Microwave-assisted Extraction Of Bagasse Ethanol - Lignin And Its Adsorption Of Phosphorus Research

Sugarcane bagasse is the main by-product of sugar industry. 15%-25% lignin is included. In our country,it has at least 40 million tons of sugarcane bagasse in 07/08 annual. The vast majority were burned or abandoned, besides a small number of these resources for papermaking. That was not only wasted the resources, but also polluted environment seriously. So to find appropriate ways for high-value-added use was of great practical significance for the sustainable development of sugar industry.Lignin is the complex which has three dimensional network structure aromatic compound that can be obtained from renewable resources. With resource shortage and the increasingly serious environmental pollution, how to full use of their and product "environment friendly" green products, has become the research hotspot. And the purpose of waste treated by waste was attained.In this paper, I used sugarcane bagasse as raw materials, ethanol as solvent and microwave-assisted method to extract lignin. Influences of different factors on lignin yield of sugarcane bagasse was studied. The structure of lignin was analysised by infrared spectrum .It 's absorption properties and the treatment of simulated wastewater containing phosphorous was studied.(1) It has a good effect on extracting lignin from sugarcane bagasse using microwave-assisted extraction method. Compared to the conditions of cooking, lignin extraction rate significantly increases, and generally improves 20-30%. It was found that the best conditions for extracting lignin from sugarcane bagasse were the size in the rang 0.84-1.68mm and sugarcane bagasse dosage at 2.0000g and the solid-liquid ratio at 1:20 .When the microwave power at 340W, microwave heating time at 30min, volume fraction of ethanol at 95% ,catalyst (MgCl₂) dosage at 6%, the sugarcane bagasse ethanol-lignin extraction rate reached 68.06%, the yield ratereachedl3.14%.Ethanol was recycled by distillation and recovery rate was over 60%.(2) The structure of sugarcane bagasse ethanol-lignin was analysised by infrared spectrum, and showed that the lignin's chemical structure was phenylpropane. Main struc- ture is syringyl. And it contains a lot of hydroxyl, which would be beneficial to chemical modification. So the lignin has the greater potential for absorption.(3) The sugarcane bagasse ethanol-lignin methylene blue absorption value was 162 mg/g. It met the first rank criterion of wooden activated carbon chich using for water purification GB/T12496.10-1999. The sugarcane bagasse ethanol-lignin methylene iodine absorption value was 634 mg/g.(4) The absorption mechanism of sugarcane bagasse ethanol-lignin treatment of simu-lated wastewater containing phosphorous was studied. The adsorption process's adsorption isotherm was fitted with Langmuir isotherm adsorption equations. It was found that the phosphorous saturated adsorption capacity was 3.43mg /g when the reaction temperature at 25℃and the pH6. The adsorption process was based on chemical adsorption. The remove rate in acid conditions was better than alkaline conditions. The best phosphorous removal rate was at pH6; It reached adsorption equilibrium after 48h; The adsorptions of phosphorus was endothermic process. But temperature had a little effect on the removal rate. By comparing pre and post the lignin absorption of infrared spectra of that in the process of absorption, hydroxy played a major role, the absorption process should be the first exchange with the hydroxyl in response to the hydroxyl replacement by hydrogen.