| Due to a direct wide band gap (3.37 eV) and large excitation binding energy (60 meV) at room temperature, zinc oxide (ZnO) has remarkable optical and electrical properties. It displays a promising application. ZnO has many advantages such as low prices, non-toxic, harmless and can be used repeatedly as photocatalyst. Organic pollutants can be completely mineralized into water and inorganic ions when ZnO used as photocatalyst without secondary pollution, which is a broad application of environmental control technology of green background. This paper concentrates on the use of low-cost resources of lignin to prepare nanocrystalline zinc oxide, so that it can reduces the preparation cost of ZnO.The experiments of lignin activation were catalyzed by polyacid Keggin structure. The reaction time, the amount of catalyst and the solvent in the system were studied. The optimum condition of lignin activation by the polyacid was ensured. Alcohol hydroxyl content and carboxyl content of lignin increased by 51.31% and 113.7% in homogeneous reaction, while increased by 132.6% and 73.89% in heterogeneous reaction, respectively. Phenolic hydroxyl content of lignin increased by 89.92% in homogeneous reaction, while kept amostly a constant in heterogeneous reaction. Lignin-based surfactant was synthesized with the Mannich reaction by three steps. FTIR and XPS analysis were used to characterize surfactant and showed that the prepared surfactant was lignin quaternary ammonium phosphate ester amphoteric surfactant (LQAPEAS). The surface tension was 52.106 mN·m-1.ZnO nanocrystals with many mesoporous were prepared using LQAPEAS as structure-directing agent with direct precipitation method. In direct precipitation method, the addition of LQAPEAS and the concentration ratio of zinc ions and hydroxide ions which could affect the morphology of product zinc oxide were discussed. The concentration of hydrogen ion had prominent influence on the morphology of the product when the addition of LQAPEAS was fixed. Small rod-like zinc oxide was synthesized with low concentration of hydrogen ions; Spherical zinc oxide was synthesized with moderate concentration of hydrogen ions while flower-like nano-zinc oxide was synthesized with high concentration of hydrogen ions. The amount of LQAPEAS in synthesis process had a little effect on the morphology of zinc oxide according to SEM, but the morphology of the basic unit changed. UV absorption spectra of the samples showed that the prepared zinc oxide was made of smaller particles and the growth of zinc oxide was well controlled by the LQAPEAS. The photocatalytic activities of ZnO were evaluated by degradation of methylene blue (MB) under UV Light radiation. The photocatalytic degradation curve indicates that as-synthesized ZnO has good performance as photocatalytic catalyst. Hydrothermal methods were also carried out to prepare nanocrystalline of ZnO by using LQAPEAS. Flower-like ZnO were obtained by this method. When the addition of LQAPEAS was appropriate, the flower-like zinc oxide was integrity. While the ratio of the length and diameter decreased and ZnO in the [0 1 1 0] crystal face disappeared when the concentration of hydrogen ions increased.Compared the photoluminescence spectrums of samples prepared by direct precipitation method and by hydrothermal method, it showed different light emission. ZnO prepared by direct precipitation had strong blue light emission, green light emission, yellow light emission m, orange light emission. The photoluminescence spectrums of samples prepared with hydrothermal method had blue light emission between 400 nm-500 nm and green emission centered in the around 568 nm between 500 nm-600 nm with a broad peak.
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