Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, 310018, China.
College of Environmental Science and Engineering, Hunan University, Changsha, 410082, China.
Environ Sci Pollut Res Int. 2018 Jul;25(19):18443-18450. doi: 10.1007/s11356-018-1933-2. Epub 2018 Apr 25.
This work found that the removal of chromium by a straw-derived biochar was significantly promoted or inhibited by various surfactants. For example, the anionic surfactant sodium dodecyl benzene sulfonate (SDBS) inhibited the removal of Cr(VI) by the biochar but significantly promoted the removal of Cr(III) by the biochar. The nonionic surfactant Triton X-100 (TX-100) promoted the removal of Cr(VI) at low concentrations (< 100 mg L) but inhibited the removal at high concentrations. Different mechanisms were found for the two surfactants. As an anionic surfactant, surface-sorbed SDBS changed the surface functional groups of the biochar, making the biochar negative charged and changing the sorption ability of the biochar. For the nonionic TX-100, monomers and micelles in the aqueous phase had a major influence on the sorption of chromium due to the impact on the interfacial tension between the biochar and the solution phase as well as the solution pH. The results suggest that when biochar is used to treat heavy metal wastewater containing coexisting surfactants, the type and concentration of surfactants must be considered as important factors. Under certain surfactant conditions, biochar will enable the simultaneous and efficient removal of heavy metals and surfactants.
这项研究发现，稻草衍生生物炭对铬的去除受到各种表面活性剂的显著促进或抑制。例如，阴离子表面活性剂十二烷基苯磺酸钠（SDBS）抑制生物炭对六价铬（Cr(VI)）的去除，但显著促进生物炭对三价铬（Cr(III)）的去除。非离子表面活性剂曲拉通 X-100（TX-100）在低浓度（<100mg/L）下促进 Cr(VI)的去除，但在高浓度下抑制去除。这两种表面活性剂的作用机制不同。作为阴离子表面活性剂，吸附在表面的 SDBS 改变了生物炭的表面官能团，使生物炭带负电荷，并改变了生物炭的吸附能力。对于非离子 TX-100，由于其对生物炭和溶液相之间的界面张力以及溶液 pH 值的影响，水相中的单体和胶束对铬的吸附有很大影响。结果表明，当生物炭用于处理含有共存表面活性剂的重金属废水时，表面活性剂的类型和浓度必须被视为重要因素。在某些表面活性剂条件下，生物炭将能够同时高效地去除重金属和表面活性剂。
