矽藻土為一種礦物性黏土，為多孔洞特性結構，表面具有負電荷，被廣泛使用於工業製程之過濾程序，作為去除雜質的吸附劑。此種廢矽藻土大部分是以工業廢棄物丟棄或棄置於掩埋場，而無進一步處理作為資源利用。
本研究之目的乃利用一套仿旋轉窯爐之水平式旋轉反應爐於不同條件下進行熱再生；並進一步利用硫酸、硝酸、鹽酸、氫氧化鈉等試劑配合不同活化參數(濃度、時間、溫度)進行化學活化。研究結果顯示熱活化對提升廢矽藻土物性效果並不明顯，而化學活化之最佳條件為活化濃度2.25 M NaOH、活化時間2 hr、活化溫度為沸騰狀態、樣品重/活化液比為5/100的條件下，比表面積由0.3 m2/g提升至約100 m2/g，孔洞體積也由0.0039 cm3/g提升至0.258 cm3/g。
對活化後之產物做其物理/化學特性分析，包括表面積/孔洞體積、掃描式電子顯微鏡(SEM)、X光繞射(XRD)、傅利葉紅外線光譜(FTIR)及主要元素，顯示所得之產物從N2之等溫吸脫附分析大致為中孔性結構(Type IV)。進一步以活化後最佳物性產物對環境污染有機物巴拉刈進行吸附實驗，從Langmuir及Freundlich等溫吸附迴歸，發現此產物為具可觀吸附能力之礦物吸附劑。 Diatomaceous earth, a clay mineral and characteristic of pore structure and negatively polar nature in the surface, is used extensively as filter and/or filter aid for the removal of all impurities in the industrial processes. The spent diatomaceous earth is thus generated and mostly disposed of landfill without further treatment for resource utilization.
The objective of this work is to study thermal regeneration by using horizontally rotary activation furnace under different parameters. Further, chemical activation has been carried out by using acid /alkaline agents such as sulfuric acid, acetic acid, hydrochloric acid and sodium hydroxide, and different activation parameter such as concentration, time and temperature. Under the experimental conditions investigated, the thermal regeneration process is not good for upgrading the physical properties of spent diatomaceous earth, The impregnation conditions at concentration of NaOH 2.25 M, impregnation temperature of boiling, holding time of 2 hr and sample/solution ratio of 5/100 seemed to have the most determining effects on the development of pores. The chemically activated clay have larger surface areas (109 vs 0.3 m2/g) and total pore volumes (0.26 vs 0.004 cm3/g) than those of the spent diatomaceous earth.
The physical and chemical characterization of the resulting products obtained in this study were further examined based on the analyses of surface area/pore volume, scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and main elements. Results showed that these samples are characteristic of type IV from N2 isotherm, indicating mesoporous structure. Further, the optimal porous material thus obtained was used as mineral adsorbent for paraquat adsorption, showing that it has a good adsorption capacities for removal of this organic contaminant from the fittings of Langmuir and Freundlich isotherms.
