| 초록 |
To efficiently adsorb silver ions from industrial wastewater, powdered coffee grounds were immobilized as a bead form by modified polyvinyl alcohol and boric acid method. The beads with 2.0mm of diameter have the 9.87 m2/g of surface area and were stable in the range of ~45oC and to all pH range in wastewater without untangling. In addition, the beads have excellent mechanical strength and low swelling ratio. The Langmuir isotherm model showed significant fit to the equilibrium adsorption data and maximum adsorption capacity of 39.583 mg/g of silver ions was achieved at the pH 6.0 of wastewater. The breakthrough point was appeared around 180 (1.0 mL/min) and 340 bed volumes (0.5mL/min), respectively, and 6 bed volumes of 1.0M HNO3 solution was required to get desorption efficiency of 95% in continuous process. And, the bed volumes can be still maintained as 310 even though secondary reused immobilized coffee ground beads were used. |
