NOPR Collection:

Extensive investigation on the study for the adsorption of Bromocresol Green (BCG) dye using activated Phragmites karka

Sat, 01 Sep 2018 00:00:00 GMT

Title: Extensive investigation on the study for the adsorption of Bromocresol Green (BCG) dye using activated Phragmites karka Authors: Murmu, B M; Behera, S S; Das, S; Mohapatra, R K; Bindhani, B K; Parhi, P K Abstract: Removal of Bromocresol green (BCG) dye from aqueous solution has been investigated using activated bio-sorbent Phragmites karka (PK). Batch adsorption method has been adopted and different parameters such as; pH of the solution, contact time, agitation speed, APK/BCG dose and temperature has been studied. From the resulted adsorption data the process is optimised and the transportation mechanism of BCG onto APK phase is proposed. In this study the bio-adsorbent PK is charred using H₂SO₄ to produce activated Phragmites karka (APK) which appears as an effective adsorbent on enhancing the loading efficiency of BCG than PK without activation. The BCG adsorption efficiency is increased from 16.05 to 84.2 % with increasing in acidity of the solution and maximized at pH 0.5 of solution. Maximum loading capacity of 392.3 mg/g is resulted using APK as adsorbent while removing BCG at ambient condition. The PK, APK, BCG loaded APK, and BCG are characterized by SEM, UV-vis and FTIR to ascertain the adsorption process as well as mechanism. The absorption peak obtained at 3450 cm^-1 due to ν (O-Hstr) of BCG was shifted to a broad band at 3270 cm^-1 shows the conjugation of BCG on surface of the APK, confirming the transporation of BCG to APK Phase as resulted from FTIR analysis. From the adsorption kinetics study, the rate of BCG adsorption shows well fit to the pseudo second order model than pseudo first order kinetic model. The positive value of, ∆H^o 2.49 kJ/ mole obtained by thermodynamic study reveals the endothermic nature of adsorption and and ∆S^o 24.87 J.K^-1mol^-1 shows the increase in degrees of freedom of BCG during adsorption. Equilibrium data are analysed by Langmuir, Freundlich and Tempkins adsorption isotherm to establish adsorption mechanism and the results shows best fit with Freundlich (R²=0.99) isotherm and reveals that the adsorption is of chemisorptions type. Page(s): 409-420

Development of dendritic growth patterns of polythiophene copper composite during electropolymerization: Characterization and bidirectional sensing applications

Sat, 01 Sep 2018 00:00:00 GMT

Title: Development of dendritic growth patterns of polythiophene copper composite during electropolymerization: Characterization and bidirectional sensing applications Authors: Mishra, Abhishek Kumar; Agrawal, Namita Rani; Das, Ishwar; Pandey, Prem Chandra Abstract: The development of three dimensional dendritic growth patterns of conductive polythiophene and its copper composite by electrochemical method from systems containing (A) thiophene, perchloric acid, acetonitrile and (B) thiophene, perchloric acid, cupric chloride and acetonitrile have been studied. Height of three dimensional hyper branched polymer aggregates is measured at different time of polymerization. Morphology and growth kinetic studies have been made and aggregates have been characterized by electrical conductivity, FT-IR, X-ray diffraction and TGA/DTG analysis. ESR and SEM-EDS studies confirm the presence of metal ion in the polymer composite. SEM studies show the formation of globular aggregates while TEM studies reveal the formation of nanosized polythiophene particles in the range 20-50 nm which increase on addition of copper salt. Solid-state potassium ion sensor with conductive polythiophene copper composite as novel matrix for assembling ion sensing membrane has been demonstrated. Cyclic voltammetric and amperometric studies show excellent electrocatalytic ability for H₂O₂ sensing at lower operating potential. Page(s): 421-430

Sequential acid-autoclave and microwave-alkali pretreatment of rice straw for bioethanol production

Sat, 01 Sep 2018 00:00:00 GMT

Title: Sequential acid-autoclave and microwave-alkali pretreatment of rice straw for bioethanol production Authors: Kaur, Jaspreet; Taggar, Monica S; Kocher, Gurvinder S; Javed, Mohammed Abstract: Two-step acid-autoclave and microwave-alkali pre-treatment process of rice straw have been carried out for bioethanol production. The reaction conditions of both the steps are optimized using Response Surface Methodology. The studies reveal that the optimum conditions for acid-autoclave pretreatment are found to be 1.90 per cent acid concentration, 51.85 min time and 1:17.51 solid:liquid ratio with maximum release of reducing sugars (16.94 g per 100 g) and minimum release of furfurals (0.93 g per 100 g). For second step pretreatment i.e. microwave-alkali, optimized conditions are observed to be 3.75 percent alkali concentration, 9.16 min time and 475W microwave power with minimum lignin content of 2.96 percent in pre-treated straw. Scanning electron micrographs reveal extensive damage of silicified waxy surface and disruption of the cell wall structure of straw after two step pre-treatment process. It has been concluded that sequential pre-treatment of rice straw using acid-autoclave and microwave-alkali process efficiently remove hemicellulose and lignin from straw, thereby increasing accessibility of cellulose to enzymatic hydrolysis for enhanced production of fermentable sugars and bioethanol. Page(s): 431-440

Studies on corrosion inhibitory action of Ocimum sanctum (Tulsi) leaves extract in mild steel corrosion induced by Desulfovibrio desulfuricans

Sat, 01 Sep 2018 00:00:00 GMT

Title: Studies on corrosion inhibitory action of Ocimum sanctum (Tulsi) leaves extract in mild steel corrosion induced by Desulfovibrio desulfuricans Authors: Chaithra, S; Gupta, Apeksha; Manivannan, R; Victoria, S Noyel Abstract: Studies on the effect of Ocimum sanctum (Tulsi) leaves extract as corrosion inhibitor for mild steel corrosion caused by Desulfovibrio desulfuricans has been carried out. The extract provides 74% inhibition efficiency and is effective up to two weeks. Potentiodynamic polarization studies show the occurrence of pitting corrosion. The electrochemical impedance spectroscopy studies reveal that the nature of the biofilm formed changes continuously. The scanning electron microscopy studies on samples immersed for different durations indicate two layers of different morphologies formed at the end of third and fourth weeks in the uninhibited sample. Energy dispersive x-ray diffraction studies show an increase in sulfide content in uninhibited sample indicating formation of corrosion products. Page(s): 441-450