Aqueous Agro-Industrial Waste as Corrosion Inhibitor for Stainless Steel AISI 304 in Acidic Media

The use of corrosion inhibitors is one of the most common methods to combat acid corrosion. The current studies aim to apply natural products as corrosion inhibitors, once the most used compounds are mostly toxic to the environment and to humans. The present paper purposes the application of an aqueous extract of agro-industrial waste (AEAW) to inhibit the corrosion of stainless steel AISI 304 in sulfuric acid. Gravimetric and electrochemical experiments were performed. The gravimetric experiments revealed that the extract acts as an inhibitor for stainless steel, showing inhibitory efficiency up to 81.6%. The electrochemical tests show that the AEAW makes the steel surface more noble. The extract acts by adsorption in the metallic surface, following a Temkin isotherm. The results indicate that the AEAW is a promising substitute of conventional organic compounds as a corrosion inhibitor to AISI 304 stainless steel in sulfuric acid.

使用缓蚀剂是对抗酸性腐蚀最常用的手段之一。当前研究致力于将天然产物用作缓蚀剂，鉴于此前最常用的缓蚀化合物大多对环境与人体具有毒性。本研究旨在采用农业工业废料水提物（aqueous extract of agro-industrial waste，缩写AEAW），抑制硫酸介质中AISI 304不锈钢的腐蚀。本研究开展了重量法与电化学实验。重量法实验结果表明，该提取物对不锈钢具有缓蚀作用，缓蚀效率最高可达81.6%。电化学测试结果显示，AEAW可使钢表面更具贵金属特性。该提取物通过吸附于金属表面发挥缓蚀作用，其吸附行为符合Temkin吸附等温式。研究结果表明，在硫酸介质中，AEAW有望替代传统有机化合物，用作AISI 304不锈钢的缓蚀剂。