产甲烷阶段季铵化合物的厌氧生物降解性研究(英文)

基于厌氧序批式测试系统,研究了一组季铵化合物的最终生物降解性和对生物气产生过程的毒性效果.四个测试物中每个化合物均带有四个相同的烷基,通式为R4N+Br-(TEAB,TPAB,TOAB和TODAB分别对应R=C2,C5,C8,C18,).测试物的矿化程度被用来评估其最终厌氧生物降解性;对碳源D-葡萄糖代谢过程的毒性可以利用测试物对生物气生成过程的抑制效果来指示.研究结果表明:带有偶碳数烷基链的季铵化合物,即TEAB、TOAB和TODAB在20 mg/L(以C计)能够被很容易地降解为CO2和CH4,它们对生物气生成过程的毒性随着所带烷基链长的增长而减小.测试物中带有最长碳链的TODAB,即使碳浓度提高到100 mg/L也可以顺利降解;并且在200 mg/L的高浓度条件下也没有发现其对代谢过程的毒性证据.相反,带有奇数碳链的TPAB很难被厌氧生物降解,而且在所有测试物中显示出最强的厌氧毒性,200 mg/L时的生物气抑制率高达69%.

Study on Anaerobic Biodegradability of Quaternary Ammonium Compounds under Methanogenic Conditions

The ultimate biodegradation and potential toxicities to biogas production (carbon dioxide (CO2) and methane (CH4)) of different alkyl chain length homologs of quaternary ammonium compounds (QAC) were investigated based on an anaerobic batch test system. Each screened sample has four same alkyl chains by the general formula R4N+Br- (R:C2, C5, C8, C18, named TEAB, TPAB, TOAB and TODAB, respectively). The extent of mineralization of samples was used to evaluate the ultimate biodegradability of QAC, and the inhibitory effects of the tested compounds on biogas production were utilized to describe the toxicities to metabolic process of D-glucose, which was selected as a carbon resource. The results showed that all tested QAC with even carbon-numbered alkyls, i.e. TEAB, TOAB and TODAB, could be easily biodegraded into CO2 and CH4 at low concentration of 20 mg/L, their toxicities to biogas production decreased with the increase of alkyl chain length at the same concentrations. TODAB, as the homolog with the longest alkyl chains in screened samples, could be degraded at the carbon concentration as high as 100 mg/L and no toxic effects on biogas production were observed even if the carbon concentration was increased to 200 mg/L. On the contrary, TPAB, a homolog with odd carbon-numbered alkyls, was difficult to be biodegraded ultimately at all tested concentrations accompanied with the acutest toxicity to anaerobic bacteria among all tested substance under the same conditions, its inhibition rate achieved 69% at 200 mg/L.