吐温20浓度对鞘氨醇单胞菌脱硫胎面胶的影响

The influence of Tween 20 concentration on biodesulfurization of ground tire rubber by Sphingomonas Sphingomonas sp.

鞘氨醇单胞菌(Sphingomonas sp.)对废胎面胶粉(GTR)中的化合硫有代谢作用,但其与亲油性的橡胶相容性差.通过在细菌-GTR共培养脱硫过程中添加表面活性剂吐温20可改善两者之间的亲和性,进而提高脱硫效果.本文研究吐温20用量对鞘氨醇单胞菌生长及鞘氨醇单胞菌对GTR表面一定深度范围内化学结构的影响,并将脱硫废胎面胶粉(DGTR)与丁苯橡胶(SBR)共混,探讨共混胶的性能及形态.结果表明:在研究的吐温20用量范围内,其对鞘氨醇单胞菌的生长代谢基本无抑制作用,少量吐温20还可促进细菌的生长;当吐温20用量为0.5 g/L时,DGTR-0.5的溶胀值比GTR增加6.6%,交联密度减小9.4%,比未加吐温20的DGTR-0分别增加和减少3%和4%.橡胶表面的S—S键、S—C键减少,S—O键增多,其中DGTR-0.5的S含量比GTR降低63.6%,比DGTR-0降低37%;氧含量比GTR增加62.1%,比DGTR-0增加16%,此时脱硫效果最好;与GTR/SBR共混胶相比,DGTR/SBR并用胶的物理性能有所改善,胶粉与基胶间的界面相互渗透作用增强.其中,DGTR-0.5/SBR胶料的力学性能改善最为显著.所以,在用鞘氨醇单胞菌脱硫废胎面胶的过程中,0.5 g/L为吐温20的最佳使用浓度.

Sphingomonas sp. has metabolic function on combined sulfur of waste ground tire rubber（GTR）. However, its poor compatibility with lipophilic rubber limits its desulfurization effect. Adding surfactant Tween 20 in the desulfurization process can significantly improve the desulfurization effect through increasing the affinity between rubber and bacteria. This research used different dosage of Tween 20 as a variable in desulfurization process to study the effect of Tween 20 concentration on the growth of Sphingomonas sp. and Sphingomonas sp. on chemical structure of GTR surface within a certain depth range. We also investigated the properties and morphology of styrene butadiene rubber（SBR） composite filled with desulfurized ground tire rubber（DGTR）. The results showed that the Tween 20 dosages studied had no inhibitory effect on the metabolism of Sphingomonas sp, with a small amount of Tween 20 even promoting the growth of bacteria. Among all the concentrations, Tween 20 of 0.5 g/L showed the best effect in enhancing bio-desulfurization. The swelling value of DGTR-0.5（the desulfurized ground tire rubber with 0.5 g/L Tween 20） was 6.6% higher than that of GTR and 3% higher than that of DGTR-0（the desulfurized ground tire rubber without Tween 20）; the crosslinking density of DGTR-0.5 was 9.4% and 4% respectively lower than that of GTR and DGTR-0. DGTR-0.5 showed less S-S bonds and S-C bonds but more S-O bonds with the content of S on the surface 63.6% and 37% respectively lower than that of GTR and DGTR-0. The content of O on surface in DGTR-0.5 was 62.1% and 16% respectively higher than that of GTR and DGTR-0. Compared with the mechanical properties of GTR/SBR composite, those of DGTR/SBR composite were improved with enhanced interaction between DGTR surface and base rubber, in particular the most significant improvement in DGTR-0.5/SBR. The results indicated that 0.5 g/L Tween 20 is the best dosage on bio-desulfurization of ground tire rubber by Sphingomonas sp.