Sorption Of Tetracycline On Attapulgite

China has a lot of attapulgite mineral resources, as an industrial widely applied non-metallic mine, attapulgite is good of sorption ability. Recent years, people have been focusing on antibiotic pollution seriously. This paper takes attapulgite as adsorbent, studies the sorption of antibiotic on attapulgite.Used different methods to modify attapulgite, it was found from the result: Sorption ability of modified attapulgites is hydrochloric acid modified attapulgite > raw attapulgite > high-fired attapulgite > KH550 modified attapulgite > Octodecyl trimethyl ammonium chloride modified attapulgite; On this basis, optimized hydrochloric acid modification, the optimum conditions are hydrochloric acid concentration 0.5 mol/L, temperature 40 oC, solid-to-liquid ratio 1:8, reaction time 1 hour.The result from the study of the mechanism of sorption of tetracycline on attapulgite was: the experimental kinetic data were appropriate to fit the pseudo-second-order kinetics model; the sorption rate of tetracycline on attapulgite was determinated by surface diffusion; the sorption of tetracycline was a spontaneous endothermic process, Freundlich isotherm was more appropriate method to determine the present system; there is a hysteresis in desorption process.Changed the pH and ionic concentration of tetracycline solution to research their effect on sorption of tetracycline on attapulgite, it was drawed from the result that the sorbed tetracycline amount increased as the pH increased, and raise to maximum when pH was 3.0, after that, decrease as the pH increased; the sorbed tetracycline amount decrease as the ionic concentration increased, the ionic effect is Mg2+ > Ca2+>K+>Na+.Regenerated the used attapulgite adsorbent with different methods, the result could be found that taking thin alkali to regenerate attapulgite adsorbent under heating condition was a effective way; On this basis, optimized regeneration, the optimum conditions are sodium hydroxide concentration 0.004 mol/L, temperature 60 oC, reaction time 1 hour, regeneration rate 93.5%; with thin alkali theated, attapulgite adsorbent regenaretion had a good repeatability. Analysed the change of the attapulgite structure, the result showed that: FTIR, thermogravimetric analysis and XRD indicated hydrochloric acid modification did not change attapulgite structure radically; the specific surface area and average pore diameter of hydrochloric acid modified attapulgite enlarged slightly, regenerated attapulgite's specific surface area declined obviously, its average pore diameter reduced a little, the saturated sorbed attapulgite's specific surface area reduced sharply, its average pore diameter had a certain reduction. At last, we determined that the sorption of tetracycline on attapulgite is a surface sorption process.