Interactions in Ternary Aqueous Solutions of NMA and Osmolytes—PARAFAC Decomposition of FTIR Spectra Series

Intermolecular interactions in aqueous solutions are crucial for virtually all processes in living cells. ATR-FTIR spectroscopy is a technique that allows changes caused by many types of such interactions to be registered; however, binary solutions are sometimes difficult to solve in these terms, while ternary solutions are even more difficult. Here, we present a method of data pretreatment that facilitates the use of the Parallel Factor Analysis (PARAFAC) decomposition of ternary solution spectra into parts that are easier to analyze. Systems of the NMA–water–osmolyte-type were used to test the method and to elucidate information on the interactions between N-Methylacetamide (NMA, a simple peptide model) with stabilizing (trimethylamine N-oxide, glycine, glycine betaine) and destabilizing osmolytes (n-butylurea and tetramethylurea). Systems that contain stabilizers change their vibrational structure to a lesser extent than those with denaturants. Changes in the latter are strong and can be related to the formation of direct NMA–destabilizer interactions.

SELECTIVE DECOLORIZATION OF ANIONIC TEXTILE DYE FROM BINARY SOLUTIONS BY ADSORPTION ONTO CHITOSAN-POLYANILINE/Fe3O4 NANOCOMPOSITE

In this study, chitosan-polyaniline/Fe3O4 nanocomposite material (CS-PANI/Fe3O4) was prepared by means of in-situ emulsion polymerization method. The synthesized material was then utilized as an adsorbent for the removal of Reactive blue 198 (RB198) from a single and binary dye system. The effects of pH, contact time, and initial dye concentration on the removal efficiency of the adsorbent were systematically investigated. The obtained results indicated that the adsorption ability toward RB198 of the prepared adsorbent decreased with an increase in the initial dye concentration and pH media. Meanwhile, the removal percentage of dye increased with increasing contact time. Importantly, approximately 92.4% RB198 was removed for an adsorption time of 120 min in single dye system. Adsorption experiment using a binary system of dyes indicated that the removal percentages of RB198 were 72.8% and 94.7% in the RB198-RR198 and RB198-CY mixture, respectively.

Simultaneous Adsorption of Chromium and Acidic Dye from Leather Tannery Model Wastewater Using a Novel Modified Nanoclay

Simultaneous removal of Cr^3+ and acidic dye from model tannery wastewater was investigated using local nano clay modified by 3-chloro-2-hydroxypropyltrimethylammonium chloride (CHPTAC) surfactant. X-ray fluorescence (XRF), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), carbon, hydrogen, nitrogen and sulfur analysis (CHNS), Brunauer-Emmet-Teller (BET) analysis and pH of zero point charge (pH_ZPC) analyses were carried out for characterization of the adsorbent, and adsorptive properties of the modified clay were investigated by batch experiments. The effects of essential parameters, such as adsorbent dosage, initial solution pH, initial solution concentration, contact time, and temperature, were studied. Maximum adsorption values (99.74% for Cr^3+ and 83.26% for dye) were obtained in the following conditions: pH of 4, initial concentration of 100 mg/L, adsorbent dosage of 15000 mg/L, contact time of 30 min. The effect of contaminants’ concentration was also investigated through response surface methodology (RSM), central composite face-centered (CCF) design and an empirical model was presented. The results of kinetic models’ studies demonstrated that simultaneous adsorption of contaminants follows the pseudo-second-order model, and the adsorption data of single and binary solutions fitted nonlinearly to isotherm models showed that the adsorption of Cr (III) from binary and single solutions follow Langmuir and Dubinin-Radushkevitch (D-R) isotherms, respectively. Adsorption of dye from both single and binary solutions follows Redlich- Peterson (R-PT) isotherm. Maximum adsorption capacities were obtained to be 193.1390 mg/g and 144.1782 mg/g for Cr^3+ and dye, respectively. Synergistic and antagonistic adsorptions were observed in binary solutions.

FTIR Spectroscopic Studies on the Binary Solutions of 1 – Propanol with Xylene Isomers

FTIR spectroscopic study is performed in 4000 – 400cm−1wavenumber rangeon pure Propanol(PRO), pure o-xylene (OXY), pure m-xylene(MXY), pure p-xylene(PXY) and their binary solutions (SS1 = 0.2 PRO + 0.8 OXY/MXY/PXY, SS2 =0.4+0.6 , SS3 = 0.6 + 0.4 and SS4 = 0.8 + 0.2)at various mole fractions. It was observed that neat propanol liquid appearsto be multimer especially as cyclic tetramer and involve in classical and non-classical hydrogen bond interactions with the three xylene isomers in all the binary solutions.

Time Domain Reflectometric Studies on Methylcellosolve – Acetylacetone Binary Solutions

Time Domain Reflectometric studies has been applied on the binary solutions of methylcellosolve (MCS) with acetylacetone (ACACT) in the entire concentration range at 298 K in the frequency range of 10 MHz – 32 GHz. The values of relaxation time (τ), effective Kirkwood correlation factor (geff ), corrective Kirkwood correlation factor (gf ) and excess permittivity (εE ) have been calculated. The relaxation time of MCS slowly decreases with increase in ACACT concentration suggesting that the size of the heteroassociated rotating unit decreases. The rate at which τ value decreases is more in MCS rich solutions which means that the formation of heteromolecular H – bonds dominantly occur in MCS rich solutions. Parallel orientation among the dipoles occur as suggested by the g^eff values which are greater than unity in all the solutions. The excess permittivity ε^E values calculated using mole and volume fractions qualitatively exhibit the same deviation from ideal behaviour.