Equilibrium, Thermodynamic, and Kinetic Studies

Publisher Copyright: © 2022 Razia Sulthana et al.The economic viability of adsorbing crystal violet (CV) using pepper seed spent (PSS) as a biosorbent in an aqueous solution has been studied. A parametrical investigation was conducted considering parameters like initial concentration of dye, time of contact, pH value, and temperature variation. The analysis of experimental data obtained was carried out by evaluating with the isotherms of Freundlich, Sips, Tempkin, Jovanovic, Brouers-Sotolongo, Toth, Vieth-Sladek, Radke-Prausnitz, Langmuir, and Redlich-Peterson. The adsorption kinetics were studied by implementing the Dumwald-Wagner, Weber-Morris, pseudo-first-order, pseudo-second-order, film diffusion, and Avrami models. The experimental value of adsorption capacity (Qm=129.4 mg g-1) was observed to be quite close to the Jovanovic isotherm adsorption capacity (Qm=82.24 mg g-1) at (R2), coefficient of correlation of 0.945. The data validation was found to conform to that of pseudo-second-order and Avrami kinetic models. The adsorption process was specified as a spontaneous and endothermic process owing to the thermodynamic parametrical values of ΔG0, ΔH0, and ΔS0. The value of ΔH0 is an indicator of the process's physical nature. The adsorption of CV to the PSS was authenticated from infrared spectroscopy and scanning electron microscopy images. The interactions of the CV-PSS system have been discussed, and the observations noted suggest PSS as a feasible adsorbent to extract CV from an aqueous solution.publishersversionpublishe

<span style="font-size:14.0pt;line-height: 115%;font-family:"Times New Roman";mso-fareast-font-family:"Times New Roman"; color:black;mso-ansi-language:EN-IN;mso-fareast-language:EN-IN;mso-bidi-language: HI" lang="EN-IN">Ac electrical properties of 60B₂O₃-(40-x) PbO-xMCl₂ and 50B₂O₃-(50-x)PbO-xMCl₂ (M=Pb, Cd) glasses</span>

445-451<span style="font-size:14.0pt;line-height: 115%;font-family:" times="" new="" roman";mso-fareast-font-family:"times="" roman";="" color:black;mso-ansi-language:en-in;mso-fareast-language:en-in;mso-bidi-language:="" hi"="" lang="EN-IN">The glasses <span style="font-size:14.0pt;line-height: 115%;font-family:" times="" new="" roman";mso-fareast-font-family:hiddenhorzocr;="" color:black;mso-ansi-language:en-in;mso-fareast-language:en-in;mso-bidi-language:="" hi"="" lang="EN-IN">60B2O3 -(40-x) PbO-xMCl 2 and 50B2O3 -(50-x)PbO – xMCl2 <span style="font-size:14.0pt; line-height:115%;font-family:" times="" new="" roman";mso-fareast-font-family:"times="" roman";="" color:black;mso-ansi-language:en-in;mso-fareast-language:en-in;mso-bidi-language:="" hi"="" lang="EN-IN">(M = Pb, Cd) containing different concentrations of PbCl2 and CdCl2 were prepared. The ionic transference number of the glass samples was determined using dc polarization technique. The ionic transference number obtained is nearly 1 indicating that the electrical conduction in the glass samples is purely ionic. The dependence of ac conductivity and dielectric constant on temperature and frequency was investigated and the electrical moduli were analyzed. The variation of dielectric constant and ac conductivity with increase in mole percentage of PbCl2 or CdCl2 has been investigated on the basis of structural changes occurring in the glass samples.</span

Grain size tuning of nanostructured Cu2O films through vapour phase supersaturation control and their characterization for practical applications

