Analysis of Polycyclic Aromatic Hydrocarbon,Toxic Equivalency Factor and Related Carcinogenic Potencies in Roadside Soil within a Developing City of Northern India

Preliminary analysis was performed to assess contamination levels in roadside soils, distribution behavior and human exposure with Polycyclic Aromatic Hydrocarbons (PAHs) during summer, winter, rainy, and autumn during 2013 in one of the developing cities of northern India. The concentration of PAHs was measured at ten different locations (at 1, 2, and 3 m) from roadside soil. Recovery range was 30% and 80% with lower value corresponding to the lower molecular weight PAHs compound. Identification and quantification of PAHs was done by GC-FID. Average PAHs concentration (city average) was found to be 16.53, 4.04, 17.49, and 7.82 μg g^?1, during summer, winter, autumn, and the rainy seasons, respectively. Average concentration of low and high carcinogenic PAHs during summer, winter, autumn, and rainy was 5.1 and 31.29, 2.1 and 6.4, 4.74 and 35.08, 3.97 and 12.77μg g^?1_, respectively. The average ratio of low and high carcinogenic PAHs was found to be 1:6, 1:3, 1:7.6, and 1:3.21 during summer, winter, autumn, and the rainy seasons at most intercepts. Dib(ah)A and B(a)P were the two individual PAHs found in highest concentration during summer, winter, and the rainy seasons, whereas B(a)P and IP were individual PAHs found in highest concentration during autumn. It was also analyzed that high carcinogenic PAHs concentration was quite higher (around 85%) in comparison to low carcinogenic PAHs (around 15%) at most intercepts. This article also deals with the behavior of PAHs at places of average/high population and traffic density intercepts. Five-ringed PAHs were in highest concentration at all intercepts and seasons. Two-tailed T test was applied for authenticity of the data and results. Toxic equivalency factor of B(a)P and Dib(ah)A was maximum as compared to other PAHs.     

Rietveld refinement,micro-structural,optical and thermal parameters of zirconium titanate composites

Pure titania and zirconium titanate composites have been synthesized using sol-gel technique and annealed at 650, 875 and 1100 °C for 4 h. Acetylacetone was used to control the rate of hydrolysis of precursors. The Rietveld refinement, micro-structural, optical and thermal parameters of prepared composites was investigated. Effect of annealing and concentration of Zr and Ti in composites on their crystal structure, morphology, PL emission wavelength and band gap have been studied. X-ray diffraction and Rietveld analysis exhibit that all prepared samples of composites have orthorhombic single phase of zirconium titanate with space group pbcn. The lower values of profile parameters such as R_p, R_wp, R_B, R_F, χ² indicated that the calculated diffraction pattern is in fair agreement with observed pattern. The increase in zirconia concentration decreases the degree of crystallization of ZrTiO₄. The photoluminescence spectra show the blue shifting of emission peak at 420 nm as the zirconia concentration increases. The optical band gap of zirconium titanate composites also blue shifted (3.24–3.64 eV) with decrease in crystallite size of composites.     

Screening and optimization through response surface methodology for synthesis of pH,temperature and salt‐sensitive Aloe vera–acrylic acid‐based biodegradable hydrogel: Its evaluation as dye adsorbent

A pH‐, temperature‐, and salt‐sensitive hydrogel was synthesized using acrylic acid (AA) as monomer, natural polysaccharide Aloe vera as backbone, ammonium persulfate–N,N‐methylene‐bis‐acrylamide as an initiator–crosslinker system via free‐radical grafting method. Different parameters such as treatment time, temperature, amount of solvent, pH, concentration of initiator, crosslinker and monomer were screened using Plackett–Burman design (PBD). The PBD showed that pH, monomer, and crosslinker were taken as the most important variables, which highly impact the swelling behavior of the synthesized hydrogel as compared to the rest of the variables. The half normality plot was used to find the significant parameters regarding the swelling capacity of the hydrogel. The center composite design was used for further optimizing the important variables like pH, monomer, and crosslinker. The pH and monomer interaction on percentage swelling (Ps) was studied through the analysis of variance model. Synthesized hydrogel Av‐cl‐poly(AA) was characterized by different techniques such as Fourier‐transform infrared spectroscopy (FTIR), X‐ray diffraction, and scanning electron microscopy (SEM). The effect of different chloride salt solutions like KCl, NaCl, BaCl₂, FeCl₃, and CoCl₃·6H₂O on Ps of synthesized Av‐cl‐poly(AA)‐based hydrogel was also studied. Biodegradation studies of the synthesized polymer were also carried out using soil burial and vermicompositing methods. Biodegradation of semi interpenetrating polymer network (SIPN) was confirmed by SEM and FTIR techniques. Synthesized SIPN was also used as a device for the removal of dye and was found very effective as an adsorbent. POLYM. ENG. SCI., 59:2323–2334, 2019. © 2019 Society of Plastics Engineers     

