Khalid Z. Elwakeel

Removal of Reactive Black 5 from aqueous solutions using magnetic chitosan resins

Chitosan was cross-linked using glutaraldehyde in the presence of magnetite. The resin obtained was chemically modified through the reaction with tetraethylenepentamine followed by glycidyl trimethylammonium chloride, to produce chitosan/amino resin (R1) and chitosan bearing both amine and quaternary ammonium chloride moieties (R2), respectively. The uptake of Reactive Black 5 (RB5) from aqueous solutions using R1 and R2 resins was studied using batch and column methods. The resins showed high affinity for the adsorption of RB5 where an uptake value of 0.63 and 0.78 mmol/g was reported for resins R1 and R2, respectively at 25 degrees C. Both kinetics and thermodynamic parameters of the process were estimated. These data indicated an endothermic spontaneous adsorption process and kinetically followed the pseudo-second order model. Breakthrough and regeneration curves for the removal of RB5 were studied. The adsorbed dye was eluted from the investigated resins effectively.

Environmental Application of Chitosan Resins for the Treatment of Water and Wastewater: A Review

Chitosan is a polysaccharide formed mainly from repeating residues of D-glucosamine, having primary amino groups. It is of great interest not only as an underutilized resource, but also as a new functional material of high potential in various fields, and recent progress in chitin chemistry is quite noteworthy. The purpose of this review is to take a closer look at chitosan application in water technology based on (a) its ability to bind toxic pollutants, (b) the mod of chitosan modification, (c) the nature of the interaction of chitosan with different pollutants, and (d) chitosan regeneration and recycling.

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.

Arsenic(V) sorption using chitosan/Cu(OH)2 and chitosan/CuO composite sorbents.

The removal of As(V) ions from aqueous solution was carried out using composite sorbents based on chitosan (as the encapsulating material) and Cu(OH)2 or CuO. The sorbents were characterized using SEM, EDX and Zeta potential analysis. Sorption uptake was highly dependent on pH, temperature, initial As(V) concentration and sorbent dosage (SD): the optimum initial pH for arsenic removal was found close to 4. The sorption isotherm was described by the Langmuir equation. The metal ion can be bound through two different sorption sites: one having a strong affinity for As(V) (probably Cu(OH)2 or CuO) and the other having a lower affinity (probably the encapsulating material). The uptake kinetics was well fitted by the pseudo-second order rate equation. The effect of temperature was also evaluated, verifying the endothermic nature of the sorption process. Arsenic elution was performed using a saline solution (30 g L(-1) NaCl) at pH 12. The recycling of the sorbent was tested, maintaining a removal efficiency and a metal recovery over 95% for five successive sorption/desorption cycles.

Efficient removal of Reactive Black 5 from aqueous media using glycidyl methacrylate resin modified with tetraethelenepentamine

Glycidyl methacrylate/methelenebisacrylimide resin loaded with tetraethelenepentamine ligand was prepared and investigated. The adsorption characteristics of the obtained resin towards Reactive Black 5 (RB5) from aqueous solutions at different experimental conditions were established by means of batch and column methods. The mechanism of interaction between RB5 and resins active sites was discussed. The resin showed high affinity for the adsorption of RB5 where an uptake value of 0.63 mmol/g was reported for the obtained resin, at 25 °C. The kinetics and thermodynamic behavior of the adsorption reaction were also defined. These data indicated an endothermic spontaneous adsorption process and kinetically followed the pseudo-second order model. Breakthrough curves for the removal of RB5 were studied at different flow rates and bed heights. The critical bed height for the studied resin column was found to be 0.764 cm at flow rate of 8 mL/min. The adsorbed dye was eluted from the investigated resin effectively. Regeneration and durability of the loaded resin towards the successive resin were also clarified.

Removal of ferrous and manganous from water by activated carbon obtained from sugarcane bagasse

AbstractActivated carbon was prepared from sugarcane bagasse impregnated with phosphoric acid at 500°C activation temperature and 2 h activation time, resulting in the carbon yield of 27.13%. The prepared activated carbon has high BET surface area (671.54 m2/g) and the maximum adsorption of iodine is 602.23 mg/g. The adsorption characteristics of the obtained carbon towards both Fe(II) and Mn(II) at different experimental conditions were conducted by means of batch and column methods. The adsorbent showed high affinity for the removal of both Fe(II) or Mn(II) from aqueous medium, where an uptake values of 7.01 and 5.40 mg/g were reported for Fe(II) and Mn(II), respectively, at 25°C. Various parameters such as pH, agitation time and speed, adsorbent dose, metal ion concentration, temperature, and ionic strength had been studied. The kinetic and thermodynamic behavior of the adsorption reaction was defined, these data indicated pseudo-second-order model and the adsorption is endothermic in nature and mainly...

