Saravanan Pichiah

Enhanced magnetic separation and photocatalytic activity of nitrogen doped titania photocatalyst supported on strontium ferrite

An enhanced ferromagnetic property, visible light active TiO(2) photocatalyst was successfully synthesized by supporting strontium ferrite (SrFe(12)O(19)) onto TiO(2) doped with nitrogen (N) and compared with N-doped TiO(2). The synthesized catalysts were further characterized with X-ray diffraction (XRD), transmission electron microscope (TEM), energy dispersive X-ray spectroscopy (EDS), BET surface area analysis, vibrating sample magnetometer (VSM), X-ray photon spectroscopy (XPS) and visible light spectroscopy analysis for their respective properties. The XRD and EDS revealed the structural and inorganic composition of N-TiO(2) supported on SrFe(12)O(19). The supported N-TiO(2) exhibited a strong ferromagnetic property with tremendous stability against magnetic property losses. It also resulted in reduced band gap (2.8 eV) and better visible light absorption between 400 and 800 nm compared to N-doped TiO(2). The photocatalytic activity was investigated with a recalcitrant phenolic compound namely 2,4-dichlorophenol (2,4-DCP) as a model pollutant under direct bright and diffuse sunlight exposure. A complete degradation of 2,4-DCP was achieved with an initial concentration of 50mg/L for both photocatalysts in 180 min and 270 min respectively under bright sunlight. Similarly the diffuse sunlight study resulted in complete degradation for supported N-TiO(2) and >85% degradation N-TiO(2), respectively. Finally the supported photocatalyst was separated under permanent magnetic field with a mass recovery ≈ 98% for further reuse.

Synergetic effect of conductive polymer poly(3,4-ethylenedioxythiophene) with different structural configuration of anode for microbial fuel cell application

PEDOT was synthesized by chemical polymerisation and characterised for its electrochemical insights. Three different anode configuration, namely graphite plate (GP), carbon cloth (CC) and graphite felt (GF) were then loaded with a fixed amount of PEDOT (2.5 mg/m(2)) denoted as GP-P, CC-P and GF-P respectively. The PEDOT coating improved the electrochemical characteristics and electron transfer capabilities of the anodes. They also contributed for enhanced MFC performances with maximum energy generation along with coulombic efficiency than the unmodified anodes. The morphological characteristics like higher surface area and open structure of felt material promoted both microbial formation and electrochemical active area. A maximum current density of 3.5A/m(2) was achieved for GF-P with CE and COD of 51% and 86% respectively. Thus, the GF-P anode excelled among the studied anodes with synergetic effect of PEDOT coating and structural configuration, making it as a potential optimum anode for MFC application.

Responses of surface modeling and optimization of Brilliant Green adsorption by adsorbent prepared from Citrus limetta peel

Abstract An adsorbent prepared from Citrus limetta peel was used to study its sorption potential on removing Brilliant Green dye. The initial dye concentration and sorbent dosages were varied between 10–100 mg/L and 0.5–5.0 g/L, respectively. The influence of parameters like pH, temperature, initial concentration, and adsorbent dosage on dye adsorption was also studied. A maximum dye removal of 95% was achieved with an initial concentration of 10 mg/L. The percentage removal was mathematically described as a function of experimental parameters and modeled through response surface methodology. The results show that the responses on adsorption of dyes were significantly affected by the synergistic effect of linear term of time and dosage and the quadratic term of temperature and time. A 24 full factorial design of experiments was adopted and statistical analysis was performed in the form of ANOVA and student “t” test, which gave good interpretation in terms of interaction of experimental parameters.

Intimate coupling of electro and biooxidation of tannery wastewater

AbstractTannery wastewater contains high organic loadings and other pollutants, making it challenging to be treated efficiently. A combined process involving both advance oxidation process and biological treatment seems to be the best solution to achieve the regulatory standard for discharge. This investigation reports on the degradation of tannery wastewater which was represented by the removal Chemical Oxygen Demand (COD) using electrochemical process, biological degradation and finally, the combination of both processes. Electrolysis was carried out in batch reactor under different current density and dilution. Biological degradation was carried out with three isolated microbial strain and optimization of pH, nutrients, and growth factors were analyzed. The combined process involved an electrooxidation reactor connected to a column packed with immobilized biomass. Electrooxidation technique was found to obtain maximum percentage COD reduction in 73.1% at 1.5 A dm−2 using raw effluent. Bacillus Strain B...

Preparation and characterization of zeolite polymer composite proton exchange membrane

AbstractSulfonated polystyrene (SPS) and sulfonated polystyrene zeolite composite (SPS-Z) membranes were prepared by solution casting technique. SPS was synthesized using acetyl sulfate as a sulfonating agent in a reflux condenser under nitrogen atmosphere. The membrane casting was done without isolating the SPS. The SPS-Z membrane was fabricated by adding the zeolite to the SPS solution by the same technique. The synthesized SPS and SPS-Z membranes were characterized with Fourier transform infrared spectroscopy, thermogravimetric analysis, field emission scanning electron microscopy, and atomic force microscopy to identify the −SO3H functional group attached onto the polymer membrane, thermal stability, and surface morphology. The membranes were further examined for their water uptake capacity, swelling behavior, and degree of sulfonation. In addition, the performance of the fabricated membranes was examined based on their ion exchange capacity (IEC) and proton conductivity. The results revealed that bot...

