Faculty Publications
Permanent URI for this communityhttps://idr.nitk.ac.in/handle/123456789/18736
Publications by NITK Faculty
Browse
89 results
Search Results
Item Potential environmental applications of Helianthus annuus (sunflower) residue-based adsorbents for dye removal in (waste)waters(Elsevier, 2022) Anastopoulos, I.; Giannopoulos, G.; Islam, A.; Ighalo, J.O.; Iwuchukwu, F.U.; Pashalidis, I.; Kalderis, D.; Giannakoudakis, D.A.; Nair, N.; Lima, E.C.Under the framework of Circular Economy, agricultural residues that once were considered an unwanted byproduct, are currently gaining popularity as novel bio-based products for environmental applications. This chapter evaluates the potential of Helianthus annuus (sunflower) biomass residues for (waste)water dye removal considering the factors regulating its subsequent chemical processes and equilibria. The initial pH, which affects both the dye speciation in solution and the surface charge of the adsorbent, is one of the most critical parameters and determines the optimum conditions for efficient dye removal. The soluble dyes, that present a high affinity for water, are generally ionized (e.g., possess positive or negative charge), and therefore, the sorption capacities of an adsorbent are strongly affected by the initial pH of the dye solution. The equilibrium data regarding the removal of various dyes from aqueous solutions using sunflower-based adsorbents (in pristine or chemically modified form) are usually better described by the Langmuir equation; however, in some cases, the Freundlich adsorption model seems to better fit the experimental data. The majority of the kinetic data associated with the removal of dyes using sunflower-based adsorbents follows the pseudo-second-order model. In addition to the thermodynamic adsorption data, this chapter summarizes and discusses also data of desorption experiments performed using dye-loaded adsorbents. © 2022 Elsevier Inc. All rights reserved.Item Experimental Transient Analysis of Radial Flow Clay Desiccant Packed Bed(Springer Science and Business Media Deutschland GmbH, 2021) Boche, A.; Kadoli, R.In this work, an experimental investigation on the desiccant bed with radial flow is discussed. The spherical clay balls with the average diameter of 11 mm is used as desiccant in the radial bed. Two sizes of radial test section are developed based on the diameter of the inner cylinder and outer cylinder. The diameter ratio is evaluated based on the space needed to accommodate the spherical clay desiccant as a single layer and two layered. For the present work, the behavior of 850 g of clay desiccant in the single layer and double layer radial packed bed is being compared. Both the experimental test units were kept at nearly same relative humidity during the process of adsorption and nearly same temperature during desorption process. The parameters such as exit air humidity, exit air temperature, mean bed temperature during the process of adsorption, and desorption are being compared. © 2021, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.Item A Study on Aquaculture Waste Leachate Transport Through Soil(Springer Science and Business Media Deutschland GmbH, 2023) Thotakura, T.V.; Sunil, B.M.; Chaudhary, B.Aquaculture waste is one of the emerging wastes due to rapid expansion and intensification of aquaculture practices and less attention has been paid for environmental concern as compared with municipal waste. Moreover, in the delta region of Andhra Pradesh, nearly one-third of the land cover is occupied by the aquaculture ponds. Major contaminants in aquaculture ponds are rich in nutrients, chemicals, disinfectants, feed residues, metals, minerals, and nitrates. This paper presents the aquaculture waste leachate and clay interaction. Our findings revealed that ammonia interaction with the clay particles significantly influence the hydraulic behavior of the clays. Further, long-term clay-leachate interactions lead to negative environmental consequences. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.Item Green Synthesis of Zinc Oxide Nanoparticles and Study of Its Adsorptive Property in Azo Dye Removal(Springer Science and Business Media Deutschland GmbH, 2023) Anupama, C.; Shrihari, S.Dyes are important colouring chemical compounds widely used in textile, paper, food, cosmetics and pharmaceutical industries. Most of the dyes are highly toxic and potentially carcinogenic. Exposure to high doses of these compounds can have severe effects in the human body. When untreated dye effluents are directly discharged into water bodies it leads to water contamination. Adsorption is an efficient method for the dye removal. It is also an economical technique. Green synthesis helps in the production of cost-effective and ecofriendly adsorbent. In this paper, green-synthesized zinc oxide nanoparticles were widely used for the removal of azo dye; methyl orange. Zinc oxide nanoparticles (ZnO NPs) were synthesized using Plectranthus Amboinicus leaf extract. The structure of nanoparticles was visualized using Field Emission Scanning Electron Microscope (FESEM). Nanoparticles due to their small size and thus large specific area are strong adsorbents. The effect of various parameters like dye dosage, zinc oxide nanoparticle loading, pH and contact time was evaluated. In batch adsorption study, maximum removal efficiency of 85.41% was obtained with zinc oxide nanoparticle dosage of 3 g initial dye concentration of 10 mg/l, pH 6 and contact time of 3 h. Adsorption parameters fitted well in the Langmuir isotherm model with a correlation coefficient (R2) of 0.975. Adsorption kinetic studies revealed that adsorption strongly followed pseudo-second order. This paper suggests a safe, economical and environment-friendly technique for the removal of azo dyes. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.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.