| Abstract |
| Batch adsorption experiments were performed to remove arsenate and selenite, fatal aqueous toxins, with adsorbents(bentonite and kaolinite) modified by tetradecyl trimetyl ammonium bromide(TTAB). The cation exchange capacity of bentonite was 68.3 meq/100 mg and that of kaolinite was 14.3 meq/100 mg. The specific surface area of bentonite was 118 m2/g and that of kaolinite was 13 m2/g. As the amount of added TTAB was increased, specific adsorptions were occurred for bentonite and kaolinite. The electric charges were moved to positive values in all pH ranges with 5×10-5 M TTAB surface modification. With the initial concentration of 1×10-5 M for bentonite, 96 % of the surface modification were occurred at all pH ranges and relatively higher surface modifications were occurred around pH 7. However, 72 % of the surface modification were occurred around pH 7 with the initial concentration of 1×10-5 M for kaolinite and the lower surface modifications were shown at all other pH levels. Higher surface modificaitons were shown for both bentonite and kaolinite when ionic strengths were low. Surface modified adsorbents are stable at all pH ranges as a result of desorption test. And bentonite could remove more than 95∼97 % of arsenic and selenium at all pH ranges. However, kaolinite showed only 40∼60 % removal efficiency for arsenic and selenium at all pH ranges. The physical properties such as cation exchange capacity, specific surface area and surface modification would bring difference between bentonite and kaolinite. |
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| Key Words |
| adsorbent, surface impregnation rate, TTAB-impregnated adsorbents |
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