Enhanced hydrophilic organic matter removal ability of Al₁₃ in the presence of organic matters under modified MWCNTs' assistance

Disinfection by-products (DBPs), which formed in the process of chlorination disinfection of water, has a potential threat to human health. To date, Natural organic matter (NOM) is the precursor of DBPs so that it is important to remove the NOM to reduce the generation of DBPs. Coagulation is a key process to remove the NOM from water. However, the traditional coagulants have poor removal ability for hydrophilic(HPI) NOM. In this study, multi walled carbon nanotubes was modified with Mg, Ca and Fe to produce modified multi walled carbon nanotubes and then reacted with Al-13 to produce composite coagulant. Al-13 and composited coagulants were utilized to treat water with bovine serum albumin to compare the removal efficiency for HPI NOM. The results showed that the composited coagulant had a relatively high removal efficiency for organic matter, and among them, the effect of Al-13-MgMW is best. The DOM removal rates of Al-13 and Al-13-MgMW at doses of 0.12 mmol/L were 64.8 % and 75 %, respectively. Meanwhile, Al-13-MgMW had an 89.2 % removal rate for HPI NOM. The XPS and FTIR of flocs showed that the Al-13-MgMW had a significant removal ability for OC substances such as proteins. MgMW has a larger specific surface area and pore volume. ESI-TOF-MS results showed the composited coagulants retain the original structure of Al-13, and thus preserve and improve the advantages of Al-13.