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Item A review on adsorptive removal of oil pollutants (BTEX) from wastewater using carbon nanotubes(Elsevier B.V., 2019) Anjum, H.; Johari, K.; Francisco Nirmala, N.; Ganesapillai, M.; Arunagiri, A.; Iyyaswami, R.; Murugesan, M.A progressive economic growth and proliferating global population caused adequate provision of clean water as a global issue. The systematic eradication of toxic pollutants from the environment has become a predominant matter from a biological and environmental perspective. Thus, adsorptive removal of hazardous components from wastewater is one of the most captivating strategies for purification technologies. Recently, carbon nanotubes (CNTs) have been reported to be very promising in the adsorption of various stable organic compounds due to their unique properties essential for further surface modification. In order to get the maximum removal of these pollutants, it is mandatory to understand the interaction mechanisms between the sorbent and sorbate. This review summarizes the recent literature on the adsorptive removal of BTEX from wastewater using CNTs. The impact of various factors (sorption sites of CNTs, physical properties of nanotubes, properties of background solution, and surface chemistry of CNTs) on the adsorption of BTEX over CNTs and the plausible interaction mechanisms such as hydrophobic interaction, electrostatic interaction, dispersive/repulsive interactions, π-π interactions and hydrogen bonding are critically reviewed. The present review has sorted out numerous prevailing gaps in the available information whilst recognizing a number of encouraging avenues and approaches for the upcoming research thrust. © 2018 Elsevier B.V.Item Studies on nonlinear optical parameters of bis-chalcone derivatives doped polymer(Elsevier BV, 2006) Shettigar, S.; Chandrasekharan, K.; Umesh, G.; Sarojini, B.K.; Narayana, B.Two bis-chalcone derivatives, 1,5-[di(4-methoxyphenyl)]penta-1,4-dien-3-one and 1,5-[di(4-chlorophenyl)]penta-1,4-dien-3-one were synthesized. Their SHG conversion efficiencies are reported to be 6.0 and 5.0 times that of urea and hyper polarizabilities are 9.9×10-30 and 10.2×10-30 esu, respectively. The third-order nonlinear optical properties in PMMA matrix were studied by Z-scan technique using 7 ns laser pulses at 532 nm. The nonlinear refractive index ?, nonlinear absorption coefficient ?, magnitude of effective third order susceptibility ?(3) and the coupling factor ? have been investigated. The values obtained are of the order of 10-14 cm2/W, 1.2 cm/GW, 10-14 esu and 0.2, respectively, which are comparable with the values obtained in stilbazoleum like dyes. The experimental investigation also shows that they are very interesting optical limiting materials and their optical limiting behaviour is mainly due to two photon absorption phenomenon. © 2006 Elsevier Ltd. All rights reserved.Item Effect of media characteristics on performance of upflow aerobic biofilters(2008) Srinikethan, G.; Shrihari, S.; Pradeepan, V.S.Laboratory studies were conducted to assess the influence of media related factors such as porosity, pore size, particle size and specific surface area on the performance of upflow aerobic biofilters (ABFs). Three simple models of 8 litre capacity upflow submerged ABFs packed with support media of size 40 mm, 20 mm and 10 mm respectively were installed. The hydraulic retention time (HRT) was maintained as 12 hours. The study was carried out for a period of 90 days. The reactor performance indicated that the aerobic biofilter (ABF-3), associated with media of lowest porosity, pore size, particle size and highest specific surface area, demonstrating the highest BOD and COD removal efficiency of 93.32 % and 85.01 % respectively.Item Studies on the removal of Pb(II) from wastewater by activated carbon developed from Tamarind wood activated with sulphuric acid(2008) Singh, C.K.; Sahu, J.N.; Mahalik, K.K.; Mohanty, C.R.; Mohan, B.R.; Meikap, B.C.The low-cost activated carbon were prepared from Tamarind wood material by chemical activation with sulphuric acid for the adsorption of Pb(II) from dilute aqueous solution. The activated carbon developed shows substantial capacity to adsorb Pb(II) from dilute aqueous solutions. The parameters studied include physical and chemical properties of adsorbent, pH, adsorbent