N.C. Kothiyal

Use of pectin-thorium (IV) tungstomolybdate nanocomposite for photocatalytic degradation of methylene blue

Pectin-thorium (IV) tungstomolybdate (Pc/TWM) nanocomposite was prepared by mixing biopolymer pectin with its inorganic counterpart thorium (IV) tungstomolybdate (TWM) using the sol-gel method. The nanocomposite was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR). Distribution coefficient, thermal stability, pH titrations, elution and concentration behaviour were investigated to explore the ion exchange behaviour of nanocomposite material. Pc/TWM exhibited higher ion exchange capacity (1.10 mequiv/g) than its inorganic counterpart (0.62 mequiv/g). The Pc/TWM nanocomposite ion exchanger was thermally stable as it retained 59% of its ion exchange capacity upto 400°C. The pH titrations study revealed the bifunctional nature of Pc/TWM. In order to explore the environmental applicability of the Pc/TWM nanocomposite material, its antibacterial and photocatalytic activities was investigated. 76% of methylene blue dye was photocatalytically degraded after five hours exposure. It also totally inhibited Escherichia coli at 400 μg/ml concentration of Pc/TWM nanocomposite.

Preparation of a novel chitosan-g-poly(acrylamide)/Zn nanocomposite hydrogel and its applications for controlled drug delivery of ofloxacin.

Chitosan-g-poly(acrylamide)/Zn (CPA-Zn) nanocomposite was synthesized using simple method in the presence of microwave radiations. CPA-Zn nanocomposite was characterized by various analytical techniques. CPA-Zn nanocomposite was used for controlled drug delivery of ofloxacin. The maximum drug release was 75% which was observed in acidic medium. The cumulative drug release and drug released kinetics of CPA-Zn was investigated. It was noticed that the drug release behavior depended upon the pH of medium as well as on the the nature of matrix. CPA-Zn nanocomposites were also studied for their antibacterial activity against E. coli bacteria.

Influence of graphene oxide as dispersed phase in cement mortar matrix in defining the crystal patterns of cement hydrates and its effect on mechanical, microstructural and crystallization properties

In the present investigation, graphene oxide (GO) was prepared using oxidative treatment of graphite by Hummer’s method. The synthesized graphene oxide (GOa) was characterized by FTIR, SEM/EDS, TEM, XRD, TGA and AFM. Size-reduction of GOa (which had a 14 nm sheet thickness and 900 nm average sheet size) was done using planetary ball milling, which produced GOb with a sheet thickness of 3 nm and an average sheet size of 100 nm. The effectiveness of GOa and GOb nanosheets at different dosages (by wt% of cement) in the improvement of mechanical strength of cement mortar matrices has been evaluated, and explained on the basis of microstructural analysis using FE-SEM observations, as well as from crystallization patterns using XRD patterns of GO–cement nanocomposites (GO–CNCs). Well-defined crystal growths of cement hydrates were observed, as revealed by FE-SEM micrographs, and crystallization patterns were found to be dependent upon factors such as the type of GO nanosheets, the concentration of GO and the curing time. The as-synthesized GOa (1% by weight of cement) enhanced the compressive strength of composites by a maximum of 63%, whereas the size-reduced GOb (1% by weight of cement) promoted better crystalline structures with a maximum strength enhancement of 86%. The present research work aimed to enhance GO reactivity by increasing its exfoliation and its count by mechanical milling, and to exploit it as a low-cost dispersed phase which has different sheet thicknesses and sheet sizes, for the strength enhancement of cementitious matrices by regulating crystal patterns and microstructural features.

