TWLZ鞣及铬鞣胶原纤维对直接黄132染料的吸附性能对比研究

Study on comparison of adsorption properties of TWLZ tanned and chrome tanned collagen fibers for direct yellow 132 dye

为给TWLZ无铬金属鞣革染色工艺的研究提供理论基础,以黄牛酸皮为原料,用TWLZ或铬鞣剂鞣制后再切割研磨制得TWLZ鞣和铬鞣胶原纤维,研究它们对直接黄132染料的吸附性能.结果表明,在染料初始浓度分别为360 mg/L和500 mg/L时,TWLZ鞣和铬鞣胶原纤维的最佳吸附条件均为吸附时间8 h,pH为3,温度为40℃,胶原纤维用量为0.3 g,染料的吸附率分别可达98.7%和99.3%.两种胶原纤维对直接黄132的吸附均符合二级动力学模型和Langmuir等温吸附式.吸附机理均为染料阴离子(磺酸基)与胶原纤维表面的质子化氨基形成单分子层的化学吸附,同时伴随静电作用.吸附前后两种胶原纤维的等电点测试结果表明两种胶原纤维的等电点分别由6.8~7.0和7.0~7.2均降至4.3~4.6.此结果表明,在实际生产中可参考铬鞣革的染色工艺对TWLZ鞣革的染色工艺进行设计.

In order to provide theoretical support for the formulation of the dyeing process of TWLZ chrome-free metal tanned leather,in this work,the TWLZ tanned and chrome tanned collagen fibers were prepared by cutting and grinding the TWLZ tanned and chrome tanned leathers based on pickled hides,respectively.The adsorption properties of two fibers on direct yellow 132 dye were studied.The results showed that when the initial concentration of dye was 360 mg/L and 500 mg/L,respectively,the optimal adsorption conditions of TWLZ tanned and chrome tanned collagen fibers were as follows:adsorption time 8 h,pH 3,temperature 40℃,collagen fiber dosage 0.3 g,and the removal rate of dye could reach 98.7%and 99.3%,respectively.The adsorption of direct yellow 132 by the two kinds of collagen fibers conform to the second-order kinetic model and Langmuir isothermal adsorption model.The adsorption mechanism is the chemisorption between the dye anion(sulfonic acid group)and the protonated amino group to form a monolayer on the surface of the collagen fiber accompanied by electrostatic interaction.The results showed that the isoelectric point of the two collagen fibers decreased from 6.8~7.0 and 7.0~7.2 to 4.3~4.6 after adsorption,respectively,and the dyeing process of TWLZ tanned leather can be designed by referring to the dyeing process of chrome tanned leather in actual production.