Effects of hydrochloric acid modification on the channel characteristics,composition,surface potential and cation exchange behavior of natural clinoptilolite

Natural clinoptilolite was modified by different concentrations of hydrochloric acid. Systemic investigations were performed on the channel characteristics, chemical composition, surface potential, and cation exchange behavior of the modified clinoptilolite. It is found that the surface of the modified clinoptilolite becomes loose and rough, the contents of K⁺, Na⁺, Ca²⁺, and Mg²⁺ slightly decrease, the surface negative charges increases, and the cation exchange capacity decreases to some extent. The specif-ic surfaee area and total pore volume are improved and the maximum values of them increase from 35.97 m²·g^-1 and 0.0761 m³·g^-1 to 64.46 m²·g^-1 and 0.1156 m³·g^-1, respectively. The distribution of micropores, mesopores, and macropores is obviously impacted, and the type of zeolite cavities is determined to be uneven slits by the hysteresis loop shape, indicating that this aeid modification cannot change zeolite cavities.