Distribution behavior of polycyclic aromatic hydrocarbons in roadside soil at traffic intercepts within developing cities

A study of polycyclic aromatic hydrocarbons pollution in roadside soil was conducted in developing city environment of northern India during autumn and winter season to ascertain the contamination levels and their distribution behavior in soil. The concentration of polycyclic aromatic hydrocarbons was determined at ten locations of Jalandhar city, Punjab in India at 1, 2 and 3 m distances from roadside in soil covering all the major traffic intercepts within city. The samples were extracted in acetone and dichloromethane (1:1) using soxhlet extraction. The extracts were then filtered on a silica gel micro column to remove impurities and elute was subjected to GC-FID. The total average concentration (city average) was found to be 4.04 ⧎g/g and 16.38 ⧎g/g during winter and autumn respectively. DiBenzo (ah) Anthracene and Benzo (a) Pyrene were the individual polycyclic aromatic hydrocarbons found in highest concentration at all the intercepts ranging between 0.008 to 28.4 ⧎g/g during winter and 0.01 to 252.55 ⧎g/g during autumn. Average concentration of non-carcinogenic and carcinogenic polycyclic aromatic hydrocarbons during winter and autumn was found to be 2.1 and 6.4 and 4.74 and 35.08 ⧎g/g respectively. The average ratio of non-carcinogenic and carcinogenic Polycyclic Aromatic Hydrocarbons was found to be 1:3 during winter, and 1:7.6 during autumn at most of the intercepts. Total carcinogenic polycyclic aromatic hydrocarbons concentration was found quite high (80 %) in comparison to non-carcinogenic polycyclic aromatic hydrocarbons (20 %) at most of the intercepts.

Synthesis of chitosan-g-poly(acrylamide)/ZnS nanocomposite for controlled drug delivery and antimicrobial activity.

Nanocomposite materials are gaining grounds in the fields of medicine, environmental sciences and for basic studies. Herein, we have developed, a novel method for the preparation of chitosan-g-poly(acrylamide)/ZnS (abbreviated as CPAZ) nanocomposite using microwave radiations. The synthesized CPAZ nanocomposites were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), energy-dispersive X-ray analysis (EDX), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and thermo gravimetric analysis (TGA). FTIR results established the grafting of acrylamide onto chitosan backbone. TEM analysis revealed the size of the CPAZ nanocomposite particles in the range of 19-26 nm. XRD technique predicated the crystalline behavior of the nanocomposite. Therefore, XRD, TEM and FTIR spectrum analysis confirmed the formation of CPAZ nanocomposites. Zeta potential for CPAZ nanocomposite was found to be +28.2 mV which indicated its stability. The CPAZ nanocomposites were investigated for drug release behavior and we found a maximum of 79% drug release at pH 2.2. Moreover, CPAZ nanocomposite was also found to be antimicrobial against Escherichia coli bacteria.

Characterization of Municipal Solid Waste in Jalandhar City, Punjab, India

AbstractCharacterization of the existing municipal solid waste (MSW) in Jalandhar, India, has been performed to evaluate its suitability for various waste-processing technologies. The predominance of open dumping and the absence of reliable data regarding generation and characterization of waste has created a difficult situation for urban local bodies responsible for managing MSW generated in the city. In this study, MSW samples collected from a city dump site at different times throughout a year were analyzed for physical, chemical, and geotechnical characteristics. Physical characterization of the city waste indicates that MSW is rich in biodegradables and inerts. The waste characterization highlights the importance of waste segregation before sending the waste fractions for different waste-treatment technologies including composting, biomethanation, refuse-derived fuel, and landfilling. Further, physical and geotechnical characterization of the city waste confirms its suitability for applying bioreacto...

Synergistic effect of zero-dimensional spherical carbon nanoparticles and one-dimensional carbon nanotubes on properties of cement-based ceramic matrix: microstructural perspectives and crystallization investigations

