Electrophoretic Deposition and Fixing of Functional Mineral Fine Powder-Examination of the Technique to Prepare a Throw-in Type Environmental Cleaning Module -

环境污染仍然是当今社会的一个严重问题。一些天然矿物有可能用于清洁环境，因为它们具有吸附各种化学物质的大表面积和/或优越的离子交换能力。为了高效去除环境中的有害物质，研究了各种功能矿物粉末在多孔基质上的电泳沉积和固定制备抛掷式环境清洁剂；这些沉积的物质会迅速暴露在大量被污染的自然水中。研究了：(1)天然沸石（斜沸石，产自日本秋田县）的固液化学反应对微粉的固定作用；(2)反应物料的化学成分对天然沸石的影响；(3)普通EPD工艺难以沉积的蛋白石- ct微粉的EPD。实验采用行星磨机在<1μm范围内对矿物粉末进行细磨。经过这些研究，下列结果已得到确认：(1)利用na22o -Al_2O_3-SiO_2- h_2o反应材料，在90℃下反应24 h以上，可使天然沸石（斜发沸石）细颗粒生长并相互固定；(2)通过改变反应材料的组成（主要是SiO_2/Al_2O_3的比例），使斜发沸石颗粒转变为各种沸石；(3)与EPD易于沉积的粒径较大的钠石灰玻璃粉共沉积，可在电极上沉积非常细的蛋白石ct粉末。如上所述，本研究证明了利用天然矿物制备高性能吸附材料的可能性。

Environmental pollution is still a serious problem in the society in these days. There is a possibility that some natural minerals can be used to clean the environment because they have large surface area for adsorbing various chemicals and/or superior ion-exchange ability. In order to remove harmful materials from the environment with high efficiency, the electrophoretic deposition (EPD) and fixing of various functional mineral powders on porous substrate to prepare a throw-in type environmental cleaner was investigated ; such deposited materials can be exposed to a large amount of polluted natural water rapidly. We studied : (1)the fixing of a natural zeolite (clinoptilolite, yielded in Akita prefecture, Japan) ~fine powder by a solid-liquid chemical reaction, (2)the effect of the chemical composition of reacting materials with the natural zeolite in the reaction (1), and (3)the EPD of opal-CT fine powder, which is difficult to be deposited by a normal EPD process. In the experiments, mineral powders finely ground with a planetary potmill around <1μm were used. As a result of the studies, the following results have been cleared : (1)the natural zeolite (clinoptilolite) fine particles can be grew and fixed each other by a solid-liquid chemical reaction using Na_2O-Al_2O_3-SiO_2-H_2O reacting materials in the reaction at 90℃ for longer than 24 h, (2)the clinoptilolite particle was changed into various zeolite by changing the composition (mainly in the ratio SiO_2/Al_2O_3) of the reacting material, and (3)very fine opal-CT powder can be deposited on an electrode by the co-deposition with a soda-lime glass powder with larger particle size which can be deposited easily by the EPD. As stated above, the the possibility of the preparation of a high-performance adsorbing material prepared from natural minerals was proved in this study.