Title

Sodium Silicate Impacts On Copper Release In A Potable Water Comprised Of Ground, Surface And Desalted Sea Water Supplies

Keywords

Blended water supplies; Copper release; Inhibitor; Internal corrosion control; Silica; Sodium silicate

Abstract

The effects of sodium silicate corrosion inhibitor dosages, ranging from 3 to 12 mg/L-SiO2, on total and dissolved copper release was studied using coiled copper pipes that were exposed to differing blends of groundwater, surface water, and reverse osmosis treated groundwater that was intended to simulate desalinated seawater. The evaluation was conducted within a pre-existing, demonstration-scale drinking water distribution pilot system where samples were drawn from tapped copper coils 30 feet in length and 5/8 inch diameter. One set of loops contained water treated with sodium silicate and two loops contained water not treated with inhibitor and were designated as pHs and pHs+0.3. Testing was segmented into four different phases (I:II:III:IV), where water quality was varied in each phase by blending differing proportions of three source waters; groundwater (62:27:62:40), surface water (27:62:27:40), and simulated desalinated seawater (11:11:11:20), respectively. Total copper release decreased by approximately [34%:41%:54%:50%] when dosed with 3 mg/L-SiO2 of sodium silicate, [32%:49%:56%:59%] at 6 mg/L-SiO2, and [48%:63%:66%:70%] at 12mg/L-SiO2 for the conditions experienced in the study. Anobserved light green scale developed on loop-inserted copper coupon surfaces; elemental analyses of inserted coupon surfaces depicted evidence of a silicate-copper based surface film. Linear regression correlated total copper release in terms of dosage and water quality (R2 = 0.68). The model suggested that dosage, alkalinity, chlorides, and pH were statistically associated with copper release. © 2011 Desalination Publications. All rights reserved.

Publication Date

1-1-2011

Publication Title

Desalination and Water Treatment

Volume

30

Issue

1-3

Number of Pages

348-360

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.5004/dwt.2011.2255

Socpus ID

80052400551 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/80052400551

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