Anju Chopra

Structural features of dilute acid, steam exploded, and alkali pretreated mustard stalk and their impact on enzymatic hydrolysis

To overcome the recalcitrant nature of biomass several pretreatment methodologies have been explored to make it amenable to enzymatic hydrolysis. These methodologies alter cell wall structure primarily by removing/altering hemicelluloses and lignin. In this work, alkali, dilute acid, steam explosion pretreatment are systematically studied for mustard stalk. To assess the structural variability after pretreatment, chemical analysis, surface area, crystallinity index, accessibility of cellulose, FT-IR and thermal analysis are conducted. Although the extent of enzymatic hydrolysis varies upon the methodologies used, nevertheless, cellulose conversion increases from <10% to 81% after pretreatment. Glucose yield at 2 and 72h are well correlated with surface area and maximum adsorption capacity. However, no such relationship is observed for xylose yield. Mass balance of the process is also studied. Dilute acid pretreatment is the best methodology in terms of maximum sugar yield at lower enzyme loading.

Hydrocarbon characterization of hydrocracked base stocks by one- and two-dimensional n.m.r. spectroscopy

Abstract Characterization of a number of unconventional catalytically hydrogenated base stocks of low aromatic content and high viscosity index is discussed in terms of hydrocarbon types, with emphasis on isoparaffinic structural analysis. The analysis was carried out using multipulse one- and two-dimensional n.m.r. spectral techniques. Various spectral regions characteristic of different structural units were assigned based on DEPT, 2D COSY and HETCOR spectroscopy. The presence of eleven different types of branched structures was established. The analysis of 1D and 2D n.m.r. spectra further provided reliable average structural parameters. The aromatic carbon (C A ) content of these samples was found to be

Studies On Competitive Interactions and Blending Order of Engine Oil Additives by Variable Temperature 31P-NMR and IR Spectroscopy

Interactions between various engine oil additives including dispersant, detergent, antiwear/antioxidant, and viscosity index improvers have been investigated through changes in the 31P-NMR and IR spectra. Significant changes in the 31P-NMR and IR spectra of zinc dialkyldithiophosphate (ZDDP) have been observed by varying the blending order of additives. Dispersant-detergent (polyisobutylene succinimide-calcium overbased sulfonate) and viscosity index improver-detergent (dispersant olefin copolymer-calcium overbased sulphonate) interactions were found to be strong and irreversible in nature. Variable temperature 31P-NMR spectra have provided enough evidence to suggest that the actual performance of an additive may not be decided by its bulk interactions with other additives at room temperature, and that tribochemical reactions occurring at higher temperature play a greater role.

Reduction of pollution load of paper mill effluent by phytoremediation technique using water caltrop (Trapa natans L.)

Abstract Laboratory experiments were conducted to investigate the reduction of pollution load of paper mill effluent through phytoremediation technique using water caltrop (Trapa natans). Different concentrations, viz. 0% (control), 25, 50, 75, and 100% (absolute) were treated using T. natans for 60 days. Results showed that sewage effluent was loaded with various parameters, viz. total dissolved solids (TDS), electrical conductivity, total Kjeldhal nitrogen (TKN), phosphate (), calcium (Ca2+), magnesium (Mg2+), potassium (K+), cadmium (Cd), copper (Cu), iron (Fe), nickel (Ni), lead (Pb), and zinc (Zn). The maximum removal of different parameters was recorded after 60 days of phytoremediation experiments. Water caltrop (T. natans) significantly (p < 0.05/p < 0.01) removed TDS, BOD, COD, TKN, , Ca2+, Mg2+ and K+, Cd, Cu, Fe, Ni, Pb, and Zn of the paper mill effluent after the phytoremediation. The removal of different pollutants from the paper mill effluent was gradually increased at lower concentration i.e. (from 20 to 50%) concentrations of the paper mill effluent. The maximum fresh weight, dry weight, and LAI of T. natans were observed with 50% concentration of the paper mill effluent at 45 days of phytoremediation experiments. Therefore, T. natans can be used for the treatment of paper mill effluent up to 50% concentration for 60 days using phytoremediation technique.

Carbon type analysis of hydrotreated and conventional lube-oil base stocks by i.r. spectroscopy

Abstract An infrared spectroscopic method is described for the determination of isoparaffin carbon content in lubricating-oil base stocks. The paper also describes a modified method for the accurate estimation of paraffinic carbon content of hydrotreated base stocks. The methods are based on correlations of 13C n.m.r. hydrocarbon analysis data with area-integrated intensities of the i.r. spectral bands of skeletal vibrations in the 1200-1100 cm−1 region, the peak area in the 830-800 cm−1 region and methylene wagging bands in the 790-700 cm−1 region. The correlation coefficients obtained are 0.88 and 0.82 for the estimation of paraffin carbon content (Cp) and isoparaffin carbon content (Ip) respectively.

