The binary oxide adsorbent using Fe and Mn (Fe-Mn) has been prepared by precipitation method to enhance the removal of phosphate. Different amounts of chitosan, a natural organic polymer, were used during preparation of Fe-Mn as a stabilizer to protect an aggregation of Fe-Mn particles. The optimal amount of chitosan has been determined considering the separation of the Fe-Mn particles by gravity from solution and highest removal efficiency of phosphate (Fe-Mn10). The application of Fe-Mn10 increased removal efficiency at least 15% compared to bare Fe-Mn. According to the Langmuir isotherm model, the maximum uptake (qm) and affinity coefficient (b) were calculated to be 184 and 240 mg/g, and 4.28 and 7.30 L/mg for Fe-Mn and Fe-Mn10, respectively, indicating 30% and 70% increase. The effect of pH showed that the removal efficiency of phosphate was decrease with increase of pH regardless of type of adsorbent. The enhanced removal efficiency for Fe-Mn10 was maintained in entire range of pH. In the kinetics, both adsorbents obtained 70% removal efficiency within 5 min and 90% removal efficiency was achieved at 1 h. Pseudo second order (PSO) kinetic model showed higher correlation of determination (R2), suggesting chemisorption was the primary phosphate adsorption for both Fe-Mn and Fe-Mn10.

The adsorption process using GAC is one of the most secured methods to remove of phosphate from solution. This study was conducted by impregnating Cu(II) to GAC(GAC-Cu) to enhance phosphate adsorption for GAC. In the preparation of GAC-Cu, increasing the concentration of Cu(II) increased the phosphate uptake, confirming the effect of Cu(II) on phosphate uptake. A pH experiment was conducted at pH 4-8 to investigate the effect of the solution pH. Decrease of phosphate removal efficiency was found with increase of pH for both adsorbents, but the reduction rate of GAC-Cu slowed, indicating electrostatic interaction and coordinating bonding were simultaneously involved in phosphate removal. The adsorption was analyzed by Langmuir and Freundlich isotherm to determine the maximum phosphate uptake(qm) and adsorption mechanism. According to correlation of determination(R2), Freundlich isotherm model showed a better fit than Langmuir isotherm model. Based on the negative values of qm, Langmuir adsorption constant(b), and the value of 1/n, phosphate adsorption was shown to be unfavorable and favorable for GAC and GAC-Cu, respectively. The attempt of the linearization of each isotherm obtained very poor R2. Batch kinetic tests verified that ~30% and ~90 phosphate adsorptions were completed within 1 h and 24 h, respectively. Pseudo second order(PSO) model showed more suitable than pseudo first order(PFO) because of higher R2. Regardless of type of kinetic model, GAC-Cu obtained higher constant of reaction(K) than GAC.

The purpose of this study lies on reinterpreting the geography books in Joseon dynasty as records of the cities and consequently suggesting directions for further urban research. Geography books of Joseon dynasty are valuable references to understand the national policy, and imply that the focus of the contents is on the system. Especially, military system is an important concept to understand city type in that period, relationships between cities, selection of location, etc. The results of review are as following: First, military system is not a permanent fixture and therefore reflects changes in urban policies along with the history. The system suggests valuable clues on urban development as it is state-run, and closely associated with national land development. Second, counties and prefectures under jurisdiction of district called Eupchi(邑治) had cities as important as or even more important than local government such as Yeong-a(營衙), Jinbo(鎭堡), Yeok(驛: administrative cities). Such special regions need to be studied as other type of cities in Joseon dynasty by defining their architectural characteristics and roles. Third, the relationship of cities such as Eupch, Yeong-a, and Jinbo, was reorganized according to the local military system. Eupchi, administrative city, along with Yeong-a and Jinbo evolved into a military city as it became systematically organized. The characteristics of Yeok needs to be reconsidered in the context of such new inter-city relationship. Fourth, considerations which should be reviewed in the geography based on this concept can be mainly classified into architecture and landscape. This will also lay the foundation, and suggest new directions for further research for Eupchi, Yeong-a, Jinbo, and Yeok. Fifth, description of the geography looks simple at first sight, but with thorough understating on the system, there are chances to interpret objective reasoning of position and landscape in the overall flow of region, area, etc. Bongsu(烽燧), signal-fire, can be an object of comparison with geographical features and position. Furthermore, advantageous position is a historical and geographical element showing the major context of the region.