1. Field of the Invention
The present invention is based on the fact that phosphorus has a strong affinity for the surface of metal oxides or hydroxides, and relates to a method of preparing an adsorbent for phosphorus adsorption by absorbing and coating expanded vermiculite with aluminum and heating the coated vermiculite at high temperature to produce aluminum oxide on the surface of the expanded vermiculite so that the expanded vermiculite adsorbs phosphorus with high efficiency, and to an adsorption prepared by the method.
2. Description of Related Art
Generally, freshwater lakes, for example, eco-ponds or artificial lakes, in which water does not easily circulate and stagnates, microbial decomposition easily occurs. Particularly, surface layer water in freshwater lakes comes into active air with air, and thus the concentration of oxygen therein is high so that the propagation of plankton is active. However, when this propagation of plankton reaches a limit, the plankton dies and is deposited at the bottom of the water, and for this reason, organic matter in deep water is decomposed to produce nutrient salts such as phosphorus, which spoil the water.
In addition, nutrient salts such as phosphorus are introduced into ponds or lakes from the surroundings to cause eutrophication that causes the propagation of large amounts of green algae, a change in turbidity, offensive odors, and an increase in biochemical oxygen demand (BOD), thereby deteriorating the water quality.
In an attempt to solve the above-described problems, patent document 1 discloses a filter material for water purification, which is made of zeolite and functions to inhibit the occurrence of various foreign materials and adsorb the foreign materials.
Patent document 2 discloses a loess composition for water purification, which is based on loess and is disposed mainly in rivers and waterways for the purpose of naturally purifying running water.
Patent document 3 discloses a porous sintered aggregate for water purification, which is prepared by sintering loess so as to be able to be used as a filter material for water purification and may further contain charcoal so as to be used as a filter material for plant growth and development.
Patent document 4 discloses a water treatment agent based on natural minerals and plants, which is prepared by powdering minerals such as silicate, elvan, loess, kaolin and zeolite, dissolving the powdery materials in hot water to make a colloidal water solution containing natural mineral components and mixing the water solution with a water solution containing a natural sterilizer at a ratio of 1:1.
Particularly, as a technology of basically blocking or reducing the development of green algae by adsorbing and removing phosphorus among materials that cause the propagation of green algae in water, patent document 5 discloses a technology of forming charcoal powder consisting of, particularly, chaff, into charcoal balls capable of adsorbing phosphorus.
However, the above-described prior art technologies have a problem in that the efficiency of adsorption of phosphorus is very low. Thus, in recent years, there has been an attempt to coat expanded vermiculite with iron or glycerol in order to use the expanded vermiculite as an adsorbent for adsorbing phosphorus. However, in this case, the efficiency of adsorption of phosphorus also does not reach a satisfactory level.