Study On Actived Alkali Lignin With Ultrasonic Process And Application Of Multi-function Water Treatment Agent Based On Alkali Lignin

The research is the part of the Study on Pd/C Catalyzing and Deoxidizing Wheat-straw Alkli Lignin and Developing the Hosphono-alkali-lignin Salt,supported by the National Natural Science Foundation of China.Wheat-straw alkli lignin from black liquor is the important by-product in papermaking industry of China. It is less reaction activation centre because of the lignin's structure and its applications are limited.Then the alkali lignin of wheat-straw is processed by the ultrasonic and the activation of the ultrasonic on the alkali lignin is discussed. Three factors, the ultrasonic processing's power, the ultrasonic processing's time and the ratio of liquor to matrial are discussed on the change of the functional group's content of the alkali lignin . The functional group of alkali lignin is measured by the chemical methods ,the molecule weight measured by GPC and the chemical structure analysed by the spectrum of 1^H NMR and FTIR, these indicated that the ultrasonic how to activate the alkali lignin and make it activity.When the ultrasomc processing's time is 20 minutes, the ultrasomc processing's power is 200W, the ratio (0.2N NaOH solution: lignin , w/w ) is 100: 1, the content of phenolic hydroxyl of the alkali lignin is from 1.80mmol/g to 2.02mmol/g, the content of aliphatic hydroxyl of the alkali lignin is from 2.28mmol/g to 8.34mmol/g. The data of the ultrasonic processing under different conditions are analyzed by computer software using Uniformity Design Method. Three factors, the ultrasonic processing's power, the ultrasonic processing's time and the ratio are discussed on the change of the functional group's content of the alkali lignin . As a result, in the three factors, the ultrasonic processing's time is considered to be a primary factor on the change of content of the total hydroxyl . The ultrasonic processing's power is the second factor. The ratio is the third factor and has little effect on the change of content of the total hydroxyl.From the spectrum of 1^H NMR, FTIR, GPC and chemical methods, the increased phenolic hydroxyl and aliphatic hydroxyl is from the -OCH₃ of G-lignin,such as the -OCH₃ ruptured from the G-lignin,or carboxyl deoxidized.The numerical-average molecule weight (M_n) is from 1179 to 5031, the weight-average molecule weight (M_w) is from 5031 to 11605.The value of M_w/M_n is from 8.69 to 2.31.The alkli lignin polymerizated under the ultrasonic process.It is better to use of alkaili lignin after the ultrasonic procees because of the alkli lignin polymerization and the increased content of the total hydroxyl.Four water treatment agents were first synthesized at home basis on that alkali lignin has many functional groups. They were quaternary ammonium salt of alkali lignin, salt of sulfonation-alkali-lignin, quaternary ammonium salt of phosphono-alkali-lignin and hosphono-alkali-lignin salt. Their performance of flocculation, dispersion, chelation and scale inhibition was investigated respectively.It showed that the capability of flocculation of quaternary ammonium salt of alkali ligninto black acid ATT was good. The decolorization rate of black acid ATT was 78% when the dosage of quaternary ammonium salt of alkali lignin was 1184.5mg/L. when the dosage lower than 2500mg/L the effect of quaternary ammonium salt of alkali lignin by activation of ultrasonic was better than that of not treated. Quaternary ammonium iron reacted with sulfonate groups of black acid ATT and an insoluble substance was produced. After that the purpose of decolorization was achieved. The decolorization rate of acid-red-orange dye and acid red dye increased as the dosage increased. Low pH was favorable to the flocculation, because at low pH the carboxyl was not dissociated and H4 was beside the suspending particles of acid red dye to give a high pH. It was easy to form hydrogen bond and carboxyl offered proton. At the same time quaternary ammonium iron was adsorbed to the surface of suspending particles to neutralize the electric charge. Because particles collided to each other and adsorbed each other the performance of flocculation to acid-red-orange dye and acid red dye was good. The quaternary ammonium salt of alkali lignin had some flocculent effect to kaolin which had better be used at low pH. In addition its quaternary ammonium salt of alkali lignin had some surface activity and could disperse particles of calcium carbonate which induced that it had weak chelation to the solution with calcium and magnesium.Better flocculation effect of quaternary ammonium salt of sulfonation-alkali-lignin to black acid, acid-red-orange dye and acid red dye was achieved. Its combined with amino of dye molecule while the cation combined with sulfonate groups of dye molecule which induced the decrease of hydrophilic groups of dye solution such as sulfonate groups, amino and hydroxyl. The hydrophobic of dye solution increased. The assembles of dye molecule were removed because of the bridge-span. The bleaching efficiency and demand for adsorbent was different for different reactive dyes. It depended on the structure of the molecule. Alumina with a concentration of 500mg/L could produce synergic effect in flocculation effect compared with only agent. The removal rate of COD of monosodium glutamate solution increased with increasing of concentration of quaternary ammonium salt of sulfonation-alkali-lignin. Quaternary ammonium salt of sulfonation-alkali-lignin had some surface activity and could disperse particles of calcium carbonate and kaolin which induced that it had weak chelation to the solution with calcium and magnesium. Though the synthesis of quaternary ammonium salt of sulfonation-alkali-lignin from alkali lignin had not been reported yet, it had favorable flocculation effect, especially to the acid dye waste water.Quaternary ammonium salt of phosphono-alkali-lignin was a multi-effect water treatment agent. It had better effect of scale inhibition to calcium carbonate and calcium sulphate, had some flocculation effect to acid dye solution and had some chelation to calcium and magnesium. For calcium carbonate, the scale prohibition rate was 78.8% when the dosage was 12mg/L. Quaternary ammonium salt of phosphono-alkali-lignin didn't suit high Ca2+ of waste water,it didn't suit iddle and lower Ca2+ of waste water. The scale inhibition rate decreased with decreasing of pH especially when pH>9.0. That was because high pH could result in high concentration of CO32" and high producing rate of CaCO3. Quaternary ammonium salt ofphosphono-alkali-lignin had good dispersion effect to crystal of calcium carbonate. Because of adsorbing to the surface of CaCO3, electrostatic repellent force and dimensional resistance between particles increased and crystals dispersed highly in the solution which could avoid crystalloid to separate out. The effect of scale inhibition and applying condition to CaSO4 was almost the same.The synthesis and research of these water treatment agents by activation of ultrasonic provided a scientific basis for the use of lignin which was still not made full use of and was an abundant, nontoxic, cheap and natural resource. It indicated that a new way of improving the reaction activity of lignin was found.