Efficient removal of bacteria from aqueous media with kaolinite and diatomaceous earth products

Aims To understand the relationships between physical and chemical parameters of kaolinite and diatomaceous earth, and their capacities to remove bacteria from aqueous media. To determine the optimal aqueous media parameters for use of these products in water disinfection processes. Methods and Results Seven kaolinite and three diatomaceous earth products were evaluated. Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Bacillus megaterium were used as proxy for bacterial pathogens. Fully calcined kaolin and amorphous diatomaceous earth demonstrated the highest extent and consistency in removing all the bacteria. The removal depended on ionic strength and pH of aqueous media with 100 mmol l−1 pH 5 potassium hydrogen phthalate buffer revealing the highest (2 log per gram) extent of the removal. Al3+ cations enhanced sorption up to 4 log per gram. Conclusions Calcined kaolin and amorphous diatomaceous earth are excellent sorbents for bacteria. Significance and Impact of the Study Fully calcined kaolin and amorphous diatomaceous earth are perspective tools for wastewater and water disinfection against waterborne bacterial pathogens.