In the present investigation, hybrid effect of spherical carbon nanoparticles and carbon nanotubes as zero- and one-dimensional entities, respectively (synthesized by novel CVD route), on properties of cement ceramic matrix was studied. Ceramic matrix composites were fabricated using different dosages (% by wt. of cement) of as-synthesized nanoadditive (labeled as rCNTs) and tested for their resistance to compression at increasing hydration curing times of 7, 14, and 28 days. Evolution of different inorganic crystalline phases in composites was examined using X-ray diffraction (XRD). Improvement in mechanical behavior of composites was explained on the basis of microstructural observations using field emission scanning electron microscopy (FE-SEM). Electrical behavior was evaluated using four-probe method and it was observed that addition of nanoadditive had a semiconducting influence on ceramic matrix composites. Thermal behavior of composites was investigated using thermogravimetric analysis (TGA) and compared with that of unreinforced counterpart. All the properties of rCNT composites were compared with carbon black (pCB) cement mortar nanocomposites. Obtained results indicated a maximum improvement of 13.5% in strength in case of 0.125% rCNT cement mortar composite. Electrical and thermal properties were improved with incorporation of rCNTs indicating significant potential for the practical application of low-cost novel rCNT in the preparation of cement-based materials of high strength and smart functionality.

Sources, distribution, and health effect of carcinogenic polycyclic aromatic hydrocarbons (PAHs) – current knowledge and future directions

Polycyclic aromatic hydrocarbons (PAHs) are chemical compounds containing two or more fused benzene rings in linear, angular or cluster arrangement, consisting of only carbon and hydrogen. Polycyclic aromatic carbons (PACs) include the unsubstituted hydrocarbons (PAHs) and substituted PAHs (e.g. nitro-PAH, oxygenated PAH). PAHs are the most stable form of hydrocarbons having low hydrogen-to-carbon ratio and usually occur in complex mixtures rather than single compounds. They are usually generated under inefficient combustion conditions (e.g. in incomplete supply of oxygen).This paper deals with type carcinogenic PAHs generated in the environment from various sources, environment distribution and health effect.This paper provides a review of current information on the concentrations, burdens and fate of PAHs in the atmosphere, with reference to the historical trends in PAH emissions. The major anthropogenic sources of PAHs and their effect on the concentrations of these compounds in air on a national–inter...

Characterization of reactive graphene oxide synthesized from ball – milled graphite: its enhanced reinforcing effects on cement nanocomposites

Abstract In this study, commercial graphite powder (GP) of particle size 100 micron was subjected to high energy ball-milling (HEBM) to produce ball-milled graphite powder (BMGP) of particle size 780 nm. Both GP and BMGP were converted to respective graphene oxides (GOs) (labeled as GO1 and GO2) using Hummer’s method, which were then characterized using techniques such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X- ray diffraction (XRD). GO1 and GO2 were then investigated for their effects on compressive strength of cement mortar matrix at different curing times of 7, 14, and 28 days. Effect of variation of concentration (ranging between 0.125 and 1.00 wt% of cement) of GO1 and GO2 on the strength of matrix was examined. Microstructures of GO1-cement mortar nanocomposite and GO2-cement mortar nanocomposite were studied after 28 days of curing using SEM. Obtained results show that addition of 1.00 wt% GO1 and GO2 showed best performance by increasing the strength to 63 and 78%, respectively, in comparison to the unreinforced control sample. Improved performance of GO2 was attributed to more number of reactive sites of GO nanosheets induced by ball-milling treatment of graphite precursor.

Studies on carcinogenic PAHs emission generated by vehicles and its correlation to fuel and engine types

Abstract The objective of this study was to find major PAHs produced in ambient air from the automobile exhaust as a function of fuels (diesel, petrol, and biodiesel) and engine type qualitatively and quantitatively. The recovery range was found between 30% and 70%. The study was carried out on two, three, and four wheelers. Biodiesel samples tested in the study were synthesized indigenously from different starting raw materials and analyzed for PAHs concentration in the exhaust on a Honda genset (EBK 2000AC Model). Biodiesel samples were blended with diesel in different ratio (25:75, 35:65 and 45:55) to investigate the exhaust behavior. Biodiesel was blended with Diesel the concentration of almost all PAHs reduces in comparison to pure Diesel exhaust. B(a)A and B(a) P was the common PAH found in higher concentration in almost all fuels. FTIR results indicate esterification of vegetable oil and NMR results indicate a complete conversion of oils into biodiesel.