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
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.
