Preparation And Properties Of Oil Absorbent Materials Based On Corn Stalk

Vigorous economic development can’t make up without the support of energy. Recently oil spill accidents occurred one after another, resulting serious repercussions to the worldwide ecological environment and social economy. Among the conventional methods currently employed for oil spill cleanup the sorbent material is considered to be the most efficient and economical option. In this paper, different kinds of cellulosic oil absorbent materials based on common agricultural waste corn stalks was prepared, in order to achieve efficient utilization of corn stalks.Firstly, study the oil absorption properties of oil-absorbing material based on the physical structure of corn stalks. Because of surface wax layer and rough porous structure, corn stalks had a good oil absorption capacity. Temperature and particle size affect the performance of straw, research showed that 40 mesh straws under the temperature of 20℃exhibit best oil absorption capacity to Russian oil, reaching to 5.3g/g. Dilute hydrochloric acid, Na OH solution, Na Cl O2 solution were used to pretreatment corn straw. Pretreatment by three solutions all could improve oil-absorbing ability, but alkali pretreatment severely damaged hollow lumen structure of corn straw,while Na Cl O2 solution pretreatment didn’t affect the overall structure of straw. Corn straw pretreated by Na Cl O2 solution showed highest oil absorption capacity, which could absorb Russian oil up to 9.16 times of its own weight.After acetylation modification and hydrophobic silica particles modification, pretreated straws’ oil absorption capacity increased to 13.84 g/g, 10.42 g/g, respectively.Secondly, in order to prepare cellulose-based oil absorbent material possessing a high oil-absorption capacity, a 5-step process was used to extract pure cellulose from corn straw, which contained benzyl-alcohol extraction, acid Na Cl O2 solution treatment and Na OH solution treatment. Benzyl-alcohol extraction could remove the surface wax-layer of corn straw. Acid solution treatment could be capable of removing lignin in straw and dispersing fiber assembly into individual fibers. The hemicellulose in straw could be removed by alkali treatment, and simultaneously undermine the amorphous region strongly. During the cellulose purification, cellulose crystal structure didn’t change, but crystallization index gradually increased from 46.8% to 56.5%. In addition, in this experiment, sulfuric acid was adopted to hydrolyze pure cellulose to prepare nanocellulose. Research had shown that sulfuric acid hydrolysis of purified cellulose 40 min at 40 ℃ can obtain nanocellulose that average diameter of about 38 nm. Nanocellulose was unstable and apt to self-assemble into nanocellulose sheet structure, meanwhile with the acid hydrolysis temperature and time rise, agglomeration was more obvious.Finally, three-dimensional porous cellulose aerogel used as oil-absorbent material had been prepared with purified cellulose and nanocellulose as raw material. 0.5% purified cellulose dissolved in 60% Li Br solution at 120 ℃ and cooled the cellulose solution could get regenerated cellulose aerogel which can absorb oil up to 5-7 times of its own weight and can be recycled more than 8 times, while the porosity could reach 93.6%. Study showed that cellulose crystal structure transform from typical type I to weak type Ⅱat the cellulose dissolving-regenerating process,but cellulose derivatives weren’t discovered.In order to obtain high-performance aerogel, compositing MTMS sol and nanocellulose sol to prepare hydrophobic oleophilic nanocellulose aerogel,which could absorb oils up to 15-31 times of its own weight and retention rate as high as 89 percent for high-viscosity Russian oil.