Removal of natural organic matter by titanium tetrachloride: The effect of total hardness and ionic strength.
This study is the first attempt to investigate the effect of total hardness and ionic strength on coagulation performance and the floc characteristics of titanium tetrachloride (TiCl4). Membrane fouling under different total hardness and ionic strength conditions was also evaluated during a coagulation-ultrafiltration (C-UF) hybrid process. Coagulation experiments were performed with two simulated waters, using humic acid (HA, high molecular weight) and fulvic acid (FA, relatively low molecular weight), respectively, as model natural organic matter (NOM). Results show that both particle and organic matter removal can be enhanced by increasing total hardness and ionic strength. Floc characteristics were significantly influenced by total hardness and ionic strength and were improved in terms of floc size, growth rate, strength, recoverability and compactness. The results of the UF tests show that the pre-coagulation with TiCl4 significantly improves the membrane permeate fluxes. Under different total hardness and ionic strength conditions, the membrane permeate flux varied according to both NOM and floc characteristics. The increase in total hardness and ionic strength improved the membrane permeate flux in the case of HA simulated water treatment.
Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, No. 27 Shanda South Road, Jinan 250100, People's Republic of China.
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YX
Zhao
Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology, Sydney (UTS), P.O. Box 123, Broadway, NSW 2007, Australia.
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HK
Shon
Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology, Sydney (UTS), P.O. Box 123, Broadway, NSW 2007, Australia.
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S
Phuntsho
Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, No. 27 Shanda South Road, Jinan 250100, People's Republic of China. Electronic address: baoyugao_sdu@aliyun.com.
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BY
Gao
D001578:Benzopyrans / Q000737:chemistry*; D005427:Flocculation; D006244:Hardness; D006812:Humic Substances; D008567:Membranes, Artificial; D009994:Osmolar Concentration; D014025:Titanium / Q000737:chemistry*; D014462:Ultrafiltration / Q000379:methods; D014873:Water Pollutants / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
D001578:Benzopyrans; D006812:Humic Substances; D008567:Membranes, Artificial; D014873:Water Pollutants; C025096:titanium tetrachloride; D014025:Titanium; C005023:fulvic acid
Coagulation–flocculation; Ionic strength; Membrane fouling; Titanium tetrachloride; Total hardness