核桃青皮缓蚀剂和表面活性剂对钢在酸中的缓蚀协同效应及机理研究

Yunnan province is rich in walnut green husk resources, and there is a good opportunity of walnut industry. However, in the present situation, the utilization of walnut green husk is poor. The waste of walnut green husk resources is more and more serious. A lagre amount of walnut green husk is thrown chaos to be abandoned, which leads to a big problem of environmental pollution. In this project, the walnut green husk inhibitor (WGHI) is extracted and prepared from walnut green husk using reflux extraction method. The synergistic inhibition effect and mechanism of WGHI and surfactant on the corrosion of steel in acid solutions is studied by weight loss method, electrochemical technique, advanced instrumental analyst on metal surfaces and molecular modelling theoretical calcualtions. It is aimed to screen a series of composite systems of synergism between WGHI and surfactants. The new data of synergistic inhibition effect are accumulated. The effects of composite concentration, temperature, acid concentration and immersion time on the inhibitive performance of WGHI/surfactant mixture are revealed. It is to elucidate the adsorption behavior of composite inhibitors on steel surface and the electrochemical mechanism. The micro-topography and chemical composition of steel surface /the adsorption film of inhibitor are characterized by advanced analytic instruments. The effective constituents in WGHI are clarified. Also, using quantum chemical calculation and molecular dynamic simulation, it is to study the relationship between molecular structure and inhibitive ability, protonated effect of inhibitor molecular, interaction force between effective chemical compound in WGHI and surfactant, and the co-adsorption behavior of composite inhibitor molecules on steel surface. The reasonable synergistic inhibitive mechanism is proposed. Then the synergistic mechanism is used to provide the scientific basis in search of highly effective composite corrosion inhibitor of WGHI/surfactant for steel in acid solutions, and then lays the foundation of the exploitation of corrosion inhibitor using the waste resources of walnut green husk.

依托云南丰富的核桃青皮资源，结合云南核桃产业发展的大好机遇，针对核桃青皮资源利用滞后且浪费严重、乱扔乱弃、污染环境的现状，采用回流提取法从中提取制备出核桃青皮缓蚀剂。用失重法、电化学法、金属表面仪器分析测试、分子模拟理论计算研究核桃青皮缓蚀剂和表面活性剂对钢在酸溶液中的缓蚀协同效应及作用机理。旨在建立系列复配缓蚀协同体系；积累缓蚀协同性能的新数据；揭示缓蚀剂复配浓度、温度、酸浓度、腐蚀浸泡时间、提取条件等因素对缓蚀协同性能的影响规律；阐释复配缓蚀剂在钢表面的吸附行为及电化学作用机理；对钢表面/吸附膜层的进行微观表征；阐明核桃青皮缓蚀剂的有效成分；理论计算协同体系缓蚀剂分子的构效关系、质子化作用、相互作用及在钢表面的共吸附作用；提出合理的缓蚀协同机理；为核桃青皮缓蚀剂/表面活性剂作为钢在酸溶液中高效复配缓蚀剂提供理论依据；为核桃青皮废弃物资源用作金属缓蚀剂的开发利用奠定基础。

植物复配协同缓蚀剂是当今缓蚀剂研究领域的热点和前沿。本项目依托云南丰富的核桃青皮资源，结合云南核桃产业发展的大好机遇，针对核桃青皮资源利用滞后且浪费严重、乱扔乱弃、污染环境的现状，采用回流提取法从中提取制备出核桃青皮缓蚀剂。用失重法、电化学法、金属表面仪器分析测试、分子模拟理论计算系统深入研究了核桃青皮缓蚀剂和表面活性剂对钢在酸溶液中的缓蚀协同效应及作用机理。建立了一条相对成熟的固体核桃青皮缓蚀剂的提取路线——回流提取法。核桃青皮缓蚀剂中的化合物的主要官能团为O—H, C==C, C==O, C—O等，最佳提取率可在12%以上。建立了系列核桃青皮缓蚀剂与十二烷基硫酸钠、十二烷基苯磺酸钠、十二烷基磺酸钠、木质素磺酸钠、十六烷基三甲基溴化铵、苄基三甲基碘化铵、十八烷基二甲基甜菜碱、OP-10等缓蚀协同效应体系。缓蚀协同效应系数随核桃青皮缓蚀剂浓度用量的增加而增大。核桃青皮缓蚀剂和表面活性剂复配前后在钢表面上的吸附一般服从Langmuir或Temkin吸附等温式；复配后具有更大的吸附平衡常数和更负的标准吸附Gibbs自由能，且对阴阳两极的腐蚀产生了显著地抑制作用；复配协同缓蚀剂的电荷转移电阻明显增大，而界面双电层电容下降。添加核桃青皮缓蚀剂/表面活性剂后钢表面腐蚀程度大幅度下降，且腐蚀产物量明显减少，吸附膜层中含有核桃青皮缓蚀剂与表面活性剂。核桃青皮缓蚀剂中的有效成分主要为萘醌类化合物和黄酮类化合物，其与表面活性剂之间存在缓蚀协同作用，但协同性能低于核桃青皮提取物/表面活性剂复配缓蚀剂。核桃青皮缓蚀剂与表面活性剂发生相互作用生成中间体平行吸附在金属表面，且复配后吸附能绝对值增加。. 项目执行期内，发表学术论文22篇，其中6篇被SCI收录；授权国家发明专利2件，荣获梁希林业科学奖自然科学奖二等奖1项、中国腐蚀与防护学会杰出青年学术成就奖1项。项目负责人入选云南省享受省政府特殊津贴人员、云南省中青年学术和技术带头人、云南省首批“万人计划”青年拔尖人才。