Methods for controlling scale formation in acqueous systems

Abstract

A method of controlling scale formation and deposition and corrosion in aqueous systems is described wherein a treatment solution of a substoichiometric amount of a scale/corrosion inhibitor in combination with a substituted alkylpolycarboxylate is employed. The scale/corrosion inhibitor can be a phosphonate such as hydroxyethylidene diphosphonic acid, 2-phosphonobutane-1,2,4-tricarboxylic acid, hydroxyphosphonoacetic acids, amino phosphonates; terpolymers, copolymers and homopolymers of acrylic acid, maleic acid, epoxysuccinic acids such as polyepoxysuccinic acid or mixtures thereof. The substituted alkylpolycarboxylates are compounds of the general structure: R--X--Y.sub.n wherein R is a hydrocarbon functionality having 4 to 18 carbons; X, when present, is --NH--, --NY.sup.1 --, --N-->O, --N--OC--Y.sup.1, --O-- or --S--; n is greater than or equal to 1; and Y and Y.sup.1 each independently represent a substituted or non-substituted carboxylic acid functionality such that said alkylpolycarboxylate has at least 2 carboxylic acid functional groups.