| 摘要: | 生物炭是生物質在無氧或微氧條件下低溫熱轉化後的固體副產物，是有機碳含量高、多孔性、鹼性、吸附能力強、多用途的材料。近年來，生物炭作為土壤改良劑、肥料緩釋載體及碳封存劑備受重視。生物炭在土壤中能將碳封存固定保持數百年至數千年，生物炭亦可改善土壤理化性質及微生物的活性，培肥土壤肥力、延緩肥料養分釋放、降低肥料及土壤養分的損失與減輕土壤污染。利用農場廢棄物生產生物炭，並將生物炭應用於農業有許多有益的功效。本研究以不同製備條件將稻殼與蔗渣燒結成生物炭，完成無氧狀態下快速熱裂解(中溫，500℃，熱蒸氣快速循環)、慢速裂解(300 與 350℃，熱蒸氣慢循環)與汽化裂解(高溫，800℃，熱蒸氣極慢循環)程序製備成之生物炭，進一步進行不同製備條件之生物炭物化特性分析(包括：掃描式電子顯微鏡(SEM)、X 光繞射分析(XRD)、BET 比表面積分析、吸附特性)等以探討不同之生物炭特性(物化性質、孔隙結構、汙染物吸附能力)。結果顯示，比較生物炭原料，以蔗渣製成之生物炭可保留較高比例之碳質，熱裂解溫度為決定生物炭物化性質之重要關鍵，對生物炭之吸附及孔隙性質有極大的影響，較高溫熱裂解程序有助於生物炭之微孔發展與比表面積之提升。以培育(incubation)試驗，探討土壤中添加不同製備條件(350、500 與 800℃下裂解)與不同添加量(0、2.5、5 %)之生物炭(稻殼與蔗渣)添加至三種不同土壤(Cf 將軍系、Cc 陳厝寮系與 Si 秀水系)，對土壤性質及其溫室氣體 (CO 2 ) 排放的影響。培育期間採集土壤，分析其 pH 值、導電度(EC)、有機碳含量等，並探究土壤性質於培育期間的變化。結果顯示，添加生物炭對酸性的陳厝寮系與秀水系土壤，土壤 pH 值提升之情況較為明顯。當土壤施以較高溫裂解製成的生物炭，則土壤 pH 值明顯有增加的現象，蔗渣生物炭對土壤 pH 值提升之現象尤為顯著。添加未經裂解之稻殼與蔗渣對土壤有機碳含量約在第 14 天~21 天達到最大值，後期則趨穩定。高裂解溫度(500 與 800℃)下製成的生物炭於秀水系土壤中，在培育期 56 天結束後，土壤有機碳仍持續增加。添加未經裂解之稻殼與蔗渣對土壤二氧化碳釋放即有增加之現象，於培育至 14-28 天時，於將軍系土壤之二氧化碳釋放量達到最高，愈高添加量則土壤二氧化碳釋放量尤為明顯升高，低溫熱裂解處理製成的生物炭則在培育 22 天後，方有較高二氧化碳釋放之現象，中高溫熱裂解處理製成的生物炭則在培育期間，有較穩定且較低的二氧化碳釋放現象。
Biochar was a solid byproduct derived from pyrolysis of biomass in low or absence of oxygen, high organic carbon content, porous, alkaline,highly capability of desorption, multiple-use materials. Recent attention has been given to biochar as a soil amendment because of its potential soil conditioning properties and benefits to physico-chemical characteristics,slow-release carrier for fertilizer and carbon sequestrating agent. This carbon sequestration benefits result from the fact that biochar takes carbon from the atmosphere-biosphere pool and transfers it to a slower cycling form that has the potential to exist for hundreds to thousands of years, and improve the soil physical-chemical properties and activity of microbes, soil fertility, and delay nutrient release of fertilizer, as well as reduce nutrient losses from fertilizer and soil, and alleviate soil pollution. The multiple-functional technology was the thermal conversion of biomass wastes into biochar which was used to agriculture. However, further studies should be given to many issues about biochar. Various pyrolysis process (including fast, slow and gasification pyrolysis) of biomass can yield different chacteristics (physical-chemical properties, pore structure, sorption capacity of pollutant) of biochars. The biochars prepared with different pyrolysis process will be characterized by scanning electron microscope(SEM), X-ray diffraction (XRD), and analysis of BET surface area. The results showed that carbon storage of biochar from pyrolysis of bagasse, pyrolysis temperature was the important factor to effect the properties of biochar. Higher pyrolysis temperature would increase the micropore development and surface area of biochar. Effects of biochars produced from pyrolysis of rice husk and bagasse under different temperature.amendment on soil properties, carbon sequestration, and CO2 emission were examined using a laboratory incubation approach. Three levels of raw material/biochar (0, 2.5, 5 wt%) were added into three different series of soil (Cf, Cc and Si soils) and all samples were incubated at room temperature for 56 days. The pH, electrical conductivity(EC), organic carbon content were analyzed during incubation. The results showed that biochar amendment increased soil pH of Cc and Si soils significantly. Amendment of biochar from higher pyrolysis temperatures (500 and 800 ℃) would increase soil organic carbon after 56-day incubation. In the initial stage (14-28 days) of incubation, amendment of rice husk and bagasse (no pyrolysis) would increase CO2 emission significantly in Cf soil. |
