Majewski, Peter, et al. Applied surface science 258.7 (2012): 2454-2458.
The objective of this study was to test 3-(2-aminoethyl)aminopropyltrimethoxysilane (Diamo) as a functional coating to prepare a silica material for direct removal of various pathogens from water.The removal process required only gentle mechanical mixing of the surface-engineered silica (SES) material with contaminated water, needing no additional thermal or electrical energy input.
Synthesis: ~450 g silica stirred in 1 L pure water containing 120 mL Diamo for 120 min at room temperature in air. The suspension was left to rest overnight to sediment the powder, then decanted, washed twice with 1 L pure water, and dried at 90 °C for 24 h.
Key Results:
· Zeta potential measurements confirmed that the coating provided the silica particles with a substantially increased positive surface charge. X-ray photoelectron spectrometry and thermogravimetric analysis verified the presence of Diamo on the particle surface, with an amine group concentration of approximately 1 mmol per gram of silica.
· Broad-Spectrum Pathogen Removal: Water treatment studies showed that the material efficiently removed a number of bacteria (E. coli, P. aeruginosa, M. immunogenum, V. cholerae), a virus (poliovirus), and a protozoan (C. parvum) from water. For this, a dose of about 10 grams of SES per liter of water was sufficient to treat samples that had been spiked with concentrations ranging from 102 to 104 colony forming units (cfu; or equivalent) per mL.