Department of Chemistry, Periyar University, Salem 636011, Tamil Nadu, India.
J Hazard Mater. 2011 May 15;189(1-2):294-300. doi: 10.1016/j.jhazmat.2011.02.036. Epub 2011 Feb 22.
Effluents releasing from dyeing industries directly affect the soil, water, plant and human life. Among these dyes, plant poisoning, soil polluting and water polluting nature of organic dyes are not yet identified. The plant poisoning and non-poisoning organic dyes are identified through adsorption mechanism of cationic malachite green (MG) and anionic methyl orange (MO) on brinjal plant root powder (cellulose). The positive ΔH(o) (44 kJ mol(-1)) of MG higher than 40 kJ mol(-1) confirmed the adsorption of MG on cellulose is chemisorption and the negative ΔH(o) (-11 kJ mol(-1)) less than 40 kJ mol(-1) showed that the adsorption of MO on cellulose is physisorption. The ΔG(o) values for the adsorption of MG and MO on BPR are not much increased with increase of temperature which indicated that the adsorption is independent of the temperature. The entropy change for the adsorption of MG and MO has proved that the MG (+ΔS(o)) has less disorder at the adsorption interface and MO (-ΔS(o)) has the high disorder at the adsorption interface. The recovery of both dyes has been studied in water at 80°C on BPR surface and observed that the MO recovery is 95% and MG is 10%. The poor desorption of MG is due to the strong chemisorption on BPR (cellulose) surface proves its plant poisoning nature. The high recovery of MO due to physisorption mechanism proves that MO is not poisoning the plant.
印染工业排放的废水直接影响土壤、水、植物和人类的生活。在这些染料中，有机染料对植物的毒害、土壤的污染和水污染的性质尚未得到确定。通过阳离子孔雀石绿（MG）和阴离子甲基橙（MO）在茄子植物根粉（纤维素）上的吸附机理来鉴别植物中毒和非中毒的有机染料。MG 的正ΔH(o)（44 kJ mol(-1)）高于 40 kJ mol(-1)，表明 MG 在纤维素上的吸附是化学吸附，而负ΔH(o)（-11 kJ mol(-1)）小于 40 kJ mol(-1)表明 MO 在纤维素上的吸附是物理吸附。MG 和 MO 在 BPR 上的吸附ΔG(o)值随温度升高没有显著增加，表明吸附与温度无关。MG 和 MO 的吸附熵变化证明了 MG（+ΔS(o)）在吸附界面上的无序程度较低，而 MO（-ΔS(o)）在吸附界面上的无序程度较高。在 80°C 下，在 BPR 表面的水中研究了两种染料的回收情况，观察到 MO 的回收率为 95%，MG 的回收率为 10%。MG 的解吸效果较差是由于其在 BPR（纤维素）表面上的强化学吸附，证明了其对植物的毒害性质。MO 的高回收率是由于物理吸附机制，证明 MO 不会毒害植物。
