Removal Of Perchlorate By Modified Wheat Straw Adsorption And Bio-reduction

As an emerging contaminant, perchlorate has prompted environmental scientists to pay more attention, because of its extremely low concentrations and strong resistance to most treatment technologies. The presence of perchlorate in the human body can result in improper regulation of thyroid gland for adults, and developmental problems for infants and children because it can interfere with iodide uptake into the thyroid tissue. Recently, perchlorate has formed a potential health threat in China, efficient and harmless treatment of perchlorate is imminently needed. As an agricultural country, reasonable disposal of agricultural solid waste is an important problem. This study has worked on the utilization of agricultural solid waste, wheat straw, to be used in the treatment of perchlorate by modifying with organic reagents to compound adsorbent. In this research, the removal of perchlorate was conducted by modified wheat straw adsorption combined with microbial treatment, which could deoxidate the perchlorate and reuse the adsorbent. The main conclusions of this study are:1. The results of nitrate adsorbed by different kinds of modified wheat straw shows that the ethylenediamine-triethylamine modification is the appropriate modification method, and the product (EET-MWS) was more efficient for the treatment of perchlorate;2. The characterization of the products indicates that the surface organic functional groups plays a main role in the adsorption of anions and the surface of adsorbent is positive charged by the modifying;3. The adsorption characteristics of perchlorate shows that, the adsorption mechanism of perchlorate on EET-MWS is ion exchange, and the highest adsorption capacity at roomtemperature(25℃) is119mg g-1, which is very efficient and low cost compared with the other common adsorbents for the treatment of perchlorate;4. The culture of mixed perchlorate-reducing bacteria was conducted and the reduction of perchlorate in water was high efficient, the mixed bacteria can be directly used in the recovery of loaded EET-MWS, which was used in the column adsorption of perchlorate. The directly bio-reduction of EET-MWS performed well,and could be repeated.