Fig. 4 shows TGA and DTA curves of lignin-modified silica nanoparticles, which were prepared with lignin content of 2.7% at 20 °C under pH 8.00 and dried in an oven overnight at 80 °C. The initial weight loss of 0.46% occurred from room temperature to 150 °C and was due to moisture evaporation of the absorbed water. Upon further heating, the sample exhibited a profound exothermic transformation with the maximum temperature at 331 °C, which is attributed to the cleavage of methyl-aryl ether bonds in lignin. Another exothermic transformation was centered at 432 °C due to the decomposition or condensation of aromatic rings in lignin. There was an apparent weight loss of 3.00% involving the combustion of lignin in the sample from 150 °C to 480 °C. The residue at 500 °C amounted to 96.48% of the initial material, which is consistent with the result of FT-IR spectra.