International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 11 Issue: 03 | Mar 2024
p-ISSN: 2395-0072
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Response surface statistical optimization of photocatalytic degradation of RO86 dye using Fe-N-TiO2 Srujana Dhegam1, Sailu Chintha2, Hari babu Pengonda3, Jyothi Thati4 1,3ph.D scholar, Dept. of Chemical Engineering, University College of Technology, Osmania University, Telangana,
India
2 Professor, Dept. of Chemical Engineering, University College of Technology, Osmania University, Telangana, India 4Associate professor Dept. of Chemical Engineering, University College of Technology, Osmania University,
Telangana, India. ---------------------------------------------------------------------***---------------------------------------------------------------------
Abstract - Textile production units are the foremost
existence of substantial presence of free dye molecules [2]. Reactive dyes are significantly employed in dyeing operations to impart colour on fabrics for of their distinct reactivity and better colour longevity [3]. As the Reactive dyes are remarkably miscible with water, malignity & recalcitrancy parameters leads to serious carcinogenic diseases [4]. There exist numerous conventional methods to decolorize the textile effluents such as adsorption (using various adsorbents), electrochemical treatment, coagulation / flocculation, ozonation, biological & chemical oxidation [5]. However, these methods have inherent and distinct disadvantages in terms of feasibility of operation and cost of the technique employed towards complete degradation of dyes [6].
economic industrial zones prevailing across the globe but produce enormous amounts of wastewater which confines to high levels of chemicals and pollutants during their processing stages. To eradicate these pollutants an attempt is made by using advanced oxidation processes and solar energy. In this context, the present study includes utilization of solar energy by altering the optical Titanium dioxide (TiO2) by doping and Co-doping with Nitrogen (N), Iron (Fe). Synthesized catalysts were characterized by X-ray diffraction (XRD) Scanning Electronic Microscopy (SEM), Fourier transform infrared spectrophotometer (FTIR) & UV–Vis Diffuse Reflectance Spectra (UV–Vis DRS). Based on XRD patterns, the average crystallite size was determined using Debye-Sherrer, Williamson -Hall (W-H) and Halder-Wagner (H-W) methods. SEM explored the shape of catalyst by increasing the Fe content. Functional groups were identified in between 500 cm1- 3600 cm-1. UV- Vis DRS analyzed the band gap of Fe-N-TiO2 (2.8eV) is lesser than that of N-TiO2 (3.1eV). By selecting Fe-NTiO2_1 as a photocatalyst, the percentage degradation of RO86 dye under solar light was determined by Design of Experiments-Response Surface Methodology-Central Composite Design (DOE-RSM-CCD). Optimum conditions for maximum degradation of 97.39% of Reactive Orange-86(RO86) were achieved with a catalyst dosage of 1.388 g/250 ml, 10 mg/l concentration, reaction time of 148 min and rate constant 0.0158min-1 with first order reaction.
To overcome this, Advanced Oxidation Process (AOP’s) are set as cutting-edge technologies for treating dye effluents. AOPs rely on development of extremely reactive species like OH. to initiate oxidation of pollutant molecules which can be produced at near ambient pressure and temperature. AOP can significantly degrade the organic pollutants to CO2, H2O and salts [7]. From the diversified AOPs, heterogeneous photocatalysis is preferred choice for the degradation of stable dye complex structures [8]. In heterogeneous photocatalysis, the predominant factor is figuring out the reliable catalyst. TiO2 is the most abundantly used catalyst for photo-catalyzed reactions by virtue of its properties like electronic configuration, optical band gap (3.2eV), occurrence, thermal stability, chemical resistant and nonpoisonous [9]. In spite of this, TiO2 is suffering with two shortcomings like; it requires excess energy like UV radiation to excitation of electronics from VB to CB and rapid recombination of e- -h+ pairs [10]. On the other hand, solar radiation comprises 4-5% of Ultraviolet radiation. With a view to utilize the remaining portion of sunlight radiation like visible region, it is necessary to cut-down the band gap by employing most promising methods like doping [11].
Key Words: Advanced Oxidation Process, Reactive Orange86, Response Surface Methodology, degradation
1. INTRODUCTION In the present era, water pollution is a significant issue caused by the major contribution of industrial civilization. Treating the effluents before entering water bodies is the key challenge for the various industries like paper, textile, pulp, and metallic industries etc. Amongst all, textile industries are key corners of extensively discharging effluents in water bodies in the downstream processing units such as dyeing and finishing [1]. Effluents evolved from dyeing and rinsing units show endangered environmental impacts as it carries over much colour and is exceptionally conductive because of
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Doping can alter the optical response by creating new energy levels in between VB and CB [12]. However, doping with non-metals like N, C, and S is the most fashionable. But doping with Nitrogen (N-TiO2) is more effective which can shift absorption band spectra from UV to visible light [13]. Though N-TiO2 can absorb visible light spectra of solar
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