Photocatalytic Degradation of Organic Dyes under Visible Light on N-DopedTiO2Photocatalysts

Abstract

This study was focused on the application of white and blue light emitting diodes (LEDs) as sources for the photocatalytic degradation of organic dyes in liquid phase with visible light. The photocatalytic activity of N-doped titanium dioxide, synthesized by direct hydrolysis of titanium tetraisopropoxide with ammonia, was evaluated by means of a batch photoreactor. The bandgap energy of titanium dioxide was moved in the visible range from 3.3 eV to 2.5 eV. The visible light responsive photocatalysts showed remarkably effective activity in decolorization process and in the removal of total organic carbon. Methylene blue was also used as a model dye to study the influence of several parameters such as catalyst weight and initial concentration. The effect of dye on the photocatalytic performance was verified with methyl orange (MO). The results demonstrated that the right selection of operating conditions allows to effectively degrade different dyes with the N-doped TiO2photocatalysts irradiated with visible light emitted by LEDs.

Regarding the rejection performance of a polymeric reverse osmosis membrane for the final purification of two-phase olive mill effluents previously treated by an advanced oxidation process

“…A wide range of reclamation procedure practices and combined treatments for OMW has already been proposed and developed (Borja et al, 2006), such as lagooning or natural evaporation and thermal concentration (Paraskeva and Diamadopoulos, 2006), composting (Cegarra et al, 1996), treatments with clay (Al-Malah et al, 2000) or with lime (Aktas et al, 2001), biological processes (Ena et al, 2007;), physico-chemical procedures including coagulation-flocculation (Sarika et al, 2005;Stoller, 2011), electro coagulation (Tezcan et al, 2006) and biosorption , advanced oxidation processes including ozonation (Beltrán et al, 2000), Fenton's reaction (Martínez-Nieto et al, 2011a, 2011bHodaifa et al, 2013b) and photocatalysis (Sacco et al, 2012), electrochemical treatments (Inan et al, 2004) and hybrid processes (Grafias et al, 2010), but none has led to completely satisfactory results.…”

Recovery of iron after Fenton-like secondary treatment of olive mill wastewater by nano-filtration and low-pressure reverse osmosis membranes

“…A wide variety of stand-alone and integrated processes for the treatment of OMW have already been proposed and developed but have not yet led to completely satisfactory results (Borja et al, 2006), such as lagooning or natural evaporation and thermal concentration (Annesini and Gironi, 1991;Paraskeva and Diamadopoulos, 2006), composting (Cegarra et al, 1996;Papadimitriou et al, 1997), treatments with clay (Al-Malah et al, 2000) or with lime (Aktas et al, 2001), biological processes (Ena et al, 2007;Garrido et al, 2002;Marques, 2001;Hodaifa et al, 2008), physico-chemical procedures including coagulation-flocculation (Sarika et al, 2005), electro-coagulation (Inan et al, 2004;Tezcan et al, 2006) and biosorption , advanced oxidation processes comprising ozonation (Beltrán et al, 2000), Fenton's reaction (Martínez-Nieto et al, 2011a;Hodaifa et al, 2013b) and photocatalysis (Sacco et al, 2012), electrochemical treatments (Papastefanakis et al, 2010) and hybrid processes (Grafias et al, 2010;Lafi et al, 2009).…”

The importance of pretreatment tailoring on the performance of ultrafiltration membranes to treat two-phase olive mill wastewater

“…As a consequence, a plethora of other reclamation treatments as well as combined processes have been proposed but have not led to completely satisfactory results, such as thermal concentration (Annesini and Gironi, 1991;Paraskeva and Diamadopoulos, 2006), treatments with lime and clay (Aktas et al, 2001;Al-Malah et al, 2000), composting (Bouranis et al, 1995;Cegarra et al, 1996;Papadimitriou et al, 1997), biosorption (Martínez-Nieto et al, 2010;Hodaifa et al, 2013), coagulation-flocculation (Martínez- Nieto et al, 2011a;Sarika et al, 2005;Stoller, 2009), advanced oxidation (Beltrán et al, 2000;Martínez-Nieto et al, 2011b;Sacco et al, 2012), electrocoagulation (Inan et al, 2004;Tezcan et al, 2006) and hybrid processes (Grafias et al, 2010;Lafi et al, 2009;Rizzo et al, 2008).…”