Removal and prevention of biofilm by nanoparticle chemistries

A method for removing a biofilm from a negatively charged surface comprising:

• contacting a biofilm with a composition comprising (i) one or more positively charged aluminum chlorohydrate nanoparticles having an average particle size of from about 1 nm to about 110 nm and in the form of a colloid, and (ii) one or more of a biocide wherein the biocide is formaldehyde, glutaraldehyde, acrolein, a quaternary ammonium compound, a peroxycarboxylic acid, bronopol, isothiazolone, a carbamate, metronidazole, or a combination thereof, a scale inhibitor, corrosion inhibitor, anionic polymer, stabilizing agent, surfactant, hydrotrope, dispersant, solidification agent, aesthetic enhancing agent, wetting agent, defoaming agent, thickening agent, gelling agent, and solvent;
• and
• removing the biofilm from the surface, wherein the removing occurs by the one or more positively charged aluminum chlorohydrate nanoparticles interacting with the negatively charged surface, thereby disrupting biofilm adsorption to the negatively charged surface;
• wherein the surface is located within a water system or water source,
• wherein the one or more positively charged aluminum chlorohydrate nanoparticles, when within the water system or water source have a concentration between about 0.1 ppm and about 2000 ppm and the biocide has a concentration of between about 0.1 wt-% to about 20 wt-%;
• wherein the composition has a pH between about 6 and about 8;
• and
• wherein the composition does not include silica nanoparticles.