Competitive Removal Of Selenocyanate (SeCN-) From Synthetic Wastewater Using Uv Lamp And Solar Radiation Energized Tio2 Photocatalysis: Effect Of Co-Pollutants Thiocyanate, Cyanide, And Ammonia

Project: Research

Project Details


Though selenium is an essential micronutrient, intake of elevated selenium amounts could result in to serious human health concerns and diseases. Considering the respective health issues, several countries have imposed very low selenium regulatory limits both for water and wastewater treatment. Typically selenite (SeO32-) and selenate (SeO42-) account for most Se-species in selenium contaminated water bodies however selenocyanate (SeCN-) is another dominant Se-species in specific industrial effluents including those from petroleum refineries, mining, and (fossil fuel based) power plants. This becomes more of a concern as selenocyanate species is toxic and also poses a removal challenge. Furthermore the co-pollutants species in respective streams including thiocyanate, cyanide and ammonia, are also of environmental concern. Though several studies have reported the removal of selenocyanate from the aqueous phase using specific technologies such as direct reaction with Fe(0)/elemental iron, however concerns including sludge handling, require development of new technologies. Furthermore the presence of co-pollutants including thiocyanate, ammonia and cyanide, would render selenocyanate removal even more challenging from respective mixed streams. The titanium dioxide (TiO2) mediated photocatalytic degradation (PCD) process, which is an advanced wastewater treatment process, has been reported to successfully remove aquatic pollutants under a varying set of conditions. Furthermore a preliminary study at our lab has also shown successful removal of selenocyanate from synthetic wastewater using the TiO2 assisted PCD process employing UV lamp as the light energy source. Nevertheless no study so far has explored the effect of co-pollutants thiocyanate, ammonia, and cyanide (that are typically noted in respective wastewater streams) on to COMPETITIVE destruction of selenocyanate complex along with simultaneous removal of respective co-pollutants using the TiO2 assisted PCD process. However, for practical applications the removal of selenocyanate and associated pollutants from respective wastewater streams under COMPETITIVE environment must be understood. Hence the present study's main objective is to investigate the efficiency of TiO2 based photocatalytic degradation process for the competitive destruction of selenocyanate complex along with simultaneous removal of co-pollutants ammonia, cyanide, and thiocyanate from simulated mixed wastewater streams. We intend to determine the efficiency of PCD process for the treatment of said streams under a varying set of conditions and extend fundamental knowledge on respective subject for possible practical applications. Furthermore removal of selenite and selenate species (which will result from selenocyanate oxidation) from the above mentioned mixed systems will also be studied using hole scavenger EDTA via reduction route. We also intend to investigate use of both artificial UV lamp and solar light as the energy source for respective photocatalysis work. As stated above, this subject has not been explored, to the best of our knowledge. The findings from the present study will be of use to treat wastewater streams containing selenocyanate species and respective co-pollutants under competitive environment.
Effective start/end date1/12/1431/05/16


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