Comparative adsorption behavior between phenol and p-nitrophenol by Na- and HDTMA-clinoptilolite-rich tuff

A comparison of phenol (Phen) and p-nitrophenol (p-NPhen) sorption between sodium (ZCh-Na) and surfactant-modified (ZCh-HDTMA) clinoptilolite-rich tuffs is presented using kinetic and the isotherm parameters to describe the selectivity of the sorption processes. The clinoptilolite-rich tuff (ZCh) used in this work was obtained from a new deposit located in the state of Chihuahua (México). The effective and external cation exchange capacities (EfCEC and ECEC) of the ZCh were evaluated previous surface modification with HDTMA. The clinoptilolite-rich tuff was characterized by X-ray diffraction and electron microscopy. A batch system was used to evaluate the kinetics and the isotherms of Phen and p-NPhen sorption. The results show that EfCEC and ECEC were 112 and 17 meq/100 g, respectively. The clinoptilolite is the major mineral phase although mordenite and quartz are minor components. The pseudo-second order kinetic model better fitted the adsorption data and Langmuir model best describes the isotherms for both Phen and p-NPhen using ZCh-HDTMA. p-NPhen is adsorbed by both ZCh-HDTMA and ZCh-Na; however, ZCh-HDTMA exhibits superior performance which reflex a major selectivity. Therefore, the surfactant-modified clinoptilolite-rich tuff could be used for p-NPhen wastewater treatment.