ABSTRACT
Corrosion protection was always the important part of industrial development. Effective corrosion inhibitors prolong the life of equipment and machinery and in this way minimize the use of natural resources including ore, oil, petroleum, water, etc.
On the other hand, growing world manufacturing constantly increases the volume of utilized natural resources. A number of regulations were implemented recently for the protection of the environment. The most known among them are North Sea (UK, Norway, Denmark, The Netherlands) and US Gulf Coast lists of the chemicals environmentally acceptable in these regions, limiting the number of chemicals allowed for use in accordance with their level of biodegradability, bioaccumulation and toxicity.
This paper presents several products that are very effective in providing corrosion/scale inhibition and also formulated from biodegradable environmentally friendly raw materials, manufactured from renewable resources. Quality of these products is confirmed by laboratory testing according to ASTM and/or other standards and field results.
INTRODUCTION
Green chemistry is not an absolute goal or destination, but a dedication to a process for continual improvement, wherein the environment is considered along with the chemistry. Chemical products should be designed to preserve the efficiency of function, while reducing the impact on the environment.
These products should be designed so that at the end of their application, the product does not persist in the environment, and it should break down into innocuous degradation products. The development of "green" corrosion inhibitors is a process, which requires the knowledge of the pertinent country regulations, the evaluation of the environmental performance for the environment to which the product will be exposed, and the excellent corrosion protection in the applications this inhibitor is designed for.
The following list provides a glimpse of the principal criteria the chemist must follow to determine whether a given corrosion inhibitor is environmentally acceptable in a given region [1].
North Sea (UK, Norway, Denmark, The Netherlands)
Biodegradability: >60% in 28 days
Marine toxicity: Effective Concentration, 50% (EC50)/Lethal Concentration, 50% (LC50)>10 mg/L to North Sea species
Bioaccumulation: Log Octanol/Water Partition Coefficient (Pow)<3
US Western Gulf Coast Outer Continental Shelf (OCS)
Marine toxicity: No Observed Effect Concentration (NOEC) of effluent to mysid shrimp and silverside minnow must meet or exceed critical dilution factor (CDF) over a specified period of time (48 h or 7 days)
US Eastern Gulf Coast OCS
Marine toxicity: LC50 or effluent to mysid shrimp and silverside minnow must meet or exceed CDF
Eastern Canada
Similar to North Sea criteria
Microtox toxicity is also important
Trinidad and Tobago
Marine toxicity: Residual levels of products in effluent must not exceed 0.01 of LC50 test concentration to Metamysidopsis insularis (a crustacean)
Must also provide biodegradability data.
A different approach can be used to obtain a required or improved environmental profile: one of them is to use biodegradable materials obtained from natural resources as corrosion inhibitors.
The goal of the paper is to show that non-toxic, biodegradable inhibitors may inhibit corrosion as well or better than their more toxic traditional counterparts, depending on the system.
