Related Experiment Video
Updated: Jul 5, 2025
Procedure to Evaluate the Efficiency of Flocculants for the Removal of Dispersed Particles from Plant Extracts
Published on: April 9, 2016
Preparation, characterization and application of a composite bioflocculant
Tianju Zhu1,2, Jiao Song1, Xiaoling Zhou3
1College of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu, People's Republic of China.
Abstract:
Composite flocculant PAFS-PDM was prepared from Polymeric aluminium ferric sulphate (PAFS) and Poly (diallyl dimethyl ammonium chloride) (PDM) in this study. A bacterium was selected from the soil near the shale gas exploitation platform as a bioflocculant-producing bacterium, and polysaccharide was extracted and combined with PAFS-PDM to obtain composite bioflocculant (CBF) to treat shale gas fracturing flowback fluid. The prepared CBF was characterized and the results showed that the prepared PAFS-PDM contained aluminium-iron hydroxyl polymer, which was a cationic flocculant. By measuring the turbidity removal rate and chemical oxygen demand (COD) removal efficiency, the function mechanism of CBF on the shale gas fracturing flowback fluid was discussed. The results showed that CBF had a stable treatment effect on fracturing flowback fluid when the pH value was about 7.0. With the increase of dosage, the coagulation efficiency increased first and then decreased. When the dosage of the CBF was 2500 mg·L-1, the treatment effect of shale gas fracturing flowback fluid was the best, and COD removal rate reached 89.43%. Through Zeta potential analysis, it was concluded that one of the coagulation mechanisms was electrical neutralization. According to the characterization results, it could be concluded that both adsorption bridging and charge neutralization mechanisms played important roles in the treatment of shale gas fracturing flowback fluids.
Insights
A novel composite bioflocculant (CBF) effectively treats shale gas fracturing flowback fluid. This bioflocculant, combining Polymeric aluminium ferric sulphate (PAFS)-Poly (diallyl dimethyl ammonium chloride) (PDM) with bacterial polysaccharide, achieved an 89.43% COD removal rate.
Area of Science:
- Environmental Science
- Chemical Engineering
- Biotechnology
Background:
- Shale gas exploitation generates fracturing flowback fluid, posing environmental challenges.
- Conventional treatment methods may be insufficient for complex wastewater streams.
Purpose of the Study:
- To develop and evaluate a composite bioflocculant (CBF) for treating shale gas fracturing flowback fluid.
- To investigate the coagulation mechanisms of the CBF.
Main Methods:
- Preparation of composite bioflocculant (CBF) from Polymeric aluminium ferric sulphate (PAFS), Poly (diallyl dimethyl ammonium chloride) (PDM), and bacterial polysaccharide.
- Characterization of CBF and analysis of its performance in removing turbidity and Chemical Oxygen Demand (COD).
- Zeta potential analysis to elucidate coagulation mechanisms.
Main Results:
- The CBF, containing an aluminium-iron hydroxyl polymer, demonstrated stable performance at pH 7.0.
- Optimal CBF dosage of 2500 mg·L⁻¹ resulted in an 89.43% COD removal rate.
- Coagulation mechanisms include electrical neutralization, adsorption bridging, and charge neutralization.
Conclusions:
- The developed CBF is effective for treating shale gas fracturing flowback fluid.
- Both chemical and biological components contribute to the flocculation efficiency.
- Understanding the mechanisms aids in optimizing wastewater treatment processes.
