A reliable method to determine the boron contents in fresh water was proposed. The combination of anion exchange preconcentration and ICP-AES was a key process in this method. Five hundred cm³ of water sample was acidified to 0.1 mol dm^-3 with hydrofluoric acid and allowed to stand for 1 h. The sample was then passed through an anion exchange column (Bio-Rad AG1, X-8, 100-200 mesh, F form, 2 g) at a flow rate of 1 cm³ min^-1. The boron adsorbed on the ion exchange column was eluted with 7.5 cm³ of 6.5 mol dm^-3 HNO₃ solution. The effluent was collected in a 50-cm³ PTFE standard flask and diluted to the mark with water, followed by the measurement of boron by ICP-AES (182.6 nm) . The present method was successfully applied to the analysis of drinking water on the market and the boron contents obtained ranged from 10 to 70 ng cm^-3. The relative standard deviations (n=4 or 5) were 7 to 12% at a level of ca.50 ng B cm^-3.

View full abstract

Radiation-induced graft polymerization is applicable to the modification of various shapes of trunk polymers; by this technique, we have prepared novel ion-exchange materials based on porous hollow-fiber membranes made of polyethylene. The ion-exchange-group-containing polymer chains were appended onto the pore surface uniformly across the membrane. This assisted in the transport of target ions to the ion-exchange group by convective flow. In addition, the graft chains extended from the pore surface toward the pore interior due to electrostatic repulsion. This phenomenon enabled the multilayer binding of proteins into the graft chains. The ion-exchange polymeric materials exhibited superior performance over conventional ionexchange materials.

View full abstract

Various chemical materials have been contributed to our life remarkably. Like diaxions' case, the influence that might be caused by“ng”or“pg”on order to our body has been recently discussed. When we expose the chemical materials, we have to consider degradation, volatility, accumulation, and concentration in environment.
We can give examples that might be serious porblems in the future followed by these pollutants; sorts of dioxin and its related compounds, tin-organic and other metal organic compounds, chlorine-promine flame detardars, carcinogenic aromatic hydrocarbons, chlorinic hydrocarbons, various pestioides, dioctyl phthalate, toxic products by biological metabolism, and endocrine disruping chemicals. Furthermore, we will be under influences of water pollution itself, flowing through those chemical materials which mentioned earilier and chloride byproducts occured during the process of chlorination in the water supply.
It will be important for us to understand the properties of chemical materials, survey those dangerous sides, and manage them with the safe water and its role in order to coexist with chemical materials.

View full abstract

An Electrodeionization apparatus GDI with ion-exchange non-woven fabric (TEN), and ion conducting spacer (ICS) has been developed for the production of ultra pure water. Electrodeionization have the advantages both of electrodialysis and ion-exchange. TEN and ICS are novel ion exchange materials prepared by radiation induced graft polymerization technology. By the application of IEN and ICS between ion-exchange membranes, cell pair resistance is reduced and scaling by water dissociation and current leakage are diminished. GDI thus facilitated the production of high quality water with resistivity of up to 18 MΩ⋅cm, low TOC and low silica concentration. In this paper, typical flow of GDI system and its performance are introduced. Mechanisms of deionization and prevention of scaling are referred.

View full abstract

Ion exchange resin is one of the functional polymers with a long historical background, Nowadays, the ion exchange resin have been widely used not only in desalinations, but also in foods, pharmaceuticals and catalyst fields. Now wide varieties of products are available, chelating resins, synthetic adsorbent and packings for protein separation, as well as conventional anion and cation exchange resins. In this paper, I will describe the general explanation of ion exchange resins and the recently developed ion exchange resins and novel ion exchange technologies. Especially, I will explain, 1) pure water treatment in the power industries and the LSI manufacturing fields, 2) chelating resins for heavy metal uptake and recovery, 3) chromatographic separation using novel amphoteric resin in membrane dialysis, 4) novel anion exchange resin with thermal durability and chemical stability, 5) analytical and preparative scale packings for high performance protein separations.

View full abstract