ABSTRACT
In this chapter, silver-, copper-, and zinc-containing microporous materials have been composed on the basis of heulandite-clinoptilolite-containing tuff rock from the Rkoni plot of the Tedzami deposit (Eastern Georgia) using ion-exchange reactions between zeolite microcrystals (250 BBS mesh) and a salt of a comparable transition metal (AgNO3, CuCl2, or ZnCl2) in the solid phase, accompanied by washing using distilled water. Obtained adsorbention-exchangers reside in the zeolite crystal structure, contain 130 mg/g of silver, 63–72 mg/g of copper, and 30–58 mg/g of zinc, and show bacteriostatic activity against a wide range of microorganisms, while the mixtures of different forms are synergistic and have higher activities than individual materials. Filled papers containing up to 3.0, 1.6, and 1.4 mg/g of silver, copper, and zinc, respectively, were manufactured in a paper mill of GPM company, which produces paper and three-layer corrugated paperboard from recycled waste. It was concluded that the application of zeolite fillers leads to a change in the grammage, caliper, density, tensile, and stretching of the paper, and these characteristics of paper filled with metal-containing bactericidal zeolites are highly dependent on the nature of the filler and the content of metals in it. The introduction of zeolite fillers holding divalent metals brings 192about a notable change in the surface properties. This brings some remarkable changes in our experimental samples with a certain copper content as well. On the other hand, bacteriostatic activity testing by the colony-forming unit assay specifies that all metal-containing samples are active against gram-positive bacterium Staphylococcus aureus, and zinc-containing papers are more active against gram-negative bacterium Escherichia coli than those containing silver. These results are very decisive regarding the practical aspects, since they open up the potentiality of replacing expensive silver with cheaper copper and zinc. For the production of paper active against E. coli, a filler with a zinc content of 1.4 mg/g is recommended, and for the production of waterproof paper active against Staphylococcus, a filler with a copper content of about 1.6 mg/g is recommended.