dose, contact time and initial concentrations. The kinetic data were best fitted to the Lagergren pseudo-first-order and pseudo-second order models. The isotherm equilibrium data were well fitted by the Langmuir and Freundlich models. The maximum removal of lead(II) was obtained 97.95% (experimental) and 134.22 mg/g (from Langmuir isotherm model) at initial concentration 40 mg/l, adsorbent dose 3 g/l and pH 6.5. This high uptake showed Tamarind wood activated carbon as among the best adsorbents for Pb(II). © 2007 Elsevier B.V. All rights reserved.Item Corrosion inhibition of mild steel in acid media by quinolinyl thiopropano hydrazone(2009) Saliyan, R.V.; Vasudeva Adhikari, A.V.3-([8-(trifluoromethyl)quinolin-4-yl]thio)-A''-(2)3,4- trihydroxybenzylidene)propano hydrazide (TQTHBH) was synthesized, characterized and tested as a corrosion inhibitor for mild steel in HC1 and H2SO4 solutions using weight loss method, electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization methods. The corrosion inhibition efficiency results obtained by all the above three techniques were in good agreement with each other. Scanning electron microscopy (SEM) technique is used to confirm the effectiveness of inhibition of mild steel corrosion in acid media. The results showed that TQTHBH is a good inhibitor for mild steel in acid media. The inhibition efficiency of TQTHBH in different media was in the following order: 2 M HC1 < 1 M H2SO4 < 1 M HC1 < 0.5 M H2S04. The inhibition was assumed to occur via adsorption of the inhibitor molecule on the metal surface. The adsorption follows Langmuir isotherm. TQTHBH acts as an anodic inhibitor. The protection efficiency increased with increasing inhibitor concentration in the range 0.222 x 10"4 - 11.086 x 10^ M, also slightly increased with increasing temperature. Chemisorption mechanism is proposed. The apparent activation energies and enthalpies for the adsorption process were determined. The fundamental thermodynamic functions were used to gain information about TQTHBH inhibitory behaviour.Item Modelling, analysis and optimization of adsorption parameters for H3PO4 activated rubber wood sawdust using response surface methodology (RSM)(2009) Helen Kalavathy, M.H.; Iyyaswami, I.; Ganesapillai, M.G.; Miranda, L.R.Adsorption capacity of Cu2+ from aqueous solution onto H3PO4 activated carbon using rubber wood sawdust (RSAC) was investigated in a batch system. Kinetic and isotherm studies were carried out, the thermodynamic parameters like standard Gibb's free energy (?G°), enthalpy (?H°) and entropy (?S°) were evaluated. The pseudo-second-order model was found to explain the kinetics of Cu2+ adsorption most effectively. The process optimization was performed through Central Composite Rotary Design using response surface methodology (RSM) by Design Expert Version 5.0.7 (STAT-EASE Inc., Minneapolis, USA). An initial concentration of 35 mg L-1, temperature of 26 °C, carbon loading of 0.45 g (100 mL)-1, adsorption time 208 min and pH of 6.5 was found to be the optimum conditions for the maximum uptake of copper ions of 5.6 mg g-1 in batch mode. © 2009 Elsevier B.V. All rights reserved.Item Optimization and analysis of nickel adsorption on microwave irradiated rice husk using response surface methodology (RSM)(2009) Ganesapillai, M.G.; Iyyaswami, I.; Helen Kalavathy, M.H.; Murugesan, T.; Miranda, L.R.Background: The removal of heavy metals using adsorption techniques with low cost biosorbents is being extensively investigated. The improved adsorption is essentially due to the pores present in the adsorbent. One way of improving the porosity of the material is by irradiation of the precursor using microwaves. In the present study, the adsorption characteristics of nickel onto microwave-irradiated rice husks were studied and the process variables were optimized through response surface methodology (RSM). Result: The adsorption of nickel onto microwave-irradiated rice husk (MIRH) was found to be better than that of the raw rice husk (RRH). The kinetics of the adsorption of Ni(II) from aqueous solution onto MIRH was found to follow a pseudo-second-order model. Thermodynamic parameters such as standard Gibbs free energy (?G°), standard enthalpy (?H°), and standard entropy (?S°)were also evaluated. The thermodynamics of Ni(II) adsorption onto MIRH indicates that it is spontaneous and endothermic in nature. The response surface methodology (RSM) was employed to optimize the design parameters for the present process. Conclusion: Microwave-irradiated rice husk was found to be a suitable adsorbent for the removal of nickel(II) ions from aqueous solutions. The adsorption capacity of the rice husk was found to be 1.17 mg g-1. The optimized parameters for the current process were found as follows: adsorbent loading 2.8 g (100 mL)-1; Initial adsorbate concentration 6 mg L-1; adsorption time 210 min.; and adsorption temperature 35°C. © 2008 Society of Chemical Industry.Item N?