CHARACTERIZATION OF CLINOPTILOLITE BY INTERACTION OF H2S, CO, AND SO2BY THE ESR TECHNIQUE

A study was made of the interaction of H2S, CO, and SO2 over activated clinoptilolite at 400-degrees-C using the electron spin resonance (e. s.r.) technique. It was observed that the CO- paramagnetic ions are fo rmed over fresh activated clinoptilolite when treated with CO at appro ximately 400-degrees-C. It was also observed that two types of SO2- io ns, i.e., A-type SO2- with hyperfine structure (h.f.s.) and B-type SO2 - without h.f.s. are formed over clinoptilolite depending on the exper imental conditions. The B-type SO2- ion takes part in the reduction of SO2 by CO or H2S. The presence of CO over fresh activated clinoptilol ite poisons the sites that are responsible for the formation of B-type SO2- ions. At room temperature, adsorbed H2S on the fresh activated c linoptilolite is responsible for the formation of paramagnetic Al3+ io ns in the structure of clinoptilolite. Clinoptilolite has both electro n-accepting and -donating sites. A plausible mechanism for the interac tion of H2S, CO, and SO2 over activated clinoptilolite is discussed.