Asem A. Atia

Effect of structural properties of acid dyes on their adsorption behaviour from aqueous solutions by amine modified silica

Monoamine modified silica particles (MAMS) were prepared and characterized by infrared (FT-IR) and thermogravimetric analysis (TGA). The modified silica particles were used for removal of acid orange 10 (AO-10) and acid orange 12 (AO-12) from their aqueous solutions. The adsorption behaviour of the two dyes was studied at different experimental conditions of pH, contact time, concentration of dye, temperature and salt solution. The adsorption of AO-10 followed pseudo-first order kinetics whereas AO-12 followed pseudo-second order. The two dyes showed different modes of interaction with silica surface. Desorption of the loaded dyes was carried out at pH 10 and found to be 10.4 and 91.6% for AO-12 and AO-10, respectively.

Synthesis of amine and thio chelating resins and study of their interaction with zinc(II), cadmium(II) and mercury(II) ions in their aqueous solutions

Chelate forming resins containing amino and thio groups have been prepared. The interaction of the obtained resins with Zn(II), Cd(II) and Hg(II) from their aqueous solutions was studied. The metal ion uptake behaviour and selectivity of the resins towards the metal ions were investigated by both batch and column methods. Hg(II) showed higher affinity towards the amino and the thio resins compared to Zn(II) or Cd(II). The mechanism of interaction between the resin and the studied metal ions could be explained on the basis of the formation of resin–metal complex in neutral conditions. In mediums acidified by HCl, the interaction of Hg(II) was interpreted to proceed via ion-exchange mechanism. Hg(II) could be separated from Cd(II) in acidic medium. The studied resins were regenerated using HNO3 or acidified thiourea. It was not recommended to use HCl for elution of Hg(II) from the loaded resins due to its affinity for interaction with resins via ion-exchange.

Studies on uptake behaviour of copper(II) and lead(II) by amine chelating resins with different textural properties

Glycidyl methacrylate resins with different ratios of divinylbenzene as cross-linking agent have been prepared. The textural properties such as density, porosity, pore area and pore diameter of the resins obtained were elucidated. The resins were anchored by chelating amino groups through the treatment with ethylenediamine (en). The amino group concentration on the resins was determined. The uptake behaviour of Cu(II) and Pb(II) from their aqueous solutions by the resins was studied. Both uptake capacity and selectivity of the resins towards the studied metal ions were discussed in terms of amino group concentration as well as the textural properties. The study indicated that metal-resin interaction proceeds via surface and diffusion mechanisms. The pH 5.8 found to be the most suitable for the uptake of the investigated metal ions. Copper was selectively separated from lead (using resin RI-en). The studied resins showed good durability and regeneration using HNO3.

Fast removal of uranium from aqueous solutions using tetraethylenepentamine modified magnetic chitosan resin

Chitosan was cross-linked using glutaraldehyde in the presence of magnetite. The resin was chemically modified through the reaction with tetraethylenepentamine (TEPA) to produce amine bearing chitosan. The resin showed a higher affinity towards the uptake of UO2(2+) ions from aqueous medium: maximum sorption capacity reached 1.8 mmol g(-1) at pH 4 and 25 °C. The nature of interaction of UO2(2+) ions with the resin was identified. Kinetics were carried out at different temperatures and thermodynamic parameters were evaluated. Breakthrough curves for the removal of UO2(2+) were studied at different flow rates, bed heights and after 3 regeneration cycles. Hydrochloric acid (0.5 M) was used for desorbing UO2(2+) from loaded resin: desorption yield as high as 98% was obtained.

Inhibition of acid corrosion of steel using cetylpyridinium chloride

The cationic surfactant cetylpyridinium chloride (CPC) showed high inhibition efficiency for the corrosion of low carbon steel in 1 M H2SO4. Electrochemical measurements were dedicated to test the performance of CPC at different concentrations and temperatures. CPC has a significant inhibiting effect on the corrosion of steel and protection efficiencies up to 97% were measured. The inhibitor shifted the corrosion potential in the cathodic direction. It was found that adsorption is consistent with the Bockris–Swinkels isotherm in the studied temperature range (30–60 °C). The negative values of the free energy of adsorption and the decrease in apparent activation energy in the presence of the inhibitor suggest chemisorption of the CPC molecule on the steel surface.