-[4-(diethylamino)benzylidine]-3-{[8-(trifluoromethyl) quinolin-4-yl]thio}propano hydrazide) as an effective inhibitor of mild steel corrosion in acid media(2009) Ramesh, S.V.; Vasudeva Adhikari, A.V.N?-[4-(diethylamino)benzylidine]-3-{[8-(trifluoromethyl)quinolin-4-yl]thio}propano hydrazide (DEQTPH) was newly synthesized, characterized and tested as a corrosion inhibitor for mild steel in HCl (1 M, 2 M) and H2SO4 (0.5 M, 1 M) solutions using weight loss method, electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization method. The corrosion inhibition efficiencies measured by all the above three techniques were in good agreement with each other. The mild steel samples were also analyzed by scanning electron microscopy (SEM). The results showed that DEQTPH is an excellent inhibitor for mild steel in acid media. The inhibition efficiency in different acid media was found to be in the order, 0.5 M H2SO4 > 1.0 M HCl > 2.0 M HCl > 1.0 M H2SO4. The inhibition was assumed to occur via adsorption of the inhibitor molecule on the metal surface. It acts as an anodic inhibitor. In the 30-60 °C temperature range, the DEQTPH adsorption follows Langmuir isotherm model. The protection efficiency increased with increasing inhibitor concentration in the range 0.2 × 10-4 to 10.5 × 10-4 M and slightly increased with increasing temperature. Thermodynamic characteristics were discussed. Chemisorption mechanism is proposed. © 2009 Elsevier B.V. All rights reserved.Item The inhibition action of ethyl-2-phenyl hydrozono-3-oxobutyrate on the corrosion of 6061 Al alloy/SiCp composite in hydrochloric acid medium(Sociedad Chilena de Quimica, 2010) Kini U, U.A.; Shetty, P.; Shetty, S.D.; Isloor, A.M.; Herle, R.The inhibition behavior of ethyl-2-phenyl hydrozono-3-oxobutyrate on the corrosion of 6061 Al alloy/SiCp composite in 0.1, 0.5 and 1 N hydrochloric acid solution at four different temperatures (30-60 °C) has been investigated using potentiostatic polarization techniques and weight loss method. The results indicated that the corrosion inhibition efficiency and the extent of surface coverage were increased with the increase in inhibitor concentration up to a critical concentration. The adsorption of the inhibitor compound on the composite surface was found to obey Temkins' and Langmuir adsorption isotherms. The potentiostatic polarization results have revealed that oxobutyrate acts as an efficient cathodic inhibitor for the corrosion of 6061 Al alloy/SiCp composite in HCl medium. The thermodynamic parameters for the corrosion and adsorption processes were determined. © 2010.Item Equilibrium and kinetic study for the removal of malachite green using activated carbon prepared from Borassus flabellofer male flower(2010) JagadeeshBabu, P.E.; Kumar, V.; Visvanathan, R.Activated carbon was prepared from dried Borassus flabellofer male flower and batch adsorption experiments were conducted to study its potential to remove malachite green (MG) dye. The process was further optimized by studying the operating variables like initial pH of the stock solution, activation temperature, initial dye concentration, adsorbent loading and contact time. The optimized pH and activation temperatures were found to be 7.55 and 450.C respectively, where further analysis was made using these optimal variables. Linear, Freundlich and Langmuir isotherms were studied and it was found that the Langmuir isotherms have the highest correlation coefficients compared to the others. Further, the sorption kinetics were analysed using pseudo-first-order and pseudo-second-order kinetic models. The data showed that the second-order equation was the more appropriate, which indicate that the intra-particle diffusion is the rate limiting factor. © 2009 Curtin University of Technology and John Wiley & Sons, Ltd.