The Desorption And Regeneration Of Adsorbent For Arsenic Removal

In recent years, the removal of arsenic in the water has been focused by manystudies. Mostly, the process and the mechanism of adsorption for the arsenic (arsenate/arsenite) have been noticed. There are less research about the arsenic desorption fromthe loaded adsorbent, and less attention about its regeneration. To regenerate the loadedmaterial to prevent secondary pollution of the natural environment, to conserve resourceand, it is necessary to study the process of desorption.The adsorption of arsenic by TiO2-pillared interlayer montmorilonite and its dopedwith Fe3+ was carried out. After complete adsorption, the adsorbent has been took intonon-ion water for researching its process of desorption, mainly with different time,temperature and the value of pH, and on the effect of supersonic and UV-light. Theresults indicated that the initial desorption rate of As(â…¢) was higher than As(â…¤), but thefinal desorption percentage of As(â…¤) was two times higher than As(â…¢); that in therange of pH(6.5-8.5), the desorption of As(â…¤) was the lowest(pH=6.5),and thepercentage increased with the pH value increasing or deescalating, but for the As(â…¢),thepercentage increased with the increase of pH; that the supersonic accelerated desoptionof arsenic and the final percentage was lower than non-supersonic; that on the conditionof UV-light ,in a word, it took negative effect to desorption The"reproduced process"has been used in the procedure of regeneration. The properties ( mainly the capacity andthe selectivity of the mixture of phosphate and arsenite) of the original and theregenerated materials indicated that the capacity deescalated less than 5%, but theselectivity for arsenic increased with time of regeneration increase .The difference of internal microstructure, bond-group and surface area about theoriginal and the regenerated materials were characterized by XRD, FT-IR, TGA, EPR,TEM-EDS and BET etc. The characterization of the EPR for the iron-doped titaniumpillared montmorillonite indicated the iron mainly were on the iron-rich phases in themontmorillonite adsorptive state. With the time of regeneration increasing, the qualityof iron-rich phases between layers increase, and then improve the the selectivity for arsenic.