Effect of Chain Length of Aliphatic Amines Immobilized on a Magnetic Glycidyl Methacrylate Resin towards the Uptake Behavior of Hg(II) from Aqueous Solutions

Abstract Magnetic resin particles with magnetite (Fe3O4) core and glycidyl methacrylate/divinylbenzene resin shell were prepared. The core‐shell particles obtained were immobilized with ethylenediamine, diethylenetriamine, or tetraethylenepentamine to give resins with names, R‐1, R‐2 and R‐3, respectively. These resins showed good magnetic properties and could be easily retrieved from their suspensions using an external magnetic field. The uptake values of resins towards Hg(II) were found to be 2.1, 3.2, and 4.8 mmol/g for resins R‐1, R‐2, and R‐3, respectively. The effect of chain length as well as the content of amine sites on the uptake behavior was studied at different temperatures. The values of kinetic and thermodynamic parameters of the uptake process were reported. These values reflected the effective role of amine type and chain length on both the rate of uptake and the maximum capacity of the resins. Moreover, the column studies showed that the longer the amine chain was the shorter was the critical bed height.

Cysteine-Functionalized Chitosan Magnetic Nano-Based Particles for the Recovery of Light and Heavy Rare Earth Metals: Uptake Kinetics and Sorption Isotherms

Cysteine-functionalized chitosan magnetic nano-based particles were synthesized for the sorption of light and heavy rare earth (RE) metal ions (La(III), Nd(III) and Yb(III)). The structural, surface, and magnetic properties of nano-sized sorbent were investigated by elemental analysis, FTIR, XRD, TEM and VSM (vibrating sample magnetometry). Experimental data show that the pseudo second-order rate equation fits the kinetic profiles well, while sorption isotherms are described by the Langmuir model. Thermodynamic constants (ΔG°, ΔH°) demonstrate the spontaneous and endothermic nature of sorption. Yb(III) (heavy RE) was selectively sorbed while light RE metal ions La(III) and Nd(III) were concentrated/enriched in the solution. Cationic species RE(III) in aqueous solution can be adsorbed by the combination of chelating and anion-exchange mechanisms. The sorbent can be efficiently regenerated using acidified thiourea.

Fast kinetic and efficient removal of As(V) from aqueous solution using anion exchange resins.

Glycidyl methacrylate/methelenebisacrylamide resin with immobilized tetraethylenepentamine ligand was prepared. This pentamine containing resin was transformed to two anion exchange resins through treatment by glycidyl trimethylammonium chloride to give (RI) or hydrochloric acid giving (RII). The resins were used to adsorb As(V) at different experimental conditions using batch and column methods. Kinetics and thermodynamic properties as well as the mechanism of interaction between As(V) and resin active sites were discussed. The maximum adsorption capacities of As(V) on RI and RII were found to be 1.83 and 1.12 mmol/g, respectively. The regeneration and the durability of the loaded resin towards the successive reuse were also investigated.

Preparation and Characterization of Modified Cellulose Adsorbents with High Surface Area and High Adsorption Affinity for Hg(II)

Cellulose was modified via chlorination using phosphorous oxychloride followed by functionalization with amine and thiol moieties. The obtained modified cellulose samples were investigated by means of FTIR, TGA, TEM, and nitrogen-adsorption surface area (BET). The BET measurements showed a remarkable increase in the surface area of Cell-N-S (477.7 m2/g) and Cell-N (706 m2/g). The resins gave an uptake capacities of 38 and 7.2mmol/g for Cell-N-S and Cell-N, respectively toward Hg(II) from its solutions. These values are considered much better compared with other reported resins. Regeneration of the resins was achieved effectively using acidified thiourea.

Efficient Adsorption of Cu(II) and Hg(II) from their Aqueous Solutions Using Amine Functionalized Cellulose

Cellulose was modified with glycidyl methacrylate (GMA) and diethylenetriamine. The modified cellulose obtained was characterized by FTIR, TGA, elemental analysis, and BET measurements. The adsorption behavior of the modified cellulose toward Cu(II) and Hg(II) in aqueous solution was studied using batch technique. Maximum uptake values of 2.0 and 1.0 mmol/g were recorded for Hg(II) and Cu(II), respectively. The uptake was studied at different temperatures where the thermodynamic parameters indicated endothermic nature for the adsorption process. The adsorption process was found to follow pseudo-second-order kinetics. Regeneration was achieved using acidified thiourea.