轉爐石去除河水中磷之探討

Investigation of Phosphorous Removal in River Water with Basic Oxygen Furnace Slag

郭育宗(Yu-Tsung Kuo)

指導教授 ： 陳庭堅

國立屏東科技大學/工學院/環境工程與科學系所/碩士(2009年)

https://doi.org/10.6346/NPUST.2009.00263

摘要

水是人類生長的要素之一，河川、湖泊及水庫是生活的主要水源，卻常有優養化的問題，若無妥善處理將可能對生活與環境極為不利。轉爐石為煉鋼過程之副產物，其化學特性對磷具有良好的吸附效果，是為低成本有效濾材。

　　本研究主要以轉爐石作為磷的吸附材，將爐石樣品篩分為A（< 2 mm）、B（0.149~2 mm）、C（< 0.149 mm）、D（0.42~2 mm）四種大小不同的粒徑，使用BET及SEM/EDS分析爐石的基本特性。分別進行動力、批次吸附試驗並模擬爐石在不同酸鹼環境及水質接觸程度下，觀察其對磷的吸附能力、pH值、導電度之變化。最後以實際受磷污染的河水進行管柱淋洗試驗，探討不同的爐石與石英砂混合之配比、進流水之流率在試驗中對磷吸附程度的影響，以模擬轉爐石在現地應用的可行性。

　　四種爐石經前述試驗，結果以爐石C性能為最佳、爐石A次之，但是爐石C粒徑極小，在應用上可能容易吸水膨脹且具有高pH值，其顆粒之間孔隙也較小，易造成堵塞，因此對現地應用可能不適合。爐石A與B雖然含有較大的顆粒，但是在管柱淋洗試驗仍亦有堵塞現象，因此不適用。爐石D雖然吸附能力小於爐石A、B、C，但其平均粒徑皆比前三種爐石大，在管柱淋洗試驗中不易堵塞且初期淋洗所釋出之pH值與導電度也較低，對環境友善程度較高。

　　在管柱淋洗試驗中，爐石D與石英砂1:1、1:2、1:3三種不同配比，其吸附能力與爐石含量相關。實驗結果顯示配比以1:1之吸附能力為最大、1:3為最小。爐石D與石英砂1:2以5 mL/min、20 mL/min兩種流率進行試驗，結果顯示流率越大越快達到飽和且pH值與導電度降低速度亦快，但20 mL/min之累積去除量比5 mL/min流率的累積去除量低。推測原因為流率較小與爐石接觸之停留時間較長，故使其吸附量較大。

　　雖然轉爐石僅在淋洗初期具有高pH值，但目前使用規範不可將其直接埋入水中。因此建議可將轉爐石應用鋪設在人工溼地或具有緩衝能力的地方，一方面引水入流除磷，同時也可以緩衝轉爐石釋出的高pH值。

關鍵字

轉爐石 ； 管柱淋洗 ； 磷之去除 ； 批次吸附 ； 優養化

並列摘要

Water is one of essential elements for the human grows. The river, lake, and reservoir are the main water sources for living but usually the eutrophication causes the water deterioration. If the eutrophication doesn’t have proper treatment it will be unfavorable to the human life and the environment. Basic oxygen furnace slag (BOF) is the by-product in the steel making process, the chemical characteristics of BOF have good adsorption effect of phosphorous and it is a low cost of effectively filter material.

　　This study took the BOF as phosphorus adsorption material. The BOFs were divided into four classed with different sizes; named A slag (< 2 mm), B slag (0.149~2 mm), C slag (< 0.149 mm), and D slag (0.42~2 mm). The basic properties of BOF were analyzed with BET and SEM/EDS. Batch experiments were carried on to examine the kinetic and adsorption behaviors under different acid and alkali conditions and the degree of water contact time. These experiments were observed the change of the phosphorus adsorptive capacity, pH value and conductivity of the mixture solution. Finally, with real river water the column leaching tests were conducted to investigate the phosphorous adsorption under different parameters including mix ratio between BOF and quartz sand and different flow rate. The purpose of column experiment was to test the feasibility of BOF in field application.

　　The results showed that C slag had best performance following was slag A. However, slag C was the smallest size was readily water adsorption and caused swelling, and caused high pH to the water in the application. In addition, the small pore between grains may cause an obstruction that is one of disadvantages to the field application. Although, slag A and B had larger size than slag C the column tests still produced obstructions in experiments. The slag were not further carried on experiments. Although slag D had less adsorption ability than slag A, B, and C. The large grain size did not cause block in column tests and produced low pH value and conductivity that made slag D more friendly to environment.

　　In the column tests three mix ratios 1:1, 1:2, and 1:3 between slag D and quartz sand were carried out to investigate adsorption behavior. The results showed 1:1 mix ratio had the best adsorption ability and ratio 1:3 had the lowest adsorption ability. Mix ratio 1:2 was in the middle and was further conducted on two different flow rates, 5 and 20 mL/min, the high flow rate had short time to achieve phosphorous adsorption saturation but low flow rate had higher maximum adsorption ability than high flow rate. The possible reason was low flow rate had longer contact time than high flow rate causes great adsorption. Although, the leaching water from column test had high pH value in the begging period and the slag can not directly immerse into water in application. Therefore, the slag can apply in laying to constructed wetland or someplace with buffer capacity that can remove phosphorous in water and decrease pH value released from slag.

並列關鍵字

Basic oxygen furnace slag (BOF) ； Column leaching test ； Phosphorous removal ； Batch adsorption ； Eutrophication

參考文獻

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