| 摘要: | 本研究以化學處理法修飾大麥萃取殘渣成吸附劑，提升應用大麥萃取殘渣去除水中重金屬離子的效能，此舉將可同時處理食品加工廢棄物和廢水二種環境污染問題，不但有益於廢棄物減量及再利用之推廣，更有助於整體環境之永續利用。
本研究以四種化學修飾法製備六種吸附劑進行重金屬離子(Cu2+、Pb2+、及Zn2+)吸附試驗，探討吸附劑吸附金屬量受pH值、接觸時間、溫度及重金屬離子種類之影響，並以等溫吸附平衡、吸附動力及吸附熱力平衡模式，探討修飾化吸附劑效能。
各種經修飾化吸附劑對Cu2+、Pb2+、及Zn2+於最佳操作條件下吸附量為383.2、113.3、及89.5 mg/g；最差吸附量為30.8、24.7、及17.7 mg/g；最佳吸附pH為4.5～7.0。吸附反應約在吸附120分鐘後可達吸附穩定平衡。對重金屬離子(Cu2+、Pb2+、及Zn2+)之動力學吸附行為最適宜以pseudo-second order吸附模式進行描述。
經硫脲及0.25mL甲醛修飾大麥渣對Cu2+之等溫吸附為物理性吸附，其餘六種吸附劑對Cu2+之等溫吸附為化學性離子交換吸附。全部七種吸附劑對Pb2+之等溫吸附為化學性離子交換吸附。除大麥渣、經硫脲修飾大麥渣、經磷酸修飾大麥渣、經硫脲及磷酸修飾大麥渣、經硫脲及醋酸修飾大麥渣外，對Zn2+之等溫吸附為化學性離子交換吸附。
Barley residual modified with chemical methods into adsorbent, which was used to increase the adsorption capacity of heavy metals than bare barley residual. The solid and liquid waste from food processing plant could be solved in the same time. Waste reduction and reuse could be promoted and the sustainable utilization of overall environment.
Four chemical modification methods were used to prepare 6 modified adsorbents. The adsorption capacity of heavy metal ions (Cu2+, Pb2+, and Zn2+) was characterized by pH, contact time, contact temperature and heavy metal ions. The adsorption efficiencies also described with isothermal adsorption, adsorption dynamic and adsorption kinetics models.
The best adsorption capacity of Cu2+, Pb2+ and Zn2+ into bare and modified adsorbents were 383.2, 113.3, and 89.5 mg/g, respectively; the lowest adsorption capacity for Cu2+, Pb2+ and Zn2+ were 30.8, 24.7 and 17.7 mg/g, respectively; the optimum operation pH ranged between 4.5 ~ 7.0. 120 minutes was needed to reach equilibrium state of adsorption.The pseudo-second order rate equation was valid for the description of dynamic adsorption behavior of heavy metal ions (Cu2+, Pb2+, and Zn2+). The adsorption of Cu2+ into thiourea and 0.25mL formaldehyde modified barley residual was physical adsorption. The other adsorbents for Cu2+ belong to chemical ion exchange. The adsorption of Pb2 + into bare and 6 modified adsorbents was chemical ion exchange behaviour. Except the bare barley residual, thiourea modified barley residual, phosphoric acid modified barley residual, phosphoric acid and thiourea modified barley residual, thiourea and acetic acid modified barley residual, the isothermal adsorption of Zn2+ was chemical ion exchange behaviour. |
