CHARACTERISTICS OF THE SYNTHETIC HEULANDITE-CLINOPTILOLITE FAMILY OF ZEOLITES

Heulandite-clinsptilolite zeolites can be synthesized over the complet e range of Si/Al ratio (2.5 to 6) found for the natural minerals. The unit cell parameters, framework infrared vibrational characteristics a nd thermal properties an similar to those of their natural counterpart s. Results of environmental studies involving the removal of toxic met al ions such as lead, strontium and cesium from solution show that tho ugh natural clinoptilolite efficiently removes these ions from solutio n, the higher aluminum content of heulandite results in an improvement in the capacity of this topology for divalent cations. The ability to readily prepare synthetic heulandite and clinoptilolite using environ mentally benign methods is expected to lead to improvements in the use of this family of zeolites for similar environmental applications. (C ) 1998 Elsevier Science B.V. All rights reserved.