察尔汗盐湖卤水中氯化钠浮选剂十二烷基吗啉在 氮化碳光催化剂作用下的降解特性

Degradation Characteristic of Sodium Chloride Flotation Collector Dodecyl Morpholine in Qarhan Salt Lake with Carbon Nitride Photocatalyst

中文关键词:  高浓度盐溶液  十二烷基吗啉  浮选药剂  光催化降解  氮化碳

英文关键词:High concentration salts solution  dodecyl morpholine  flotation reagent  photocatalytic degradation  carbon nitride

中文摘要:

      针对察尔汗盐湖氯化钠浮选尾卤中残留的十二烷基吗啉(DMP)难以有效去除问题，采用多孔状石墨相氮化碳(mpg-C3N4)为光催化剂，系统考察盐湖卤水中典型的高浓度无机盐NaCl、KCl和MgCl2等存在条件下，对mpg-C3N4光催化降解DMP浮选剂的影响规律与特性。结果表明，卤水中无机盐对降解过程有显著影响，其中高浓度的NaCl对mpg-C3N4的光催化降解特性有促进作用，当NaCl为80 g/L时，DMP的降解速率相对于无NaCl时提升幅度达到20.59%。KCl在低浓度时也能部分促进降解，其中当KCl为25.5 g/L时，DMP的降解速率相对于无KCl时提升幅度为3.71%。但是，体系中存在的MgCl2对mpg-C3N4光催化降解DMP有较大的抑制作用，当MgCl2为65.2 g/L时，DMP的降解速率相对于无MgCl2时抑制率达到44.90%。最后，通过自由基淬灭试验确定光催化降解DMP的主要活性物种为·O2-，其次为·OH。通过对光催化降解前后的产物进行深入对比分析与表征，结果显示经光催化降解后十二烷基吗啉分子中主要基团特征峰几乎完全消失，这表明DMP分子被有效破坏和降解掉，中间产物及小分子产物大部分也被有效分解矿化。

英文摘要:

      Aiming at solving the problem that dodecyl morpholine (DMP) remained in the tail brine of sodium chloride in Qarhan Salt Lake is difficult to be effectively removed, porous graphite phase carbon nitride (mpg-C3N4) was adopted as the target photocatalyst to degradation of DMP Flotation Collector. Besides, the influence of typical high concentration inorganic salts such as NaCl, KCl and MgCl2 in salt lake brine on mpg-C3N4 photocatalyst were also systematically investigated. The results showed that the existed inorganic salts had a significant effect on the degradation process, and high concentration of NaCl promoted the photocatalytic degradation rate of mpg-C3N4. When the concentration of NaCl was 80 g/L, the degradation rate of DMP increased by 20.59% compared with no NaCl. KCl can also partially promote the degradation rate at low concentration, and when KCl is 25.5 g/L, the degradation rate of DMP was increased by 3.71% compared with no KCl. However, the MgCl2 in the system had a greater inhibition on mpg-C3N4 photocatalytic degradation of DMP. When the concentration of MgCl2 is 65.2 g/L, the inhibition rate of DMP degradation rate reached 44.90% compared with no MgCl2. Finally, the free radical quenching test confirmed that the main active species of photocatalytic degradation of DMP was ·O2-, followed by ·OH. Through in-depth comparative and characterization analysis of products of DMP before and after photocatalytic degradation, the results showed that the characteristic peaks of main groups in dodecyl morpholine molecules almost disappeared after photocatalytic degradation, which indicated that DMP molecules were effectively destroyed and degraded, and most intermediate products and small molecular products were also effectively decomposed and mineralized.