本研究探討以烘烤製備之玉米芯生物碳(biochar ) 特性及評估生物碳 (biochar )在城市模擬逕流中鉛 (Pb)和銅(Cu)之穩定性，烘烤製備過程在不同的加熱溫度(200、250 和 300°C)與加熱時間(1、2和3小時)下操作生產玉米芯生物碳 (biochar )。以管柱試驗測試城市模擬一年逕流的生物碳 (biochar )對鉛(Pb)和銅(Cu) 污染的穩定性，同時討論管柱溶出試驗中金屬鉛和銅之吸附機制。生物碳 (biochar )的產量和物理化學性質受到溫度的影響顯著，在溫度300°C和時長3小時情況下，生物碳 (biochar ) 產率約為50%並隨溫度上升而降低。然而隨著烘烤溫度和時間分別從200°C增加至300°C和1小時增加至3小時，固定碳含量從12.92%增加至56.5%。 實驗結果指出，土壤和生物碳 (biochar )層可以有效降低城市模擬逕流中98%的Pb(II)和57%的Cu(II)，同時單金屬管柱吸附試驗中4.25%的Pb(II)和25.15%的Cu(II)會留在生物碳 (biochar )層中。在雙金屬管柱吸附試驗中，約有99%的Pb(II)和77%的Cu(II)留在土壤和生物碳 (biochar )層中，而生物碳 (biochar )則含有8%的Pb(II)和33.5%的Cu(II)。在土壤-生物碳 (biochar )層之單一金屬吸附試驗中Pb(II)吸附效率高於Cu(II)，而在雙金屬吸附試驗中Cu(II)之吸附效率則略高於Pb(II)，其原因為銅複合物使官能基團和可溶性有機碳從生物碳 (biochar )中釋放所導致。總體而言，從本研究之結果可以得知提高烘烤玉米芯生物碳 (biochar )產量及其吸附應用之關鍵資訊。烘焙玉米芯生物碳 (biochar )將會是一種替代吸附材料，其可以有效穩固城市逕流中Pb(II)和Cu(II)，並可以清除承受水體中之目標金屬污染物。 ;This study investigates the characteristics of torrefied corncob biochar and evaluates the immobilization performance of lead (Pb) and copper (Cu) by biochar in a simulated urban runoff. The torrefaction process was operated at three different temperatures (200, 250 and 300oC) and heating times (1, 2, and 3 hours) to produce corncob biochar. The immobilization of Pb and Cu by biochar was examined using the column test for simulating one-year urban runoff containing Pb and Cu contaminates. Metal Pb and Cu adsorption mechanism by the column leaching test was also discussed. The biochar yield and physicochemical properties were significantly affected by torrefaction temperature. In the case of temperature operated at 300oC and 3 hours holding time, the biochar yield was approximately 50% and decreased with the temperature increased. However, the fixed carbon content of biochar was increased from 12.92% to 56.5% with an increase in the torrefaction temperature and time from 200oC to 300oC and 1 hour to 3 hours, respectively. The experimental results indicated that soil and biochar layers could effectively reduce 98% of Pb(II) and 57% of Cu(II) in simulated urban runoff as well as 4.25% of Pb(II) and 25.15% of Cu(II) could be retained in biochar layer in single metal adsorption column test. In terms of the binary metal adsorption column test, approximately 99% of Pb(II) and 77% Cu(II) could retain in the soil and biochar layer, and 8% of Pb(II) and 33.5% of Cu(II) had in the biochar layer, respectively. In single metal adsorption test, Pb(II) adsorption efficiency is higher than Cu(II) in the soil-biochar layer. In comparison Cu(II) adsorption efficiency is slightly higher than Pb(II) in binary metal adsorption test. This is because the Cu complex formation resulted in the functional groups and dissolved organic carbon (DOC) released from the biochar. In summary, the results obtained from this study could provide the critical information for producing higher biochar yield torrefied from corncob and its adsorption application. The torrefied corncob biochar would be an alternative adsorbent material that could effectively immobilize heavy metals Pb(II) and Cu(II) from urban runoff and eliminate the tested metals contaminant in the receiving water.
