Polyaluminium silicate chloride—A systematic study for the preparation and application of an efficient coagulant for water or wastewater treatment
The coagulation behaviour of the new coagulant agent polyaluminium silicate chloride (PASiC) was investigated in this study. The main purposewas the examination of several possible derivatives of polyaluminium silicate chloride, based on different basicity (OH/Al molar ratio), silica content (Al/Si molar ratio) and preparation method (co-polymerization or composite polymerization) to evaluate the respective coagulation behaviour of them. Moreover, a systematic study was conducted to define the optimum values of aforementioned major parameters, in order to produce an improved product, in comparison with the commonly applied polyaluminium chloride. Overall, 32 silica-based coagulant samples were prepared with different OH/Al (1–2.5), or Al/Si (5–20) molar ratios and preparation methods. The coagulation performance of PASiC products were evaluated for the treatment of contaminated tap water (in terms of turbidity and of NOM removal, as well as of residual Al concentrations and of zetapotential measurements). Also, they were examined for the tertiary treatment of municipal wastewater(mainly for phosphates removal). Additionally, the newproductswere compared with the laboratory prepared PACl, with alum (i.e. Al2(SO4)3·18H2O), as well as with commercially available PACl samples. These experiments were completed with the study of coagulation kinetics by using the Photometric Dispersion Analyzer (PDA), in order to compare the respective floc growth rates. Overall, the obtained results suggest that in order to produce a silica-based polyaluminium coagulant with improved coagulation properties, the basicity (OH/Al ratio) should be between 1.5 and 2.0, the silica content (Al/Si molar ratio) between 10 and 15 and should be prepared preferable with the co-polymerization technique. However, attention has to be given in the specific application of these products, as in the case of tertiary wastewater treatment(phosphates removal) more efficient seem to be the silica-based coagulant with lower basicity (i.e. OH/Al 1–1.5)
Αριστοτέλειο Πανεπιστήμιο Θεσσαλονίκης, Σχολή Θετικών Επιστημών, Τμήμα Χημείας
Journal of Hazardous Materials, vol.162  p.1379-1389 [Published Version]
This record is part of 'IKEE', the Institutional Repository of Aristotle University of Thessaloniki's Library and Information Centre found at http://ikee.lib.auth.gr. Unless otherwise stated above, the record metadata were created by and belong to Aristotle University of Thessaloniki Library, Greece and are made available to the public under Creative Commons Attribution-ShareAlike 4.0 International license (http://creativecommons.org/licenses/by-sa/4.0).
Unless otherwise stated in the record, the content and copyright of files and fulltext documents belong to their respective authors. Out-of-copyright content that was digitized, converted, processed, modified, etc by AUTh Library, is made available to the public under Creative Commons Attribution-ShareAlike 4.0 International license (http://creativecommons.org/licenses/by-sa/4.0). You are kindly requested to make a reference to AUTh Library and the URL of the record containing the resource whenever you make use of this material.
*Institutions are responsible for keeping their URLs functional (digital file, item page in repository site)