Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

Department of Chemical Engineering

Two narrow-band gap of donor-acceptor based conjugated polymers, BTTP and BTTP-CN were synthesized by Wittig copolymerization with thiophene or cyano-vinylene thiophene as the donor and 2,1,3-benzothiadiazole as acceptor units. The polymers were investigated by FT-IR, UV-V is, fluorescence spectroscopy, thermal stability and cyclic voltammetry (CV). The thermal analysis revealed that the BTTP polymer was stable up to 220 °C and BTTP-CN was stable up to 254 °C. The absorption spectra showed absorption maxima at 403 nm for BTTP and 397 nm for BTTP-CN. The polymers BTTP exhibited orange colour fluorescence emission at 585 nm and BTTP-CN exhibited yellow color fluorescence emission at 520 nm. The optical band gap values of undoped polymers BTTP and BTTP-CN were calculated as 2.2 and 2.13 eV respectively. Novel synthesized polymers were then enforced as dopant/additive-free hole transport materials in perovskite solar cells. Both polymers has shown the photovoltaic performance of 3.80 % for BTTP and 3.48 % for BTTP-CN under 1 sun illumination. The photovoltaic performance are compared with reference hole transporting material of spiro-OMeTAD with and without additive as 12.53 and 7.55% respectively. © 2018 Elsevier B.V.

School of Chemical Engineering

Vellore Campus

Department of Chemistry

School of Advanced Sciences

World University root node

Journal of Photochemistry and Photobiology A: Chemistry

Role of cyano substituents on thiophene vinylene benzothiadiazole conjugated polymers and application as hole transporting materials in perovskite solar cells

Sulfur recovery is a core process in both midstream and downstream oil and gas industries. Changing the feed composition, temperature, and pressure, degrading the equipment and catalysts, suboptimal operations due to inadequate control of temperature, pressure and air flow rate are some of the obstacles which reduce the performance of the sulfur recovery units. Low performance of sulfur recovery units creates the issues of safety and environmental problems. The objective of work is improving the performance of sulfur recovery unit in a gas plant. Aspen HYSYS V10 sulsim modified Claus three stage simulation model is used to mimic the behavior of a real sulfur recovery unit and it is considered as the base case. The performance of the base case is 93.89%. Base case process is optimized by controlling the air demand percent and the adjusting the sulfur dew point margin. These changes improved the performance to 98.60%. The performance of the plant is tested for a challenging feed composition case and this change reduced the performance to 96.39%. Arranging the selective oxidation converter improved the performance to 99.14%. Adding the tail gas section with the recycle stream and replacing the alumina catalyst with titania catalyst improved the performance to 99.92%. The simulation procedure developed in this work is useful to process engineers to smoothly handle the sulfur recovery unit in challenging situations. © 2019 Petroleum and Coal.

Petroleum and Coal

Studies on sulfur recovery plant performance using Aspen HYSYS sulsim simulations

Fluoride removal in drinking water is usually performed through cost and energy intensive membrane techniques such as reverse osmosis, dialysis and electro-dialysis. Defluoridation using an effective and low cost ultra filtration membrane system is reported in this work. Iron (III) oxide (Fe2O3) nanoparticles modified polyethersulfone (PES)/cellulose acetate (CA) blend membranes were fabricated by phase inversion method. Composite membranes were prepared by incorporating incremental amounts of Fe2O3 nanoparticles. Synthesized membranes were analysed for morphological studies and ultra filtration characteristics. It was observed that the inclusion of iron oxide nanoparticles influenced the membrane structure resulting in enhanced ultra filtration properties. All of the iron oxide nanoparticles incorporated PES/CA membranes possessed increased hydrophilicity, porosity, water uptake and pure water flux as compared to pristine PES membrane. Membrane with 0.5 wt% Fe2O3 nanoparticles exhibited a maximum water flux of 156 L m–2 h–1. Fluoride removal performance confirmed the defluoridation potential of the Fe2O3 nanoparticles blended PES/CA membranes. Maximum fluoride removal efficiency of 70.3% was observed for a single ultra filtration run. SEM and AFM examinations showed the structural alterations in the composite membranes due to the nanoparticles addition. Reusability studies confirmed the enhanced durability of the blended membrane. Domestic application of the composite membrane was carried out by assessing its fluoride removal ability in natural water samples obtained from fluoride endemic area. © 2019 Desalination Publications. All rights reserved.

