制革用表面活性剂在复杂环境中的生态安全性评价与预测方法研究

The surfactants are widely used in complex mixtures during the leather manufacture. However, current environmental quality standards and ecological risk assessments are mainly based on single toxicities, and pay little attention to the potential hazards of mixture exposure. This project aims to build quantitative assessment and prediction method for eco-toxicity of surfactant mixture used in leather manufacture by luminous bacteria. Firstly, the optimization of toxicity test should be carried out using both photobacterium phosphorem T3 and Vibrio qinghaiensis sp. Q67 as testing bacterium. The culture, growth stage and bacterial density will be optimized to obtain luminescent bacteria with high sensitivity and reproducibility of toxicity test. Secondly, the method of toxicity test for individual surfactant is established and the mechanism of toxicity should be explored by molecular docking technology. According to the principle of surfactant applied in the process of leather-making, the components and the corresponding concentration ranges could be determined and mixture model is created to represent the concentration diversity in the real mixtures. Then the whole concentration-response curves are obtained by both eco-toxicity test and regression analysis, and a numbers of mathematical or biological models will be applied to investigate the combined effects of surfactant and other auxiliaries in the process of leather-making. Finally, quantitative structure-activity relationship (QSAR) models for mixture toxicities of surfactant mixtures should be established. This project will provide evaluation methodology for the environmentally friendly alternatives to harmful chemicals for leather industry to prevent ecological risk, as well as for the enterprises to respond effectively to the green trade barriers of developed countries.

针对目前国内外皮革行业缺乏皮革化学品（混合物）生态安全性识别和评估机制的现实，拟以发光细菌为受试生物，建立制革用表面活性剂在复杂环境中的生态安全性评价方法和预测方法。通过优化发光细菌培养和复苏条件获得发光强度相对稳定的发光细菌，以EC50及标准毒性化学品为参照，建立常用制革表面活性剂的生态毒性测试方法，探究其毒性作用机理；根据制革过程表面活性剂-其它助剂复配使用原则，确定表面活性剂复合物典型组分及比例范围，建立表面活性剂复合物模型；测试复合物模型生态毒性，获得表面活性剂复合物浓度-效应曲线，探究各组分之间的毒性作用机制，模拟复合物浓度-效应曲线，建立表面活性剂复合物生态性评价方法；进一步建立复合物结构-效应关系，实现表面活性剂复合物生态毒性预测。本项目实施将为皮革行业防范生态风险、研究开发环境友好的替代化学品提供评价方法，也为企业有效应对发达国家的绿色贸易壁垒开辟新的途径。

制革过程包括系列界面反应，因而表面活性剂应用广泛。针对制革过程含盐的特点，以明亮发光杆菌为受试生物，通过二次优化，培养了发光稳定的新鲜菌液，以0.1mg/L氯化汞为标准毒性参比物，测试介质pH 4.0-9.0，建立了适合制革体系的生态毒性评价方法。发现有机配体显著增加Cr(III)的生态毒性，申请了皮革生态毒性评价的方法专利，立项起草行业标准（征求意见阶段）。评价了制革常用阴、阳和非离子九种表面活性剂的生态毒性，发现阳离子表面活性剂（CTAB＞DTAB＞SKC）>> 阴离子表面活性剂（渗透剂 T＞拉开粉和太古油）＞非离子表面活性剂（AEO、Triton X-100 和 Tween80），为清洁制革选用表面活性剂提供了生态性参数。针对常用阴/非离子表面活性剂复配的SDBS/AEO、SDS/AEO，研究了复配比例与表面活性及生态毒性之间的关系，提出实验CM与理论CM间的差值ΔCM预测混合表面活性剂毒性。根据剂量-效应曲线，SDBS/AEO混合体系可分为三组：组1 SDBS:AEO = 4:1和3:2，组2为等质量比复配，组3 SDBS:AEO = 2:3和1:4。三组混合物的毒性：组2 >组3>组1；SDS/AEO体系可分为两组：组1SDS:AEO = 4:1和3:1，组2 SDS:AEO =3:2、1:1、2:3、1:4；组1随AEO复配比例的增加毒性减小；组2生物毒性随AEO比例变化较小，但SDS:AEO = 1:1的混合物毒性稍大。胶束化研究发现，实验CM与理论CM间的差值ΔCM，可表征组分间相互作用， ∆CM < 0，两者表现为协同作用，∆CM > 0，为拮抗作用，|∆CM|越大，相互作用越强。SDBS/AEO体系ΔCM的大小为组2 >组3 >组1，与毒性大小一致，即组分间拮抗作用越大，抑制混合胶束的形成，毒性越大。SDS/AEO体系基于Rubingh模型获得的相互作用参数，与∆CM随复配比例的变化趋势一致。DTAB/AEO及SKC/AEO复配体系的生物毒性及胶束化行为表明，组分间相互作用小，复配后体系毒性变化小。阴、阳离子表面活性剂复配体系，高浓度NaCl致DTAB/SDBS表现出拮抗作用，毒性变化不明显；而DTAB/SDS在高盐浓度下，仍有强协同作用，且DTAB:SDS = 2:3和1:4的毒性最低。研究提出从表面活性参数预测相互作用，进而预测混合物毒性。