Immobilization of Ligands on Surfactant Coated Alumina for Removal of Cations

In this research new adsorbents were prepared by modification of surfactant-coated gamma-alumina with three ligands; 1-(2-pyridylazo)-2-naphtol (PAN), dithizone (HDZ) and dimetyl golyoxime (DMG). The adsorbents were used for removal and pre-concentration of Pb+2, Cd+2, Ni+2, Cu+2, Co+2. Aqueous solutions of the metal ions were passed through a column filled with the adsorbent and the retained cations were eluted with nitric acid. Recoveries greater than 96% were obtained for most studied cations. The selectivity of the adsorbent was examined in the presence of different interfering cations. The results showed that the synthesized adsorbents posseses good capacity and selectivity for the most studied cations. The reusability test of the adsorbent showed its capability after five adsorption-elution cycles

A comprehensive study on removal of cadmium from aqueous solution by using mesoporous SBA-15 functionalized by 1,5-diphenyl carbazide: experimental design, kinetic, thermodynamic, and isotherm aspects

In this study, a new adsorbent, which was synthesized by using SBA-15Santa Barbara Amorphous. modified with 1,5-diphenyl carbazide, was employed to extract cadmium (Cd) from aquatic systems. First, the sorbent was identified via various characterization techniques, and then the response surface methodology approach was applied for modeling and optimizing the adsorption performance of the sorbent. Under optimum conditions ($\mathrm{pH}=5.75$, an adsorbent dose of 4.55 mg, and a Cd concentration of 25.39 mg/L), an adsorption capacity of 160 mg/g was obtained. In addition, the sorption process was fast; it attained equilibrium in 25.39 min. Furthermore, the sorbent regenerated by nitric acid was reused without any significant loss of adsorption capacity. Finally, the experimental data were studied by different isotherm models and well described by the Langmuir model

A comprehensive study on removal of cadmium from aqueous solution by using mesoporous SBA-15 functionalized by 1,5-diphenyl carbazide: experimental design, kinetic, thermodynamic, and isotherm aspects

In this study, a new adsorbent, which was synthesized by using SBA-15Santa Barbara Amorphous. modified with 1,5-diphenyl carbazide, was employed to extract cadmium (Cd) from aquatic systems. First, the sorbent was identified via various characterization techniques, and then the response surface methodology approach was applied for modeling and optimizing the adsorption performance of the sorbent. Under optimum conditions ($\mathrm{pH}=5.75$, an adsorbent dose of 4.55 mg, and a Cd concentration of 25.39 mg/L), an adsorption capacity of 160 mg/g was obtained. In addition, the sorption process was fast; it attained equilibrium in 25.39 min. Furthermore, the sorbent regenerated by nitric acid was reused without any significant loss of adsorption capacity. Finally, the experimental data were studied by different isotherm models and well described by the Langmuir model

Removal of PAHs from n-Paraffin by Modified Clinoptilolite

ABSTRACT: The ability of natural clinoptilolite and its modified forms were studied for removal of PAHs from n-paraffin. Surfactant modified zeolite (SMZ) was obtained by modifying clinoptilolite with hexadecyltrimethylammonium ion. Homoionic forms of zeolite were obtained by ion exchange process using inorganic salts of desirable cations (e.g. Ag + , Fe 3+ …). Natural clinoptilolite and its cation exchanged forms show small affinity toward PAHs, due to their hydrophil nature, whereas SMZ removed more than 50 percent of the initial PAHs contents of n-paraffin. The structure of zeolite did not change upon modification. Regeneration of zeolite was performed efficiently with chloroform

Removal of Cysteine (an Aliphatic Amino Acid) by Natural Clinoptilolite

ABSTRACT: Amino acids have been extensively used in several processes of the pharmaceutical and food industries. Treatments for the recovery and reuse of the wastewaters generated from these processes are few and little known. This work aims at studying the influence of different variables on the sorption of L-cysteine, contained in aqueous solutions, on clinoptilolite mineral. L-Cysteine (Cys) was sorbed by Clinoptilolie (Clino) from aqueous solutions of variable concentrations, temperatures and pHs. The powder X-Ray Diffraction (XRD), InfraRed (IR) spectroscopy and thermal analysis (TG, DTG and DSC) techniques were applied for characterization of materials. The results indicated that the sorption process depends strongly on pH, temperature and concentration of amino acid. Cysteine is specifically sorbed on clinoptilolite surface sites, probably through its NH 3 + moiety. The pH dependence suggests that these sites may be silanolate groups ( Si-O -). The experimental data of sorption isotherms obtained and analyzed with Langmuir model showed that this model fitted the sorption data. Calculated thermodynamic parameters ( H°, S°, and G°) indicate that the sorption processes were exothermic