without nanoparticles, under UV irradiation and under
darkness conditions were 32% and 23.3% , respectively. In addition, we found
that presence of sulfate and chloride anions in aqueous solution reduced
efficiency of nitrate removal.
Conclusion: Results of
this study showed that Ag-doped TiO2 nanoparticles may be
efficiently used for nitrate removal from aqueous solutions.
Bijan Bina, Mohamadmahdi Amin, Mohamadreza Zare, Ali Fatehizadeh, Mohsen Mohseni, Mahdi Zare, Ali Toulabi,
Volume 6, Issue 2 (9-2013)
Abstract
Background and Objectives: Toxicity assessment of material related to nanotechnology is
necessary before excess development of this industry. On the other hand, specific
characteristic of nanomaterials can be used in disinfection of other material. In
this study toxicity and antibacterial properties of nano-TiO2 and nano-CuO
were investigated with four bacterial species in solid media.
Material and Methods: Stock
suspension of nanoparticles (10g-TSS/L) was diluted using Muller Hinton Agar to
achieve 5-6000mg-TSS/L concentration. We prepared three Petri dishes for each concentration
and refined bacteria were cultured on these Petri dishes. After culturing of these
bacteria on the media containing nanoparticles, growth inhibition was determined.
According to this data, 50% growth inhibition (EC50), no observed effect
concentration (NOEC) and 100% growth inhibition were determined.
Results: Our results showed
that toxicity of TiO2 is more than CuO in solid media. In this regard,
nano-TiO2 EC50 for Escherichia coli, Bacillus subtilis, Staphylococcus
aureus, and Pseudomonas aeruginosa was calculated 181, 571, 93 and 933mg-TSS/L respectively.
These figures for nano-TiO2 were 2550, 1609, 946, and 1231mg-TSS/L respectively.
Conclusion: This study
showed that compared with other bacteria studied, E. aureus due to high sensitivity
and E. coli due to high resistance to both TiO2 and CuO nanoparticles
are more proper as bioindicator in toxicity test and antibacterial test respectively.
M Panbehkar Bishe, B Ayati,
Volume 7, Issue 1 (7-2014)
Abstract
Background and Objective: Most of the dyes used in the textile industries can be toxic and carcinogenic. One of the suitable technologies to remove them is advanced oxidation processes. The main purpose of this study was to investigate the positive effect of adding oxidant Na2S2O8 to the photocatalytic process using TiO2 nano-particles immobilized on concrete and UV radiation for removal of Direct Blue71 dye. Materials and Methods: Concrete was covered by 40 g/m2 of TiO2 nanoparticles using SSP method. After selecting suitable oxidant concentration and optimum pH, initial dye concentration, UV irradiation intensity, and time, the efficiency and rate of dye removal and breaking amounts of benzene rings and COD variation were investigated in two systems of UV/TiO2 and UV/TiO2/Na2S2O8. Results: In UV/TiO2 system, 50.48 percent dye removal was observed at initial dye concentration of 100 ppm, pH 9, and 90 Watt UV lamp after 55 minutes and for UV/TiO2/Na2S2O8 system, initial dye concentration of 200 ppm, pH 6.9, and 0.24 g/L oxidant under the same abovementioned conditions resulted in 88.65 percent dye removal. Conclusion: Oxidant addition increased the dye removal efficiency and decreased total time for complete decolorization indicating the positive effect of oxidant on photocatalytic process in dye removal.
N Rastkari, F Izadpanah ,
Volume 9, Issue 1 (6-2016)
Abstract
Background and Objective: Formaldehyde is a toxic volatile organic compound, which its removal from polluted air is essential. One of the techniques available for removing such compounds is photocatalytic degradation. The aim of this study was to investigate the photocatalytic degradation of gaseous formaldehyde on TiO2 nanoparticles coated on reduced graphene oxide
Materials and Methods: The synthesized reduced graphene oxide- TiO2 nanocomposite was characterized using SEM, EDS, and FTIR spectra. The photocatalytic activity of prepared reduced graphene oxide- TiO2 nanocomposite was investigated for degradation of gaseous toluene under different operational conditions such as different initial concentration, flow rate, and time.
Results: The photocatalytic degradation efficiency of the RGO-TiO2 nanocomposite was much higher than P25 TiO2. The photocatalytic degradation efficiency of the RGO-TiO2 nanocomposite decreased by increasing the flow rate so the flow rate is a key factor for the use of RGO-TiO2 nanocomposite as a photocatalyst. The results showed that the photocatalytic degradation rates decreased from 89 to 30% with increasing formaldehyde initial concentration from 0.1 to 1 ppm.
Conclusion: This research indicated that RGO-TiO2 nanocomposite can be effectively used as suitable photocatalyst to remove gaseous pollutants. One of the advantages of the as-prepared composite was using visible light instead of UV to activate the oxidation process.