Enzyme-based green approach for the synthesis of gum tragacanth and acrylic acid cross-linked hydrogel: its utilization in controlled fertilizer release and enhancement of water-holding capacity of soil

Enzyme lipase catalyzed graft copolymerization of acrylic acid onto gum tragacanth was carried out in an aqueous medium using glutaraldehyde as a cross-linker, one more step towards green chemistry. Various reaction variables such as time, amount of solvent, temperature, pH, lipase concentration, and monomer and cross-linker concentrations were optimized to achieve a cross-linked candidate polymer with maximum fluid absorbance capacity. The structure and morphology were confirmed by Fourier transform infrared spectroscopy and scanning electron microscopy. The synthesized hydrogel held a large amount of water and was used as a device for controlled release of urea. A 10 % (w/w) of swelled hydrogel was found to enhance the water-holding capacity of the soil. The synthesized device could increase the moisture content up to 52 % in sandy loam soil and 72 % in clay soil and was found to enhance the water-holding capability of the soil. Further, the candidate polymer was studied for the controlled release of urea under eco-friendly conditions and showed case-II type urea release. The initial diffusion coefficient was found to be higher than the later diffusion coefficient indicating a higher urea release rate during the early stage. Thus, the synthesized polymer is important from technological point of view.     

Microwave-assisted synthesis of biodegradable interpenetrating polymer network of aloe vera–poly(acrylic acid-<Emphasis Type="Italic">co</Emphasis>-acrylamide) for removal of malachite green dye: equilibrium,kinetics and thermodynamic studies

The present work deals with the synthesis of a biodegradable interpenetrating polymer network (IPN) consisting of natural polysaccharide aloe vera, acrylamide and acrylic acid. Biodegradability of the synthesized IPN was studied through soil burial and composting methods. The synthesized IPN was completely degraded within 70 days through the composting method and showed 91% degradation within 77 days through the soil burial method. Evidence of biodegradation of the synthesized IPN was studied by different techniques, for instance Fourier infrared spectroscopy and scanning electron microscopy. The synthesized IPN was used as a device for the removal of malachite green dye. The effect of different reaction parameters on IPN synthesis and dye removal was investigated. The maximum dye adsorption occurred at pH 4.5, because at this pH methylene green dye molecules are present in monomeric state. The result of Weber–Morris intra-particle diffusion showed that the rate-limiting step was not the intra-particle diffusion. The adsorption isotherm models, i.e., Langmuir, Freundlich, Dubinin–Radushkevich, Temkin, Redlich–Peterson and Sips, were studied and it was found that the Langmuir was the best-fitting model for the experimental data. An increase in temperature resulted in a decrease in malachite green dye removal, suggesting that the adsorption process was exothermic in nature. This synthesis is important from industrial viewpoints.     

Experimental assessment of the utilization of a novel interpenetrating polymer network in different processes in the agricultural sector

We synthesized a biodegradable, controlled release formulation via the impregnation of methyl methacrylic acid onto the natural polysaccharide, gum tragacanth, and a polyacrlyic-based hydrogel with glutaraldehyde as crosslinker. The biodegradation behavior of the prepared interpenetrating polymer network (IPN) was investigated with soil burial and composting methods, and the biodegradability stages were studied with Fourier transform infrared spectroscopy and scanning electron microscopy analyses. The controlled release data of the calcium nitrate was analyzed in accordance with Fick's power law, and the kinetics parameters of the release process were calculated. The values of the initial and lateral diffusion coefficients indicated a fast initial release rate of the fertilizers in comparison to the lateral release. The synthesized IPN was degraded 91.62% within 11 weeks under composting methods, whereas it degraded 78.83% under the soil burial method. The results show that the synthesized IPN was ecofriendly and could be used for the controlled release of agrochemicals. The impact of the degraded IPN on the fertility of the soil was also studied. We concluded from the results obtained that the biodegraded IPN did not have any adverse effects on the soil fertility. Hence, this biodegradable IPN could be of great significance from a green revolution point of view. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47739.