title: Influence of shear force on floc properties and residual aluminum in humic acid treatment by nano-Al₁₃.
abstract: The impacts of various shear forces on floc sizes and structures in humic acid coagulations by polyaluminum chloride (PACl) and nano-Al13 were comparatively studied in this paper. The dynamic floc size was monitored by use of a laser diffraction particle sizing device. The floc structure was evaluated in terms of fractal dimension, analyzed by small-angle laser light scattering (SALLS). The effect of increased shear rate on residual Al of the coagulation effluents was then analyzed on the basis of different floc characteristics generated under various shear conditions. The results showed that floc size decreased with the increasing shear rate for both Al13 and PACl. Besides, floc strength and re-formation ability were also weakened by the enhanced shear force. Al13 resulted in small, strong and better recoverable flocs than PACl and moreover, in the shear range of 100-300 revolution per minute (rpm) (G=40.7-178.3s(-1)), the characteristics of HA-Al13 flocs displayed smaller scale changes than those of HA-PACl flocs. The results of residual Al measurements proved that with shear increased, the residual Al increased continuously but Al13 presented less sensitivity to the varying shear forces. PACl contributed higher residual Al than Al13 under the same shear condition.
authors.affiliation: School of Resources and Environmental Sciences, University of Jinan, Ji'nan 250022, Shandong, People's Republic of China. Electronic address: stu_xuwy@ujn.edu.cn.
authors.forename: Weiying
authors.initials: W
authors.lastname: Xu
authors.affiliation: Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Ji'nan 250100, Shandong, People's Republic of China.
authors.forename: Baoyu
authors.initials: B
authors.lastname: Gao
authors.affiliation: School of Resources and Environmental Sciences, University of Jinan, Ji'nan 250022, Shandong, People's Republic of China.
authors.forename: Bin
authors.initials: B
authors.lastname: Du
authors.affiliation: School of Resources and Environmental Sciences, University of Jinan, Ji'nan 250022, Shandong, People's Republic of China.
authors.forename: Zhenghe
authors.initials: Z
authors.lastname: Xu
authors.affiliation: School of Resources and Environmental Sciences, University of Jinan, Ji'nan 250022, Shandong, People's Republic of China.
authors.forename: Yongfang
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: School of Resources and Environmental Sciences, University of Jinan, Ji'nan 250022, Shandong, People's Republic of China.
authors.forename: Dong
authors.initials: D
authors.lastname: Wei
mesh_terms: D000535:Aluminum / Q000032:analysis* / Q000737:chemistry*; D000536:Aluminum Hydroxide / Q000737:chemistry; D005427:Flocculation; D006812:Humic Substances; D053768:Metal Nanoparticles / Q000032:analysis* / Q000737:chemistry*; D013314:Stress, Mechanical; D018508:Water Purification
chemical_list: D006812:Humic Substances; C016213:aluminum oxychloride; D000536:Aluminum Hydroxide; D000535:Aluminum
keywords: Al(13) polymer.; Floc characterization; Residual Al; Shear force