VIT Unitversity

Department of Bio-Sciences

School of Bio Sciences and Technology

DESALINATION AND WATER TREATMENT

Iron oxide modified polyethersulfone/cellulose acetate blend membrane for enhanced defluoridation application

The aim of this paper is to identify the physical and chemical mechanism of ultrasound in presence of phase transfer agent (PTA) and phosphotungstic acid on desulfurization process. With different experimental procedures, we made an effort to identify the individual effect of phase transfer agent and ultrasound on oxidative desulfurization. Ultrasound-assisted process is the modern technique to enhance the kinetic of the liquid–liquid heterogeneous system. Physical and intrinsic properties of liquid fuels such as diffusivity of PTA-cation complex and also through effect on cavitation have a strong influence on Desulfurization of liquid fuels. Due to low vapor pressure of solvents, the beneficial effect of higher static pressure (that eliminates cavitation effect) is not seen in present reaction system. Phase transfer agent or phosphotungustic acid-assisted ultrasound desulfurization has radical and ionic reaction mechanism, which is revealed in terms of lower activation energy (energetic nature of radicals) as well as collision factor (due to instability of radicals) than magnetically stirred system. This study has revealed crucial mechanistic aspects of ultrasound assisted oxidative desulfurization in presence of phase transfer agent and phosphotungustic acid, which will give more insight for further research. © 2018 Curtin University and John Wiley &amp; Sons, Ltd.

Asia-Pacific Journal of Chemical Engineering

Mechanistic investigation of Sono–Phosphotungstic acid/phase transfer agent assisted oxidative desulfurization of liquid fuel

In this present research, magnesium oxide nanoparticles (n-MgO) were prepared using co-precipitation method and assessed for photo-chemical degradation of methyl red (MR) in presence of UV light. The X-Ray Diffraction (XRD) and scanning electron microscopy (SEM) for n-MgO show spherical crystalline particles with average crystallite size of 13.89 nm. The Tauc plot through UV spectra shows the band gap of n-MgO is estimated as 4.6 eV. Response surface methodology (RSM) using the central composite design (CCD) was used to design the experiments and optimize the process and the effectiveness of methyl red destruction was obtained as 97.08% at the optimal conditions obtained by CCD. The methyl red degradation kinetics fitted with first order kinetic model. The recovery process of the MgO photo catalyst is easier and reusability studies shows that the catalyst can be reused for decolourization of dye with slight reduction in efficiency. © 2019 Elsevier Ltd. All rights reserved.

Materials Today: Proceedings

Magnesium oxide nanoparticles for effective photocatalytic degradation of methyl red dye in aqueous solutions: Optimization studies using response surface methodology

This paper discusses about the results of a short term monitoring study of sea coast contaminated with oil spill. Collision of two oil-cargo ships, namely BW Maple and MT Dawn Kanchipuram near the Ennore Port, Chennai had released an approximately 200 tonnes of heavy fuel oil. We analyzed four different oil spill samples collected from Chennai beaches for different time intervals (1st, 3rd, 6th, 10th day of oil spill) from 1 km away from the source of the off shore spill location. The physicochemical characteristics of spilled oil sludge, concentration of total petroleum hydrocarbons (TPH) and polycyclic aromatic hydrocarbons (PAHs) present in the spilled oil were investigated. The variations in pH, moisture content and volatile hydrocarbon content, viscosity and density of the spilled oil were in the range of 7 ± 0.2, 255–575 g/kg, 118 to 850 PaS and 1.04 to 0.98 g/cm3 respectively. Elemental analysis showed that C, H, N and S were in the range of 9.9–13.3 (%), 0.63 to 1.76 (%), 1.88 to 1.02 (%) and 0.29 to 0.27 (%) respectively. Analysis of oil spill samples using gas chromatography and mass spectrometry (GCMS) shows the presence of recalcitrant and hazardous PAHs such as fluoranthene and pyrene. Ocean sediments were collected at different locations along the coast line from Ennore to Cooum after 60 days of oil spill and analyzed for TPH in GCMS. The results showed that the residual concentrations of TPH varied from 0.19 to 3.43 mg/g. The presence of heavy PAHs, which are highly toxic and recalcitrant, could pose a severe threat to the marine environment and ecology.The long term effects of these compounds were unexplored on marine environment. This environmental monitoring study gives an overview about the post oil spill activities and steps taken to remediate the sludge along the coastline. © 2019

Journal of Cleaner Production

Studies on short term weathering of spilled oil along Chennai coast in South India