Distribution, Enrichment and Accumulation of Heavy Metals in Soil and Vigna Mungo L. Hepper (Black gram) after Irrigation with Distillery Wastewater

The present investigation was aimed to study the distribution, enrichment and accumulation of heavy metals in soil and Vigna mungo (Black gram, var. Pant U-30) after irrigation with distillery wastewater. A field experiment was conducted in the experi mental garden of Gurukula Kangri University, Haridwar during the year 2012 and 2013. Treatments of distillery wastewater viz. 20%, 40%, 60%, 80% and 100% was used for irrigation of V. mungo along with bore well water (control). The results revealed that distillery wastewater showed significant (P Cr>Zn>Cu>Mn for soil and Cu>Mn>Zn>Cr>Cd for V. mungo after irrigation with distillery wastewater. The accumulation of various heavy metals in different parts of V. mungo were in order of leaves>shoot>root> fruits for Cu, Mn and Zn, root>shoot>leaves>fruit for Cd and Cr after distillery wastewater irrigation. Therefore, the distillery wastewater with appropriate dilution can be used as a bio-fertigant for the V. mungo.

Use of HPLC to monitor olefins, dienes, and aromatics in the dehydrogenated products of higher n-paraffins

ABSTRACT The linear higher olefins are generated through catalytic dehydrogenation of long-chain linear paraffins. During the catalytic dehydrogenation, a variety of dienes and aromatics are also formed. These side products not only cause coking of the catalyst, but also hamper in the reaction course of olefins with other substrate. A method has been developed based on the High-Performance Liquid Chromatography with Refractive Index detection for simultaneous estimation of olefins, dienes, and aromatics in the catalytic dehydrogenated product of model compound decane. The application of method for monitoring of the dehydrogenated stream from C10-C14 n-paraffins has also been discussed.

Sulfur compounds in the fuel range fractions from different crude oils

ABSTRACT A gas chromatograph coupled with sulfur chemiluminscence detector (GC-SCD) has been used for the speciation of individual sulfur compounds in fractions of different crude oils. The crude oil fractions characterized were light naphtha (C5-90°C), heavy naphtha (90–140°C), kerosene (140–240°C), and gas oil (240–370°C) fractions obtained from true boiling point distillation process. Low boiling fractions (up to 140°C) were analyzed by existing ASTM D5623 (American Society for Testing and Materials, 2009a) method for sulfur compound speciation. As there is no standard method for the distribution of sulfur compounds in high boiling samples (up to 370°C), therefore, a methodology has been developed for the diesel range samples. The identification of individual sulfur compounds were carried out by using reference sulfur compounds. The results show that type of sulfur compounds depends upon the boiling range of the fraction and source of crude oil. The major changes in the sulfur compounds profiles of different fractions are discussed. The results of this study can be used to predict the suitability of crude oil for the production of Euro-IV and V gasoline and diesel fuels.

Novel HPLC-RI-UV based method for simultaneous estimation of saturates, olefins, conjugated dienes and aromatics in full range cracked gasoline

Abstract A fast method based on High performance liquid chromatography technique for the estimation of Saturates, Olefins, Conjugated dienes and Aromatics in Cracked gasoline samples has been developed. In this work, the focus was on choosing the right reference standard against which olefin could be estimated. The olefin reference standard was first shortlisted using Nuclear Magnetic Resonance spectroscopy and Gas chromatography based Simulated Distillation analysis as per ASTM D2887. The values estimated against shortlisted standards using HPLC were compared with values obtained using standard Flourescent Indicator Adsorption(FIA) based ASTM D1319 method to select one. The aromatics were estimated against o-Xylene.

Estimation of Static Dissipater Additives in Aviation Turbine Fuels Using ASTM D7524 and ASTM D2624: Observation, Precautions, and Suggestions Thereof

Static dissipater additives (SDAs) are conductivity improver additives that are added to aviation turbine fuels (ATFs) to avoid sudden increase in conductivity that may occur during transfer/pumping of ATF. STADIS 450 has been used globally as the SDA in aviation jet A1. The dosage of SDA into jet fuels is very closely specified (1–3 ppm). Due to surface active nature, SDA dosage may deplete with time. The monitoring of concentration of SDA is very critical and is generally carried out using conductivity measurement as per ASTM D2624 or as per liquid chromatographic technique based ASTM D7524 method entitled in “Determination of static dissipater additive (SDA) in aviation turbine fuel using HPLC technique with UV detector in the range of 1 to 12 ppm”. In this work, SDA blended ATFs in the range of 1–5 ppm have been analyzed for estimation of SDAs using both HPLC based ASTM D7524 and conductivity measurement based ASTM D2624. This paper suggests precautions that need to be taken while using the two method...