Collagen Fiber Immobilized Myrica rubra Tannin and Its Adsorption to

Abstract

Tannins, which are rich in ortho-hydroxyl groups, have a high affinity for UO2(2+). In this paper, Myrica rubra tannin was immobilized on collagen fiber by an aldehydic cross-linking reaction to prepare a novel adsorbent for uranium (UO2(2+)) recovery from wastewater. The adsorption equilibrium, the adsorption kinetics, and the effects of temperature and pH on the adsorption equilibrium were investigated in detail. It was found that the Myrica rubra tannin immobilized on collagen fiber exhibits an excellent adsorption capacity for UO2(2+). The adsorption capacity at 293 K and pH 5.0 was as high as 1.19 mmol UO2(2+)/g (283.3 mgU/g) when the initial concentration of UO2(2+) in solution was 7.5 mmol/L. The adsorption isotherms could be described by the Freundlich equation, and the increase of temperature promoted the adsorption to UO2(2+) . The adsorption kinetics data were fitted very well by the pseudosecond-order rate model, and the equilibrium adsorption capacity calculated by the pseudo-second-order rate model was almost the same as that determined by the actual measurement with the error < or = 4%. The pH has a significant effect on the adsorption process. According to our experiments, the suitable pH scope should be 5-8.

Synthesis of Porous Carbon Fibers from Collagen Fiber

“…[16] Zr-A C H T U N G T R E N N U N G (SO 4 ) 2 Reaction of metal ions with collagen fiber: Collagen fiber (15.0 g) was soaked in deionized water (400 mL) at 25 8C for 2 h. The collagen fiber was first treated with an appropriate amount of glutaraldehyde or black wattle tannin according to the requirement. The pH of the mixture was adjusted to pH 2.0 with 1 m H 2 SO 4 solution, and then an appropriate amount of metal salt (ZrA C H T U N G T R E N N U N G (SO 4 ) 2 , Al 2 A C H T U N G T R E N N U N G (SO 4 ) 3 , or Fe 2 A C H T U N G T R E N N U N G (SO 4 ) 3 ) was added and the reaction mixture was stirred at 25 8C for 4 h. NaHCO 3 solution (15 % w/w) was gradually added within 4 h to increase the pH of the solution to pH 4.0-4.5, and the reaction mixture was allowed to stir at 40 8C for 10 h. When the reaction was complete, the precursor of the porous carbon fiber was collected by filtration, washed, and vacuum-dried.…”

“…Vegetable tannin is rich in ortho-hydroxylated phenolic rings and thus has a high affinity for both metal ions and collagen fiber. [15,16] In fact, the synergic reaction of Al III and vegetable tannins with collagen fiber has been used as an effective method in leather manufacturing. [17] In the case of the other metal ions, glutaraldehyde was used to treat the collagen fiber before reaction with Zr IV or Fe III (see below).…”

The effect of solution chemistry on the adsorption of uranium(VI) onto sericite

“…species) are observed at pH 4.0-8.0. The main negatively charged U(VI) species (e.g., (UO 2 ) 3 (OH) 7 2 , UO 2 (OH) 3 -and UO 2 (OH) 4 2-species) are observed at pH [ 8.0. The suppressed adsorption of U(VI) on sericite at pH [ 7.5 is due to the electrostatic repulsion between the negative charged surface of sericite (pH [ pH PZC ) and negative U(VI) species.…”

“…, [UO 2 OH] ? , UO 2 CO 3 (aq), and UO 2 (CO 3 ) 3 4-at other pH ranges, which is soluble under environmental conditions [3][4][5][6]. Many studies have been carried out to remove U(VI) from aqueous solutions by various methods such as biological treatment [7], solvent extraction [8], ion-exchange processes [9] and adsorption [10,11].…”

Extraction of uranium from nuclear industrial effluent using polyacrylhydroxamic acid sorbent

“…Recently, separation of uranium from diluted aqueous solution has been playing important role in separation sciences and has been engaging more attention than before (De 2000;Gupta and Singh 2003) with regard to environmental impact. Release of uranium-bearing aqueous solution from uranium material processing plant is found to be one of the major sources of environmental contaminants with the radioactive material, which is required to be separated to avoid a detrimental effect to aquatic life as well as human beings (Liao et al 2004;Van Horn and Huang 2006;Li et al 2010;Zhang et al 2011). …”