Journal of Physical and Theoretical Chemistry
Volume:19 Issue: 3, Autumn 2022

A quantitative structure- activity relationship (QSAR) has been widely used to investigation a correlation between chemical structures of molecules to their activities. In the present study, QSAR models have been carried out on 76 camptothecin (CPT) derivatives as anticancer drugs to determine the 14N nucleus quadrupole coupling constants (QCC). These quantum chemical properties have been calculated using Density Functional Theory (DFT) and B3LYP/6-311G (d, p) method in the gas phase. A training set of 60 CPT derivatives were used to construct QSAR models and a test set of 16 compounds were used to evaluate the build models that were made using multiple linear regression (MLR) analysis. Molecular descriptors were calculated by Dragon software, and the stepwise multiple linear regression and the Genetic algorithm (GA) techniques were used to select the best descriptors and build QSAR models respectively.  QSAR models were used to delineate the important descriptors responsible for the properties of the CPT derivatives. The statistically significant QSAR models derived by GA-MLR analysis were validated by Leave-One-Out Cross-Validation (LOOCV) and external validation methods. The multicollinearity of the descriptors contributed in the models was tested by calculating the variance inflation factor (VIF) and the Durbin–Watson (DW) statistics. The predictive ability of the models was found to be satisfactory. The results of QSAR study show that quantum parameters, 2D autocorrelations and Walk and path counts  descriptors contains important structural information sufficient to develop useful predictive models for the studied activities.

This study describes the construction of a new electrochemical sensor and applies for determination of Hg2+ ion. This sensor was prepared using a new nanocomposite base on (Co3O4-CeO2-ZnO). Although the other methods (gas or liquid chromatographic, electrophoresis, flow injection) for measuring Hg2+ ion has advantages such as excellent accuracy and reproducibility, it has limitations such as long-time measure, high equipment cost. In this study, for determination Hg2+ ion we used a from sensor Co3O4-CeO2-ZnO/CPE and voltammetric method.  The calibration curve was linear in the range of (0.03 to 35.0 µgL−1). The standard deviation of less than (3%), and detection limits (3S/m) of the method (0.09 nM) for Hg2+ ion were obtained for the proposed electrochemical sensor by Co3O4-CeO2-ZnO/CPE with (95%) confidence evaluated. Finally, Co3O4-CeO2-ZnO/CPE has been successfully applied for the determination of Hg2+ ion in water samples. The method introduced to measure Hg2+ ion in water samples was used and can be used for other samples.

In the present study, the applicability of PSF/Fe2O3 mixed matrix membrane synthesis for eliminating humic acid rapidly from aqueous solutions. Identical techniques, including FT-IR, XRD and SEM has been utilized to characterize this novel material. The investigation showed the applicability of PSF/Fe2O3 mixed matrix membrane as an available, suitable and low-cost adsorbent for proper deletion of humic acid from aqueous media. Also, the impacts of variables including initial humic acids (HAs) concentration (X1), pH (X2), adsorbent dosage (X3), sonication time (X4) came under scrutiny using central composite design (CCD) under response surface methodology (RSM). Additionally, the impacts of the pH of the solution, the amount of nanoparticles, concentration of humic acids (HAs), and contact time were investigated. The experiments have been designed utilizing response surface methodology. In this current article the values of 12 mg L-1, 0.03g, 7.0, 4.0 min were considered as the ideal values for humic acids (HAs) concentration, adsorbent mass, pH value and contact time respectively. The kinetics and isotherm studies proved the appropriateness of the second-order and Langmuir models for the kinetics and isotherm of the adsorption of humic acids (HAs) on the adsorbent. The adsorbent was proved to be recyclable for more than once. Since almost 99.5% of humic acids (HAs) was deleted with ideal adsorption capacities of 105 mg g−1 for humic acid (HAs). The overall results confirmed that PSF/Fe2O3 mixed matrix membrane could be a promising adsorbent material for humic acids (HAs) removal from aqueous solutions.

