In this research, the cadmium sulfide -graphite carbon nitride (CdS-g-C3N4) nanocomposite was synthesized and characterized by X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectrometer (EDX), and transmission electron microscopy (TEM) techniques. The photocatalytic activity of asprepared nanocomposite was evaluated in the degradation of ceftriaxone sodium (CTX) antibiotic from aqueous solution under visible light irradiation. The influence of the operational variables such as the amount of photocatalyst (g/L), initial CTX concentration (mg/L), pH, and irradiation time (min) on the photodegradation process was investigated and optimized using response surface methodology (RSM) -central composite design (CCD) model. The maximum degradation percentage (92.55 %) was obtained in the optimal condition, including 0.06 g/L of CdS-g-C3N4 photocatalyst, 15 mg/L of CTX, pH= 10.5, and irradiation time = 81 min. The efficient photocatalytic performance of CdS-g-C3N4 nanocomposite is due to the appropriate alignment of energy levels between the CdS and g-C3N4, which synergistically impact the charge separation and the degradation efficiency of CTX. The kinetics of the photocatalytic degradation process was well described by Langmuir-Hinshelwood's pseudo-first-order model (kapp = 0.0336 min -1 ).

Abstract:In this study, the three forms of B 2 N p´,0,`q -radical, anion and cation-have been compared in terms of electric potential and atomic charges, ESP, rather than the well-known cut of the potential energy surface (PES). We have realized that the double minimum of the BNB radical is related to the lack of the correct permutational symmetry of the wave function and charge distribution. The symmetry breaking (SB) for B 2 N (0, +) exhibits energy barrier in the region of (5-150) cm´1. The SB barrier goes through a dynamic change with no centrosymmetric form which depends on the wave function or charge distribution. In spite of r A 2 Σg exited state, the r B 2 ś g excited configuration contributes to the ground state ( r B 2 ś g´r X 2 Σù q for forming radicals. The SB did not occur for the anion form (B 2 N p´q ) in any electrostatic potential and charges distribution. Finally, we have modified the Columbic term of the Schrödinger equation to define the parameters "αα 1 and ββ 1 " in order to investigate the SBs subject.

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Density functional theory calculations (DFT), as well as hybrid methods (B3LYP) and HF method for MWCNTs have been carried out to study structural stability. The geometry of the MWCNTs have been optimized at DFT and HF methods within CCPTZ-CCPVZ, EPR-II, EPR-II, 6-31G* and 6-31++G** basis sets. According to GIAO method, NMR parameters have been evaluated. The Gaussian quantum chemical package is used for all calculations. The gauge including atomic orbital (GIAO) approach was applied for chemical shielding calculations of (5, 5)@(10, 10), (3, 3)@(7, 7), (4, 4)@(8, 8) DWCNTs.

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