Characterization and coagulation of a polyaluminum chloride (PAC) coagulant with high Al13 content.
A polyaluminum chloride (PAC) coagulant was prepared from AlCl3 x 6H2O and Na2CO3. The Al13 species in PAC was separated and purified by the SO4(2-)/Ba2+ deposition-replacement method, and characterized by 27Al-NMR and XRD. From 27Al-NMR spectroscopy, it was found that PAC obtained after separation and purification contained more Al13 (PAC-Al13, for short) than original PAC before separation and purification. In XRD spectra, a strong Al13 signal appeared in the range of 2theta from 5 to 25 degrees. Jar tests were performed to test the coagulation efficiency of AlCl3, PAC and PAC-Al13 in treating synthetic or actual water samples. Compared with PAC and AlCl3, PAC-Al13 gives the best results for turbidity, humic acid and color removal, and achieves the highest charge-neutralizing ability. Under the study conditions, PAC-Al13 gave about 90% humic acid removal and almost 100% reactive blue dye removal when its dosages were 4.0 and 15 mg/L as Al, respectively. The Al13 species has a higher positive charge and is the most effective polymeric Al species in water and wastewater treatment.
Gao
Bao-Yu
BY
School of Environmental Science and Engineering, Shandong University, No.27 Shanda South Road, Jinan 250100, Shandong, People's Republic of China. bygao@sdu.edu.cn
Chu
Yong-Bao
YB
Yue
Qin-Yan
QY
Wang
Bing-Jian
BJ
Wang
Shu-Guang
SG
D000535:Aluminum / Q000737:chemistry*; D000536:Aluminum Hydroxide / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D014865:Waste Disposal, Fluid / Q000379:methods*; D014961:X-Ray Diffraction
C016213:aluminum oxychloride; D000536:Aluminum Hydroxide; D000535:Aluminum