Preparation of polyaluminum chlorides containing nano-Al13 from Egyptian kaolin and application in water treatment

In this study, a novel approach to metakaolin dealumination to produce aluminum chloride from Egyptian kaolin has been described and the prepared aluminum chloride can be used to produce polyaluminum chlorides (PACs) with various basicities (B = OH/Al values). The prepared PACs which contain Al13 ([AlO4Al12(OH)24(H2O)12]7+) was investigated using XRD and colorimetric method . In XRD spectra, a strong Al13 signal appeared in the range of 2? from 5 to 25o (Wang,1999). Jar test was performed to test the coagulation efficiency and a comparative study was achieved between different coagulants as alum, AlCl3, PAC and PAC–Al13 with various basicities in treating actual water samples. PAC–Al13 with highest content of Al13 has more turbidity removal, and achieves the highest charge-neutralizing ability than alum, AlCl3 and PAC under the study conditions. The dosages from 5 to 25 mgl-1 were used in the comparative studies.