Department of Applied Chemistry, University of Johannesburg, Johannesburg, South Africa.
National Centre for Nano-structured Materials, Council for Scientific and Industrial Research (CSIR), Pretoria, South Africa; Department of Civil and Chemical Engineering, University of South Africa (UNISA), South Africa.
Int J Biol Macromol. 2015 Jan;72:732-9. doi: 10.1016/j.ijbiomac.2014.09.018. Epub 2014 Sep 27.
Polyaniline-coated lignin-based adsorbent (PLC) was synthesized and used for uptake of reactive dye eosin yellow (EY) from aqueous solution. The adsorption capability of the adsorbent was found to be more effective than the unmodified adsorbent (LC). In particular, the adsorption capability of the PLC was effective over a wider pH range. This could be owing to its higher point of zero charge, which is more favorable for the uptake of the anionic dye. Adsorption isotherm models suggested a monolayer adsorption was predominant. The mean free energy of adsorption (E(DR)) was found to have values between 8 and 16 kJ mol(-1) which suggests that an electrostatic mechanism of adsorption predominated over other underlying mechanisms. The adsorption process was also found to be spontaneous, with increasing negative free energy values observed at higher temperatures. Chemisorption process was supported by the changes in enthalpy above 40 kJ mol(-1) and by the results of desorption studies. This new adsorbent was also reusable and regenerable over four successive adsorption-desorption cycles. The single stage adsorber design revealed that PLC can be applicable as an effective biosorbent for the treatment of industrial effluents containing EY dye.
聚胺基苯涂层木质素基吸附剂 (PLC) 被合成并用于从水溶液中摄取活性染料曙红黄 (EY)。发现该吸附剂的吸附能力比未改性的吸附剂 (LC) 更有效。特别是，PLC 的吸附能力在更宽的 pH 范围内有效。这可能是由于其更高的零电荷点，更有利于阴离子染料的摄取。吸附等温线模型表明，单层吸附占主导地位。平均自由能的吸附（E(DR)）的值在 8 到 16 kJ mol(-1) 之间，这表明吸附的静电机制占主导地位，而不是其他潜在机制。吸附过程也是自发的，在较高温度下观察到负自由能值增加。焓的变化大于 40 kJ mol(-1) 以及解吸研究的结果支持了化学吸附过程。这种新型吸附剂在四个连续的吸附-解吸循环中也是可重复使用和可再生的。单级吸附剂设计表明，PLC 可以作为一种有效的生物吸附剂，用于处理含有 EY 染料的工业废水。
