The removal of silver nanoparticle by titanium tetrachloride and modified sodium alginate composite coagulants: floc properties, membrane fouling, and floc recycle
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In this study, a modified sodium alginate (MSA) composited with TiCl4 was used to treat the synthetic Ag nanoparticles (AgNPs) water in coagulation-ultrafiltration process. The floc properties and membrane fouling of TiCl4 and MSA composite coagulants (TiCl4 + MSA) were investigated by a laser diffraction instrument and ultrafiltration fouling model. The recycle of the AgNP-containing flocs was evaluated by XRD and photocatalytic experiments. The results showed that TiCl4 + MSA could achieve better coagulation performance than TiCl4 alone with AgNP and DOC removal up to 97 and 59% at the optimum condition (pH = 5 and dosage = 12 mg TiCl4/L). TiCl4 + MSA produced larger and looser flocs than TiCl4 and TiCl4 + SA composite coagulant (TiCl4 + SA), which was benefit for the inhibition of subsequence membrane fouling. The strongly attached external fouling resistance (Ref-s) and the reversible internal fouling resistance (Rif-r) of TiCl4 + MSA were only 43 and 39.2% of those achieved by TiCl4 at the optimal coagulation condition. Besides, the adopted AgCl-TiO2 could be recycled from AgNP-containing flocs. And MSA could promote the form of TiO2 anatase. It gives us a possible way for silver nanoparticle recycle.
KeywordsNanoparticles Coagulation Ultrafiltration Flocs Recycle
This study was supported by the Chinese National Science and Technology (No. 21377072, No. 51508308, No.51478250) and the Outstanding Young and Middle-Aged Scientists Research Fund of Shandong Province (BS2012HZ004).
- Tang T (2012) Release and removal mechanism of nanosilver particles by coagulantion process. Dissertation, Anhui University of Science and TechnologyGoogle Scholar