Journal of Physical and Theoretical Chemistry
Volume:15 Issue: 1, Spring and Summer 2019

In this study, carbon was made from walnut wood as a low-cost and non-toxicnatural adsorbent.Walnut wood(WC), were successfully synthesized by an in chemical vapor deposition methodthen characterized using FT-IR techniques and used for the removal of trihalomethanes(THMs) from aqueous solution. The trihalomethanes(THMs) removal by the developed adsorbent was investigated using batch adsorption technique and allparameters influencing the removal efficiency such as: dose of adsorbent, pH and initial trihalomethanes(THMs) concentrationwere considered. The optimal conditions for the trihalomethanes(THMs) removal were found to be 5, 65 min, 10 mg/L, and 50 mg for pH, contact time, initial THMs concentration, and adsorbent dosage, respectively. The rapid adsorption of the THMs is an advantage of this adsorbent. Various isotherm models were used to fit the experimental equilibrium data. The results showed the suitability and applicability of Langmuir model.The maximum sorption capacity qmaxandR2 in Freundlichisotherm of trihalomethanes(THMs) 3.0 mg/g and 0.995 showed onto Walnut wood(WC). Kinetic models such as pseudo-first-order and pseudo-second-order diffusion models indicated that the second-order equation model controls the kinetic of the adsorption process. Thermodynamic parameters of adsorption process (G°,H°,S°) were also evaluated. The negative ΔGo value indicates that the process is feasible and the adsorption spontaneous in nature. The negative ΔHo value indicates the exothermic nature of adsorption and the value of ΔSo the change in the randomness at the activecarbon from Walnut wood(WC) solution interface during the sorption.The overall adsorption process was exothermic and spontaneous in nature. The results indicated that trihalomethanes(THMs) adsorption onto Walnut wood(WC) might be a physical adsorption.

The substitution reaction of pure, silicon doped and germanium doped fullerenes and tetryl were evaluated computationally at two configurations, in this study. For this purpose, all of the studied structures were optimized geometrically and then IR and NBO calculations were performed on them in the temperature range of 300-400 K at 10˚ intervals. The obtained negative values of Gibbs free energy variations(ΔGf), formation enthalpy alterations (ΔHf) and great values of thermodynamic equilibrium constant (Kth) prove that the reaction of the doped and also undoped fullerenes with tetryl is exothermic, spontaneous, one-sided and experimentally feasible. The impact of temperature on the thermodynamic parameters of the reaction was also inspected and the results indicate that 298.15 K is the optimum temperature for the synthesis of all of the derived products from the interaction of tetryl and the studied nanostructures. The calculated specific heat capacity values (Cv) show that the sensitivity of tetryl to the shock and heat has decreased significantly after its junction to fullerene nanostructures. Moreover, the increasing of N-O bond lengths after the fullerene substitution shows that the explosive power of tetryl has defused after its binding to the surface of fullerene. The obtained density values demonstrate that germanium doped C20 has the best impression on the improvement of the blasting power of tetryl in comparison to ordinary and silicon doped fullerene.

Naphthoquinones are natural aromatic compounds that can be discovered in various plant families. In recent times a diversity of biological activities of these compounds has been reported. In most cases, these pharmacological activities are related to redox and acid-base properties, which can be modulated synthetically by modifying the substituents attached to the 1, 4- naphthoquinone ring, in order to enhance their therapeutic actions. In the current study we used dipole moment and nuclear magnetic resonance (NMR) to depict these molecules properties. The density functional theory (DFT) calculations at the level of B3LYP/6-31G* have been applied to analyze the substituent effect on the electronic structural properties including thermochemical parameters of Naphtoquinone Derivatives in gas phase using Gaussian 98. Dipole moment (Debye), energy of structure formation (HF/Kcal/mol) and point group, NMR parameters such as isotropic shielding (σiso) and anisotropic shielding (σaniso), σ11, σ22, σ33 obtained. Also thermodynamic properties and natural bond orbitals (NBO) were calculated. It dovetails our recent work of electron transfer pathways on Naphtoquinone Derivatives in different replacement is a fundamental step in constructing a knowledge base which will ultimately be of use in many cases.

