Phenyl and methyl groups are known functional groups of all materials and were present in the control soil and remediated soil but absent in polluted soil. A shift in the band at 1442–1380 cm−1 of the remediated soil which was absent in the control soil and dye contaminated soil indicated the presence of alkanes which could also play a role in the binding property of the dye to the plant material. The presence of amines, carboxylic acid, phenyl group and alkanes of the plant material could be responsible for the binding property of the dye. The same pattern of research by Moran et al. (1997) reported that low-cost biosorbents are able to bind to dye molecules and easily be regenerated.