This research investigated the feasibility of rice husk as a biosorbent for removal of ammonium ion from aqueous solutions. To improve the sorption functionality of rice husk, the carboxyl groups were chemically bound to the surface of the rice husk by graft polymerization of acrylic acid using potassium peroxydisulphate as a redox initiator. The removal of ammonium ion by rice husk grafted with acrylic acid (RH-g-AA) was studied in a batch mode and fixed bed columns. The kinetic and equilibrium data obtained from batch experiments follow the second-order kinetics and fit well with the Langmuir isotherm model. The sorption energy determined from D-R model was 8.61 kJ/mol indicating an ion-exchange process as the primary sorption mechanism. To determine the characteristic parameters of the column useful for process design, four mathematical models; Bed Depth Service Time (BDST), Bohart-Adams, Clark and Wolborska models were applied to experimental data obtained from the fixed bed columns with varying bed heights. All models were found to be suitable for simulating the whole or a definite part of breakthrough curves, but the Wolborska model was the best. The fixed bed sorption capacity determined from the Wolborska model was in the range 33.3 ~ 40.5 mg/g close to the value determined in the batch process. The thickness of mass-transfer zone was calculated to be approximately 40 mm from DBST model. The RH-g-AA sorbent could be regenerated by a simple acid washing process without a serious lowering the sorption capacity or physical durability.

Abstract
 I. 서 론
 II. 대상시설 및 실험방법
  1. 대상시설
  2. 실험방법
 III. 결과 및 고찰
  1. 대상시설 시료 기초분석
  2. 대기오염물질 배출 특성
  4. PCDDs/PCDFs 배출특성
 IV. 결 론
 References

• 나춘기(목포대학교 환경공학과) | Choon-Ki Na
• 송명기(목포대학교 환경공학과) | Myung-Ki Song Corresponding author