New insights into adsorption equilibrium of organic pollutant on MnO2 nanorods: Experimental and computational studies

The effect of various partial atomic charges on the bulk and liquid/vacuum interface properties of iodobenzene derivatives at their melting points

In this work, various atomic charge schemes including natural bond orbital (NBO), electrostatic potential based (CHELPG), and σ-hole model charges were applied in the OPLS-AA force field to investigate their effects on the thermophysical and structural properties of iodobenzene and its derivatives. Molecular dynamics simulations presented in this work show that the studied structural and thermophysical properties are in good agreement with experiments when the CHELPG charge was coupled with the OPLS-AA force field. Also, the arrangement of iodobenzene derivatives in the liquid phase was investigated via combined radial/angular distribution functions (CDFs) analyses and halogen-bonding theory. The most probable orientation of iodobenzene derivatives at the liquid/vacuum interface was assigned by atom density profile and bivariate orientational distribution maps. For all studied iodobenzene derivatives, benzene rings are oriented such that the iodine atoms tend toward the vacuum phase.

Adsorption removal and photocatalytic degradation of azithromycin from aqueous solution using PAC/Fe/Ag/Zn nanocomposite

The improper use of antibiotics and their discharge into the environment can have serious and hazardous consequences. The purpose of this research is to synthesize an activated carbon impregnated magnetite composite (PAC/Fe), prepare PAC/Fe/Ag/Zn nanocomposites, and innovate by simultaneously synthesizing two metals, zinc and silver, on magnetically activated carbon and check its ability to remove azithromycin antibiotic (AZT) from an aqueous solution via UV system. PAC/Fe/Ag/Zn nanocomposites were characterized by various techniques including XRD, FESEM, and EDX. A series of batch experiments were carried out under various experimental conditions such as pH of the solution (3-11), contact time (0-120 min), initial concentration of AZT (10-40 ppm), amount of PAC/Fe/Ag/Zn nano-absorbent (0.01-0.04 g/l), and recoverability and reuse. Some common isotherm models were used for the study of AZT adsorption removal and finding the best model. Also, kinetic studies of AZT removal were performed by fitting the experimental data on first-order and second-order models. In this system, under optimal conditions of pH = 9, 120 min with 0.04 g/l of PAC/Fe/Ag/Zn, 99.5% of 10 ppm AZT were degraded under UV-C irradiation. Furthermore, the obtained results of isotherm and kinetic studies revealed that Langmuir (R² = 0.9336) isotherm model, and the pseudo-first-order kinetic model (R² = 0.9826) had the highest correlation with the experimental data of AZT antibiotic adsorption. Finally, the reusability experiments showed that PAC/Fe/Ag/Zn nanocomposites have a high ability of antibiotic adsorption and high stability after four cycles of application (99.5 to 40%).