Sonophotocatalytic degradation of bisphenol A and its intermediates with graphitic carbon nitride

Since bisphenol A (BPA) exhibits endocrine disrupting action and high toxicity in aqueous system, there are high demands to remove it completely. In this study, the BPA removal by sonophotocatalysis coupled with nano-structured graphitic carbon nitride (g-C3N4, GCN) was conducted with various batch tests using energy-based advanced oxidation process (AOP) based on ultrasound (US) and visible light (Vis-L). Results of batch tests indicated that GCN-based sonophotocatalysis (Vis-L/US) had higher rate constants than other AOPs and especially two times higher degradation rate than TiO2-based Vis-L/US. This result infers that GCN is effective in the catalytic activity in Vis-L/US since its surface can be activated by Vis-L to transport electrons from valence band (VB) for utilizing holes (h+VB) in the removal of BPA. In addition, US irradiation exfoliated the GCN effectively. The formation of BPA intermediates was investigated in detail by using high-performance liquid chromatography-mass spectrometry (HPLC/MS). The possible degradation pathway of BPA was proposed.

A Review on Advanced Oxidation Processes for Effective Water Treatment

Advanced oxidation processes (AOPs) such as fenton, ozonation, sonolysis, photocatalysis, UV photolysis, and wet air oxidation are one amongst the most suitable techniques for water and wastewater treatment. These, AOPs have also been chosen for the complete degradation of various categories of emerging pollutants that could not be managed byany conventional technologies.The mineralization is achieved by chemical reactions between the various reacting species generated and the pollutants. The present article provides avivid view of the mechanistic features of various AOPs and its possible synergisation for process enhancement to achieve better treatment efficiency. current World Environment Journal Website: www.cwejournal.org ISSN: 0973-4929, Vol. 12, No. (3) 2017, Pg. 470-490 cONTAcT Saravanan Pichiah saravananpichiah@iitism.ac.in Department of Environmental Science and Engineering, Indian Institute of Technology (ISM), Dhanbad 826004, Jharkhand, India.

Light Driven Nanomaterials for Removal of Agricultural Toxins

Globalization has catalyzed the agricultural sector for prompting the trade across the globe with derived benefits to the growth of the nation. Many nations depend highly on the agricultural industry both for earning foreign exchange and fullfilling local needs. In the last decades the industry has emerged owing to the superior technology development and its demand in global market. As a consequence industry has contributed to the diffusion of new xenobiotics, such as pesticides, in to the aquatic environment. Pesticides are used for reducing crop infection and increasing crop yield. The usage pesticides and fungicides can rarely be stopped because of the complexity of the pests. Thus removal of xenobiotics from the aquatic environment is mandatory, since they contribute for wide range of detrimental effects to flora, fauna and well beings. Heterogeneous photocatalysis, a subset of advanced oxidation processes, is one of the means to clean waters.

Synthesis and characterization of proton exchange membrane employing waste polystyrene as precursor

Abstract In the present work, waste polystyrene was successfully applied as a precursor for the synthesis of proton exchange membrane (PEM). The study also examined the membrane characteristics before and after sulfonation and the latter reaction was facilitated with the aid of acetyl sulfate. The obtained membranes were characterized for its inherent nature. The functional group analysis of the raw precursor clearly discloses the presence of sulfonic groups in the raw precursor and increase in sulfonic groups were observed for the sulfonated samples. The thermogravimetric results revealed that the raw precursor and the sulfonated membrane (SM) exhibited almost similar thermal stability. The sulfonation contributed for better water uptake and is further proven by ion exchange capacity and proton conductivity analysis where SM achieved higher IEC and proton conductivity. The IEC increased from 0.105 to 0.536 meq/L and from 4.357 × 10−7 to 1.327 × 10−6 S/cm for proton conductivity. Thus, the study has proven the viability of waste plastics as a precursor for the synthesis of PEMs.

Nanocrystal TiO2 Engulfed SiO2-Barium Hexaferrite for Enhanced Electrons Mobility and Solar Harvesting Potential

Barium hexaferrite embedded-silica-titania photocatalyst (TiO2-SiO2-BaFe12O19) was synthesized through sol-gel, liquid catalytic phase transformation and solid reaction routes. The magnetic photocatalyst was aimed to harvest the photoenergy from the sunlight, minimize the electron-holes recombination rate, improve the long lifetime charge-carriers transfer to maximize the photocatalytic activity and enhances the separation and reusability of it. The as-synthesized photocatalyst was characterized and the photocatalytic activity was evaluated for the reduction of 2, 4-dichlorophenol (2, 4-DCP) under direct sunlight. The presence of SiO2 interlayer in TiO2-SiO2-BaFe12O19 prevents the phase transformation of magnetic core. TiO2-SiO2-BaFe12O19 benefits the magnetic separation with appreciable magnitude of coercivity (5035.6 Oe) and saturation magnetization (18.8256E-3 emu/g), respectively. The ferrite ions from the magnetic core which dispersed into TiO2 matrix exhibited an evident shift of the absorption in the visible region. This was again confirmed with the reduced band gap energy of 1.90 eV. Furthermore, TiO2-SiO2-BaFe12O19 destructed 100% of 2, 4-DCP compound within 150 min under very bright sunlight with an average irradiance of 820.8 W/m2 (results not shown). The embedding of BaFe12O19 with a SiO2 layer onto TiO2 nanocrystals contributed for an excellent solar-light utilization and ease magnetic separation of the nanosized photocatalyst.