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Characterization and flocculation mechanism of high efficiency microbial flocculant TJ-F1 from Proteus mirabilis
Zhiqiang Zhang1, Siqing Xia, Jianfu Zhao
1State Key Laboratory of Pollution Control and Resource Reuse, Key Laboratory of Yangtze River Water Environment of Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
Abstract:
The characterization and the flocculation mechanism of microbial flocculant TJ-F1 with high flocculating activity, produced by Proteus mirabilis from a mixed activated sludge, was investigated. Mainly consisting of protein and acid polysaccharide, TJ-F1 owns a molecular weight of 1.2 x 10(5)Da, which brings strong van der Waals forces and ample binding-sites. It contains carboxyl, hydroxyl, amino groups and hydrogen bonds preferred for the flocculation process. The key parameters influencing the flocculation behavior were investigated by analyzing both the Zeta potentials of the flocculation systems and the flocculating efficiencies of TJ-F1. An alkaline condition promotes its flocculating efficiency. CaCl(2) aids TJ-F1 by effectively decreasing the absolute value of Zeta potential. Appropriate dose of TJ-F1 is crucial to the flocculating efficiency. During the precipitating process, the growing flocs sweep the small flocs and the suspended particles to form big flocs, which also contribute to the excellent flocculating efficiency of TJ-F1.
Insights
Microbial flocculant TJ-F1, composed of protein and polysaccharide, effectively clarifies water through strong binding forces and optimal conditions like alkalinity and CaCl2. Its flocculation mechanism involves sweeping small particles to form larger, settleable flocs.
Area of Science:
- Microbiology
- Biochemistry
- Environmental Science
Background:
- Microbial flocculants offer sustainable solutions for water treatment.
- Understanding the properties of flocculants is key to optimizing their application.
- TJ-F1, derived from Proteus mirabilis, exhibits high flocculating activity.
Purpose of the Study:
- To characterize the microbial flocculant TJ-F1.
- To elucidate the flocculation mechanism of TJ-F1.
- To identify key parameters influencing TJ-F1 flocculation efficiency.
Main Methods:
- Characterization of TJ-F1 composition and molecular weight.
- Analysis of functional groups involved in flocculation.
- Investigation of Zeta potential and flocculating efficiency under varying conditions.
- Observation of floc formation and particle sweeping during precipitation.
Main Results:
- TJ-F1 primarily consists of protein and acid polysaccharide with a molecular weight of 1.2 x 10(5)Da.
- Functional groups (carboxyl, hydroxyl, amino) and hydrogen bonds contribute to flocculation.
- Alkaline conditions and CaCl2 enhance flocculating efficiency by influencing Zeta potential.
- Optimal TJ-F1 dosage is critical for effective flocculation.
- The sweeping flocculation mechanism significantly contributes to particle removal.
Conclusions:
- TJ-F1 is a potent microbial flocculant with a well-defined composition and molecular weight.
- Its flocculation efficiency is significantly influenced by pH, presence of CaCl2, and dosage.
- The study provides insights into the mechanism of microbial flocculation for water treatment applications.