Environmental remediation of thorium(IV) from aqueous medium onto Cellulosimicrobium cellulans isolated from radioactive wastewater

Abstract Cellulosimicrobium cellulans (C. cellulans) was isolated from radioactive wastes and identified by Biological examination. The investigation of the removal of thorium from aqueous solutions was carried out using the isolated living and dead C. cellulans. The biosorption of thorium was studied using different thorium ion concentrations. Electron microscopic examinations of both living and dead C. cellulans before and after biosorption of thorium ions were done to locate the sites of metal ion biosorption and to find the difference between living and dead bacterial cells. The obtained results showed that living and dead C. cellulans could sorp 151.94 and 220.56 mg/g, respectively. The kinetic behavior and biosorption isotherm were defined. These data kinetically followed the pseudo-second-order model and indicated a good fitness with the Langmuir model.

Influence of Mo(VI) immobilization and temperature on As(V) sorption onto magnetic separable poly p-phenylenediamine-thiourea-formaldehyde polymer

The immobilization of Mo(VI) on magnetic poly p-phenylenediamine-thiourea-formaldehyde composite polymer (MpPDTF) (through an intermediary adsorption step) increased sorption of As(V) ions: retention capacity increased from 35.15mg As g-1 for MpPDTF to 99.04mg As g-1 for MpPDTF immobilized Mo(VI) at 298±1K. The impact of temperature and Mo(VI) immobilization on the kinetic and equilibrium constants of As(V) sorption on MpPDTF was evaluated. The thermodynamic study shows that Mo(VI) immobilization on MpPDTF changes the sorption process of As(V) on MpPDTF from exothermic associated with entropy decrease to endothermic associated with entropy increase. Also the impact of phosphate competition was studied. MpPDTF immobilized Mo(VI) was successfully tested for As(V) removal from the industrial effluents of insecticides manufacturing industry. NaHCO3 solution (0.5M) can be efficiently used for sorbent regeneration for at least 3 cycles with limited decrease in sorption performance.

Enhanced Remediation of Reactive Black 5 from Aqueous Media Using New Chitosan Ion Exchangers

Chitosan was cross-linked using epichlorohydrine to form chitosan gel. The resins obtained were chemically modified through the reaction with to 1,1,1,3,3,3 hexafloro,2-bis (3-amino,2-hydroxyphenyl) propane to produce resin (RI), 3-amino-1,2,4 triazole,5-thiol to produce resin (RII), and melamine to produce resin (RIII). The uptake of Reactive Black 5 (RB5) from aqueous media by the obtained resins was studied using batch method. Various parameters such as pH, agitation time, RB5 concentration and temperature were studied. The resins showed high affinity for the adsorption of RB5 where uptake values of 0.63, 0.45, and 0.33 mmol/g were reported for resins RI, RII, and RIII, respectively at 25°C. Both kinetics and thermodynamic parameters of the process were estimated. These data indicated an endothermic spontaneous adsorption process and kinetically followed the pseudo-second order model, Fickian diffusion low and Elovich equation. Desorption of RB5 from the surface of the prepared resins was efficiently done using sodium hydroxide.

Magnetic chitosan grafted with polymerized thiourea for remazol brilliant blue R recovery: Effects of uptake conditions

ABSTRACT Magnetic chitosan was prepared by co-precipitation with polymeric Schiff’s base resulting from the reaction of thiourea with glutaraldehyde. This material has great potential as high-effective sorbent for Remazol Brilliant Blue R (RBBR): maximum sorption capacity reached 0.441 mmol g−1 at pH 1.6 and at 25°C. Kinetic plots, pH dependence, isotherm data, and influences of ionic strength were reported. The data from equilibrium sorption experiments are well fitted to the Langmuir isotherm and the pseudo-second-order sorption kinetics indicates that chemisorption controls the process. The distribution coefficient was calculated at different temperatures and the thermodynamic parameters have been calculated: the sorption reaction is endothermic, spontaneous, and increases the entropy of the system. Alkaline solution (0.5 M NaOH) was used for desorbing RBBR from loaded sorbent. The sorbent exhibited good regenerability over several repeated adsorption/desorption cycles. GRAPHICAL ABSTRACT