| 摘要: | 近年來隨著科技的進步人們開始追求更便利的生活，同時也嚴重污染了環境，極端氣候的影響造成農作物收成不易，農民為了得到更好的豐收，過量的施加肥料造成肥料的浪費，其中磷是肥料中非常重要的元素之一，提供了植物生長的必需元素，同時磷元素也是容易造成水體優養化的關鍵之一，過量施肥會使磷大量流逝到大海，造成陸地上可使用的磷礦越來越少，因此開發磷回收的技術更是破在眉睫。同時，台灣四面環海養殖漁業發達，牡蠣養殖為台灣西部沿海一代的重要產業，大量的廢棄牡蠣殼時常被任意棄置在岸邊，經過風吹日曬雨淋容易孳生病媒蚊或產生惡臭對人體造成極大的危害，綜合上述兩點，本研究使用煅燒廢棄牡蠣殼參雜對磷有良好親和力的鑭元素，希望能回收水體中的磷降低磷資源的浪費。
本研究製備了多種吸附材料，主要以煅燒至900°C的煅燒牡蠣殼(POS900)及對燒過的牡蠣殼參雜鑭元素(POS900-La)兩種吸附材料進行探討，透過材料表面特性分析(SEM, BET, FTIR, XRD, XPS, pHzpc)初步了解本研究製備之材料對於磷元素的吸附可行性，再將本研究製備之吸附材料投入於吸附實驗當中，為了更全面的了解材料的吸附能力，本研究設計了不同初始濃度、不同初始pH及水體溶液中同時存在其他陰離子之吸附實驗。
實驗結果主要可分為POS900和POS900-La兩部分，兩種吸附劑的結果均表明，900°C的煅燒溫度提供了最佳的磷去除效率。在初始磷濃度為500 mg/L的情況下，POS900和POS900-La的最大磷吸附容量分別為257.09和178.07 mg/g。POS900-La在300 mg/L的磷中表現出良好的50%的磷去除效率。同時，POS900-La可以限制pH值的增加，在材料達到平衡時將pH值控制在弱鹼性範圍內，這顯示POS900-La對於後端的應用具有一定的潛力，而本研究製備之吸附材料對於水中磷的去除機制包含表面沉澱、靜電吸引力及配位基的置換。
;In recent years, with the advancement of technology, people have begun to pursue a more convenient life, while also severely polluting the environment. The impact of extreme weather conditions has made it difficult to harvest crops, and farmers apply excessive amounts of fertilizer to obtain better yields. Phosphorus is one of the most important elements in fertilizer, providing essential elements for plant growth, but it is also one of the key factors that can cause eutrophication of water bodies. Excessive fertilization can cause a large amount of phosphorus to flow into the sea, causing a decrease in the amount of phosphorus ore available on land. Therefore, the development of phosphorus recovery technology is urgent. At the same time, Taiwan has developed a thriving aquaculture industry surrounded by the sea, and oyster farming is an important industry along the west coast of Taiwan. Large amounts of wasted oyster shells are often randomly discarded on the shore, and after being exposed to wind, sun, and rain, they can easily breed disease-carrying mosquitoes or produce odors that pose a great threat to human health. Combining the above two points, this study used calcined waste oyster shells mixed with lanthanum elements that have good affinity for phosphorus, hoping to recover phosphorus from water bodies and reduce the waste of phosphorus resources.
This study prepared multiple adsorbent materials, mainly investigating two adsorbent materials: oyster shells calcined at 900°C (POS900) and calcined oyster shells modified with lanthanum (POS900-La). Through the analysis of material surface characteristics (SEM, BET, FTIR, XRD, XPS, pHzpc), the feasibility of the prepared materials for the adsorption of phosphorus elements was preliminarily understood. Then, the prepared adsorbent materials were put into the adsorption experiment. In order to have a more comprehensive understanding of the adsorption capacity of the materials, this study designed adsorption experiments with different initial concentrations, different initial pH, and the simultaneous presence of other anions in the water solution.
The experimental results can be mainly divided into two parts: POS900 and POS900-La. The results of both adsorbents indicate that the calcination temperature of 900°C provides the best phosphorus removal efficiency. When the initial phosphorus concentration is 500 mg/L, the maximum phosphorus adsorption capacity of POS900 and POS900-La are 257.09 and 178.07 mg/g, respectively. POS900-La shows good 50% phosphorus removal efficiency in 300 mg/L phosphorus. At the same time, POS900-La can limit the increase of pH value and control the pH value within the weak alkaline range when the material reaches equilibrium. This shows that POS900-La has certain potential for backend applications. The adsorption mechanism of the adsorbent materials prepared in this study for the removal of phosphorus in water includes surface precipitation, electrostatic attraction, and substitution of coordination bases. |