The wastewater from chemical industries encapsulates a variety of different volatile organic compounds. Among these hydrophobic pollutants, benzene, toluene and xylene (BTX) are the most harmful organic compounds. The abatement of these deleterious compounds is mandatory. The efficacy of surface modified activated carbon for the uptake of these carcinogenic moieties was analyzed. The commercial activated carbon was functionalized with green oxidizing agents. The structural properties of pristine AC (P-AC) and oxidized AC (O-AC) were analyzed by BET surface area analyzer, Fourier transform infrared spectroscopy-attenuated total reflection (FTIR-ATR), thermogravimetric analysis (TGA), Raman spectroscopy, X-ray diffraction (XRD), and variable pressure field emission scanning electron microscope (VPFESEM). The effect of all the variables namely contact time, temperature, pH and dose was substantially analyzed and optimized. The sorption equilibrium was quickly established within 30 min. The present sorption process conforms to pseudo 2nd order kinetic model and is controlled by intra-particle diffusion. The maximum sorption capacity was computed to be 260.78 mg/g, 263.16 mg/g, 269.55 mg/g for benzene, toluene, and p-xylene respectively, outlining that Langmuir isotherm model fits the data reasonably well as compared to that of Freundlich and D-R model. Furthermore, electrostatic interaction is the plausible mechanism for sorption of BTX onto O-AC. Thus, this mode of functionalization is regarded as the contemporary protocol with high adsorption capacity towards the uptake of BTX as compared to that of previous studies reported in literature. © 2019 Elsevier B.V.

Journal of Molecular Liquids

Impact of surface modification on adsorptive removal of BTX onto activated carbon

The effect of viscosity on heat transfer behaviour is analyzed for binary mixtures (ionic liquid + water and nanofluid + water) over the base fluid (water). Viscosities of 1-butyl-3-methylimidazolium bromide with water under ambient pressure are studied at different concentrations (0.1–0.6% w/w) and temperatures (296–336 K). Viscosities of nanofluid (γ-Al2O3/water) are estimated at the same concentration and temperature range and then compared with the ionic liquid solution. Viscosity of aqueous 1-butyl-3-methylimidazolium bromide solution increases with concentration and decreases with temperature. A similar trend is observed for γ-Al2O3/water. In addition, a model is developed with response surface methodology and artificial neural network to predict the viscosity of 1-butyl-3-methylimidazolium bromide with water. © 2019 Elsevier B.V.

Impact of viscosity of nanofluid and ionic liquid on heat transfer

In this current work, activated carbon from date seeds (ACDS) was prepared through single step chemical activation using phosphoric acid. ACDS was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), Thermogravimetric studies (TGA/DTA), surface chemistry and specific area analysis. Performance assessment of the ACDS was carried out through adsorption of chromium (VI) from its aqueous solution. Effect of adsorption parameters such as contact time (1–120 min), pH (2–8), operating temperature (10–50°C), adsorbent dosage (0.01–0.2 g/50 mL) and initial chromium concentration (5–50 mg/L) on Cr(VI) removal by ACDS was studied in detail. Maximum Cr(VI) adsorption of 42.57 mg/g was obtained for a contact time of 60 min and pH of 2 at 30°C using adsorbent dose of 0.1 g/50 mL for an initial feed concentration of 50 mg/L. The Cr(VI) adsorption efficiency of the ACDS was better as compared against commercial activated carbon. Experimental equilibrium data fitted well with Langmuir isotherm (R2 = 0.9958) and kinetics studies predicted the pseudo-second order for Cr(VI) adsorption on ACDS. Re-usability studies showed that the ACDS could be used for a maximum of 3 times with a slight reduction in the Cr(VI) removal efficiency (&lt; 10%). Results indicated the promising use of date seed biomass as a cheap and efficient starting material to prepare activated carbon for Cr(VI) removal from chromium polluted wastewater. © 2019 Desalination Publications. All rights reserved.

Activated carbon from date seeds for chromium removal in aqueous solution

Oilfield wastewater or produced water is a complex mixture contains oil, organic and inorganic matter and other compounds dissolved in water that ranges from fresh to brine. Discharging produced water pollute soil surface and underground water and create environment hassle. The objective of this study is to investigate and summarize the novel method of fluidization processes, used for the treatment of oilfield produced water and oil refinery wastewater. Characteristics of oilfield produced water and oil refinery wastewater from different field and various methods for treating these wastewaters are discussed. Oilfield produced water and oil refinery wastewater are strongly acidic (pH 3-4), have a high chemical oxygen demand (1200-2600 mg/L), high polyphenol content (23 mg/L) and are highly variable. Primary attention is focused on the fluidization treatment of oilfield produced water and oil refinery wastewater, mainly by inverse fluidization. Finally, areas where further research and attention are required are identified.