Anionic sorption onto modified natural zeolites using chemical activation

The sorption of arsenate on modified-natural zeolites was investigated at varying chemical pretreatment. Zeolites were used extensively for water softening, however, a few arsenic studies have been conducted with zeolites. Arsenic pollution of the environment has received renewed attention due to toxicological evidence of its potential health hazards to humans. The ability of modified natural zeolites (stilbite and laumontite) to remove inorganic anion was investigated. The zeolites used in this work are stilbite-laumontite from Zeolitic Zone of the Corda Formation. Experiments were conducted to evaluate the relationships of the arsenate in the modified natural zeolites. Laboratory experiments were conducted examining the effect of the sorption of cationic surfactants and coagulant on stilbite-laumontite mixtures and on the subsequent sorption of arsenate by modified zeolites. Removal of arsenate using hexadecyltrimethylammonium (HDTMA)-modified zeolites was satisfactory whereas ethylhexadecyldimethylammonium (EHDDMA) and ALUM-modified zeolites were not removed with the same efficiency.