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A current study demonstrates the removal of Reactive Blue 19 (RB-19) from industrial wastewater by synthesizing p-piperdinocalix­[4]­arene-immobilized silica resin (PASR). The surface morphology and functional group analysis were performed with scanning electron microscopy and Fourier transform infrared spectroscopy. The dye removal efficiency of PASR was analyzed through adsorption studies. Different parameters were optimized such as the pH value of dye, amount of resin, concentration of dye, and effect of electrolyte on adsorption. The adsorption mechanism was analyzed with Langmuir, Freundlich, and Dubinin–Radushkevich (D–R) isotherms. It was found that experimental data follow the Freundlich isotherm, which suggests multilayer adsorption. The column adsorption study was also evaluated by breakthrough and Thomas models. The Thomas model rate constant k TH (cm3 mg–1 min–1) and maximum solid phase concentration was found to be q o = 2.702 mg·g–1. The thermodynamic study reveals that the adsorption process is exothermic and spontaneous in nature. The kinetic study suggests that the adsorption process follows the pseudo-second-order kinetic model.

The purpose of present study is to investigate the effi ciency of different kinds of Turkish commercial bleaching earth materials for changes in different colour pigment concentrations in neutralized sunfl ower oils. The bleaching experiments were performed in a pilot system under at stable vacuum (50 mmHg) and temperature (100ºC) for 30 min. By examining the changes in chlorophyll, β-carotene and red colour, bleaching process parameters such as type and dosage of the bleaching material were optimised. The sorption characteristics of colour pigments were evaluated using common adsorption isotherms and Scatchard plot analysis. Ads-3 acid-activated earth material at 1% (w/w) per samples was found to be the most appropriate sorbent and the amount of sorbed pigments was calculated as 1.01x10 -4 mmol/g ads. for chlorophyll, 1.15x10 -3 mmol/g ads. for carotene and 1.70 red on Lovibond colour scale. The procedure indicated that this system can be easily adapted to the actual oil refi ning systems. Unauthenticated Download Date | 5/11/18 5:46 AM

This work assesses the use of immobilized humic acid (ImHA) onto aminopropyl silica (APS) as a sorbent for the removal and preconcentration of trace amounts of cobalt ions by on-line solid phase extraction (SPE) technique in the column system prepared in our laboratory. Different parameters, such as the effect of the pH, concentration, and flow rate, were studied and throughput was observed by a UV detector. All SPE steps were monitored by breakthrough curves used to visualize distribution of cobalt concentration between mobile and solid phase. The solutions collected from stripping steps were analyzed in atomic absorption spectrometer (AAS) and the amount of sorbed ions was calculated. Sorption characteristics were evaluated by using common adsorption isotherms and Scatchard plot analysis. From the obtained results, it was seen that sorption mechanism of cobalt ions were fitted to Langmuir model on a large scale and thought to be localized. Mean free energy (E0 40.82 kJ mol −1) calculated from D-R isotherm showed that chemical interactions are more effective than physical interactions. This investigation reveals a new, simple, environmentally friendly, and costeffective method for removal and preconcentration of cobalt ions from aqueous solutions by a new aminopropyl silica-immobilized humic acid material.

This study focuses on the synthesis, characterization and application of p-tetranitrocalix[4]arene-appended silica-based material as a stationary phase in high-performance liquid chromatography for the simultaneous separation of some basic dyes such as methyl violet, methyl green and methylene blue. The effect of the pH of mobile phase on the retention, separation and selectivity of these compounds was investigated. The method was validated for system efficiency, linearity, accuracy, precision, limit of detection and quantification. The limits of detection were 0.1, 0.5 and 0.3 mg L À1 ; whereas, the limits of quantification were observed to be 1, 1.2 and 0.9 mg L À1 for methyl violet, methyl green and methylene blue, respectively. The separation efficiency of the p-tetranitrocalix[4]arene-appended silica-based column was also compared to that of the octadecylsilane column.