Sarin is a very toxic organophosphorus chemical warfare agent which has been used in different wars. According to an immediate demand of detection, secure approachs to break down this toxic nerve agent, the study on decomposition of sarin achieve significance. In this work, we have made endeavors of discovering an approach to neutralize this hazardous kind by adsorption of this molecule by C20 fullerene and its boron doped derivative. The results show that Sarin can form interactions with the C20 cage in its neutral state and the interactions can be enhanced significantly by introducing an extra boron atom to the system. The adsorption energy values and equilibrium distances for various adsorption states were calculated, and it was found that the GB molecule adsorbs onto the boron doped derivative with greater affinity than on pure fullerene. Probably, the GB is physisorbed on fullerene, while its adsorption on the boron doped derivative from O and P heads has a chemical nature. In that case, a partial positive charge was developed on boron atom, and was delocalized by O-P=O functional group in GB. As a result, GB is chemisorbed on boron doped derivative, contrary to the GB–fullerene interaction, which occurs physically.

The electronic structure and spectra of 3-formylchromone and some of its derivatives are investigated using TD-DFT/B3LYB/6-311G (d, p) level of theory. The results of calculations show that all the studied compounds 1–6 are planar, as indicated from the dihedral angles. The electronic absorption spectra of the studied compounds are recorded in the UV-Vis region, in both ethanol (as polar solvent) and dioxane (as non-polar solvent). The observed vertical electronic transitions assignments are facilitated via time-dependent density functional theory TD-DFT. The theoretical spectra computed at CAM-B3LYP/6-311G (d, p) in gas phase, ethanol and dioxane nicely reproduce the observed spectra. The natural bond orbital (NBO) analysis were discussed in terms of the extent of delocalization, intermolecular charge transfer and second order perturbation interactions between donor and acceptor MOs. The calculated EHOMO and ELUMO esame level of theory and compared with the proto type Para-Nitro-Aniline (PNA), show promising optical properties. 3D-plots of the molecular electrostatic potential (MEP) for some of the studied compounds are investigated and analyzed showing the distribution of electronic density of orbital's describing the electrophilic and nucleophilic sites of the selected molecules. The biological activity of the studied compounds was tested against gram positive, gram negative and Fungi.

This study was designed to compute the spectroscopic properties of aniline family, and educates the 3chloro-4-fluoro-aniline, which have unique pharmaceutical important. The structural and spectroscopic properties were investigated using a quantum calculation. The density functional theory approach at B3LYP/6–31G(d) data set is apply. IR and UV-Visible spectrophotometric estimated through GAMESS, Raman spectrogram was obtain through Gaussian and NMR C1 and C13 spectrums were also predicted through computational methods. After obtaining the results, they were tabulated. The results of current computational analysis is in sense useful to predict even a complex aniline precursor and advantage of the current computational strategy is beneficial for other aniline molecules containing chlorine and fluorine atoms. The success of this Density function theoretical results opens a pathway to apply a correct algorithm and a force field for the assignments of aniline family spectroscopy property.

Electrocoagulation (EC) in a batch cell with Al anode and Fe cathode in monopolar parallel (MP) connection was used for the removal of basic dye, Bromophenol Blue (BPB). The effects of current density, pH, temperature and initial dye concentration, on the process were investigated. Equlibrium data were analyzed using four model equations: Langmuir, Freudlinch, Temkin and Dubinin–Radushkevich. Data obtained from the time dependent electrocoagulation removal of BPB were analyzed with pseudo-first-order, pseudo-second-order and Elovic kinetic models. The study showed that the process depend on current density, temperature, pH and initial dye concentration. The process attained equilibrium after 15 minutes at 30 oC, all the isotherm models fitted the data with R2 > 0.9. The maximum removal capacity Qm value of 166.50 mg g-1 was obtained for the study while the first order kinetic model best described the process based on the lower values of %SSE. The calculated thermodynamics parameters (∆Go, ∆Ho and ∆So) indicated that the process is spontaneous and endothermic in nature.

Corn cob as a low cost adsorbent was used in the present work for the removal of toxic heavy metal Co2+ from aqueous solutions. Bath experiments were used to determine the best adsorption conditions. The equilibrium adsorption level was determined as a function of solution pH, temperature (T), contact time (tc), initial adsorbate concentration, and adsorbent dosage. Effective removal of metal ions was demonstrated at pH values of 8. Metal adsorption onto corn cob was evaluated by Langmuir and Freundlich isotherms. Results indicate that the Langmuir isotherm model is the most suitable one for the adsorption process using corn cob (R2=0.9503), thus, indicating the applicability of monolayer coverage of Co+2 ion on corn cob surface. The relationship between thermodynamic parameters was used to predict the absorption process. According to Thermodynamic analysis, the process was found to be endothermic and natural: (ΔHo= -18.7 J mol-1 and ΔSo = -47.6 J mol-1 K-1). Keywords: Cobalt (II); Adsorption; Thermodynamic; Corn cob