A strategy for creating nanostructured films is the alignment of nanoparticles into ordered superstructures as living organisms synthesize biomaterials with superior physical properties using nanoparticle building blocks. We synthesized nanostructured films of Cu2O of variable grain size by establishing the condition of supersaturation for creation of nanoparticles of copper which deposited as nanograined films and which was then oxidized. This technique has the advantage of being compatible with conventional vacuum processes for electronic device fabrication. The Cu2O film samples consisted of a secondary structure of spherical particles of almost uniform size, each particle being an agglomerate of primary nanocrystals. Fractal analysis of the AFM images of the samples is carried out for studying the aggregation mechanism. Grain size tuning of the nanostructured Cu2O films has been studied using XRD, and micro-Raman and photoluminescence spectroscopy

<span style="font-size:14.0pt;line-height: 115%;font-family:"Times New Roman";mso-fareast-font-family:"Times New Roman"; color:black;mso-ansi-language:EN-IN;mso-fareast-language:EN-IN;mso-bidi-language: HI" lang="EN-IN">Impedance spectroscopic analysis of nanophase Ag₂HgI₄ and Ag₂HgI₄-Al₂O₃ nanocomposites</span>

366-372Nanoparticles of Ag2HgI4 have been prepared by chemical precipitation. The average particle size has been determined from x-ray line broadening. Grain and grain boundary contributions to the electrical conductivity of nanophase Ag2HgI4 and Ag2HgI4- Al2O3 nanocomposites are analyzed using impedance spectroscopy. The variations of these contributions with temperature and with the weight percentage of nano alumina are determined. The grain boundary conduction has been found to be less than the grain conduction in all the samples. The enhanced impedance of grain boundaries are attributed to the grain boundary properties of nanophase materials and the microsize space charge effects

Dc conductivity of consolidated nanoparticles of zinc sulfide

Zinc sulfide nanoparticles with average grain sizes ranging from 3 to 12 nm were prepared by arrested chemical preparation, followed by suitable thermal processing. The size of the grains was determined by x-ray line broadening. Dc measurement was performed on compacts of nanoparticles using a Keithley electrometer in the temperature range of 313–423 K. The dc conductivity, σdc, of our samples is much higher than that of ZnS single crystals; σdc increases with a decrease in the grain size

Effect of ball milling on chemically synthesized nanoparticles of CaCO3CaCO_3

Nanoparticles of $CaCO_3$ with an average size of $\sim 28$ nm was synthesized by chemical precipitation method. The as prepared sample was of vaterite phase, possibly due to the high value of surface energy associated with the smaller size. The as prepared sample was subjected to ball milling for different milling times and the milled samples were characterized using XRD analysis, and FTIR and FT Raman spectroscopy. Ball milling induced vaterite to calcite phase transformation along with the formation of a small percentage of aragonite phase. The grain size of the vaterite phase was not much affected by milling, while that of calcite phase was found to be reduced from $\sim50$ to $\sim32$ nm. The results were explained in terms of the enhanced diffusion due to ballistic displacement of atoms during ball milling

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Not AvailableChanges in climate and weather could profoundly affect the population dynamics and status of insect pests of crops. Aphids are ubiquitous insect herbivores whose behavior could be influenced by climate change. We studied the impact of elevated CO2 (eCO2) on Aphis craccivora Koch on cowpea (Vigna unguiculata L.). Cowpea plants were grown under ambient (380 ppm) and elevated (550 and 700 ppm) CO2 conditions in open top chambers (OTCs). Feeding trials were conducted using ‘cut leaf’ technique and the aphids were cultured individually in the laboratory. Results showed that the host plant and aphid species were significantly and positively influenced by eCO2. The mean fecundity (number of nymphs per day, 80%), Mean relative growth rate (MRGR, 8%) and adult weight (22%) of aphids increased but the longevity (5 %) and development time (5%) decreased significantly at eCO2 conditions over ambient CO2. Bio chemical analysis of cowpea foliage indicated an increased C:N ratio (8%) and decreased nitrogen content (7%) and non-significant variation of carbon and phenol content at eCO2 conditions.Not Availabl