Ngouné Bertrand, Pengou Martin, Nouteza Armel Megha, Nanseu-Njiki Charles Peguy, Ngameni Emmanuel
Laboratoire de Chimie Analytique, Faculté des Sciences, Université de Yaoundé 1, B.P. 812 Yaoundé, Cameroon.
Faculté des Sciences-ENS, Université de Maroua, B.P. 46 Maroua, Cameroon.
ACS Omega. 2019 May 23;4(5):9081-9091. doi: 10.1021/acsomega.9b01076. eCollection 2019 May 31.
Alkaloid extract from Stapf (AERMS) was studied as the corrosion inhibitor for C38 steel in 1 M HCl and 0.5 M HSO using electrochemistry and surface analysis. The corrosion inhibition was efficient and proceeds via adsorption of AERMS on the steel surface due to the active functional groups present in the molecules. AERMS acts as a mixed inhibitor in HCl and as a cathodic inhibitor in HSO. In HSO corrosive medium, the presence of iodides improves the adsorption of the alkaloid molecules by reducing the surface charge of the electrode and thus substantially decreases the corrosion rate. Two pure alkaloids (tetrahydroalastonine (THA) and perakine (PER)) were quantitatively isolated from AERMS, and their anticorrosive properties for C38 steel in 1 M HCl and 0.5 M HSO were evaluated. THA showed the highest efficiency while the performance of PER was less important compared to the extract. This confirms that the efficiency of AERMS was the result of the complementary action of the chemical compounds present in the extract.
采用电化学和表面分析方法，研究了从斯塔夫（AERMS）中提取的生物碱提取物作为C38钢在1 M HCl和0.5 M H₂SO₄中的缓蚀剂的性能。由于分子中存在活性官能团，缓蚀效果显著，且是通过AERMS在钢表面的吸附来实现的。AERMS在HCl中作为混合型缓蚀剂，在H₂SO₄中作为阴极型缓蚀剂。在H₂SO₄腐蚀介质中，碘化物的存在通过降低电极表面电荷提高了生物碱分子的吸附，从而大幅降低了腐蚀速率。从AERMS中定量分离出两种纯生物碱（四氢阿拉斯通宁（THA）和佩拉金（PER）），并评估了它们在1 M HCl和0.5 M H₂SO₄中对C38钢的防腐性能。THA表现出最高的效率，而与提取物相比，PER的性能则不太重要。这证实了AERMS的效率是提取物中存在的化合物互补作用的结果。