The applicability of N-(3-nitro-benzylidene)-N-trimethoxysilylpropyl-ethane-1,2-diamine onto multi walled carbon nanotubes(NBATSPED-MWCNTs) for removing Bismarck Brown and Disulfine Blue from aqueous solutions has been reported. This novel material was characterized by different techniques such as XRD, SEM and FT-IR. The influence of nanoparticle dosage, pH of the sample solution, individual dyes concentration, contact time between the sample and the adsorbent, temperature, and ionic strength of the sample solution were studied by performing a batch adsorption technique. The maximum removal of 15 mg L-1 of individual dyes from an aqueous sample solution at pH 8.0 for Bismarck Brown (BB) and at pH 6.0 for Disulfine Blue (DSB) was achieved within 65 min when an adsorbent amount of 50 mg was used. It was shown that adsorption of the Bismarck Brown (BB) and Disulfine Blue (DSB) follows the pseudo-second-order rate equation, while the Langmuir model explains equilibrium data. Isotherms had also been used to obtain the thermodynamic parameters such as free energy (ΔG0), enthalpy (ΔH0) and entropy (ΔS0) of adsorption. The negative value of (ΔGo, ΔHo and ΔSo) confirmed the sorption process was endothermic reflects the affinity of multi walled carbon nanotubes functionalized towards Bismarck Brown (BB) and Disulfine Blue (DSB). A maximum adsorption capacity in binary-component system (6.67 mg/g for Bismarck Brown (BB), and 9.36 mg/g for Disulfine Blue (DSB)).

These days, the removal of various dyes from industrial wastewater has become an important concern. Synthetic dyes used in industries such as textiles are complex, toxic and mutant organic materials. Congored is also an acidic dye that is considered a high- risk source of contamination and threatens the lives of humans and other living organisms. Different methods, such as electrochemical, physical and biological processes, are used to remove organic pigment from aqueous samples. Adsorption is one of the most effective modern methods of industrial wastewater treatment, which is a relatively simple and inexpensive process that produces non- toxic and low- risk products. This research focuses gamma alumina nanoparticles was used for the adsorption of the cationic dye congored from aqueous solutions. Batch adsorption studies carried out to study various parameters included pH, gamma alumina nanoparticles dosage, temperature and contact time. The concentration of dye congored was measured using a UV-vis Spectrophotometer at the wavelength of 498 nm. The optimum adsorption conditions were found to be pH=6, adsorbent dose=0.04 g, temperature=298 K and contact time=40 min. The experimental results of this work were compared with Langmuir, Friendlich and Tamkin's isotherm models. The results obtained from isotherm models showed that the surface adsorption of these dye on the adsorbent used better follows the Langmuir isotherm model. Analysis of thermodynamic data showed that the adsorption process of the studied dye on the adsorbent surface is spontaneous and exothermic.

This paper will discuss the science of nanowire technology in the field of solar energy. It will elaborate on how this recent innovation improves upon the current methods in efficiency, cost, and durability. The value of this technology to its field, and its ability to make solar power a viable worldwide option will also be discussed. It is estimated that the world’s supply of fossil fuels will be reduced to a bare minimum during this century. Renewable energy sources such as wind and solar This paper will discuss the science of nanowire technology in the field of solar energy. It will elaborate on how this recent innovation improves upon the current methods in efficiency, cost, and durability. The value of this technology to its field, and its ability to make solar power a viable worldwide option will also be discussed. It is estimated that the world’s supply of fossil fuels will be reduced to a bare minimum during this century. Renewable energy sources such as wind and solar energy have yet to become major contributors to our energy supply due to their cost and efficiency. Presently, nanotechnology is being introduced into the field of solar energy to combat this fault and improve both efficiency and cost. Nanowire solar cells that have already been developed are mostly based on hybrid organic-inorganic materials or are made of semiconductors.  Presently the efficiency produced by the traditional crystalline silicon based solar cells is approximately 6.5% [1]. These first attempts at using nanowires in solar cells have increased this efficiency up to 8.5%. New technologies are looking into all-inorganic solar cells based on silicon nanowires. The silicon nanowires are relatively easy to synthesize and can be used with low cost substrate technologies like glass and metal foil. These low cost substrates will allow the nanowires to be not only durable but also much easier to produce than current silicon base solar cells [2]. Overall the continued developments in fields such as this are crucial if we as a nation are committed to securing the stability of our economy.